Patent Publication Number: US-2022226801-A1

Title: Automatic recharger brine preparation from a canister

Description:
FIELD 
     The disclosure relates to systems and methods for generating a brine solution using a canister for recharging zirconium phosphate in a reusable sorbent module. The canister can contain salt and include an inlet and an outlet. The inlet can extend upwardly into an interior of the canister above solid sodium chloride and sodium acetate. Water can be added to dissolve the salts in the canister and the resulting solution can be collected as a brine solution for use in recharging the zirconium phosphate. 
     BACKGROUND 
     Sorbent based dialysis systems can use zirconium phosphate as a sorbent material to remove potassium, calcium, and magnesium ions from spent dialysate. The zirconium phosphate is generally provided in a sorbent cartridge with other sorbent materials. After use, the spent zirconium phosphate is disposed or removed from the sorbent cartridge for further processing. However, removing spent zirconium phosphate from a sorbent cartridge, separating the zirconium phosphate from other sorbent materials, and processing the spent zirconium phosphate can require significant time and expense. Further, large quantities of solutions for processing the spent zirconium phosphate can be required along with any necessary infrastructure, storage, and transportation. Expensive manufacturing lines and plants may also be required to generate pre-made solutions for use in processing the zirconium phosphate. 
     Hence, there is a need for systems and methods that can recharge zirconium phosphate within a reusable sorbent module. There is further a need for systems and methods for generating the recharge solutions necessary for recharging the zirconium phosphate, and in particular, brine solutions. There is a need for systems and methods that can generate the brine solution on-line and quickly, reducing the manufacturing burden and reducing the storage needs and time required for preparation and recharging. 
     SUMMARY OF THE INVENTION 
     The problem to be solved by the present invention is online preparation of a brine solution for use in recharging sorbent materials. The solution is to include sodium chloride and sodium acetate in a salt canister. The sodium chloride and sodium acetate can be dissolved when needed to generate the brine solution. 
     The first aspect of the invention relates to a system. In any embodiment, the system can include a sorbent recharger; the sorbent recharger having: i) a receiving compartment for a zirconium phosphate sorbent module; ii) at least a first fluid line fluidly connectable to an inlet of the zirconium phosphate sorbent module in the receiving compartment; iii) at least a second fluid line fluidly connectable to an outlet of the zirconium phosphate sorbent module; and iv) at least one pump; the system further including a brine container fluidly connectable to the first fluid line; a salt canister; the salt canister having an inlet fluidly connectable to a water source and an acetic acid source; and an outlet fluidly connectable to the brine container; the salt canister containing sodium chloride and sodium acetate; and a control system; the control system programmed to: i) pump a preset volume of fluid from the water source into the salt canister; ii) recirculate fluid in a first flow path from the outlet of the salt canister to the brine container and then to the inlet of the salt canister; and to iii) pump a preset volume of acetic acid into the first flow path. 
     In any embodiment, the control system can be further programmed to pump fluid from the brine container through the zirconium phosphate sorbent module. 
     In any embodiment, the control system can be programmed to recirculate fluid in a first flow path until a homogeneous solution is generated in the first flow path. 
     In any embodiment, the control system can be programmed to recirculate fluid in a first flow path for a preset period of time. 
     In any embodiment, the salt canister can include a filter pad between the sodium chloride and sodium acetate and the outlet. 
     In any embodiment, the salt canister can include a cap on a bottom of the salt canister; wherein the inlet and outlet enter the salt canister through the cap. 
     In any embodiment, the salt canister can include a filter pad in the cap; the filter pad between the sodium chloride and sodium acetate and the outlet. 
     In any embodiment, the inlet of the salt canister can extend upwardly into the salt canister. 
     In any embodiment, the inlet of the salt canister can extend upwardly above the sodium chloride and sodium acetate in the salt canister. 
     In any embodiment, the salt sodium chloride and sodium acetate can be initially solid. 
     In any embodiment, the salt canister can be initially filled about ¾ with sodium chloride and sodium acetate. 
     In any embodiment, the salt canister can include an air vent at a top of the salt canister. 
     The features disclosed as being part of the first aspect of the invention can be in the first aspect of the invention, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. Similarly, any features disclosed as being part of the first aspect of the invention can be in a second, third, fourth, or fifth aspects of the invention described below, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. 
     The second aspect of the invention relates to a method for generating a brine solution for recharging zirconium phosphate. In any embodiment, the method can include the steps of: pumping water from a water source to a salt canister through an inlet of the salt canister; the salt canister containing sodium chloride and sodium acetate; recirculating fluid from an outlet of the salt canister, to a brine container, and back to the inlet of the salt canister in a first flow path; pumping acetic acid into the first flow path; and collecting fluid from the first flow path into the brine container to generate the brine solution. 
     In any embodiment, the brine container can be fluidly connected to a sorbent recharger; and the method can include the step of pumping the brine solution through a zirconium phosphate sorbent module in the sorbent recharger. 
     In any embodiment, the fluid can be recirculated in the first flow path until a homogenous solution is generated. 
     In any embodiment, the fluid can be recirculated in the first flow path for a preset period of time. 
     In any embodiment, the salt canister can have a filter pad between the sodium chloride and sodium acetate and the outlet. 
     In any embodiment, the salt canister can include a cap on a bottom of the salt canister; wherein the inlet and outlet enter the salt canister through the cap. 
     In any embodiment, the salt canister can include a filter pad in the cap; the filter pad between the sodium chloride and sodium acetate and the outlet. 
     In any embodiment, the inlet of the salt canister can extend upwardly into the salt canister. 
     In any embodiment, the inlet of the salt canister can extend above the sodium chloride and sodium acetate the salt canister. 
     In any embodiment, the salt sodium chloride and sodium acetate can be initially solid. 
     The features disclosed as being part of the second aspect of the invention can be in the second aspect of the invention, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. Similarly, any features disclosed as being part of the second aspect of the invention can be in the first, third, fourth, or fifth aspects of the invention, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. 
     The third aspect of the invention is drawn to a salt canister for use in recharging zirconium phosphate. In any embodiment, the salt canister can include an inlet fluidly connectable to a water source; an outlet fluidly connectable to a brine container; and a cap on a bottom of the salt canister; wherein the inlet and outlet enter the salt canister through the cap; the salt canister containing sodium chloride and sodium acetate. 
     In any embodiment, the salt canister can include an air vent on a top of the salt canister. 
     In any embodiment, the inlet of the salt canister can extend upwardly into the salt canister. 
     In any embodiment, the inlet of the salt canister can extend upwardly above the sodium chloride and sodium acetate in the salt canister. 
     The features disclosed as being part of the third aspect of the invention can be in the third aspect of the invention, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. Similarly, any features disclosed as being part of the third aspect of the invention can be in the first, second, fourth, or fifth aspects of the invention, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. 
     The fourth aspect of the invention is drawn to a sorbent recharger. In any embodiment, the sorbent recharger can include at least one inlet fluidly connectable to a water source; at least one inlet fluidly connectable to a brine container; and at least one outlet fluidly connectable to the salt canister of the third aspect of the invention. 
     In any embodiment, the sorbet recharger can include a control system programmed to: i) pump a preset volume of fluid from the water source into the salt canister; ii) recirculate fluid in a first flow path from the outlet of the salt canister to the brine container and then to the inlet of the salt canister; and to iii) pump a preset volume of acetic acid into the first flow path. 
     In any embodiment, the control system can be programmed to recirculate fluid in the first flow path until a homogeneous solution is generated in the first flow path. 
     In any embodiment, the control system can be programmed to recirculate fluid in a first flow path for a preset period of time. 
     The features disclosed as being part of the fourth aspect of the invention can be in the fourth aspect of the invention, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. Similarly, any features disclosed as being part of the fourth aspect of the invention can be in the first, second, third, or fifth aspects of the invention, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. 
     The fifth aspect of the invention is drawn to a brine container. In any embodiment, the brine container can include an inlet fluidly connectable to the salt canister of the third aspect of the invention; and an outlet fluidly connectable to a sorbent recharger. 
     The features disclosed as being part of the fifth aspect of the invention can be in the fifth aspect of the invention, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. Similarly, any features disclosed as being part of the fifth aspect of the invention can be in the first, second, third, or fourth aspects of the invention, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-E  illustrate a salt canister for preparation of a brine solution. 
         FIG. 2  illustrates a sorbent recharger system using a salt canister. 
         FIGS. 3A-B  illustrate a sorbent recharger for recharging sorbent materials in reusable sorbent modules. 
         FIG. 4  shows a flow path for a sorbent recharger using a salt canister. 
     
    
    
     DETAILED DESCRIPTION 
     Unless defined otherwise, all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art. 
     The articles “a” and “an” are used to refer to one to over one (i.e., to at least one) of the grammatical object of the article. For example, “an element” means one element or over one element. 
     An “acetic acid source” is a solid, fluid, or concentrate source from which acetic acid or an acetic acid solution can be obtained. 
     An “air vent” is an opening through which gas can pass in a component, allowing gas to flow into or out of the component. 
     The term “bottom” refers to a portion of a component intended to be at a lower elevation than a “top” during normal use of the component. 
     A “brine container” is a container for containing a brine solution. The container can be any suitable shape, size, or form capable of containing one or more materials, such as a brine. 
     A “brine solution” is a solution containing sodium chloride, an acid, and the sodium salt of the acid. 
     A “cap” is a removable component that, when attached, covers an opening in a container or canister. 
     A “canister” can be a container of any shape, size, or form capable of containing one or more materials. In one non-limiting embodiment, the canister can be generally round or cylindrical in form. The canister can have one or more tapered ends. However, it will be understood that the canister can be any casing having a rectangular, elliptical, triangular, or any other form. The canister should be interpreted in the broadest sense. 
     To “collect” a fluid refers to flowing a volume of the fluid into a container. 
     The term “comprising” includes, but is not limited to, whatever follows the word “comprising.” Use of the term indicates the listed elements are required or mandatory but that other elements are optional and may be present. 
     The term “consisting of” includes and is limited to whatever follows the phrase “consisting of.” The phrase indicates the limited elements are required or mandatory and that no other elements may be present. 
     The term “consisting essentially of” includes whatever follows the term “consisting essentially of” and additional elements, structures, acts, or features that do not affect the basic operation of the apparatus, structure or method described. 
     A “container” is a vessel or receptable of any shape, size, or form capable of containing one or more materials. The container should be interpreted in the broadest sense. 
     The term “containing” refers to a substance that is within a component or container. 
     A “control system” can be a combination of components that act together to maintain a system to a desired set of performance specifications. The control system can use processors, memory and computer components configured to interoperate to maintain the desired performance specifications. The control system can also include fluid or gas control components, and solute control components as known within the art to maintain performance specifications. 
     To term “extends upwardly” refers to a part of a component that is at a higher elevation vertically than the rest of the component when positioned for normal use. 
     A “filter pad” is a porous pad through which water or aqueous solutions can pass, but that prevents solid materials from passing. 
     A “flow path” is a pathway through which a fluid, gas, or combinations or mixtures thereof can travel. 
     A “fluid” is a liquid substance optionally having a combination of gas and liquid phases in the fluid. Notably, a liquid, as used herein, can therefore also have a mixture of gas and liquid phases of matter. 
     A “fluid line” can refer to a tubing or conduit through which a fluid or fluid containing gas can pass. The fluid line can also contain air during different modes of operation such as cleaning or purging of a line. 
     The term “fluidly connectable” refers to the ability of providing for the passage of fluid, gas, or combination thereof, from one point to another point. The ability of providing such passage can be any connection, fastening, or forming between two points to permit the flow of fluid, gas, or combinations thereof. The two points can be within or between any one or more of compartments of any type, modules, systems, components, and rechargers. 
     The term “fluidly connected” refers to a particular state such that the passage of fluid, gas, or combination thereof, is provided from one point to another point. The connection state can also include an unconnected state, such that the two points are disconnected from each other to discontinue flow. It will be further understood that the two “fluidly connectable” points, as defined above, can form a “fluidly connected” state. The two points can be within or between any one or more of compartments, modules, systems, components, and rechargers, all of any type. 
     The terms “generate,” “generating,” “is generated,” and the like refer to forming a solution or substance from constituent parts. 
     The term “homogeneous solution” refers to an aqueous solution wherein the concentration of solutes is substantially identical at all parts of the solution. 
     The term “initially” refers to a state of a component or system prior to a process. 
     The term “inlet” can refer to a portion of container, flow path, or component through which fluid, gas, or a combination thereof can be drawn into the container, flow path, or component. 
     The term “interior” refers to an area inside of a given component or system. 
     The term “outlet” can refer to a portion of container, flow path, or component through which fluid, gas, or a combination thereof can be drawn out of the container, flow path, or component. 
     A “preset period of time” is a length of time that is set prior to a process or step. 
     The term “preset volume” refers to an amount of fluid determined prior to a process. 
     The term “programmed,” when referring to a processor, can mean a series of instructions that cause a processor to perform certain steps. 
     The term “pump” refers to any device that causes the movement of fluids or gases by applying suction or pressure. 
     A “receiving compartment” can be a compartment, section, or chamber of any device or components. In one non-limiting example, the receiving compartment can be within a sorbent recharger into which a sorbent module can be positioned to be recharged. 
     “Recharging” refers to treating a sorbent material to restore the functional capacity of the sorbent material to put the sorbent material back into a condition for reuse or use in a new dialysis session. In some instances, the total mass, weight and/or amount of “rechargeable” sorbent materials remain the same. In some instances, the total mass, weight and/or amount of “rechargeable” sorbent materials change. Without being limited to any one theory of invention, the recharging process may involve exchanging ions bound to the sorbent material with different ions, which in some instances may increase or decrease the total mass of the system. However, the total amount of the sorbent material will in some instances be unchanged by the recharging process. Upon a sorbent material undergoing “recharging,” the sorbent material can then be said to be “recharged.” 
     To “recirculate” refers to moving fluid in a flow loop from a first point through the flow loop and back to the first point. 
     A “salt canister” can be a container or canister as defined herein, that is capable of hold or containing salts. The salts can be used to generate a brine solution. The salt canister can include an inlet for receiving water and an outlet for the formed solution to exit. 
     The term “sodium acetate” refers to CH 3 CO 2 Na either solid or in an aqueous solution. 
     The term “sodium chloride” refers to NaCl either solid or in an aqueous solution. 
     The term “solid” refers to a material in the solid phase of matter, and can include crystalline, powdered, or any other form of solid material. 
     A “sorbent module” means a discreet component of a sorbent cartridge. Multiple sorbent cartridge modules can be fitted together to form a sorbent cartridge of two, three, or more sorbent cartridge modules. The “sorbent cartridge module” or “sorbent module” can contain any selected materials for use in sorbent dialysis and may or may not contain a “sorbent material” or adsorbent, but less than the full complement of sorbent materials needed. In other words, the “sorbent cartridge module” or “sorbent module” generally refers to the use of the “sorbent cartridge module” or “sorbent module” in sorbent-based dialysis, e.g., REDY (REcirculating DYalysis), and not that a “sorbent material” that is necessarily contained in the “sorbent cartridge module” or “sorbent module.” 
     A “sorbent recharger” or “recharger” is an apparatus designed to recharge at least one sorbent material. 
     The term “water source” refers to any source from which potable or non-potable water can be obtained. 
     “Zirconium phosphate” is a sorbent material that removes cations from a fluid, exchanging the removed cations for different cations. 
     A “zirconium phosphate sorbent module” is a sorbent module that contains zirconium phosphate. 
     Brine Preparation from a Salt Canister 
       FIGS. 1A-E  illustrate a salt canister  101  that can be used to generate brine for recharging zirconium phosphate in a reusable zirconium phosphate sorbent module.  FIG. 1A  is a perspective view of a salt canister  101 ;  FIG. 1B  is the salt canister  101  connected to fluid lines,  FIG. 1C  is a transparent view of an empty salt canister  101 ,  FIG. 1D  is a transparent view of a filled salt canister  101 , and  FIG. 1E  is an exploded view showing the components used with the salt canister  101 . 
     The salt canister  101 , as illustrated in  FIG. 1A  can include an inlet  104 , and outlet  103 . The inlet  104  and outlet  103  extend through a cap  102  on the salt canister  101 .  FIG. 1B  illustrates the salt canister  102  inserted into a base frame  108 . In one non-limiting embodiment, the salt canister  101  can be generally cylindrical in form. However, one of ordinary skill will understand that any container of any suitable shape, size, or form capable of containing one or more materials of the invention can be used. For example, the salt canister  101  can be tapered or shaped symmetrically, or non-symmetrically to fit inside a compartment of another device, such as a recharger (not shown). The base frame  108  can be included to mount the salt canister  101 . The base frame  108  holds the salt canister  101  in place during use and provides a space underneath the salt canister  101  for connection to fluid line  106  and fluid line  107  at the bottom of salt canister  101 . Alternative methods of mounting the salt canister  101  can be used, including hooks or any other method known to one of skill in the art. An air vent  105  can be included in the salt canister  101  to allow air within the salt canister  101  to escape when water is added into the salt canister  101 . 
     As illustrated in  FIG. 1C , the inlet  104  and outlet  103  can extend through the cap  102  of salt canister  101 . The outlet  103  can connect to a fluid line  106 , which is fluidly connectable to a brine container (not shown). The inlet  104  can connect to a fluid line  107 , which is fluidly connectable to both a water source and an acetic acid source (not shown). The base frame  108  can include holes to allow fluid line  106  and fluid line  107  to connect to inlet  104  and outlet  103 , respectively. The inlet  104  can include a top portion  109  that extends upwardly into an interior of the salt canister  101 . The top portion  109  of the inlet  104  can extend above a salt level inside the salt canister  101 . A filter pad  112  can be included above the outlet  103 . The filter pad  112  can block solid salt or any other material from exiting the salt canister  101 , while allowing the generated brine solution to exit the salt canister  101 . The filter pad  112  can be any type of filter that will prevent most solid salt particles from passing through while allowing the brine solution to pass through. 
       FIG. 1D  illustrates the salt canister  101  filled with solid salts  110  as water  111  is added. In certain embodiments, the salt canister  101  can initially be about ¾ filled with the sodium acetate and sodium chloride, leaving about ¼ of the space available for filling with water. However, the actual amount of solid salts initially placed in salt canister  101  can vary. For example, the salt canister can initially be ½ filled, ⅔ filled, ¼ filled or any other fractional amount depending on the needs of the user. As illustrated in  FIG. 1D , the inlet  104  can include a top portion  109  that extends upwardly into an interior of the salt canister  101  above a salt level of the solid salts  110 . To generate a brine solution, water  111  can be pumped through the inlet  104 . The water  111  can spray out of the top portion  109  of the inlet  104  to spread across a top of the salts  110 . As the water  111  is added to salt canister  101 , air can escape through vent  105 . The water  111  can dissolve the sodium chloride and sodium acetate in the salt canister  101  and exit through outlet  103  in cap  102 . Filter pad  112  can be included to prevent solid particles from entering outlet  103  or fluid line  107 . The filter pad  112  can be placed between the solid salts  110  and the outlet  103  to filter brine solution exiting the salt canister  101 . The base frame  108  can include holes to allow fluid line  106  and fluid line  107  to connect to inlet  104  and outlet  103 , respectively. 
       FIG. 1E  is an exploded view of the salt canister  101 . The cap  102  of the salt canister  101  can be inserted into base frame  108 . The base frame  108  can include openings for the inlet (not shown in  FIG. 1E ) and outlet  103  to connect to fluid lines  107  and  106 , respectively. As water is pumped into the salt canister  101  through fluid line  107 , air can escape the salt canister  101  through vent  105 . 
     After the brine solution exits through the outlet  103  of salt canister  101  into fluid line  107 , the generated brine solution can be collected in the brine container (not shown). The brine solution can be recirculated back to inlet  104  of the salt canister  101 , through the outlet  103 , and back through the brine container. The brine solution can be recirculated for a preset period of time, or until full dissolution of the solid salts  110  and after a homogeneous solution is formed in a recirculation flow path as further described in  FIG. 2 . 
     The salt canister  101  can be constructed from any material capable of holding the salts  110 . In certain embodiments, the salt canister  101  can be constructed from a polymer such as polypropylene, polyethylene, or high-density polyethylene. Alternatively, metal, glass, or other materials can be used. 
     The required size of the salt canister  101  can depend on the amount of brine solution desired. As described, the salt canister  101  can initially be about ¾ filled with the sodium acetate and sodium chloride. The total volume of the salt canister can vary depending on the desired brine output volume. As a non-limiting example, the salt canister  101  can be sized about 2.5 L to hold between 1.5-2.0 kg of sodium acetate and sodium chloride with 200-300 mL left of water filling capacity. However, with larger brine outputs desired, the salt canister can be made larger as well. The volume of water added can be varied to generate a brine solution having a desired sodium concentration. In certain embodiments, about 5 L of water can be used to generate the brine solution. However, the amount of water used can be varied depending on the desired brine solution concentration and the amount of salt used. 
       FIG. 2  is a generalized diagram of a sorbent recharger system using the described salt canister  205 . As described, the salt canister  205  can contain sodium acetate and sodium chloride in any amount. Water from water source  201  can be pumped into an inlet of the salt canister  205 . In certain embodiments, the water source  201  can be fluidly connected to a sorbent recharger  202 . The water can be pumped from water source  201 , through line  209  into the sorbent recharger  202 , and then into the salt canister  205  through fluid line  207 . Alternatively, a separate fluid line (not shown) can connect the water source  201  to the inlet of salt canister  205 . 
     The water pumped into salt canister  205  can dissolve the sodium acetate and sodium chloride and exit through an outlet of the salt canister  205  into brine container  204 . To ensure complete dissolution of the sodium acetate and sodium chloride and a homogeneous brine solution, the solution can be recirculated through a flow path as shown by arrows  211 . The brine solution can be pumped from the outlet of the salt canister  205  into brine container  204  through fluid line  206 , back into sorbent recharger  202  through fluid line  208 , and then back to the inlet of the salt canister  205  through fluid line  207 . The salt canister  205 , fluid line  206 , brine container  204 , fluid line  208 , recharger  202 , and fluid line  207  define a recirculation flow path. The solution can be pumped through the recirculation flow path until a homogeneous solution is formed, or for some preset period of time that is long enough to ensure formation of a homogenous solution. The preset period of time can be any time long enough to ensure complete dissolution and homogeneity. In certain embodiments, the preset period of time can be between 20 and 45 minutes. Additionally, or alternatively, one or more sensors, such as conductivity sensors, can be included to ensure that the generated brine solution has the proper concentrations of sodium chloride and sodium acetate. 
     The brine solution, once formed, can be used to recharge zirconium phosphate in a zirconium phosphate sorbent module. The brine solution can replace cations that were bound to the zirconium phosphate during dialysis treatment with sodium and hydrogen ions. The final ratio of sodium to hydrogen ions on the recharged zirconium phosphate is a function of the pH and sodium concentration of the brine solution. As such, the sodium/hydrogen ratio of the recharged zirconium phosphate can be controlled by controlling the pH and sodium concentration of the brine solution used in recharging. Acetic acid from acetic acid source  203  can be added to the recirculation flow path while the brine is being recirculated to adjust the pH of the brine solution. Acetic acid can be pumped from acetic acid source  203  through fluid line  210  into the sorbent recharger  202  for addition to the recirculating flow path. A control system (not shown) can control one or more pumps and one or more valves within the sorbent recharger  202  to generate a brine solution having a specified pH by adding a volume of acetic acid from the acetic acid source  203 . Using a known amount of sodium chloride and sodium acetate in salt canister  205  and adding a set amount of water from water source  201  can provide a known sodium concentration in the resulting brine solution. The amount of acetic acid added from acetic acid source  203  can be controlled by the control system to generate a brine solution having a desired pH. 
     To recharge the zirconium phosphate in a zirconium phosphate sorbent module, the control system can control one or more pumps (not shown) and/or valves (not shown) to pump the generated brine solution from brine container  204 , through fluid line  208 , into sorbent recharger  202  where the brine solution is passed through the zirconium phosphate sorbent module. 
     Table 1 shows a non-limiting example of a brine solution for recharging zirconium phosphate that can be made using the described salt canister system. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 ZP Recharge-Brine Solution Preparation 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Sodium 
                 Sodium Acetate, 
                 Acetic 
                   
               
               
                 Description 
                 chloride 
                 trihydrate 
                 Acid 
                 Water 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Conc M 
                 4.70 
                 0.40 
                 0.40 
                 N/A 
               
               
                 Mol wt 
                 58.50 
                 136.00 
                 60.05 
                 N/A 
               
            
           
           
               
               
            
               
                 Mix density  
                 1.19 
               
               
                 (kg/l) @25° C. 
                   
               
            
           
           
               
               
               
               
               
            
               
                 Individual density  
                 2.16 
                 1.45 
                 1.05 
                 1.00 
               
               
                 (kg/l) @25° C. 
                   
                   
                   
                   
               
            
           
           
               
               
            
               
                 Total Volume (L) 
                 6.20 
               
               
                 Total weight (kg) 
                 7.38 
               
            
           
           
               
               
               
               
               
            
               
                 Individual weight (kg) 
                 1.70 
                 0.34 
                 0.15 
                 5.19 
               
               
                 Individual volume (L) 
                 N/A 
                 N/A 
                 0.14 
                 5.20 
               
               
                   
               
            
           
         
       
     
     The brine solution described in Table 1 uses 5.20 L of water, which is added to a salt canister containing 1.70 kg of sodium chloride and 0.34 kg of sodium acetate trihydrate. 0.14 L of acetic acid can be added during generation of the brine solution, as described. The resulting brine solution has a sodium chloride concentration of 4.70 M, a sodium acetate concentration of 0.40 M, and an acetic acid concentration of 0.40 M. However, as described, brine solutions having a higher or lower pH can be generated by adding more or less acetic acid or sodium acetate. A person of ordinary skill in the art will understand that the ratio of sodium chloride to sodium acetate used can vary depending on the needs of the user. The sodium concentration of the brine solution can be controlled by using more or less sodium chloride and sodium acetate or by varying the volume of water added to the salt canister in forming the brine solution as would be understood by one of ordinary skill in the art. One or more conductivity sensors can be used to ensure complete dissolution and homogeneity. The conductivity of the generated brine solution will vary based on the concentrations of each solute. However, the conductivity of the solution shown in Table 1 should be within 180-240 mS/cm at 25° C. 
       FIGS. 3A-B  show a sorbent recharger  301  using a salt canister  302  as described.  FIG. 3A  is a front view of the sorbent recharger  301 , while  FIG. 3B  is a rear view of the sorbent recharger  301 . As illustrated in  FIG. 3A , the salt canister  302  can be fluidly connected to the sorbent recharger  301 . Water from a water source (not shown) can be pumped through an inlet  303  of the salt canister  302  containing sodium chloride and sodium acetate through fluid line  308 . The brine solution formed can exit the salt canister  302  through outlet  304  and flow through fluid line  306  into brine container  305 . The brine solution can be recirculated from the outlet  304  of the salt canister  302 , through fluid line  306  and into the brine container  305 , out of brine container  305  through fluid line  307  back to sorbent recharger  301 , and then back into the salt canister  302  through fluid line  308 . The brine solution can be recirculated in the flow path until a homogeneous solution is formed, or for a preset period of time. While the brine solution is recirculating, acetic acid from acetic acid source  309  can be pumped through fluid line  310  into sorbent recharger  301 , where the acetic acid is added to the recirculating brine solution. After a homogeneous brine solution is formed, the brine solution can be collected in brine container  305 . The salt canister  302  can be mounted in base frame  315  on table  316 , or by any other means known in the art. 
     The sorbent recharger  301  can include one or more receiving compartments for receiving reusable sorbent modules. As illustrated in  FIG. 3A , the sorbent recharger  301  includes a first receiving compartment  317  for receiving a zirconium phosphate sorbent module  318 . To recharge the zirconium phosphate in the zirconium phosphate sorbent module  318 , the generated brine solution in brine container  305  is pumped through the zirconium phosphate sorbent module  318 , replacing potassium, calcium, magnesium, and ammonium ions bound to the zirconium phosphate with sodium and hydrogen ions. 
     In certain embodiments, additional receiving compartments can be included. For example, the sorbent recharger  301  shown in  FIG. 3A  includes a second receiving compartment  320  for receiving a zirconium oxide sorbent module  319 . Additional chemicals can be included for recharging the zirconium oxide in zirconium oxide sorbent module  319 . To recharge zirconium oxide, a basic solution can be pumped through the zirconium oxide sorbent module  319 . Sodium hydroxide from sodium hydroxide source  311  can be pumped through fluid line  312  into sorbent recharger  301  and through the zirconium oxide sorbent module  319 . Bleach from bleach source  313  can be pumped through fluid line  314  into sorbent recharger  301  and through the zirconium oxide sorbent module  319  to disinfect the zirconium oxide sorbent module  319 . Alternatively, a sorbent recharger can include two receiving compartments to recharge two different zirconium phosphate sorbent modules. In any embodiment, the sorbent recharger  301  can include any number of receiving compartments for recharging any number of zirconium phosphate and/or zirconium oxide sorbent modules. 
     The sorbent recharger can include a graphical user interface  321  shown in  FIG. 3A  that can be used to control recharging of the sorbent materials. Through graphical user interface  321 , the user can initiate, stop, and otherwise control the preparation of the brine solution and the recharging process. Further, any errors, alerts, or other messages can be provided to the user through graphical user interface  321 . 
     As illustrated in  FIG. 3B , the sorbent recharger  301  can include fluid inlet port  322  for receiving a brine solution from brine container  305 , inlet port  324  for receiving acetic acid from acetic acid source  309 , inlet port  325  for receiving sodium hydroxide from sodium hydroxide source  311 , and inlet port  326  for receiving bleach from bleach source  313 . An additional inlet port (not shown) can be included for receiving water from a water source (not shown). The sorbent recharger  301  can also include outlet port  323  for pumping fluid to the salt canister  302 . Additional outlet ports, including outlet port  327 , outlet port  328 , and outlet port  329  can be included for connection to a drain, waste container, or collection container. 
     The salt canister  302  can connect to fluid lines  306  and  308  through any means known in the art. In  FIG. 3B , the connections are shown as quick connector  331 . A similar quick connector  330  can be used to connect bleach source  313  to fluid line  314 . One of skill in the art will understand that connectors can also be used for connecting any of the fluid sources to the fluid lines. Quick connectors allow fluid lines to be connected by snapping connectors on each line together. However, other connectors that can form fluid passages can be used. As described, the salt canister  302  can be mounted on the system using base frame  315 , or by any other method. In  FIGS. 3A-B , the sorbent recharger  301  is sized to fit on a table  316 . Larger sorbent rechargers can be used for recharging additional materials, as needed. An appropriate size of the sorbent recharger can be determined by one of ordinary skill in the art depending on the desired use case. 
       FIG. 4  shows a flow diagram for a recharger system using a salt canister. The salt canister  402  can include an inlet  403  with an upper part  404  extending upwardly into an interior of the salt canister  402 . Solid sodium chloride and solid sodium acetate can be placed in a lower portion  407  of the interior of salt canister  402 . Water from water source  423  can be pumped through water line  424  and port  425  into sorbent recharger  401 . As illustrated in  FIG. 4 , in certain embodiments the sorbent recharger  401  can use two pumps  421  and  422 . Using two pumps allows fluid from multiple sources to be mixed in-line rather than using mixing chambers. However, one of skill in the art will understand that a single pump system can also be used, or any number of suitable pumps with appropriate valve arrangements. From inlet port  425 , the water is pumped through fluid line  414  and T-junction  415  into fluid lines  416  and  417 . The water is pumped through T-junction  420  and fluid line  418  to port  419 . From port  419 , the water can flow through fluid line  438  and into an empty upper portion  406  of salt canister  402 . The water  405  can spray out of the upper part  404  of the inlet  403  to soak the salt and generate the brine solution. 
     The water can dissolve at least a portion of the sodium acetate and sodium chloride in salt canister  402  and exit the salt canister  402  through outlet  409  into fluid line  410  and brine container  411 . Filter pad  408  can be included between the sodium acetate and sodium chloride in the lower portion  407  of salt canister  402  to prevent solid material from entering fluid line  410 . The brine solution can be recirculated through the flow path from brine container  411 , through fluid line  412  and port  413  of the sorbent recharger  401  into fluid line  414 , where the brine solution follows the same pathway as the water back into salt canister  402 . During recirculation of the brine solution, acetic acid from acetic acid source  426  can be pumped through fluid line  427  and port  428  for addition to the brine solution recirculating in the flow path. Once the sodium acetate and sodium chloride are fully dissolved, the acetic acid is added, and a homogeneous brine solution is formed, the brine solution can be collected in brine container  411 . 
     To recharge zirconium phosphate, a zirconium phosphate sorbent module can be placed in a receiving compartment (not shown) of the sorbent recharger  401 . An inlet of the zirconium phosphate sorbent module can be connected to fluid line  414 , and an outlet of the zirconium phosphate sorbent module can be fluidly connected to a drain or collection container (not shown). The control system can operate pump  421  and/or pump  422  to pump brine solution from brine container  411  through the zirconium phosphate sorbent module. 
     As described, in certain embodiments, the sorbent recharger  401  can include a receiving compartment for receiving a zirconium oxide sorbent module (not shown). To recharge zirconium oxide in a zirconium oxide sorbent module, bleach can be pumped from bleach container  429 , through fluid line  430  to port  431 . A separate flow path can direct the bleach solution through the zirconium oxide sorbent module to a drain or collection container. Sodium hydroxide from sodium hydroxide container  432  can be pumped through fluid line  433  and port  434 , and then through the zirconium oxide sorbent module. Additional outlet ports can be included on the sorbent recharger  401 , including outlet port  435 , outlet port  436 , and outlet port  437  for connection to waste collection containers, drains, or other components. 
     One of skill in the art will understand that  FIG. 4  is a simplified diagram of a non-limiting embodiment of a sorbent recharger  401 . Additional components, such as valves, sensors, additional pumps, and additional fluid lines can be included, as necessary. The control system can be programmed to control the pumps and valves to direct fluid through the proper flow paths for generating the brine solution and recharging the sorbent materials. 
     The described systems and methods allow for a “just in time” brine preparation. Rather than storing large quantities of premade brine solution, the salt canister system allows for preparation of the brine solution immediately before use. The time required to generate the brine solution using a salt canister can vary, but generally the generation of the brine solution will be under 1 hour, or about 45 minutes. 
     One skilled in the art will understand that various combinations and/or modifications and variations can be made in the described systems and methods depending upon the specific needs for operation. Various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. Moreover, features illustrated or described as being part of an aspect of the disclosure may be used in the aspect of the disclosure, either alone or in combination, or follow a preferred arrangement of one or more of the described elements. Depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., certain described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as performed by a single module or unit for purposes of clarity, the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a medical device.