# Patent

## Title
Acid regeneration of ion exchange resins for industrial applications

## Abstract

Methods and systems for acid regeneration of ion exchange resins are disclosed. Acid resins designed for use in a variety of cleaning application using a water source use a treated, softened, acidic water source according to the invention. Various methods of using the softened acidic water generated by acid regenerate-able ion exchange resins are disclosed to beneficially reduce spotting, filming and scale buildup on treated surfaces, reduce and/or eliminate the need for polymers, threshold reagents and/or rinse aids, and using protons generated in the acidic water effluent for triggering events useful in various cleaning applications.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a non-provisional application of U.S. Provisional Application No. 61/569,829, filed Dec. 13, 2011, which is herein incorporated by reference in its entirety.
FIELD OF THE INVENTION
The invention relates to methods and apparatus for the acid regeneration of ion exchange resins for use in various industrial cleaning applications at a point of use. In particular, an acid regenerated resin is designed for use in any cleaning application using a water source to provide a softened acidic water source exhibiting relatively lower total dissolved solids (TDS). Various methods of using the softened acidic water generated by acid regenerate-able ion exchange resins are also disclosed. In addition, the methods and apparatuses according to the invention are further beneficial in reducing spotting and filming on treated surfaces, preventing scale buildup on treated surfaces, reducing polymers and threshold reagents necessary in a detergent source, and using protons generated in the acidic water effluent for triggering events useful in various cleaning applications as disclosed herein.
BACKGROUND OF THE INVENTION
Various water treatment methods for decreasing hardness of water are known and commercially employed. Detergents and other cleaning agents often contain numerous components to improve the cleaning activity of the detergent, including for example, components to counteract the effects of water hardness. Hard water is known to reduce cleaning efficacy both by forming films on surfaces and reacting with detergent and other cleaning components, making them less functional in the cleaning process. Various methods for counteracting and/or eliminating water hardness have been implemented by those skilled in the art, including for example, adding chelating agents or sequestrants into detersive compositions in amounts sufficient to handle the hardness ions and/or softening a water source via ion exchange. Ion exchange can be used to exchange hardness ions, such as calcium and magnesium, in the water with sodium or other ions associated with a resin bed in a water softening unit.
Various ion exchange methods are known by those skilled in the art. Most commonly, water is run through an exchange resin to adhere the hardness ions calcium and magnesium to a resin in the softener. However, when the resin becomes saturated it is necessary to regenerate the resin using large amounts of sodium chloride dissolved in water. This regeneration process has numerous known disadvantages, namely requiring the use of briny solutions and chloride from added sodium chloride used to flush out the resin. Accordingly, when water softeners regenerate they produce a waste stream that contains significant amounts of sodium, creating a burden on the system, e.g., sewer system, in which they are disposed of. The generated waste presents a multitude of downstream water re-use concerns, including for example water re-use applications like potable water usage and agriculture. Further, traditional water softeners add to the salt content in discharge surface waters, which has become an environmental issue in certain locations. These and other limitations of commercially-available water softening methods are described in further detail in U.S. patent application Ser. No. 12/764,621, entitled “Methods and Apparatus for Controlling Water Hardness,” the entire contents of which are hereby expressly incorporated herein by reference.
Accordingly, it is an objective of the claimed invention to develop improved methods and retrofitted systems for regenerating ion exchange resins for use in various institutional and industrial applications.
A further object of the invention is to develop a system and methods for using acid regenerate-able ion exchange resins to pre-treat water for the various institutional and industrial applications, resulting in the reduced demand for polymers and threshold reagents in cleaning compositions (e.g. detergents).
A further object of the invention is to improve ware wash and other cleaning application results through the application of softened acidic water generated by acid regenerate-able ion exchange resins at a point of use.
A still further object of the invention is to develop methods for applying protons in a treated water source to trigger events, such as regeneration of the resins, dispensing additional detergent and/or other cleaning aids, and the like.
Still further, the invention sets forth methods and systems for reducing scale buildup, spotting and/or film formation by treating a water source using an acid regenerate-able ion exchange resin.
BRIEF SUMMARY OF THE INVENTION
In an aspect of the invention, a system employing an ion exchange resin regenerated by an acid comprises: an inlet for providing a water source to a water treatment reservoir; a water treatment component housed in the water treatment reservoir, wherein said water treatment component is at least one ion exchange resin to generate a treated water source by exchanging protons on said resin for dissolved cations including water hardness ions and total dissolved solids in said water source, wherein the treated water source is a softened, acidic, and low total dissolved solids (TDS) water; an outlet fluidly connected to the water treatment reservoir; and a water delivery line to provide the treated water source to a cleaning application and/or storage reservoir.
In another aspect of the invention, a method for treating hard water using an acid regenerated ion exchange resin comprises: contacting a hard water source with a water treatment composition in a service cycle, wherein the water treatment composition comprises at least one ion exchange resin, wherein the ion exchange resin generates a treated water source by exchanging protons on said resin for dissolved cations including water hardness ions and total dissolved solids in said water source, and wherein said ion exchange resin is regenerated using an acid;
generating the service cycle treated water source comprising softened, acidic and low total dissolved solids (TDS) water, wherein the treated water source may be used for washing and/or rinsing in a variety of cleaning applications; and regenerating the ion exchange resin upon exhaustion using an acid regenerant.
In a still further aspect of the invention, a method for using a softened acidic water source comprises: contacting an article or surface in need of cleaning with a treated water source, wherein said treated water source is a softened, acidic low total dissolved solids (TDS) water generated by treating a hard water source with at least one ion exchange resin, wherein the ion exchange resin generates a treated water source by exchanging protons on said resin for dissolved cations including water hardness ions and total dissolved solids in said water source, and wherein said ion exchange resin is regenerated using an acid.
While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.



BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1B show an embodiment of an apparatus that can be retrofitted to a system for use of an acid regenerating ion exchange resin in various cleaning applications.
FIG. 2 shows an embodiment of the apparatus that uses an acid regenerant to regenerate an ion exchange resin according to the invention.
FIGS. 3A-3B show an embodiment of the invention using a layered ion exchange resin bed (3A) and a mixed layered ion exchange resin bed (3B) for treating a water source.
FIG. 4 shows an embodiment of the invention of a retrofitted ware wash system using an acid regenerating ion exchange resin apparatus to generate acidified water for use in a cleaning application.
FIG. 5 shows an embodiment of the invention of FIG. 4 further employing an additional water treatment apparatus with the acid regenerating ion exchange resin apparatus.
FIG. 6 shows a diagram of the capacity of an acid regenerated ion exchange resin v. pH of treated water according to an embodiment of the invention.
FIG. 7 shows a diagram of the capacity of an acid regenerated ion exchange resin v. water hardness of treated water according to an embodiment of the invention.
FIG. 8 shows a diagram of the capacity of a layered weak acid ion exchange resin bed (single type of resin) v. a layered weak acid ion exchange resin and strong acid ion exchange resin bed on treatment of water hardness.
FIG. 9 shows a diagram of the pH v. the capacity (gallons) of a layered weak acid ion exchange resin bed (single type of resin) v. a layered weak acid ion exchange resin and strong acid ion exchange resin bed.
FIGS. 10A-10B show diagrams of the pH achieved from the acid resins resulting from the regeneration using a strong acid regenerant according to an embodiment of the invention.
FIG. 11 shows a diagram of the hardness of treated water after the regeneration of the resin employing the exemplary acid regenerants of FIGS. 10A-10B according to an embodiment of the invention.
FIG. 12 shows a diagram of the pH of the resin employing various suitable acid regenerants according to embodiments of the invention.
FIG. 13 shows a diagram of the hardness of treated water after the regeneration of the resin employing the various suitable acid regenerants of FIG. 12 according to embodiments of the invention.



Various embodiments of the present invention will be described in detail with reference to the drawings, wherein like reference numerals represent like parts throughout the several views. Reference to various embodiments does not limit the scope of the invention. Figures represented herein are not limitations to the various embodiments according to the invention and are presented for exemplary illustration of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The present disclosure relates to methods and systems for using acid regenerate-able ion exchange resins at a point of use (i.e. non-integrated systems) to pre-treat water for various cleaning applications, including institutional and industrial applications. The methods and systems or apparatuses for obtaining and applying softened acidic water herein have many advantages over conventional water softening systems and/or apparatuses aimed at reducing water hardness. For example, the invention provides numerous unexpected downstream benefits, including for example, improving water quality and cleaning results, reducing consumption of detergents, other polymers and/or cleaning components in various cleaning applications, and preventing scale buildup, spotting and/or filming on treated surfaces. In addition, there are various advantages of the methods, systems and apparatuses using acid softened water generated at a point of use according to the invention to initiate downstream events in a cleaning application, including for example the regeneration of the resin and/or dispensing of additional cleaning components in a system.
The embodiments of this invention are not limited to particular methods, systems and apparatuses for obtaining softened acidic water at a point of use and applying softened acidic water to a particular cleaning application, which can vary and are understood by skilled artisans. It is further to be understood that all terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting in any manner or scope. For example, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” can include plural referents unless the content clearly indicates otherwise. Further, all units, prefixes, and symbols may be denoted in its SI accepted form. Numeric ranges recited within the specification are inclusive of the numbers defining the range and include each integer within the defined range.
DEFINITIONS
So that the present invention may be more readily understood, certain terms are first defined. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of the invention pertain. Many methods and materials similar, modified, or equivalent to those described herein can be used in the practice of the embodiments of the present invention without undue experimentation, the preferred materials and methods are described herein. In describing and claiming the embodiments of the present invention, the following terminology will be used in accordance with the definitions set out below.
The term “about,” as used herein, refers to variation in the numerical quantity that can occur, for example, through typical measuring and liquid handling procedures used for making concentrates or use solutions in the real world; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients used to make the compositions or carry out the methods; and the like. The term “about” also encompasses amounts that differ due to different equilibrium conditions for a composition resulting from a particular initial mixture. Whether or not modified by the term “about”, the claims include equivalents to the quantities.
As used herein, the terms “builder,” “chelating agent,” and “sequestrant” refer to a compound that forms a complex (soluble or not) with water hardness ions (from the wash water, soil and substrates being washed) in a specific molar ratio. Chelating agents that can form a water soluble complex include sodium tripolyphosphate, EDTA, DTPA, NTA, citrate, and the like. Sequestrants that can form an insoluble complex include sodium triphosphate, zeolite A, and the like. As used herein, the terms “builder,” “chelating agent “and” sequestrant” are synonymous.
As used herein, the term “lacking an effective amount of chelating (or builder/sequestrant) agent” refers to a composition, mixture, or ingredients that contains too little chelating agent, builder, or sequestrant to measurably affect the hardness of water.
The term “cleaning,” as used herein, means to perform or aid in soil removal, bleaching, microbial population reduction, or combination thereof.
As used herein, the term “disinfectant” refers to an agent that kills all vegetative cells including most recognized pathogenic microorganisms, using the procedure described in A.O.A.C. Use Dilution Methods, Official Methods of Analysis of the Association of Official Analytical Chemists, paragraph 955.14 and applicable sections, 15th Edition, 1990 (EPA Guideline 91-2). As used herein, the term “high level disinfection” or “high level disinfectant” refers to a compound or composition that kills substantially all organisms, except high levels of bacterial spores, and is effected with a chemical germicide cleared for marketing as a sterilant by the Food and Drug Administration. As used herein, the term “intermediate-level disinfection” or “intermediate level disinfectant” refers to a compound or composition that kills mycobacteria, most viruses, and bacteria with a chemical germicide registered as a tuberculocide by the Environmental Protection Agency (EPA). As used herein, the term “low-level disinfection” or “low level disinfectant” refers to a compound or composition that kills some viruses and bacteria with a chemical germicide registered as a hospital disinfectant by the EPA.
As used herein, the phrase “food processing surface” refers to a surface of a tool, a machine, equipment, a structure, a building, or the like that is employed as part of a food processing, preparation, or storage activity. Examples of food processing surfaces include surfaces of food processing or preparation equipment (e.g., slicing, canning, or transport equipment, including flumes), of food processing wares (e.g., utensils, dishware, wash ware, and bar glasses), and of floors, walls, or fixtures of structures in which food processing occurs. Food processing surfaces are found and employed in food anti-spoilage air circulation systems, aseptic packaging sanitizing, food refrigeration and cooler cleaners and sanitizers, ware washing sanitizing, blancher cleaning and sanitizing, food packaging materials, cutting board additives, third-sink sanitizing, beverage chillers and warmers, meat chilling or scalding waters, auto dish sanitizers, sanitizing gels, cooling towers, food processing antimicrobial garment sprays, and non-to-low-aqueous food preparation lubricants, oils, and rinse additives.
As used herein, the phrase “food product” includes any food substance that might require treatment with an antimicrobial agent or composition and that is edible with or without further preparation. Food products include meat (e.g., red meat and pork), seafood, poultry, produce (e.g., fruits and vegetables), eggs, living eggs, egg products, ready to eat food, wheat, seeds, roots, tubers, leafs, stems, corns, flowers, sprouts, seasonings, or a combination thereof. The term “produce” refers to food products such as fruits and vegetables and plants or plant-derived materials that are typically sold uncooked and, often, unpackaged, and that can sometimes be eaten raw.
As used herein, the phrase “health care surface” refers to a surface of an instrument, a device, a cart, a cage, furniture, a structure, a building, or the like that is employed as part of a health care activity. Examples of health care surfaces include surfaces of medical or dental instruments, of medical or dental devices, of electronic apparatus employed for monitoring patient health, and of floors, walls, or fixtures of structures in which health care occurs. Health care surfaces are found in hospital, surgical, infirmity, birthing, mortuary, and clinical diagnosis rooms. These surfaces can be those typified as “hard surfaces” (such as walls, floors, bed-pans, etc.), or fabric surfaces, e.g., knit, woven, and non-woven surfaces (such as surgical garments, draperies, bed linens, bandages, etc.), or patient-care equipment (such as respirators, diagnostic equipment, shunts, body scopes, wheel chairs, beds, etc.), or surgical and diagnostic equipment. Health care surfaces include articles and surfaces employed in animal health care.
As used herein, the term “instrument” refers to the various medical or dental instruments or devices that can benefit from cleaning with a composition according to the present invention. As used herein, the phrases “medical instrument,” “dental instrument,” “medical device,” “dental device,” “medical equipment,” or “dental equipment” refer to instruments, devices, tools, appliances, apparatus, and equipment used in medicine or dentistry. Such instruments, devices, and equipment can be cold sterilized, soaked or washed and then heat sterilized, or otherwise benefit from cleaning in a composition of the present invention. These various instruments, devices and equipment include, but are not limited to: diagnostic instruments, trays, pans, holders, racks, forceps, scissors, shears, saws (e.g. bone saws and their blades), hemostats, knives, chisels, rongeurs, files, nippers, drills, drill bits, rasps, burrs, spreaders, breakers, elevators, clamps, needle holders, carriers, clips, hooks, gouges, curettes, retractors, straightener, punches, extractors, scoops, keratomes, spatulas, expressors, trocars, dilators, cages, glassware, tubing, catheters, cannulas, plugs, stents, scopes (e.g., endoscopes, stethoscopes, and arthoscopes) and related equipment, and the like, or combinations thereof.
As used herein, the term “laundry,” refers to woven and non-woven fabrics, and textiles. For example, laundry can include, but is not limited to, clothing, bedding, towels and the like.
As used herein, the term “microorganism” refers to any noncellular or unicellular (including colonial) organism. Microorganisms include all prokaryotes. Microorganisms include bacteria (including cyanobacteria), spores, lichens, fungi, protozoa, virinos, viroids, viruses, phages, and some algae. As used herein, the term “microbe” is synonymous with microorganism.
As used herein, the term “sanitizer” refers to an agent that reduces the number of bacterial contaminants to safe levels as judged by public health requirements. In an embodiment, sanitizers for use in this invention will provide at least a 99.999% reduction (5-log order reduction). These reductions can be evaluated using a procedure set out in Germicidal and Detergent Sanitizing Action of Disinfectants, Official Methods of Analysis of the Association of Official Analytical Chemists, paragraph 960.09 and applicable sections, 15th Edition, 1990 (EPA Guideline 91-2). According to this reference a sanitizer should provide a 99.999% reduction (5-log order reduction) within 30 seconds at room temperature, 25+/−2° C., against several test organisms.
For the purpose of this patent application, successful microbial reduction is achieved when the microbial populations are reduced by at least about 50%, or by significantly more than is achieved by a wash with water. Larger reductions in microbial population provide greater levels of protection.
Differentiation of antimicrobial “-cidal” or “-static” activity, the definitions which describe the degree of efficacy, and the official laboratory protocols for measuring this efficacy are considerations for understanding the relevance of antimicrobial agents and compositions. Antimicrobial compositions can affect two kinds of microbial cell damage. The first is a lethal, irreversible action resulting in complete microbial cell destruction or incapacitation. The second type of cell damage is reversible, such that if the organism is rendered free of the agent, it can again multiply. The former is termed microbiocidal and the later, microbistatic. A sanitizer and a disinfectant are, by definition, agents which provide antimicrobial or microbiocidal activity. In contrast, a preservative is generally described as an inhibitor or microbistatic composition.
As used herein, the term “solubilized water hardness” or “water hardness” refers to hardness minerals dissolved in ionic form in an aqueous system or source, i.e., Ca++ and Mg++. Solubilized water hardness does not refer to hardness ions when they are in a precipitated state, i.e., when the solubility limit of the various compounds of calcium and magnesium in water is exceeded and those compounds precipitate as various salts such as, for example, calcium carbonate and magnesium carbonate.
As used herein, the term “threshold agent” refers to a compound that inhibits crystallization of water hardness ions from solution, but that need not form a specific complex with the water hardness ion. This distinguishes a threshold agent from a chelating agent or sequestrant. Threshold agents include a polyacrylate, a polymethacrylate, an olefin/maleic copolymer, and the like.
As used herein, the term “ware” refers to items such as eating and cooking utensils, dishes, and other hard surfaces such as showers, sinks, toilets, bathtubs, countertops, windows, mirrors, transportation vehicles, and floors. Wares are often comprised of various types of plastics including but are not limited to, polycarbonate polymers (PC), acrilonitrile-butadiene-styrene polymers (ABS), and polysulfone polymers (PS). Another exemplary plastic includes polyethylene terephthalate (PET).
As used herein, the term “warewashing” refers to washing, cleaning, or rinsing ware. Ware also refers to items made of plastic.
As used herein, the terms “water” or “water source,” refer to any source of water that can be used with the methods, systems and apparatuses of the present invention. The embodiments of the invention are particularly suitable for use of hard (i.e. non-softened) water sources. Exemplary water sources suitable for use in the present invention include, but are not limited to, water from a municipal water source, or private water system, e.g., a public water supply or a well. The water can be city water, well water, water supplied by a municipal water system, water supplied by a private water system, and/or water directly from the system or well. The water can also include water from a used water reservoir, such as a recycle reservoir used for storage of recycled water, a storage tank, or any combination thereof. In some embodiments, the water source is not an industrial process water, e.g., water produced from a bitumen recovery operation. In other embodiments, the water source is not a waste water stream.
As used herein, the term “water soluble” refers to a compound or composition that can be dissolved in water at a concentration of more than 1 wt-%. As used herein, the terms “slightly soluble” or “slightly water soluble” refer to a compound or composition that can be dissolved in water only to a concentration of 0.1 to 1.0 wt-%. As used herein, the term “substantially water insoluble” or “water insoluble” refers to a compound that can be dissolved in water only to a concentration of less than 0.1 wt-%. For example, magnesium oxide is considered to be insoluble as it has water solubility (wt-%) of about 0.00062 in cold water, and about 0.00860 in hot water. Other insoluble compounds for use with the methods of the present invention include, for example: magnesium hydroxide with a water solubility of 0.00090 in cold water and 0.00400 in hot water; aragonite with a water solubility of 0.00153 in cold water and 0.00190 in hot water; and calcite with a water solubility of 0.00140 in cold water and 0.00180 in hot water.
The term “weight percent,” “wt-%,” “percent by weight,” “% by weight,” and variations thereof, as used herein, refer to the concentration of a substance as the weight of that substance divided by the total weight of the composition and multiplied by 100. It is understood that, as used here, “percent,” “%,” and the like are intended to be synonymous with “weight percent,” “wt-%,” etc.
Embodiments of the Invention
According to an embodiment of the invention methods, systems and apparatuses provide for the use of acid regenerate-able ion exchange resins to pre-treat water for cleaning applications. Preferably, resins having a polymer matrix with carboxylic acid functional groups are used to capture water hardness ions and thereafter acids are used to regenerate the resin for re-use in generating a softened acidic water source for use in a cleaning application. Surprisingly, the present invention provides for novel uses of the various effluent waters of the methods, systems and apparatuses of the invention. In particular, whereas the effluent from the regeneration step is put to a waste stream and/or the effluent water from a service cycle is acidic softened water and may be used for washing or rinsing in a variety of cleaning applications. While an understanding of the mechanism is not necessary to practice the present invention and while the present invention is not limited to any particular mechanism of action, it is contemplated that, in some embodiments the benefits afforded according to the invention result from the generation of protons from the exchange of water hardness ions onto the resin.
According to a further embodiment of the invention, the methods, systems and apparatuses provide novel mechanisms for monitoring water sources. As opposed to monitoring and/or measuring water hardness ions in a water source, the use of conventional pH measurements can be used to trigger various events in a cleaning application. For example, a pH measurement (i.e. caused by the increase in protons/acidic water) can be used to trigger the step of regenerating the resin of a water treatment component or apparatus, and/or varying the detergent consumption needed to wash or rinse a surface in a particular cleaning application. Alternatively, the pH of incoming hard water can be compared to the treated acidic softened water, wherein the pH differential can be used to monitor a working system.
The invention overcomes the shortfalls of commercially-available water softening methods by providing an improved method for regenerating a resin and providing cleaning benefits from the treated effluent of a system, namely the protons contributing to cleaning efficacy in various cleaning applications. In addition, the invention provides the unexpected benefits of requiring the use of reduced amounts of polymers, threshold agents/reagents and/or other components in detergent compositions. In a further unexpected application, the invention provides for the elimination of a chemistry input into a cleaning application, such as acidic rinse aids.
One skilled in the art will ascertain additional benefits, uses and/or applications based upon the disclosure of the methods and systems of the present invention disclosed herein. Such embodiments are incorporated in the scope of the present invention.
Apparatuses and Systems for Water Treatment
In some embodiments the present invention relates to apparatuses and/or systems employing an acid regenerated ion exchange resin(s). The apparatuses and/or systems are suitable for use in controlling water hardness. In some aspects, the apparatuses and/or systems of the present invention include a substantially water insoluble resin material. Preferably, apparatuses and/or systems of the present invention do not precipitate a substance out of the water (e.g. a threshold agent). Without being limited to a particular theory of the invention, the apparatuses and/or systems result in the release of protons from the resin in exchange for binding water hardness ions onto the resin, causing an alteration in pH (i.e. acidic softened water), namely a decrease in pH as a result of the generation of protons from the resin. More preferably, the apparatuses and/or systems do not increase the total dissolved solids (TDS) of the water source treated.
In some aspects, the apparatuses and/or systems of the present invention include a water treatment composition or water preparation system (herein after the terms are used synonymously). The water treatment composition may be in a variety of physical forms. In one embodiment the water treatment composition comprises a ion exchange resin.
Ion Exchange Resins
The ion exchange resin according to the apparatuses and/or systems of the invention may be in a variety of physical forms, including for example, a sheet, a bead, a membrane or the like. In some embodiments, the ion exchange resin is a substantially water insoluble resin material. In some embodiments, the ion exchange resin is an acid cation exchange resin. As disclosed herein, a variety of resin materials may be used with the apparatuses of the present invention to treat a water source by exchanging protons on the ion exchange resins for dissolved cations including water hardness ions and total dissolved solids in the water source.
In some embodiments, the resin material includes an acid cation exchange resin. The acid cation exchange resin may include a weak acid cation exchange resin, a strong acid cation exchange resin, and/or combinations thereof (often referred to as layered resin systems or beds, which may further include layered mixed resin systems or beds, as one skilled in the art appreciates).
In an embodiment the ion exchange resin is a strong acid exchange resin having a polystyrene matrix and sulfonic acid functional group. In an additional embodiment, the ion exchange resin may have a polystyrene with sulfonic acid functional group, polystyrene with sulfonic acid functional group and mixtures of thereof.
Weak acid cation exchange resins suitable for use in the present invention include, but are not limited to, a cross-linked acrylic acid with carboxylic acid functional group, a cross-linked methacrylic acid with carboxylic acid functional group, and mixtures thereof. In some embodiments, resin polymers have additional copolymers added. The copolymers include but are not limited to butadiene, ethylene, propylene, acrylonitrile, styrene, vinylidene chloride, vinyl chloride, and derivatives and mixtures thereof.
In a preferred embodiment the ion exchange resin is a weak acid exchange resin having a polyacrylic copolymer matrix and a carboxylic acid functional group. Preferably the ion exchange resin has a surface with functional groups comprising carboxylic acids. Alternatively, the ion exchange resin has a surface comprising functional groups comprising sulfonic acids.
In some embodiments, the resin material is an acrylic acid polymer that provides a polyacrylate material having a molecular weight of about 150 to about 100,000 to the water source. In other embodiments, the resin material provides a polyacrylate material having a relatively low molecular weight, such as a molecular weight less than about 20,000, to the water source. Without being limited according to the invention, all ranges of molecular weights recited are inclusive of the numbers defining the range and include each integer within the defined range.
In some embodiments, the resin includes a weak acid cation exchange resin having H+ ions attached to the active sites. In additional embodiments, the resin includes a weak acid cation exchange resin having carboxylic acid functional groups attached to the active sites.
Various commercially available weak acid cation exchange resins are available, and include but are not limited to: Amberlite® IRC 76 (Dow Chemical Company); Dowex® MAC-3 (Dow Chemical Company); and a variety of additional resins. Additional description of suitable resin materials and systems, including additional commercially available resins are disclosed in U.S. patent application Ser. No. 12/764,621, entitled “Methods and Apparatus for Controlling Water Hardness,” the entire contents of which are hereby expressly incorporated herein by reference.
An alternative embodiment of the invention is the use of an anion exchange resin. Without wishing to be bound to a particular theory of the invention, use of an anion exchange resin may provide benefits through obtaining a softened alkaline water source.
As one skilled in the art will ascertain, the resin material may be provided in any shape and size, including beads, rods, disks or combinations of more than one shape. In some embodiments, the resin material is selected from the group consisting of a gel type resin structure, a macroporous type resin structure, and combinations thereof. Without wishing to be bound by any particular theory it is thought that the resin particle size may affect the ability of the resin material to control water hardness. For example, in some embodiments, the resin material may have a particle size of from about 0.5 mm to about 1.6 mm. In other embodiments, the resin material may have a particle size as large of 5.0 mm. The resin material may also include a mixture of particle sizes, viz. a mixture of large and small particles. Without being limited according to the invention, all ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.
Additional factors that are thought to have an effect on the ability of the resin material to control water hardness include, but are not limited to, the particle size distribution, the amount of cross linking, and the polymers used. In some embodiments, the cross-linked polymer (e.g. acrylic acid) is about 0.5% cross-linked to about 25% cross-linked. In other embodiments, the polymer is less than about 8% cross-linked, less than about 4% cross-linked, or less than about 2% cross-linked. Without being limited according to the invention, all ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.
In some embodiments, the ability of the resin material to control water hardness is impacted by whether there is a narrow particle size distribution, e.g., a uniformity coefficient of 1.2 or less, or a wide (Gaussian) particle size distribution, e.g., a uniformity coefficient of 1.5 to 1.9. Without being limited according to the invention, all ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.
Further, it is thought that the selectivity of the resin can be modified to tailor the resin to have an affinity for one ion over another. For example, the amount of cross linking and type of polymers included in the resin are thought to impact the selectivity of the resin. A selective affinity for particular ions over other ions may be beneficial in situations where a high affinity for certain ions, e.g., copper, may be damaging, e.g., foul or poison, to the resin itself. The resin material may bind cations by a variety of mechanisms including, but not limited to, by ionic or electrostatic force.
Acid Regenerants
Acid regenerants suitable for use in the regeneration of the ion exchange resins according to the apparatuses and/or systems of the invention are necessary to remove water hardness ions from the resins. A variety of acid regenerants may be employed to provide protons to the resin to restore capacity to soften and acidify water in need of treatment according to the invention. In an aspect, the regenerant is an acid. Exemplary acids according to the invention include hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, citric acid, acetic acid, methane sulfonic acid and methyl sulfonic acid. In some aspects the acid regenerant is a strong acid. In other aspects the acid regenerant is a weak acid. In an additional aspect, the acid regenerant may be an inorganic and/or organic acid. In an additional aspect, the regenerant is an acid salt. Exemplary acid salts include urea sulfate and monosodium sulfuric acid. In a preferred aspect, the regenerant is urea sulfate.
In an aspect, the acid regenerant is housed in a storage reservoir in a concentrated form that is commercially-available. Concentrates preferably have pH less than about 5, preferably less than about 2, preferably less than about 1, and more preferably less than about 0. Without being limited according to the invention, all pH ranges recited are inclusive of the numbers defining the range and include each integer within the defined range. For example, concentrated urea sulfate having a pH from about −3 to about 1 is employed as a concentrated acid regenerant for the ion exchange resins of the invention.
Preferably, the acid regenerant is be diluted prior to passing over the ion exchange resin. This allows for the use of concentrated acid regenerants, which among other benefits reduces the transportation burdens and costs. In an aspect, the dilution ratio of acid regenerant to diluent (e.g. water) is from about 1:1 to about 1:20, preferably from about 1:2 to about 1:20. Without being limited according to the invention, all dilution ratio ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.
In an aspect, the acid regenerant is in contact with the resin for a period of time from a few minutes to about 90 minutes, preferably from about one minute to about 60 minutes, and more preferably from about 5 minutes to about 30 minutes.
In an aspect of the invention, the concentration of the acid regenerant used in the regeneration cycle will depend upon the type of acid regenerant employed. In some embodiments, the concentration of the acid used in a solution for providing the acid regenerant to the ion exchange resin is from about 1% to about 20%, from about 2% to about 10%, or about 5% to about 10% of access of acid for regeneration. Without being limited according to the invention, all ranges recited are inclusive of the numbers defining the range and include each integer within the defined range. In addition, the amount of hardness in need of removal from the ion exchange resin will impact the amount of acid regenerant employed for the regeneration step of the invention.
Exemplary Water Preparation Systems
The apparatuses and/or systems of the present invention may be housed within a variety of water preparation systems, to provide point of use generation of acidified water for cleaning applications. The apparatuses and/or systems may be retrofitted to a variety of cleaning systems. Cleaning systems may include for example ware wash applications and any other cleaning system suitable for employing a softened acidic water source, including those of the invention exhibiting relatively lower total dissolved solids (TDS). Such additional cleaning systems may include for example, ware washing and/or sanitizing systems, laundry applications, hard surface and/or instrument cleaning, bottle washing, clean in place applications, and the like. In addition to cleaning systems suitable for application of the retrofitted systems of the invention, any dilution systems employing the treated softened acidic water source according to the invention are included within the scope of the present invention. These may include, for example, aspirators, pumps for delivering the treated water source and/or any other dilution system that is employed to deliver chemistry and/or a water source to a system.
An example of a water preparation system or apparatus 20 for use in the present invention is shown in FIGS. 1A-1B, which may comprise, consist of and/or consist essentially of: an inlet 22 for providing a water source to a treatment reservoir 26; a treatment reservoir including a water treatment composition 28 (e.g. ion exchange resin) and the water source to be treated 29; an outlet 24 for providing treated acidic water 31 from the treatment reservoir 26; and a treated water delivery line 30 for incorporation of the treated acid water into a cleaning application, storage (e.g. reservoir) and/or shipment 32, 34, 36, respectively.
According to the various methods of the invention, the water source 29 passes over the ion exchange resin 28, and water hardness cations from the water source 29 (e.g. calcium and magnesium ions) attach to the ion exchange resin 28, displacing protons into the treated water source creating an acidic softened water 31.
The apparatuses and/or systems of the present invention are designed for regeneration using an acid regenerant. Once the ion exchange resin 28 reaches a point of exhaustion (wherein the multivalent hardness cations from the water source have loaded onto the resin such that insufficient or no further exchange of cations occurs), an acid regenerant is used to remove the multivalent hardness cations from the cation exchange resin. An exemplary embodiment of such regeneration is shown in FIG. 2, wherein the water preparation system or apparatus 20 further comprises, consists of and/or consists essentially of a housing or storage reservoir 42 containing an acid source 44 and a delivery line 46 for providing the acid source 44 to the treatment reservoir 26. The delivery line 46 connects the acid source 44 with a water source 47 to generate a more dilute acid source 48 to regenerate the ion exchange resin 28. The diluted acid source 48 is then pumped into the treatment reservoir 26 to pass over the ion exchange resin 28 and cause the displacement of water hardness cations with the protons from the dilute acid source, thereby regenerating the exhausted ion exchange resin and generating a waste source of water containing hardness ions 50 to be removed from the water preparation system or apparatus 20.
The regeneration of the ion exchange resins can be triggered by a variety of events, as set forth in the description of the invention. In an embodiment, the concentrated acid source 44 from the storage reservoir 42 is combined with the water source due to atmospheric pressure within the system triggered by an event. Triggering events, as referred to herein for the regeneration of the ion exchange resins can include, for example, scheduled regeneration cycles based upon either set amounts (i.e. threshold levels) of the following and/or measurements and targeted amounts of the following, including for example, volume of water treated by an ion exchange resin, TDS levels in the treated water and/or water source to be treated according to the invention, pH of the treated water, number of cleaning events/cycles since the previous regeneration of the ion exchange resin, and the like.
As depicted in FIG. 2, the regeneration step moves the liquids in the opposite direction through the inlets and outlets, 22 and 24 respectively, as that described with respect to FIGS. 1A-1B when the ion exchange resin 28 is used to remove water hardness to generate the softened acidified water. Beneficially, this reduces the complexity of the water preparation system or apparatus 20 in minimizing the number of inlets/outlets and delivery line. In an additional embodiment, the waste product from the regeneration step (i.e. water containing hardness ions 50) could be added to the water source 29 for subsequent treatment according to the methods of the invention.
The apparatuses and/or systems of the present invention may further employ layered resin beds and/or layered mixed resin beds, as shown in FIGS. 3A-3B, respectively. In an embodiment of the invention, a layered resin bed includes more than one acid cation exchange resin. For example, as shown in FIG. 3A, the water preparation system or apparatus 20 may comprise, consist of and/or consist essentially of: a first inlet 22 for providing a water source to a first treatment reservoir 26 (housing a first ion exchange resin 28); a first outlet 24 for providing the treated acidic water from the first treatment reservoir 26 to a second treatment reservoir 26; a second inlet 22 for providing the treated water source to the second treatment reservoir 26 (housing the second ion exchange resin 28); and a second outlet for providing the treated acidic water to a treated water delivery line 30. It is to be understood from the description of the invention that a plurality of resin beds may be employed, e.g. more than two treatment reservoir 26 and more than two ion exchange resins 28. As set forth with respect to FIG. 1B, various embodiments of the invention may be employed for the delivery of the treated acid water into a cleaning application, storage (e.g. reservoir) and/or shipment 32, 34, 36.
In a further embodiment, as shown in FIG. 3B, the water preparation system or apparatus 20 may include a layered mixed resin bed which may comprise, consist of and/or consist essentially of: a first inlet 22 for providing a water source to a first treatment reservoir 26 (housing a first ion exchange resin 28); a first outlet 24 for providing the treated acidic water from the first treatment reservoir 26 to a second treatment reservoir 26; a second inlet 22 for providing the treated water source to the second treatment reservoir 26 (housing the second ion exchange resin 28, wherein the second ion exchange resin is a different ion exchange resin from that housed in the first treatment reservoir or wherein the second ion exchange resin contains more than one type of ion exchange resin, one of which may be the same as the ion exchange resin housed in the first treatment reservoir); and a second outlet for providing the treated acidic water to a treated water delivery line 30.
The layered acid cation exchange resins depicted in FIGS. 3A-3B may include combinations of weak acid cation exchange resins, strong acid cation exchange resins, and/or combinations of both weak acid cation exchange resins and strong acid cation exchange resins.
In some embodiments, the treated water delivery line 30 of a water preparation system or apparatus 20 provides treated water 31 to a selected washing and/or cleaning system 32, as shown in FIG. 4. As shown in the illustrated embodiment, the treated water delivery line is connected to a ware wash machine as source of treated water for the depicted cleaning application. As set forth according to the invention, the treated water delivery line may be connected to a variety of additional cleaning applications, including for example, Ware washing, including for example, automatic ware washing machine, a vehicle washing system, an instrument washer, a clean in place system, a food processing cleaning system, a bottle washer, etc.; laundry applications, including for example, automatic laundry/textile washing machines; industrial and domestic applications; and hard surface cleaning applications, including for example, clean-in-place systems (CIP), clean-out-of-place systems (COP), automatic bottle washers, washer-decontaminators, sterilizers, ultra and nano-filtration systems, indoor air filters, etc.
In other embodiments, the treated water delivery line 30 provides the treated acidic water 31 to an additional water treatment apparatus 38, as shown in FIG. 5. The additional water treatment apparatus 38 may include for example, a carbon filter or a reverse osmosis filter. Thereafter the treated water may again be provided as a source for a cleaning application, stored (e.g. reservoir) and/or shipped to an alternative point of use (e.g. 32, 34, 36). The water that was treated with the additional water treatment apparatus 38 may then be connected by a second water delivery line 40 to the cleaning application, stored (e.g. reservoir) and/or shipped to an alternative point of use (e.g. 32, 34, 36). One skilled in the art shall ascertain that one or more additional water treatment apparatuses may be employed with the water preparation system or apparatus 20 of the invention. In addition, the one or more additional water treatment apparatuses may be employed before or after the water source is treated according to the methods of the invention with the water preparation system or apparatus 20. As such, the configuration of the water preparation system or apparatus 20 shown in FIG. 5 treating a water source with the ion exchange resin 28 prior to use of the additional water treatment apparatus 38 is a non-limiting embodiment of the invention. In a still further alternative embodiment, no additional water treatment apparatuses are employed with the water preparation system or apparatus 20 of the invention.
In some embodiments, there is no filter between the outlet and the treated water delivery line. In other embodiments, there is a filter between the outlet and the treated water delivery line. In addition, a flow control device 40 such as a valve or other mechanism for controlling the flow or pressure of the liquids disposed therein for transport can be provided in the treated water delivery line 30 to control the flow of the treated water 31 into the selected end use device, e.g., a washing system, or another water treatment device 32, such as shown in FIG. 1B. In an alternative embodiment, the flow rate of both the water source and/or treated water can be controlled by flow control devices. In some embodiments, the water treatment reservoir 26 is any reservoir capable of holding the water treatment composition (e.g. ion exchange resin) 28. The reservoir 26 can be for example, a tank, a cartridge, a filter bed of various physical shapes or sizes, or a column. In other embodiments, the resin material may be attached or adhered to a solid substrate. The substrate can include, but is not limited to, a flow-through filter type pad, or paper. The substrate can also be a particulate that can be fluidized.
The apparatuses and/or systems of the present invention can include one or more water treatment reservoirs 26. For example, two, three or four treatment reservoirs containing the same or different water treatment compositions 28 can be used. The one or more treatment reservoirs can be provided in any arrangement, for example, they may be provided in series, or in parallel. In some further embodiments, the entire treatment reservoir can be removable and replaceable. In other embodiments, the treatment reservoir can be configured such that water treatment composition contained within the treatment reservoir is removable and replaceable.
The treatment reservoir may include an inlet for providing water to the treatment reservoir and an outlet for providing treated water to a desired end use location, e.g., a washing device or another water treatment device. In some embodiments, the inlet is located at the top of the reservoir, and the outlet is located at the bottom of the reservoir, such as shown in FIG. 3. In alternative embodiments, the inlet is located at the bottom of the reservoir, and the outlet is located at the top of the reservoir. This allows for the water to flow up through the water treatment composition contained within the treatment reservoir. In still further embodiments, the inlet and outlet may be located at the top of the reservoir, such as shown in FIGS. 1-2. However, as one skilled in the art will ascertain, the layout and/or design of a treatment reservoir and/or the placement and orientation of the treatment reservoir within the water preparation system or apparatus will vary and may be customized to a particular institutional or industrial application for use.
In some embodiments, the treatment reservoir includes an agitated bed of the water treatment composition. Methods for agitating the composition include, for example, flow of water through a column, by fluidization, mechanical agitation, air sparge, educator flow, baffles, flow obstructers, static mixers, high flow backwash, recirculation, and combinations thereof. The treatment reservoir can further include a head space above the composition contained therein, in order to allow for a more fluidized bed. In some embodiments, the resin material has a density slightly higher than the density of water to maximize fluidization and/or agitation of the resin material.
In some embodiments, the inlet can further include a pressurized spray nozzle or educator nozzle. The spray nozzle can provide the water at an increased force to the treatment reservoir. This increased pressurized force can increase the agitation of the water treatment composition and can circulate the resin through the educator nozzle. In some embodiments, the spray nozzle provides the water to the treatment reservoir at a rate of about 5 feet per minute to about 200 feet per min.
As disclosed herein, the treatment reservoirs housing the resins employed according to the invention may vary in its set-up, orientation, shape and/or size while maintaining the functionality disclosed herein for the treatment of water to provide a softened, acidic water source. For example, in an aspect of the invention a longer or narrower housing may be employed for the treatment reservoirs and/or resins to maximize or increase the contact time of the water source with the resin systems. In another aspect of the invention, the treatment reservoirs and/or resins may be shorter in length and/or wider to have a relatively shorter contact time between the water source and the resin system and/or to maximize flow rate and/or pressure drop within the system. According to an aspect of the invention, the shape and size of the housing for the treatment reservoirs and/or resins is adjustable and/or can be modified in order to balance the amount of time a water source is in contact with the cation exchange resin. As one skilled in the art shall appreciate based on the disclosure of the invention, such contact time between the water source and the exchange resin will further impact the characteristics of the treated acidified water source, such as the extent of acidification of the water, amount of TDS and/or extent of removal of hardness ions.
Additional Functional Groups
In some embodiments, an additional functional ingredient may be included in the water preparation systems along with the water treatment composition (e.g. ion exchange resin) housed within a treatment reservoir. The additional functional ingredients can be included within the treatment reservoir and/or water treatment composition, or they can be provided to the treatment reservoir from an external source, e.g., an additional functional ingredient inlet.
Additional functional ingredients can be added directly to the water source to be treated prior to the water source entering the treatment apparatus. Alternatively, the additional ingredient can be added to the treatment reservoir prior to the water source being passed through the ion exchange resin.
Additional functional ingredients suitable for use with the apparatuses and/or systems of the present invention include any materials that impart beneficial properties to the water treatment methods, the water source being treated, or any combination thereof. Examples of suitable additional functional ingredients include surfactants, preferably surfactants exhibiting wetting properties (e.g. rinse additives to increase sheeting), sanitizing agents and/or sterilizing agents (e.g. providing sanitizing rinse), acidic detergents, enzymatic detergents and the like.
Methods of Treating a Water Source According to the Invention
In some aspects, the present invention provides methods for controlling water hardness and producing an acidic softened water source. An acidic softened water having a hardness of less than about 2 grains and having a pH less than about 7, more preferably less than about 6, is produced according to the methods of the invention. Thereafter the acidic softened water can be employed for a variety of cleaning applications, whether at a point of use or stored for such use at a later time and/or point of use.
The methods directed to controlling water hardness are also understood to include methods for reducing scaling, buildup and/or soiling on treated surfaces wherein the acidic softened water according to the invention is applied. In addition, the methods of the present invention are further understood to include the protecting of equipment, e.g., industrial equipment, from the same scale build up and/or soiling and provide increased cleaning efficacy through the application of the softened acidic water to a surface in need of treatment. Each of the same methods are also effective in reducing the use of conventional detersive compositions as a result of the acidic softened water; and/or reducing the need for specific chemistries, e.g., those containing threshold agents, chelating agents, or sequestrants, or phosphorous, in downstream cleaning processes.
The methods as disclosed herein may include contacting a water treatment composition (e.g. acid regenerated resin material) with a water source, namely a hard water source. In some embodiments, the water treatment composition is contained within a treatment reservoir and/or a water preparation system. The step of contacting can include, but is not limited to, running the water source over or through the water treatment composition (e.g. ion exchange resin). As one skilled in the art will ascertain, the contact time for the water source is dependent on a variety of factors, including, for example, the pH of the water source, the hardness of the water source, and the temperature of the water source.
A water source may be applied (i.e. water source contacted with the resin) at a variety of flow rates, as one of skill in the art can apply without undue experimentation. For example, in preferred embodiments the flow rate through the systems of the invention is from about 0.5 to about 50 gallons per minute. In other embodiments the flow rate is less than about 8 gallons per minute, less than about 40 gallons per minute, less than about 100 gallons per minute, less than about 200 gallons per minute, or from about 100 to about 1500 gallons per minute, from about 160 to about 1400 gallons per minute, or about 400 to about 1200 gallons per minute. For further example, in some embodiments, the apparatuses of the present invention have a flow through rate of about less than about 1 cubic feet per minute, less than about 5 to about 200 cubic feet per minute, about 20 to about 175 cubic feet per minute, or about 50 to about 150 cubic feet per minute. Without being limited according to the invention, all flow rate ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.
For further example, a conventional ion exchange device is designed for a flow rate of about 0.3 to about 3.0 feet per minute of water velocity. This flow rate is important to allow time for the diffusion of ions to the surface of the resin from the water for the ion exchange process to occur. Without being limited according to the invention, all flow rates ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.
Optionally, in some embodiments, the method includes heating the water source prior to the step of contacting the water treatment composition (e.g. resin). Any means of heating the water source may be used with the methods and apparatuses of the present invention. In some embodiments, the water is heated to a temperature of about 30° C. to about 100° C. All temperature ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.
In some aspects the water treatment according to the invention provides a cold, hard water source to a water preparation system. After contacting the water source with the water treatment composition (e.g. resin) and heating, a treated, soft, acidic water is obtained and may be applied to the various applications of use disclosed herein. Although not intending to be bound to any particular theory of the invention, protons from the resin (e.g. H+ from the carboxylic acid group on the weak acid ion exchange resin) are exchanged with water hardness ions in the water source to provide the treated, soft, acidic water.
Preferably the controlling of water hardness and producing an acidic softened water source according to the invention result in a treated water source having a pH less than about 7, more preferably less than about 6. Without being limited according to the invention, all pH ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.
The treated water source preferably has a water hardness less than about 3 grains, more preferably less than about 2 grains, more preferably less than about 1 grain, and still more preferably about 0 grains. Without being limited according to the invention, all ranges of water hardness recited are inclusive of the numbers defining the range and include each integer within the defined range.
According to the methods of the invention the resin of the water treatment composition may be contacted with the water source until a point of exhaustion, viz. loaded with a plurality of multivalent hardness cations as a result of having a sufficient amount of water source run over it. In some embodiments, the plurality of multivalent cations includes, but is not limited to, the calcium and magnesium present in the water source. Without wishing to be bound by any particular theory, it is thought that as the water runs over the resin, the calcium and magnesium ions in the water will attach to the resin, displacing protons into the treated water source creating an acidic softened water.
At the point the resin is exhausted, e.g. can no longer exchange protons with the water hardness ions of the water source, the resin is regenerated according to the methods disclosed herein. According to the invention, the ion exchange resin is regenerated using an acid, namely an acid regenerant. According to the invention, the acid regenerant provides protons to the resin to restore capacity to soften and acidify water in need of treatment according to the invention. In an aspect, the acid regenerant is a strong mineral acid or an acid salt. A preferred embodiment for regenerating the ion exchange resin uses urea sulfate as the acid regenerant.
The contacting of the exhausted resin with the acid regenerant may be from a few minutes to about 90 minutes, preferably from about one minute to about 60 minutes, and more preferably from about 5 minutes to about 30 minutes. Without being limited according to the invention, all ranges are inclusive of the numbers defining the range and include each integer within the defined range.
According to the methods of the invention, the effluent water in the regeneration step may be disposed of in a waste stream. However, thereafter, the effluent water (e.g. treated water) in the normal service cycle is again acidic softened water and can be used according to the various methods disclosed herein.
The regeneration of the resins according to the invention may occur based on measurements obtained from the apparatus and/or systems of the invention. In an alternative embodiment, regeneration of the resins according to the invention may occur based on the lapse of a measured amount of time and/or volume of water treated.
Methods to Trigger Events Using the Acidic Softened Water
The methods, apparatuses and/or systems of the invention may be used for a variety of purposes. For example, the generation of the acidic softened water according to the invention may be used to trigger different events in a water preparation system or other apparatus or system. In particular, the protons generated from the exchange of hardness ions onto the resin may be monitored or measured to trigger different events in the water preparation system, other apparatuses and/or systems according to the invention.
The measurements and/or monitoring according to the invention are distinct from various commercial sensors for detecting changes and/or measuring water hardness in a system. For example, U.S. Pat. No. 7,651,663 entitled, “Appliance Using a Water Hardness Sensor System and Method of Operating the Same”, incorporated herein by reference in its entirety, measures water hardness according to the amount of hardness ions (e.g. Ca2+, Mg2+) in a water source. According to the invention, the methods, apparatuses and/or systems do not measure water hardness. As opposed to these types of calorimetric or fluorescent assays measuring the concentrations of ions such as calcium and magnesium, the present invention measures the output and/or effluent from a water treatment system, measuring the proton released from the ion exchange resin.
In some aspects, the monitoring or measuring of the protons is achieved by conventional pH measurements measurement of the output from the water preparation system or other apparatuses or systems of the invention. Sensors can be used to measure the pH as one example of a suitable measuring device. According to additional embodiments, the monitoring or measuring device to measure the pH can be employed through the use of electrodes, reference electrodes and/or solid state devices to sense pH. For example a pH measurement loop can be employed, such as a pH sensor, including a measuring electrode, a reference electrode and a sensor, a preamplifier and an analyzer or transmitter. Each of these are examples of suitable measuring devices according to the invention.
In additional aspects, the pH of an incoming (e.g. non-treated) water source containing hardness ions can be compared to the treated acidic softened water exiting the water preparation system, other apparatuses and/or system according to the invention. In such an embodiment, the pH differential can be used for a variety of purposes, including monitoring a working system. In an embodiment, the measuring of pH differential would detect a decrease in pH differential, triggering an applicable event, such as regeneration of the ion exchange resin, adding detergent and/or rinse additives or other cleaning agents to be used with the treated water. Measuring the pH differential is often useful as a result of the variability of water hardness depending upon a water source employed, as it is well known that hardness levels in influent waters are not constant. Therefore, as a result of methods of the invention employing the measurement of pH differential, variations in water hardness will not be detrimental to a use application as a result of the apparatuses and/or systems being able to monitor and adjust for such differential (e.g. through the triggering of various events as disclosed herein).
The regeneration of the ion exchange resins disclosed herein can be triggered by a variety of events and/or measurements as disclosed herein. In an aspect, the regeneration of the ion exchange resin may be triggered by the measurement of TDS in a system, which shall be dependent on the particular water chemistry inputted to the system. For example, in an aspect of the invention, the ion exchange resins remove from about 70% to about 100% TDS from the water source. In a preferred aspect, the ion exchange resins remove from about 80% to about 100% TDS, or from about 90% to about 100% TDS from the water source. Therefore, in the event the removal of TDS from a treated water source drops below about 70%, or about 80%, or about 90%, such measurement in the differential of the TDS between the untreated water and the treated water source may trigger the regeneration of the ion exchange resins.
In an additional aspect, the regeneration of the ion exchange resins may be triggered by pH measurement of the water source and/or the treated water. For example, the increase in pH of a treated water source above about 7 may trigger the regeneration of the ion exchange resins. Without being limited to a particular theory of the invention, the ion exchange resin may be exhausted between a pH of about 4.9 to about 5, therefore when the pH of the treated water source increases to about 7, or above 7 the ion exchange resin no longer contributes protons from the resin to acidify and soften the water source. Accordingly, the regeneration of the ion exchange resin is triggered.
One skilled in the art is knowledgeable of the various means for monitoring and/or measuring the pH according to the methods of triggering events using the acidic softened water disclosed herein. Therefore, the scope of the invention is not limited according to the methods for monitoring and/or measuring. Conventional measuring techniques include the use of sensors. Preferably a sensor is configured to output a signal to a controller. The sensor may include a substrate and a sensing element disposed on the substrate. The sensing element is in contact with the flow of water in the apparatus and/or system; preferably the sensing element in contact with both the flow of incoming (e.g. non-treated) water and effluent (e.g. treated acidic softened) water.
Events triggered according to use of the apparatuses and/or systems and/or methods according to the invention include, for example: dispensing of detergents, rinse aids and/or other cleaning compositions; varying the detergent consumption needed to wash or rinse a surface according to the methods of the invention; regeneration of the ion exchange resins; starting and/or stopping the generation of treated water disclosed herein, etc. The triggering of events is initiated through the measurement step, thereafter communicating with a controller to receive a signal. Thereafter, the controller works to trigger the desired event for an apparatus and/or system according to the invention.
Methods Employing the Acidic Softened Water
The methods, apparatuses and/or systems of the invention may be used for a variety of cleaning applications to employ the acidic softened water. Thus, an apparatus of the present invention can be used to control water hardness and/or reduce scale formation and/or enhancing cleaning efficiency and/or reduce spotting and filming caused by high TDS waters and/or reduce or eliminate use of additional chemistry streams for cleaning (e.g. polymers, threshold agents, etc.). Unexpectedly, according to the invention, the protons in the acidic softened water contribute to the performance of the treated water source.
The systems of the present invention and the methods employing the same can be included as part of any system or appliance which uses a water source and is in need of water treatment, e.g., acidification and/or softening using a water treatment system. In particular, the systems and apparatuses of the present invention can be used with any appliance or device which can provide a water source that would benefit from treatment using the apparatuses of the present invention, including either or both of acidification and/or softening.
In some aspects, the present disclosure includes methods of using the acidic softened water for low-temperature ware washing and sanitizing. The treated acidic water may be provided to an automatic washing machine from the treated water delivery line of the apparatuses and/or systems. The apparatus can be located in a variety of locations relative to the washing machine. For example, the apparatus may be upstream from the feed line of the washing machine. Exemplary automatic washing machines suitable for use with the apparatuses and methods of the present invention include, but are not limited to, an automatic ware washing machine, a vehicle washing system, an instrument washer, a clean in place system, a food processing cleaning system, a bottle washer, and an automatic laundry washing machine. Alternatively, the treated water may be used in a manual washing system. Any automatic washing machine or manual washing process that would benefit from the use of water treated in accordance with the methods of the present invention can be used.
In some aspects, the present disclosure includes methods of using the acidic softened water for ware washing applications, including those disclosed for example in various ware washing applications using acid formulations, including U.S. Pat. Nos. 8,114,222, 8,092,613, 7,942,980, and 7,415,983, U.S. patent application Ser. Nos. 13/474,771, 13/474,765, 13/474,780 and 13/112,412, including all references cited therein, which are herein incorporated by reference in their entirety. A particularly suitable application for use of the treated acidic water is for use in an acidic rinse cycle. For example, the treated acidic water may be dispensed with additional acidic compositions through a rinse arm, without or without an additional water rinse step, in order to lower the pH in the final rinse. In an additional application of use, the treated acidic water may be used in an alternating fashion with alkaline detergents and steps to improve soil removal.
In some aspects, non-limiting example of dish machines suitable for using the systems of the invention for water conditioning and/or a source of cleaning and/or rinsing waters are disclosed, for example, in U.S. Pat. No. 9,289,107, entitled Dishmachine, the entire contents of which are hereby expressly incorporated herein by reference. Further examples of dish machines suitable for employing the treated acidic water disclosed herein, includes, U.S. Pat. Nos. 8,202,373, 8,092,613, 7,942,978, 7,871,521, 5,609,174, 4,826,661, 4,690,305, 4,687,121, 4,426,362 and in U.S. Pat. Nos. Reissue 32,763 and 32,818, the entire contents of which are hereby expressly incorporated herein by reference. Some non-limiting examples of dish machines include door machines or hood machines, conveyor machines, undercounter machines, glasswashers, flight machines, pot and pan machines, utensil washers, and consumer dish machines. The dish machines may be either single tank or multi-tank machines.
A door dish machine, also called a hood dish machine, refers to a commercial dish machine wherein the soiled dishes are placed on a rack and the rack is then moved into the dish machine. Door dish machines clean one or two racks at a time. In such machines, the rack is stationary and the wash and rinse arms move. A door machine includes two sets arms, a set of wash arms and a rinse arm, or a set of rinse arms. Door machines may be a high temperature or low temperature machine. In a high temperature machine the dishes are sanitized by hot water. In a low temperature machine the dishes are sanitized by the chemical sanitizer. The door machine may either be a recirculation machine or a dump and fill machine. In a recirculation machine, the detergent solution is reused, or “recirculated” between wash cycles. The concentration of the detergent solution is adjusted between wash cycles so that an adequate concentration is maintained. In a dump and fill machine, the wash solution is not reused between wash cycles. New detergent solution is added before the next wash cycle. Some non-limiting examples of door machines include the Ecolab Omega HT, the Hobart AM-14, the Ecolab ES-2000, the Hobart LT-1, the CMA EVA-200, American Dish Service L-3DW and HT-25, the Autochlor A5, the Champion D-HB, and the Jackson Tempstar.
The temperature of the cleaning applications in ware wash machines according to the invention may also vary depending on the dish machine, for example if the dish machine is a consumer dish machine or an institutional dish machine. The temperature of the cleaning solution in a consumer dish machine is typically about 110° F. (43° C.) to about 150° F. (66° C.) with a rinse up to about 160° F. (71° C.). The temperature of the cleaning solution in a high temperature institutional dish machine in the U.S. is about typically about 150° F. (66° C.) to about 165° F. (74° C.) with a rinse from about 180° F. (82° C.) to about 195° F. (91° C.). The temperature in a low temperature institutional dish machine in the U.S. is typically about 120° F. (49° C.) to about 140° F. (60° C.). Low temperature dish machines usually include at least a thirty second rinse with a sanitizing solution. The temperature in a high temperature institutional dish machine in Asia is typically from about 131° F. (55° C.) to about 136° F. (58° C.) with a final rinse at 180° F. (82° C.).
The disclosed methods of using the acidic softened water may also be used in a pot and pan washer, a utensil washer, glasswashers and/or a conveyor machine. A conveyor machine refers to a commercial dish machine, wherein the soiled dishes are placed on a rack that moves through a dish machine on a conveyor. A conveyor machine continuously cleans racks of soiled dishes instead of one rack at a time. Here the manifolds are typically stationary or oscillating and the rack moves through the machine. A conveyor machine may be a single tank or multi-tank machine. The conveyor machine may include a prewash section. A conveyor machine may be a high temperature or low temperature machine. Finally, conveyor machines primarily recirculate the detergent solution. Some non-limiting examples of conveyor machines include the Ecolab ES-4400, the Jackson AJ-100, the Stero SCT-44, and the Hobart C-44, and C-66.
In some embodiments, the dish or ware machine can incorporate an acid regenerate-able ion exchange resin system at a point of use. Beneficially, the use of the acid regenerate-able ion exchange resin system at a point of use avoids the need for an extra, external, water conditioning system. Further benefits result from the use of the system at a point of use is that the demands on the water within the facility or location are associated with the particular dish or other machine, instead of the rest of the water used in the facility.
In additional aspects, the present disclosure includes methods of using the acidic softened water for laundry applications. For example, the acidic treated water can be used in an automatic textile washing machine at the pre-treatment, washing, souring, softening, and/or rinsing stages. In a particular embodiment, the present invention may be used with a washing machine in a variety of ways. In some embodiments, a treatment reservoir housing the ion exchange resin may be connected to a laundry detergent dispensing device. The treatment reservoir may be used to supply treated water to a washing system and/or to a rinsing system of a laundry washing machine. In some embodiments, the treatment reservoir may be used to supply a mixture of treated water and detergent to a laundry washing system.
In still additional aspects, the present disclosure includes methods of using the acidic softened water in a variety of additional industrial and domestic applications. For example, according to embodiments of the invention the acidic softened water can be delivered to a variety of cleaning applications through the use of dilution systems, which may include for example an aspirator or other pump that feeds into a cleaning system.
The water treatment methods and apparatuses can be employed in a residential setting or in a commercial setting, e.g., in a restaurant, hotel, hospital. In addition to the ware washing (e.g., washing eating and cooking utensils and dishes) and laundry applications, for example, a water treatment method, system, or apparatus of the present invention can be used in: other hard surfaces such as showers, sinks, toilets, bathtubs, countertops, windows, mirrors, and floors; in vehicle care applications, e.g., to treat water used for pre-rinsing, e.g., an alkaline presoak and/or low pH presoak, washing, polishing, and rinsing a vehicle; industrial applications, e.g., cooling towers, boilers, industrial equipment including heat exchangers; in food service applications, e.g., to treat water lines for coffee, espresso and tea brewers, espresso machines, ice machines, pasta cookers, water heaters, booster heaters, steam tables, grocery mister, steamers and/or proofers; in healthcare instrument care applications, e.g., soaking, cleaning, and/or rinsing surgical instruments, treating feed water to autoclave sterilizers; and in feed water for various applications such as humidifiers, hot tubs, and swimming pools. In some embodiments, an apparatus of the present invention can be used to treat water provided to an ice machine.
Additional hard surface cleaning applications for the treated acidic water source include clean-in-place systems (CIP), clean-out-of-place systems (COP), automatic bottle washers, washer-decontaminators, sterilizers, textile laundry machines, ultra and nano-filtration systems and indoor air filters. CIP systems include the internal components of tanks, lines, pumps and other process equipment used for processing typically liquid product streams such as beverages, milk, juices. COP systems can include readily accessible systems including wash tanks, soaking vessels, mop buckets, holding tanks, scrub sinks, vehicle parts washers, non-continuous batch washers and systems, and the like.
In additional aspects, use of a treated acidic water source according to the invention reduces or eliminates use of additional chemistry streams for cleaning (e.g. polymers, threshold agents, etc.). Preferably, use of a treated acidic water source according to the invention allows for the use of specific environmentally friendly detersive compositions, e.g., those substantially free of or free of builders, chelants, sequestrants and/or phosphorous.
The various methods of use employing the acidic softened water according to the invention may be used in combination with any detersive compositions. For example, a cleaning composition, a rinse agent composition and/or a drying agent composition can be combined with treated water to form a use solution. The articles to be cleaned and/or rinsed are then contacted with the use solution. Exemplary detergent compositions include ware washing detergent compositions, laundry detergent compositions, CIP detergent compositions, environmental cleaning compositions, hard surface cleaning compositions (such as those for use on counters or floors), motor vehicle washing compositions, and glass cleaning compositions. Exemplary rinse agent compositions include those compositions used to reduce streaking or filming on a surface such as glass. Exemplary drying agent compositions include dewatering compositions. In the vehicle washing industry, it is often desirable to include a dewatering step where a sheeting or beading agent is applied to the vehicle exterior.
However, according to a preferred embodiment the use of the treated acidic water reduces and/or eliminates the need for additional cleaning compositions (e.g. polymers, threshold agents, etc.) and/or reduces the overall detergent consumption due to the increased cleaning efficacy of the treated water. Therefore, in some embodiments, the detersive composition for use with the methods of the present invention includes a detergent that is substantially free of a chelant, builder, sequestrant, and/or threshold agent, e.g., an aminocarboxylic acid, a condensed phosphate, a phosphonate, a polyacrylate, or the like. Without wishing to be bound by any particular theory, it is thought that because the methods and apparatus of the present invention reduce the negative effects of hardness ions in the water source, when used with a detergent, there is a substantially reduced or eliminated need to include chelating agents, builders, sequestrants, or threshold agents in the detergent composition in order to handle the hardness ions.
For example, use of a water source treated in accordance with the methods of the present invention increases the efficacy of conventional detergents. It is known that hardness ions combine with soap and detergents to form a scale or scum. Further, hardness ions limit the amount of lather formed with soaps and detergents. Without wishing to be bound by any particular theory, it is thought that by reducing the amount of these hardness ions the amount of these detrimental side effects can be reduced.
In some embodiments of use, there is a substantial reduction in the detergent consumption as a result of the use of the treated acidic water source for the cleaning application, including for example, at least a 5% detergent consumption reduction, at least a 10% detergent consumption reduction, at least a 20% detergent consumption reduction, or at least a 25-30% detergent consumption reduction. Without being limited according to the invention, all percentages of detergent consumption reduction ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.
As one skilled in the art will ascertain, in some embodiments, the detersive composition may include other additives, including conventional additives such as bleaching agents, hardening agents or solubility modifiers, defoamers, anti-redeposition agents, threshold agents, stabilizers, dispersants, enzymes, surfactants, aesthetic enhancing agents (i.e., dye, perfume), and the like. Adjuvants and other additive ingredients will vary according to the type of composition being manufactured. It should be understood that these additives are optional and need not be included in the cleaning composition. When they are included, they can be included in an amount that provides for the effectiveness of the particular type of component.
Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures, embodiments, claims, and examples described herein. Such equivalents are considered to be within the scope of this invention and covered by the claims appended hereto. The contents of all references, patents, and patent applications cited throughout this application are hereby incorporated by reference. The invention is further illustrated by the following examples, which should not be construed as further limiting.
All publications and patent applications in this specification are indicative of the level of ordinary skill in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated by reference.
EXAMPLES
Embodiments of the present invention are further defined in the following non-limiting Examples. It should be understood that these Examples, while indicating certain embodiments of the invention, are given by way of illustration only. From the above discussion and these Examples, one skilled in the art can ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the embodiments of the invention to adapt it to various usages and conditions. Thus, various modifications of the embodiments of the invention, in addition to those shown and described herein, will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims.
Example 1
Previous experiments show that ware washing results will be improved using softened water by conventional means and acidified by consumable detergents and/or rinse additives. When conventional ion exchange resins are exhausted, the water is no longer softened and brine is typically used to regenerate the resin. The water that is no longer softened often causes poor washing results unless additional detergents concentration containing builders, chelants or polymers are increased and additional rinse additive is used.
An experiment showing the proof of scale build up on ware was conducted using a carbonate 500 ppm, 75 cycle test. Table 1 quantifies the results of ware treated according to the experiment, wherein Glasses 1A were treated using only hard water (17 Grain/Gal hardness water) and Glasses 1B were treated using the acidic softened water according to the invention. The resultant scale build up on the treated ware surfaces were depicted by photograph and measured visually according to the grading scale (below).
The 75 cycle test employed was performed using six 10 oz. Libbey glasses and four plastic tumblers (SAN=Styrene Acrylonitrile) on a Hobart AM-14 ware wash machine and 17 grain water (1 grain=17 ppm). The specifications of the Hobart AM-14 ware wash machine include: Washbath volume: 60 L; Rinse volume: 4.5 L; Wash time: 40 sec.; Rinse time: 9 sec.
Initially the glasses were cleaned according to procedures ensuring removal of all film and foreign material from the glass surface. The 75 cycle test was initiated. After the completion of each cycle, the machine is appropriately dosed (automatically) to maintain the initial concentration. Glasses and tumbles dry overnight and then are graded for film accumulation using a strong light source. (1—No film; 2—Trace film; 3—Light film; 4—Medium film; 5—Heavy film). As shown in Table 1, Glasses 1A (hard water—17 grain) were graded a level 5, demonstrating heavy film. The glasses treated according to the invention shown in Glasses 1B (acidic softened water) were graded a level 1, demonstrating no film.











TABLE 1







Evaluated Glasses
1A
1B









Film Accumulation
5
1










Example 2
An experiment showing the proof of protein removal on ware was conducted using the detergent APEXNC 1000 ppm (Ecolab®) and the 7 cycles protein removal test. Table 2 show the results of ware treated according to the experiment, wherein Glasses 2A were treated using only hard water (5 Grain/Gal hardness water) and Glasses 2B were treated using the acidic softened water according to the invention. The resultant scale build up on the treated ware surfaces are depicted by photograph and measured visually according to the grading scale (below).
The 7 cycle protein test employed was performed to provide a generic method for evaluating glass filming, spotting, and soil removal in an institutional dish machine. Clean test glasses are washed in an institutional dish machine. The performance of the detergent or rinse aid is measured by the prevention of water spotting or filming and the removal of soil from plastic tumblers and Libbey Glass tumblers. According to this experimentation the performance of use of softened acid water (as opposed to 5 grain hard water) were evaluated.
Clean Libbey glasses were used for each test product and new plastic tumblers were used for each experiment. Food soils were prepared food soils. The dish machine was filled with the tested water sources (described according to Glasses 2A-2B) and heaters were turned on. The final rinse temperature was adjusted to 180° F. for the high temperature machines. Glasses and plastic tumblers were soiled and placed in the oven at 160° F. for 8 minutes. While glasses were drying, the ware wash machine was primed with 120 g of soil previously prepared (corresponding to 2000 ppm of food soil in the sump). Soiled glasses/plastic tumblers are placed in the rack beside the re-deposition glasses/plastic tumblers. The wash machine is started and glasses are run through an automatic cycle. When the cycle has ended, the top of the glasses are mopped with a dry towel. The soiling procedure is repeated. At the beginning of each cycle, the appropriate amount of detergent and food soil are added to the wash tank to make up for the rinse dilution. The steps are repeated until seven cycles are complete.
Results were evaluated using the de-staining methods employing a Coomassie Blue R Stain solution to evaluate glasses visually against a while background. Glasses are first stained using the Coomassie Blue R Stain solution and rinsed thoroughly with de-staining solution (methanol and acetic acid in distilled water). Each glass is then visually rated in a viewing area against a white background, wherein residual protein remains stained blue. (1—No protein; 2—20% of glass surface covered in protein; 3—40% of glass surface covered in protein; 4—60% of glass surface covered in protein; 5—greater than 80% of glass surface covered in protein As shown in Table 2 the Glasses 2A (hard water—5 grain) were graded a level 2, demonstrating 20% of glass surface covered in protein. The glasses treated according to the invention shown in Glasses 2B (acidic softened water) were graded a level 1, demonstrating no protein on the glasses.











TABLE 2







Evaluated Glasses
2A
2B









Film Accumulation
2
1










Example 3
The capacity of a commercially-available weak acid resin against pH of water was tested. An Amberlite® IRC 76 ion exchange resin (commercially-available from Rohm and Haas Company) was tested. Amberlite® IRC 76 ion exchange resin is one example of a commercially-available weak acidic resin having a polyacrylic copolymer with carboxylic acid functional group. This particular resin is characterized by a volume variation smaller than conventional weak acid resins and can be used in H+, Na+ or NH4+ forms and can also be used to remove bicarbonate hardness from water. The resin is known to be sensitive to chlorine in water (affecting the lifetime and performance of the resin). The operating capacity of the resin is a function of analysis, temperature and service flow rate of water. The resin is readily regenerated with little over stoichiometric amounts of strong acids.
On average, the use of a conventional weak acid resin used in ion exchange water softening applications are designed for bed depths of 2.6 feet for water treatment rates of about 2 to about 20 gallons per minute. However, one skilled in the art may vary the water treatment rates, including for example from about 0.5 to about 50 gallons per minute. The configuration used for the testing of the capacity of the ion exchange resin used a flow rate of about 5-10 gallons of water per minute and consumed less than 1 cubic foot of resin for the system. In addition, various monitoring devices were in use within the system to measure flow, water hardness (e.g. hardness ions measured by titration method), pressure within the system (e.g. measurement of presume required for effective
e rinsing, preferably pressure measurement of about 20 psi), pH of the effluent (e.g. electrode measurement), and TDS (e.g. ICP analytical method for TDS).
FIG. 6 shows a diagram of the capacity of an acid regenerated ion exchange resin v. pH of treated water according to an embodiment of the invention. The best results are obtained from the resin with a pH less than about 6. Preferably the pH is less than about 7.
Example 4
The capacity of a commercially available weak acid resin against hardness of water was tested. An Amberlite® IRC 76 ion exchange resin (commercially-available from Rohm and Haas Company) was tested. Amberlite® IRC 76 ion exchange resin is one example of a commercially-available weak acidic resin having a polyacrylic copolymer with carboxylic acid functional group. This particular resin is characterized by a volume variation smaller than conventional weak acid resins and can be used in H+, Na+ or NH4+ forms and can also be used to remove bicarbonate hardness from water. The resin is known to be sensitive to chlorine in water (affecting the lifetime and performance of the resin). The operating capacity of the resin is a function of analysis, temperature and service flow rate of water. The resin is readily regenerated with little over stoichiometric amounts of strong acids.
The configuration used for the testing of the capacity of the ion exchange resin used a flow rate of about 5-10 gallons of water per minute and consumed less than 1 cubic foot of resin for the system. In addition, various monitoring devices were in use within the system to measure flow, water hardness (e.g. hardness ions measured by titration method), pressure within the system (e.g. measurement of presume required for effective rinsing, preferably pressure measurement of about 20 psi), pH of the effluent (e.g. electrode measurement), and TDS (e.g. ICP analytical method for TDS).
FIG. 7 shows a diagram of the capacity of an acid regenerated ion exchange resin v. water hardness of treated water according to an embodiment of the invention. The best results are obtained from the resin system with a water hardness less than about 2 grains.
Example 5
Layered resin bed systems were evaluated to assess the impact on treated water hardness using more than one acid cation exchange resin. 4710 grams of the Dowex® MAC-3 weak cation exchange resins (commercially-available from Dow Chemical Company) were used to form a layered bed using two of the weak acid cation exchange resins, such as shown in FIG. 3A. The Dowex® MAC-3 LB resin is one example of a commercially-available weak acidic resin having a carboxylic acid functional groups. The MAC-3 WAC resins were packed into two connected 19 inch by 5 inch diameter housing tubes. 3575 grams of the Dowex® MAC-3 weak cation exchange resin (commercially-available from Dow Chemical Company) and 1235 grams of Dowex® Marathon-C (H form) strong cation exchange resin (commercially-available from Dow Chemical Company) were used to form a mixed layered bed, such as shown in FIG. 3B. The cation exchange resins were packed into two connected 19 inch by 5 inch diameter housing tubes.
Hard water (17 grains) was provided to the layered resin bed systems depicted in FIGS. 3A-3B at a controlled rate of about 0.8 gallons per minute. The water from the outlet of the second treatment reservoir was measured for both hardness and pH. Water samples were taken to test pH levels against capacity.
FIG. 8 shows a diagram of the capacity of the layered bed systems. As shown, the layered weak acid regenerated ion exchange resin provided softened water having between about 0.5 to 1 grains, whereas the layered mixed bed of weak acid regenerated ion exchange resin and a strong acid regenerated ion exchange resin provided softened water having 0 grain hardness. The use of the layered mixed bed employing the strong acid cation exchange resin provided greater reduction in water hardness, despite its overall lower capacity for reducing water hardness if used alone. However, the water softened using the layered weak acid regenerated ion exchange resins provided the additional benefit of providing reduced pH softened water, which provides additional cleaning benefits.
As shown in the figure, each of the layered beds demonstrated softening efficacies sustained for at least about 150 gallons of treated water. Thereafter between about 150 gallons to 200 gallons the resins became exhausted and were unable to continue to sufficiently remove water hardness. According to aspects of the invention, for the evaluated water treatment apparatuses in this Example, the use of acid regeneration would need to be employed after about 150 gallons of treated water.
FIG. 9 shows a diagram of the pH versus the capacity of the layered bed systems. As shown, the layered weak acid ion exchange resin bed (i.e. employing a single type of resin) resulted in less acidified treated water source as the capacity of the system was tested. Namely, above about 200 gallons of treated water, the pH of the single resin layered bed began to increase above about 4, whereas the layered mix resin bed system maintained a constant acidified water having a pH between about 3 to about 3.5.
Example 6
The use of an acid regenerant according to embodiments of the invention were analyzed. A single weak acid resin bed, such as disclosed in Example 4 was regenerated using various acid regenerants disclosed herein. It was found that the regeneration process is initially dominated by thermodynamics. A regenerant with a sufficiently low pH will drive the process over the energy barrier, showing a fast pH drop at the first several minutes. Thereafter, the regeneration process is controlled by kinetics. This requires a regenerant to be used for a sufficient amount of time (e.g. about 5 to about 90 minutes) to drive the regeneration of the resin to completion.
As shown in FIGS. 10A-B the use of a strong acid regenerant (HCL 0.38M (FIG. 10A), HCL 1.8M (FIG. 10B)) is required to sufficiently decrease the pH in the weak acid resin. According to embodiments of the invention the concentration of the acid regenerant used in the regeneration cycle will depend upon the molarity of the acid employed. In some embodiments, the concentration of the acid used in a solution for providing the acid regenerant to the ion exchange resin is from about 1% to about 20%, from about 2% to about 10%, or about 10% for regeneration.
After the resin has been regenerated, as shown in FIGS. 10A-B, an exemplary service cycle (i.e. treating hard water with the acid regenerated resin) can be used to again provide a treated acidified water source. As shown in FIG. 11, the use of the strong acid regenerant of FIG. 10B provides superior treatment capacity for a longer service cycle.
Example 7
The use of additional acid regenerants was evaluated pursuant to the results of Example 6. The following acid regenerants were employed and reported in equivalence of the various acids employed: 1.2 eq sulfuric acid, 1.2 eq urea sulfate, 1.2 eq hydrochloric acid, 1.2 eq MSA, and 1.4 eq citric acid. FIG. 12 shows the drop in pH of the resin during a regeneration step employing the various acid regenerants. Beneficially, the use of equivalence of the various acids employed in this examples takes into account the various fluctuating factors, including for example, the size of the system, amount of hardness to be removed, etc.
After the resin has been regenerated, as shown in FIG. 12, an exemplary service cycle (i.e. treating hard water with the acid regenerated resin) was employed to determine the efficacy of service cycles, as measured by water hardness of the treated water source, based on the use of the various acid regenerants. As shown in FIG. 13, the service cycle of various acid regenerant provided treated acidic water having a hardness of about 1 or less than about 1 for at least 100 gallons of treated water.
The inventions being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the inventions and all such modifications are intended to be included within the scope of the following claims.

## Claims

1. A method for treating hard water using an acid regenerated ion exchange resin comprising:
contacting a hard water source with a water treatment composition placed in front of a dilution system
in a service cycle, wherein the water treatment composition comprises at least one ion exchange resin, wherein the ion exchange resin generates a treated water source by exchanging protons on said resin for dissolved cations including water hardness ions and total dissolved solids in said water source, and wherein said ion exchange resin is regenerated using an acid;

generating the service cycle treated water source comprising softened, acidic and low total dissolved solids (TDS) water having a hardness level of less than about 2 grains per gallon (gpg) and a pH less than about 6, wherein the treated water source may be used for washing and/or rinsing in a variety of cleaning applications; and
regenerating the ion exchange resin upon exhaustion using an acid regenerant.

2. The method according to claim 1, wherein said ion exchange resin is a weak acid cation exchange resin selected from the group consisting of a cross-linked polyacrylic with carboxylic acid functional group, a cross-linked polymethacrylic with carboxylic acid functional group and mixtures of thereof, and/or a strong acid cation exchange resin selected from the group consisting of a polystyrene with sulfonic acid functional group, a polystyrene with sulfonic acid functional group and mixtures of thereof.

3. The method according to claim 2, wherein said ion exchange resin is a layered bed system employing at least two of said cation exchange resins.

4. The method according to claim 1, further comprising measuring pH and/or proton concentration and/or total dissolved solids within the water treatment composition, water source and/or treated water source, and triggering an event as a result of the obtained measurement.

5. The method according to claim 4, wherein a pH and/or proton concentration measurement is obtained from said treated water source.

6. The method according to claim 4, wherein a differential pH and/or proton concentration measurement is obtained from said water source and said treated water source.

7. The method according to claim 4, wherein the triggered event is selected from the group consisting of regenerating the resin of the water treatment component, varying a detergent or other chemistry addition to the treated water source and combinations thereof.

8. The method according to claim 7, wherein the regeneration of the resin is triggered and comprises providing an acid regenerant to the resin, displacing water hardness ions on the resin with protons from the acid regenerant, and generating a regeneration step effluent water.

9. The method according to claim 8, wherein the effluent water is put to a waste stream.

10. A method for treating hard water using an acid regenerated ion exchange resin comprising:
contacting a hard water source with a water treatment composition placed in front of a dilution system in
a service cycle, wherein said dilution system is an aspirator or other pump that feeds into a cleaning system, wherein the water treatment composition comprises at least one ion exchange resin, wherein the ion exchange resin generates a treated water source by exchanging protons on said resin for dissolved cations including water hardness ions and total dissolved solids in said water source, and wherein said ion exchange resin is regenerated using an acid;

generating the service cycle treated water source comprising softened, acidic and low total dissolved solids (TDS) water having a hardness level of less than about 2 grains per gallon (gpg) and a pH less than about 6, wherein the treated water source may be used for washing and/or rinsing in a variety of cleaning applications; and
regenerating the ion exchange resin upon exhaustion using an acid regenerant.