Filtration - wikipedia Filtration This article is about operation of solid - fluid separation. For the mathematical concept, see filtration ( mathematics ). For the equipment used, see Filter ( disambiguation ). For filtration used in winemaking, see Filtration ( wine ). Diagram of simple filtration : oversize particles in the feed can not pass through the lattice structure of the filter, while fluid and small particles pass through, becoming filtrate. Filtration is any of various mechanical, physical or biological operations that separate solids from fluids ( liquids or gases ) by adding a medium through which only the fluid can pass. The fluid that passes through is called the filtrate. In physical filters oversize solids in the fluid are retained and in biological filters particulates are trapped and ingested and metabolites are retained and removed. However, the separation is not complete ; solids will be contaminated with some fluid and filtrate will contain fine particles ( depending on the pore size, filter thickness and biological activity ). Filtration occurs both in nature and in engineered systems ; there are biological, geological, and industrial forms. For example, in animals ( including humans ), renal filtration removes wastes from the blood, and in water treatment and sewage treatment, undesirable constituents are removed by absorption into a biological film grown on or in the filter medium, as in slow sand filtration. Contents 1 Applications 2 Methods 3 Filter media 3.1 Achieving flow through the filter 3.2 Filter aid 4 Alternatives 5 Examples 6 See also 7 References Applications Filtration is used to separate particles and fluid in a suspension, where the fluid can be a liquid, a gas or a supercritical fluid. Depending on the application, either one or both of the components may be isolated. Filtration, as a physical operation is very important in chemistry for the separation of materials of different chemical composition. A solvent is chosen which dissolves one component, while not dissolving the other. By dissolving the mixture in the chosen solvent, one component will go into the solution and pass through the filter, while the other will be retained. This is one of the most important techniques used by chemists to purify compounds. Filtration is also important and widely used as one of the unit operations of chemical engineering. It may be simultaneously combined with other unit operations to process the feed stream, as in the biofilter, which is a combined filter and biological digestion device. Filtration differs from sieving, where separation occurs at a single perforated layer ( a sieve ). In sieving, particles that are too big to pass through the holes of the sieve are retained ( see particle size distribution ). In filtration, a multilayer lattice retains those particles that are unable to follow the tortuous channels of the filter. Oversize particles may form a cake layer on top of the filter and may also block the filter lattice, preventing the fluid phase from crossing the filter ( blinding ). Commercially, the term filter is applied to membranes where the separation lattice is so thin that the surface becomes the main zone of particle separation, even though these products might be described as sieves. Filtration differs from adsorption, where it is not the physical size of particles that causes separation but the effects of surface charge. Some adsorption devices containing activated charcoal and ion exchange resin are commercially called filters, although filtration is not their principal function. Filtration differs from removal of magnetic contaminants from fluids with magnets ( typically lubrication oil, coolants and fuel oils ), because there is no filter medium. Commercial devices called ' magnetic filters ' are sold, but the name reflects their use, not their mode of operation. Methods There are many different methods of filtration ; all aim to attain the separation of substances. Separation is achieved by some form of interaction between the substance or objects to be removed and the filter. The substance that is to pass through the filter must be a fluid, i.e. a liquid or gas. Methods of filtration vary depending on the location of the targeted material, i.e. whether it is dissolved in the fluid phase or suspended as a solid. Hot Filtration, solution contained in the Erlenmeyer flask is heated on a hot plate in order to prevent re-crystallization of solids in the flask itself There are several filtration techniques depending on the desired outcome namely, hot, cold and vacuum filtration. Some of the major purposes of getting the desired outcome are, for the removal of impurities from a mixture or, for the isolation of solids from a mixture. Hot Filtration for the separation of solids from a hot solution Hot filtration method is mainly used to separate solids from a hot solution. This is done in order to prevent crystal formation in the filter funnel and other apparatuses that comes in contact with the solution. As a result, the apparatus and the solution used are heated in order to prevent the rapid decrease in temperature which in turn, would lead to the crystallization of the solids in the funnel and hinder the filtration process. One of the most important measures to prevent the formation of crystals in the funnel and to undergo effective hot filtration is the use stemless filter funnel. Due to the absence of stem in the filter funnel, there is a decrease in the surface area of contact between the solution and the stem of the filter funnel, hence preventing re-crystallization of solid in the funnel, adversely affecting filtration process. Cold Filtration, the ice bath is used to cool down the temperature of the solution before undergoing the filtration process Cold Filtration method is the use of ice bath in order to rapidly cool down the solution to be crystallized rather than leaving it out to cool it down slowly in the room temperature. This technique results to the formation of very small crystals as opposed to getting large crystals by cooling the solution down at room temperature. Vacuum Filtration technique is most preferred for small batch of solution in order to quickly dry out small crystals. This method requires a Büchner funnel, filter paper of smaller diameter than the funnel, Büchner flask, and rubber tubing to connect to vacuum source. Filter media Two main types of filter media are employed in laboratories : a surface filter, a solid sieve which traps the solid particles, with or without the aid of filter paper ( e.g. Büchner funnel, Belt filter, Rotary vacuum - drum filter, Cross-flow filters, Screen filter ) ; and a depth filter, a bed of granular material which retains the solid particles as it passes ( e.g. sand filter ). The first type allows the solid particles, i.e. the residue, to be collected intact ; the second type does not permit this. However, the second type is less prone to clogging due to the greater surface area where the particles can be trapped. Also, when the solid particles are very fine, it is often cheaper and easier to discard the contaminated granules than to clean the solid sieve. Filter media can be cleaned by rinsing with solvents or detergents. Alternatively, in engineering applications, such as swimming pool water treatment plants, they may be cleaned by backwashing. Self - cleaning screen filters utilize point - of - suction backwashing to clean the screen without interrupting system flow. Achieving flow through the filter Fluids flow through a filter due to a difference in pressure -- fluid flows from the high - pressure side to the low - pressure side of the filter, leaving some material behind. The simplest method to achieve this is by gravity and can be seen in the coffeemaker example. In the laboratory, pressure in the form of compressed air on the feed side ( or vacuum on the filtrate side ) may be applied to make the filtration process faster, though this may lead to clogging or the passage of fine particles. Alternatively, the liquid may flow through the filter by the force exerted by a pump, a method commonly used in industry when a reduced filtration time is important. In this case, the filter need not be mounted vertically. Filter aid Certain filter aids may be used to aid filtration. These are often incompressible diatomaceous earth, or kieselguhr, which is composed primarily of silica. Also used are wood cellulose and other inert porous solids such as the cheaper and safer perlite. These filter aids can be used in two different ways. They can be used as a precoat before the slurry is filtered. This will prevent gelatinous - type solids from plugging the filter medium and also give a clearer filtrate. They can also be added to the slurry before filtration. This increases the porosity of the cake and reduces resistance of the cake during filtration. In a rotary filter, the filter aid may be applied as a precoat ; subsequently, thin slices of this layer are sliced off with the cake. The use of filter aids is usually limited to cases where the cake is discarded or where the precipitate can be chemically separated from the filter. Alternatives Filtration is a more efficient method for the separation of mixtures than decantation, but is much more time consuming. If very small amounts of solution are involved, most of the solution may be soaked up by the filter medium. An alternative to filtration is centrifugation -- instead of filtering the mixture of solid and liquid particles, the mixture is centrifuged to force the ( usually ) denser solid to the bottom, where it often forms a firm cake. The liquid above can then be decanted. This method is especially useful for separating solids which do not filter well, such as gelatinous or fine particles. These solids can clog or pass through the filter, respectively. Examples Filter flask ( suction flask, with sintered glass filter containing sample ). Note the almost colourless filtrate in the receiver flask. Examples of filtration include The coffee filter to keep the coffee separate from the grounds. HEPA filters in air conditioning to remove particles from air. Belt filters to extract precious metals in mining. Horizontal plate filter, also known as Sparkler filter. Furnaces use filtration to prevent the furnace elements from fouling with particulates. Pneumatic conveying systems often employ filtration to stop or slow the flow of material that is transported, through the use of a baghouse. In the laboratory, a Büchner funnel is often used, with a filter paper serving as the porous barrier. An experiment to prove the existence of microscopic organisms involves the comparison of water passed through unglazed porcelain and unfiltered water. When left in sealed containers the filtered water takes longer to go foul, demonstrating that very small items ( such as bacteria ) can be removed from fluids by filtration. In the kidney, renal filtration is the filtration of blood in the glomerulus, followed by selective reabsorbtion of many substances essential for the body to maintain homeostasis. See also Separation process Category : Filters Separation of mixtures Microfiltration Ultrafiltration Nanofiltration Reverse osmosis Filter Crossflow filtration Sieve Sieve analysis References Look up filtration in Wiktionary, the free dictionary. Jump up ^ Article on `` Water treatment solution : Filtration '', retrieved on 15 October 2013 from http://www.lenntech.com/chemistry/filtration.htm Jump up ^ Lecture notes, Postgraduate course on Filtration and Size separation at the Department of Chemical Engineering, University of Lougborough, England Jump up ^ `` Filtration Methods '' ( PDF ). University of Calgary. University of Calgary. Retrieved 4 June 2015. Separation processes Processes Absorption Acid - base extraction Adsorption Chromatography Cross-flow filtration Crystallization Cyclonic separation Dialysis ( biochemistry ) Dissolved air flotation Distillation Drying Electrochromatography Electrofiltration Filtration Flocculation Froth flotation Gravity separation Leaching Liquid -- liquid extraction Electroextraction Microfiltration Osmosis Precipitation ( chemistry ) Recrystallization Reverse osmosis Sedimentation Solid phase extraction Sublimation Ultrafiltration Devices API oil - water separator Belt filter Centrifuge Depth filter Electrostatic precipitator Evaporator Filter press Fractionating column Leachate Mixer - settler Protein skimmer Rapid sand filter Rotary vacuum - drum filter Scrubber Spinning cone Still Sublimation apparatus Vacuum ceramic filter Multiphase systems Aqueous two - phase system Azeotrope Eutectic Concepts Unit operation Wastewater Sources Acid mine drainage Ballast water Bathroom Blackwater ( coal ) Blackwater ( waste ) Boiler blowdown Brine Combined sewer Cooling tower Cooling water Fecal sludge Greywater Infiltration / Inflow Industrial effluent Ion exchange Leachate Manure Papermaking Produced water Return flow Reverse osmosis Sanitary sewer Septage Sewage Sewage sludge Toilet Urban runoff Quality indicators Adsorbable organic halides Biochemical oxygen demand Chemical oxygen demand Coliform index Dissolved oxygen Heavy metals pH Salinity Temperature Total dissolved solids Total suspended solids Turbidity Treatment options Activated sludge Aerated lagoon Agricultural wastewater treatment API oil - water separator Carbon filtration Chlorination Clarifier Constructed wetland Decentralized wastewater system Extended aeration Facultative lagoon Fecal sludge management Filtration Imhoff tank Industrial wastewater treatment Ion exchange Membrane bioreactor Reverse osmosis Rotating biological contactor Secondary treatment Sedimentation Septic tank Settling basin Sewage sludge treatment Sewage treatment Sewer mining Stabilization pond Trickling filter Ultraviolet germicidal irradiation UASB Vermifilter Wastewater treatment plant Disposal options Combined sewer Evaporation pond Groundwater recharge Infiltration basin Injection well Irrigation Marine dumping Marine outfall Reclaimed water Sanitary sewer Septic drain field Sewage farm Storm drain Surface runoff Vacuum sewer NDL : 00569637 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Filtration&oldid=831830518 '' Categories : Analytical chemistry Laboratory techniques Alchemical processes Filtration Hidden categories : Use dmy dates from November 2017 Pages using div col with deprecated parameters Talk Contents About Wikipedia Bân - lâm - gú Català Čeština ChiShona Deutsch Eesti Ελληνικά Español Esperanto فارسی Français 한국어 Hrvatski Bahasa Indonesia Italiano עברית ქართული Kreyòl ayisyen Lietuvių Bahasa Melayu Nederlands 日本 語 ਪੰਜਾਬੀ Plattdüütsch Polski Português Română Русский Slovenčina Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Українська 粵語 中文 27 more Edit links This page was last edited on 22 March 2018, at 11 : 44. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: property of earth to allow water to pass through it is known as
Answer: Filtration