Abstract: An ocean alkalinity enhancement (OAE) system that reduces atmospheric CO2 and mitigates ocean acidification by electrochemically processing feedstock solution (e.g., seawater or brine) to generate an alkalinity product that is then supplied to the ocean. The OAE system includes a base-generating device and a control circuit disposed within a modular system housing deployed near a salt feedstock. The base-generating device (e.g., a bipolar electrodialysis (BPED) system) generates a base substance that is then used to generate the ocean alkalinity product. The control circuit controls the base-generating device such that the alkalinity product is supplied to the ocean only when (1) sufficient low/zero-carbon electricity is available, (2) it is safe to operate the base-generating device, and (3) supplying the alkalinity product will not endanger sea life.

Abstract: A device and process for the separate removal of oppositely charged ions from electrolyte solutions and recombining them to form new chemical compositions. The invention provides the ability to create multiple ion flow channels and then form new chemical compositions therefrom. The process is accomplished by selectively combining oppositely charged ions of choice from different electrolyte solutions via the capacitive behavior of high electrical capacitance electrodes confined in insulated containers. Industrial plants employing the inventive process can have the flexibility to produce needed industrial chemical compounds such as Soda Ash, Caustic Soda, hydrochloric acid and chlorine gas, based on market demand, and can be located near points of consumption to significantly reduce transportation costs.

Abstract: An ion suppressor includes ion exchange membranes between a pair of electrodes. Regeneration liquid channels are provided in the spaces between the electrodes and the ion exchange membranes, and an eluent channel is provided between the ion exchange membranes. Ion re-exchange in the eluent on the downstream side of the eluent channel is suppressed, thereby making it possible to improve the detection sensitivity for the ion to be measured. For example, the eluent channel has a folded structure, thereby increasing the amount of current on the downstream side of the eluent channel, and thus, the accumulation of ions is suppressed, and accordingly, ion re-exchange in the eluent can be suppressed.

Abstract: An ion suppressor includes ion exchange membranes between a pair of electrodes. Regeneration liquid channels are provided in the spaces between the electrodes and the ion exchange membranes, and an eluent channel is provided between the ion exchange membranes. In the space between the electrode and the eluent channel, an element that increases the resistance in the voltage application direction is disposed. For example, ion permeable membranes are disposed in contact with the ion exchange membrane, thereby increasing the resistance in the voltage application direction.

Abstract: A device and process for using the device are provided for the production of commodity, specialty, performance or fine chemicals by redox enzyme systems which require the addition of reducing equivalents. The device allows operating conditions to be conveniently altered to achieve maximal electrochemical efficiencies for a given enzymatically mediated redox reaction or series of reactions.

Abstract: Bioelectrochemical systems (BES) having configurations with spiral wound structures and with frame-and-plate structures are provided. Systems may allow for production of an electrical current that is at least partially generated by anodophilic microorganisms connected directly or indirectly to an electrode. A spiral wound or frame-and-plate type bioelectrochemical system may include an anolyte influent point, a catholyte influent point, electrodes, ion selective membranes, mesh separators, gas collection devices, an exterior containment vessel, and one or more external electrical devices.

Abstract: The present invention relates to a process for purifying, such as salt/ion depletion, and/or ash reduction, and/or sulphur removal, and/or free sugar depletion, and/or VOC depletion or fractionating, preferably by using dewatering, of a slurry comprising a lignin or lignin derivative or a combination thereof. A lignin or lignin derivative obtainable from said process and uses thereof are also disclosed.

Abstract: A device and process for the separate removal of oppositely charged ions from electrolyte solutions and recombining them to form new chemical compositions. The invention provides the ability to create multiple ion flow channels and then form new chemical compositions therefrom. The process is accomplished by selectively combining oppositely charged ions of choice from different electrolyte solutions via the capacitive behavior of high electrical capacitance electrodes confined in insulated containers. Industrial plants employing the inventive process can have the flexibility to produce needed industrial chemical compounds such as Soda Ash, Caustic Soda, hydrochloric acid and chlorine gas, based on market demand, and can be located near points of consumption to significantly reduce transportation costs.

Abstract: An apparatus for removal of ions from water having: a carbon coated first current collector; a second current collector; a spacer in between the first and second current collectors to allow water to flow in between the first and second current collectors; a first charge barrier in between the first carbon coated current collector and the spacer to selectively allow anions or cations to flow through the first charge barrier. The apparatus may have a second charge barrier coated on the carbon coated first current collector and in contact with the first charge barrier to improve contact. A third charge barrier functioning as a membrane may be provided in between the second current collector and the spacer.

Abstract: Ion Concentration Polarization (ICP) purification devices and methods for building massively-parallel implementations of the same, said devices being suitable for separation of salts, heavy metals and biological contaminants from source water.

Abstract: Certain embodiments disclosed herein pertain to methods and apparatus for electrodepositing material on a substrate. More particularly, a novel membrane for separating the anode from the cathode/substrate, and a method of using such a membrane are presented. The membrane includes at least an ion exchange layer and a charge separation layer. The disclosed embodiments are beneficial for maintaining relatively constant concentrations of species in the electrolyte over time, especially during idle (i.e., non-electroplating) times.

Abstract: An energy storage system employing a reversible salination-desalination process includes an electrochemical desalination battery (EDB) unit including an anode and a cathode. The EDB unit runs a salination process while storing energy from a direct current power supply unit, and runs a desalination process while releasing energy to an electrical load. The energy storage system can store power from a variable output electrical power supply unit such as solar cells and wind turbines while running a salination process, and release energy, e.g., during peak energy demand hours while running a desalination process. Combined with a capacitive deionization (CD) unit, the energy storage system can generate fresh water by running desalination processes in the EDB unit and the CD unit while releasing stored energy from the EDB unit. The energy storage unit can function as a dual purpose device for energy storage and fresh water generation.

Abstract: A rechargeable battery is provided such that the positive electrode comprises graphite, the negative electrode also comprises graphite, and the electrolyte is a solution of lithium bromide in a lactone.

Abstract: An electrochemical device converts carbon dioxide to a reaction product. The device includes an anode and a cathode, each comprising a quantity of catalyst. The anode and cathode each has reactant introduced thereto. A polymer electrolyte membrane is interposed between the anode and the cathode. At least a portion of the cathode catalyst is directly exposed to gaseous carbon dioxide during electrolysis. The average current density at the membrane is at least 20 mA/cm2, measured as the area of the cathode gas diffusion layer that is covered by catalyst, and CO selectivity is at least 50% at a cell potential of 3.0 V. In some embodiments, the polymer electrolyte membrane comprises a polymer in which a constituent monomer is (p-vinylbenzyl)-R, where R is selected from the group consisting of imidazoliums, pyridiniums and phosphoniums. In some embodiments, the polymer electrolyte membrane is a Helper Membrane comprising a polymer containing an imidazolium ligand, a pyridinium ligand, or a phosphonium ligand.

Abstract: Described herein are a method and system for desalinating saltwater using concentration difference energy. A “five stream” dialytic stack is described that can be used to desalinate saltwater at a relatively high recovery ratio. The dialytic stack may include, for example, one or more drive cells having a paired concentrate and a diluent-c chamber in ionic communication with a product chamber that is adjacent to an anion and a cation discharge chamber each filled with diluent-p. The drive cell applies a drive voltage across the product chamber, and when the drive voltage exceeds a desalination voltage of the product chamber, the saltwater in the product chamber is desalinated. The dialytic stack may accept brine discharged from a first desalination plant as saltwater to be desalinated. Processing the brine in the dialytic stack may decrease its volume, decreasing costs associated with treating or otherwise disposing of the brine.

Abstract: A low energy water treatment system and method is provided. The system has at least one electrodialysis device that produces partially treated water and a brine byproduct, a softener, and at least one electrodeionization device. The partially treated water stream can be softened by the softener to reduce the likelihood of scale formation and to reduce energy consumption in the electrodeionization device, which produces water having target properties. At least a portion of the energy used by the electrodeionization device can be generated by concentration differences between the brine and seawater streams introduced into compartments thereof. The brine stream can also be used to regenerate the softener.

Abstract: Electrochemical devices and methods for water treatment are disclosed. An electrodeionization device (100) may include one or more compartments (110) containing an ionselective media, such as boron-selective resin (170). Cyclic adsorption of target ions and regeneration of the media in-situ is used to treat process water, and may be driven by the promotion of various pH conditions within the electrochemical device.

Abstract: The present disclosure is directed at an apparatus, method and plant for desalinating saltwater and contaminated saltwater. The apparatus includes a stack and a manifolding assembly. The stack includes a product chamber, a first and second concentrate chamber, an anion exchange membrane forming a boundary between the first concentrate chamber and the product chamber and a cation exchange membrane forming a boundary between the second concentrate chamber and the product chamber. The manifolding assembly includes product and concentrate manifolding fluidly coupled to the product and concentrate chambers respectively, to convey a saltwater being desalinated to and away from the product chamber, and a concentrate to and away from the concentrate chambers. The stack may include a diluent chamber and adjacent anion or cation exchange membranes between the product chamber, diluent chamber and concentrate chamber to respectively convey anions or cations across multiple chambers.

Abstract: A process for producing ultrapure water, in which a stream of water is purified in a reverse osmosis device, wherein the water stream is subject to pretreatment including splitting the water stream into at least two partial streams, partial exchange of cations present in at least one of the partial streams for H+ ions by a cation exchanger operated in the H+ mode, and complete exchange of the anions present in at least one further of the partial streams for OH? ions by a softener operative in parallel to the cation exchanger, and treating the partial streams treated by the cation exchanger and the softener by at least one anion exchanger operating in the OH? mode, and wherein the water stream obtained from the pretreatment is fed into the reverse osmosis device.

Abstract: A desalination system comprises a silica removal unit. The silica removal unit comprises first and second electrodes, a plurality of ion exchange membranes disposed between the first and second electrodes and a plurality of spacers disposed between adjacent ion exchange membranes and between the first and second electrodes and the respective ion exchange membranes. The plurality of the ion exchange membranes comprises a pair of cation exchange membranes and a pair of anion exchange membranes disposed between the pair of cation exchange membranes. A first channel is defined between the anion exchange membranes and second and third channels are defined between each anion exchange membrane and an adjacent cation exchange membrane. A silica removal apparatus and a desalination method are also presented.

Abstract: The present invention provides a resin-wafer electrodeionization (RW-EDI) apparatus including cathode and anode electrodes separated by a plurality of porous solid ion exchange resin wafers, which when in use are filled with an aqueous fluid. The apparatus includes one or more wafers comprising a basic ion exchange medium, and preferably includes one or more wafers comprising an acidic ion exchange medium. The wafers are separated from one another by ion exchange membranes. The fluid within the acidic and/or basic ion exchange wafers preferably includes, or is in contact with, a carbonic anhydrase (CA) enzyme to facilitate conversion of bicarbonate ion to carbon dioxide within the acidic medium. A pH suitable for exchange of CO2 is electrochemically maintained within the basic and acidic ion exchange wafers by applying an electric potential across the cathode and anode.

Abstract: A liquid electrolyte can be desalinated and purified using a system that includes a first electrode and a configuration selected from (a) a second electrode and at least one distinct ion-selective boundary and (b) a second electrode that also serves as the ion-selective boundary. The ion-selective boundary is contained in the liquid conduit adjacent to a porous medium that defines pore channels filled with the liquid and that have a surface charge, and the charge of the ion-selective boundary and the surface charge of the pore channels share the same sign. A liquid including at least one charged species flows through the pore channels, forming a thin diffuse electrochemical double layer at an interface of the liquid and the charged surface of the pore channels.

Abstract: An apparatus, method and plant for desalinating saltwater and contaminated saltwater. The apparatus includes a stack and a manifolding assembly. The stack includes a product chamber, a first and second concentrate chamber, an anion exchange membrane forming a boundary between the first concentrate chamber and the product chamber and a cation exchange membrane forming a boundary between the second concentrate chamber and the product chamber. The manifolding assembly includes product and concentrate manifolding fluidly coupled to the product and concentrate chambers respectively, to convey a saltwater being desalinated to and away from the product chamber, and a concentrate to and away from the concentrate chambers. The stack may include a diluent chamber and adjacent anion or cation exchange membranes between the product chamber, diluent chamber and concentrate chamber to respectively convey anions or cations across multiple chambers.

Abstract: A device and process are disclosed for the separate removal of oppositely charged ions from electrolyte solutions and recombining them to form new chemical compositions. The invention provides the ability to create multiple ion flow channels and then form new chemical compositions therefrom. The process is accomplished by selectively combining oppositely charged ions of choice from different electrolyte solutions via the capacitive behavior of high electrical capacity electrodes confined in insulated containers.

Abstract: A device according to one embodiment includes a porous membrane having a surface charge and pore configuration characterized by a double layer overlap effect being present in pores of the membrane. A device according to another embodiment includes a porous membrane having a surface charge in pores thereof sufficient to impart anion or cation selectivity in the pores. Additional devices, systems and methods are also presented.

Abstract: An embodiment is a method and apparatus to provide de-ionization. A plurality of cylindrical-shaped conductive membranes are placed in a feed channel having a feed flow with a first flow direction. Each of the conductive membranes encloses a concentration channel having a second flow direction and an electrode positioned inside the conductive membrane. A voltage distribution network coupled to the conductive membranes provides independent voltages across the channels to cause movement of ions in the feed and concentration flows toward the electrode.

Abstract: A continuous electrochemical pump comprising a water generator compartment, an anode compartment on one side of said generator compartment, a cation exchange barrier, separating the generator compartment from the anode compartment, it first electrode in electrical communication with the anode compartment, a cathode compartment adjacent the generator chamber, an anion exchange barrier, separating the generation compartment from the cathode compartment, and a second electrode in electrical communication with the cathode compartment. Use of the pump as a sample concentrator. A feedback loop for the pump. A reservoir, with or without an intermediate piston, on the output side of the pump.

Abstract: Electrochemical devices and methods for water treatment are disclosed. An electrodeionization device (100) may include one or more compartments (110) containing an ionselective media, such as boron-selective resin (170). Cyclic adsorption of target ions and regeneration of the media in-situ is used to treat process water, and may be driven by the promotion of various pH conditions within the electrochemical device.

Abstract: A capacitive deionization device includes; at least one flow path configured to receive influent fluid, at least one pair of electrodes, at least one charge barrier disposed between the at least one flow path and a corresponding electrode of the at least one pair of electrodes, at least one electrolyte solution disposed between at least one of the at least one pair of electrodes and a corresponding charge barrier of the at least one charge barrier, and at least one electrolyte compensation device in fluid communication with the at least one electrolyte solution, wherein the at least one electrolyte solution differs from the influent fluid.

Abstract: Buffer generators are described based on electrodialytic devices. The methods of using these devices can generate buffers for diverse applications, including separations, e.g., HPLC and ion chromatography. Also provided are chromatographic devices including the buffer generators, generally located upstream from a chromatography column, sample injector valve or both.

Abstract: A coagulation generating system that combines the advantages of conventional and electrocoagulation. In the coagulation generating system electro-coagulation is performed on an input (e.g., salt/brine) solution to generate a concentrated coagulant solution, which is then added to the source water in the same way as a standard stored chemical coagulant.

Abstract: An apparatus and method for abating scale formation during the purification and demineralization of water in an electrochemical deionization apparatus. In the apparatus and method, scale forming ions in a raw water feed are precipitated at a controlled location remote from the deionization chambers of the deionization apparatus. Concentrate water produced during the deionization process to produce demineralized product water is acidified and circulated through the deionization apparatus to prevent scale formation and build-up in the deionization apparatus.

Abstract: An embodiment is a method and apparatus to provide de-ionization. First and second conductive porous membranes are placed between a feed channel having a feed flow and first and second concentration channels having first and second concentration flows to separate the feed channel from the concentration channels. Cathode and anode electrodes are placed on external sides of the concentration channels. A voltage supply distribution network provides independent voltages across the channels to cause movement of ions in the feed and concentration flows toward the electrodes.

Abstract: In one embodiment, this invention relates to an electrodialysis device comprising an inlet for directing a feed stream into a plurality of first feed paths and a plurality of second feed paths; the feed stream is comprised of a first anionic scaling species and a first cationic scaling species; the first cationic scaling species is transferred from the second feed paths to the first feed paths through a first membrane group, the first anionic scaling species is transferred from the first feed paths to the second feed paths through the first membrane group. In another embodiment, this invention relates to a method for passivating scaling species in an electrodialysis device.

Abstract: An electrodialytic buffer generator is described. The buffer generator may include a central buffer-generating channel having an inlet and outlet, a second chamber, and a third chamber. The buffer-generating channel, the second chamber, and the third chamber may each include an electrode. The buffer generator may also include a first ion exchange barrier and a second ion exchange barrier. The first ion exchange barrier can be disposed between the second chamber and the buffer-generating channel. The second ion exchange barrier can be disposed between the third chamber and the buffer-generating channel.

Abstract: To provide an electrolyte membrane having excellent dimensional stability even upon absorption of water, a high proton conductance and high power generation performance; and a process for producing the electrolyte membrane with a high productivity. An electrolyte membrane for polymer electrolyte fuel cells, which is made mainly of an ion exchange resin and reinforced with a nonwoven fabric made of fiber of a fluororesin wherein at least some of intersecting points of the fiber are fixed, and which has, as the outermost layer on one side or each side, a layer not reinforced, made of an ion exchange resin which may be the same as or different from the above ion exchange resin, wherein the fluororesin is an ethylene/tetrafluoroethylene copolymer having a melting point of at most 240° C., and the above fixing is fixing by fusion of the fiber.

Abstract: The present disclosure is directed at a modular apparatus for a saltwater desalinating system, and a method for using same. The apparatus includes multiple internal modules that are compressively coupled to each other. Each of the internal modules includes a pair of rigid end plates located at opposing ends of the internal module, and a stack of membrane bounded compartments that are layered from one of the end plates to the other. The modular apparatus can be used in a membrane based desalination system, which includes concentration difference energy systems, electrodialysis reversal systems, and membrane distillation systems. The modular apparatus helps to mitigate problems such as leakage and buckling in such systems, and can be used to increase membrane packing density and, accordingly, desalination efficiency.

Abstract: A method and system are described to treat ammonia-containing wastewater or process waters. Sewage containing human or animal waste and certain process liquids, typically water, contains high levels of nitrogen in the form of ammonia. An electro-chemical method to extract the ammonia from the wastewater is also described. The system described is one implementation of this method. One or more electrolysis cells convert ammonium to ammonia where the generated ammonia gas can readily be extracted for disposal or reuse. Such a system can involve electrolysis cells of numerous types as described herein.

Abstract: Described herein are a method and system for desalinating saltwater using concentration difference energy. A “five stream” dialytic stack is described that can be used to desalinate saltwater at a relatively high recovery ratio. The dialytic stack may include, for example, one or more drive cells having a paired concentrate and a diluent-c chamber in ionic communication with a product chamber that is adjacent to an anion and a cation discharge chamber each filled with diluent-p. The drive cell applies a drive voltage across the product chamber, and when the drive voltage exceeds a desalination voltage of the product chamber, the saltwater in the product chamber is desalinated. The dialytic stack may accept brine discharged from a first desalination plant as saltwater to be desalinated. Processing the brine in the dialytic stack may decrease its volume, decreasing costs associated with treating or otherwise disposing of the brine.

Abstract: Described herein are a method and system for desalinating saltwater using concentration difference energy. A “five stream” dialytic stack is described that can be used to desalinate saltwater at a relatively high recovery ratio. The dialytic stack may include, for example, one or more drive cells having a paired concentrate and a diluent-c chamber in ionic communication with a product chamber that is adjacent to an anion and a cation discharge chamber each filled with diluent-p. The drive cell applies a drive voltage across the product chamber, and when the drive voltage exceeds a desalination voltage of the product chamber, the saltwater in the product chamber is desalinated. The diluent-p may be at a lower ionic concentration than the diluent-c, which may be at a lower concentration than the concentrate.

Abstract: A method for recovering and extracting lithium from a feed liquid that may have a mixture of lithium and non-lithium salts present in the feed liquid. Salts of varying solubility are precipitated out of the feed liquid using water evaporation or other techniques. Pure lithium hydroxide is obtained using electrolysis or electro-dialysis processes in combination with a lithium ion selective inorganic membrane such as LiSICON. The negative effect of sodium and potassium on the lithium ion selective inorganic membrane is reduced by reversing the polarity of the current placed across the membrane.

Abstract: A method and apparatus for desalinating saltwater using concentration difference energy is disclosed. In order to desalinate saltwater that is contained within a product chamber, a drive cell is used to generate a drive voltage. The product chamber has a desalination voltage such that when a sufficient voltage is applied to the product chamber, anions and cations migrate out of the product chamber, thereby desalinating the water. The sufficient voltage, which includes the drive voltage and which is equal to or greater than the desalination voltage, is applied to the product chamber, consequently effecting desalination. Beneficially, concentration difference energy can be generated using a concentrated solution, which can be generated using, for example, solar energy.

Abstract: A continuous electrochemical pump comprising a water generator compartment, an anode compartment on one side of said generator compartment, a cation exchange barrier, separating the generator compartment from the anode compartment, a first electrode in electrical communication with the anode compartment, a cathode compartment adjacent the generator chamber, an anion exchange barrier, separating the generation compartment from the cathode compartment, and a second electrode in electrical communication with the cathode compartment. Use of the pump as a sample concentrator. A feedback loop for the pump. A reservoir, with or without an intermediate piston, on the output side of the pump.

Abstract: The invention relates to a composite or a composite membrane consisting of an ionomer and of an inorganic optionally functionalized phyllosilicate. The isomer can be: (a) a cation exchange polymer; (b) an anion exchange polymer; (c) a polymer containing both anion exchanger groupings as well as cation exchanger groupings on the polymer chain; or (d) a blend consisting of (a) and (b), whereby the mixture ratio can range from 100% (a) to 100% (b). The blend can be ionically and even covalently cross-linked. The inorganic constituents can be selected from the group consisting of phyllosilicates or tectosilicates.

Abstract: The present disclosure is directed at a modular apparatus for a saltwater desalinating system, and a method for using same. The apparatus includes multiple internal modules that are compressively coupled to each other. Each of the internal modules includes a pair of rigid end plates located at opposing ends of the internal module, and a stack of membrane bounded compartments that are layered from one of the end plates to the other. The modular apparatus can be used in a membrane based desalination system, which includes concentration difference energy systems, electrodialysis reversal systems, and membrane distillation systems. The modular apparatus helps to mitigate problems such as leakage and buckling in such systems, and can be used to increase membrane packing density and, accordingly, desalination efficiency.

Abstract: An electrochemical cell for producing copper having a dense graphite anode electrode and a dense graphite cathode electrode disposed in a CuCl solution. An anion exchange membrane made of poly(ethylene vinyl alcohol) and polyethylenimine cross-linked with a cross-linking agent selected from the group consisting of acetone, formaldehyde, glyoxal, glutaraldehyde, and mixtures thereof is disposed between the two electrodes.

Abstract: A wastewater treatment process and wastewater treatment device for generating current and desalting simultaneously are provided. The device may comprise an anode compartment, an anion exchange membrane, a middle desalting compartment, a cation exchange membrane and a cathode compartment. Wastewater flows into the anode compartment, and is oxidized under the action of an electricigenic microbe. In the desalting compartment, anions are transferred to the anode compartment through the anion exchange membrane, and cations are transferred to the cathode compartment through the cation exchange membrane, thus achieving a desalting process and forming an internal current. Electrons are transferred to the cathode through an external circuit such that a reduction reaction takes place and a current generation is achieved. The wastewater treatment, the current generation and the desalination are achieved simultaneously in the process.

Abstract: A deionization device including at least one flow path configured for an influent fluid; at least one pair of electrodes; at least one charge barrier disposed between the at least one flow path and a corresponding electrode of the at least one pair of electrodes; and at least one electrolyte solution disposed between at least one electrode of the at least one pair of electrodes and a corresponding charge barrier of the at least one charge barrier, wherein at least one electrode of the at least one pair of electrodes includes an electrochemical redox active material, and the at least one electrolyte solution and the influent fluid are different.

Abstract: A device according to one embodiment includes a porous membrane having a surface charge and pore configuration characterized by a double layer overlap effect being present in pores of the membrane. A device according to another embodiment includes a porous membrane having a surface charge in pores thereof sufficient to impart anion or cation selectivity in the pores.

Abstract: Described herein are a method and system for desalinating saltwater using concentration difference energy. A “five stream” dialytic stack is described that can be used to desalinate saltwater at a relatively high recovery ratio. The dialytic stack may include, for example, one or more drive cells having a paired concentrate and a diluent-c chamber in ionic communication with a product chamber that is adjacent to an anion and a cation discharge chamber each filled with diluent-p. The drive cell applies a drive voltage across the product chamber, and when the drive voltage exceeds a desalination voltage of the product chamber, the saltwater in the product chamber is desalinated. The diluent-p may be at a lower ionic concentration than the diluent-c, which may be at a lower concentration than the concentrate.