JP7305742B2 - Faradic porous cell - Google Patents

Description

Detailed description of the invention

[Background of the Invention]
(Field of Invention)
[001] The field of the invention is the production of metal ions, halide ions, metal and halide derivatives, and ionic particulate matter from solution by combining selected faradic reactions with carbon electrode pore size profiling. Removal, eg removal of lead from water.

[definition]
[002] "Adsorption" means attracting ions in an input stream to an electrode surface and retaining the ions on the electrode surface.

[003] "Flocculation" means removing metal ions, halide ions, metal or halide derivatives, or particulate metal from the input stream to a cell by one or more of the following: (ii) capacitive adsorption; (iii) electrochemical pH control and metal _{immobilization} ; (iv) electrochemical peroxide ( _H2O2 ) generation and metal oxidation; (v) electrodeposition. (vi) electrochemical oxidation or reduction; (vii) deposition; (viii) pore size profile, (ix) electrode treatment, (x) electrode spacing, and (xi) flow-by vs. flow-through vs. carbon block. cell design.

[004] "BET surface area" means surface area as determined by the Brunauer-Emmett-Teller method, a physisorption-based method that uses nitrogen to determine the surface area of a material.

[005] "Breakthrough curve" means the course of the adsorbed concentration of the effluent at the outlet of a stationary adsorber. The breakthrough curve allows calculation of the technically usable sorption capacity. A breakthrough curve typically plots target species concentration versus treated volume. For example, see FIG.

[006] A "carbon block" is an extruded carbon material in which carbon particles are combined with a polymer into a bulk solid form. Typically used for dechlorination and particulate filters. In the design of carbon block cells used in FPCs, each of the one or more pure carbon blocks is typically split into two electrically isolated halves in the FPC; one half of each block is used as the anode and the other half of each block is used as the cathode.

[007] "Capacitive adsorption" means the adsorption of ions or other charged species to an electrode as a result of electrical attraction.

[008] A "CCC" or "capacitive coagulation cell" or "CCC device" primarily uses capacitive adsorption to transfer metal ions, metal derivatives, or particulate metals to a liquid (typically aqueous) input. means a purification cell that removes from a stream and produces an output stream with a metal, metal derivative, or particulate content below government regulated limits. For example, the US EPA specifies a lead content of 15 ppb as an "action level" for drinking or irrigation water.

[009] "CCC parameters" means user-selected FPC parameters in a CCC.

[0010] "Cell" generally means a plurality of electrodes exposed to an input stream (inflow), an outlet for an output stream (outflow) during operation, a shorting switch or power source attached to the electrodes, Manual or computerized means for controlling the power supply and any inlet valves, and sensors for monitoring the operation of the cell and interfacing with the manual or computerized control means. The cell may optionally include further means of controlling the input and output streams, for example to select various output stream collection vessels or other arrangements during operation of the cell. Unlike capacitive deionization cells, FPCs do not regenerate electrodes (also called desorption) during operation to produce a waste stream of desorbed target species. Alternatively, for example, the FPC containing CCC or EDC is replaced if the concentration of the target species in the output stream exceeds a user-selected threshold. Exchange criteria other than the target species concentration in the output stream may be specified, such as the cumulative volume of the flow-through for a given FPC and the presence of certain reaction by-products.

[0011] "Charging potential" means the voltage applied to a cell to perform work.

[0012] "Conductivity" means the electrical conductivity of an input, through, output, or waste stream. Conductivity is a surrogate measure of the molar concentration of ions in an input, output, or waste stream. Conductivity is directly proportional to the molar concentration of ions in such a liquid stream.

[0013] "CG" means carbon with a predominantly mesoporous structure and a nominal surface area of about 700 ^m2 /g. CG was formulated by the inventors using the pore size profile method disclosed herein and manufactured for the inventors by Calgon Corporation (Naperville, Ill.). CG is sometimes referred to as Calgon® in the tables.

[0014] "CV" means cyclic voltammogram.

[0015] "CX" means carbon xerogel. The CX electrode has a mesoporous structure and a nominal surface area of about 200 m ² /g.

[0016] "Cycle" means a cycle of operation in which a series of positive then negative or negative then positive potentials are applied to the FPC electrodes.

[0017] "DO" means dissolved oxygen.

[0018] "E" means voltage, also called potential. For DC, E has a fixed polarity (positive or negative).

[0019] "Electrode" means an electrically conductive material, typically porous carbon.

[0020] "EDC" means an electrodehalogenation cell disclosed herein. EDC is a kind of water purification cell belonging to FPC.

[0021] "EDC parameters" means user-selected FPC parameters in the EDC.

[0022] "EDX" means energy dispersive X-ray analysis.

[0023] " _Eo " is the potential versus the reference electrode when the electrodes are shorted (ie, _Eo is the potential during the shorted condition).

[0024] " _EPZC " or "potential of zero charge" means the potential of an electrode at which ion adsorption on the surface is minimal. E _PZC can be intentionally shifted by surface modification of the carbon electrode, or can be inherently displaced as a result of oxidation of the electrode surface by extended applied potentials or voltages. The E _PZC of a pure carbon electrode is typically between -0.1V and +0.1V. Shifting Epzc of electrodes by surface modification is disclosed in detail in US Provisional Patent Application No. 62/702,286, which is incorporated herein. The E _PZC of the FPC electrode for a given target species varies with water chemistry and is determined experimentally.

[0025] "Faradic immobilization" means electron transfer to a target species in an electrolyte, or electron transfer to a species in an electrolyte, followed by a homogeneous reaction in solution with the target species of interest, The reaction products are then adsorbed onto the electrodes.

[0026] A "flow-by" cell design means that the flow through the FPC flows across the surfaces of the electrodes in the FPC, rather than through the electrodes. A flow-by-cell design can offer the following advantages compared to a flow-through-cell design: lower pressure drop, higher flow rate, equivalent degradation of carbon electrodes, equivalent pH region.

[0027] "Flow rate" means the flow rate of an input, throughput, output, or waste stream, typically in units of L/hr, ml/min, and the like.

[0028] A "flow-through" cell design means that the flow through the FPC is forced through the electrodes in the FPC. A flow-through cell design can offer the following advantages compared to a flow-by-cell design: extreme pH range, better control over outlet pH.

[0029] An "FPC" or "Faradic porous cell" or "FPC device" uses aggregation to extract metal ions, halide ions, target metals or target halides from a liquid (typically aqueous) input stream. (eg, other species), or a purification cell that removes particulate metals and produces an output stream that is reduced in metal, halide, or particulate content. Different species of FPC can be used in series or parallel to remove multiple target species from the aqueous influent to the purification system. "FPC system" means one or more FPCs and optionally other types of purification cells (see definition of "hybrid system"), e.g. capacitive deionization ("CDI") cells, membrane CDI means water purification systems containing cells (“MCDI”), inverse CDI (“i-CDI”) cells, and non-electrochemical cells and filters. Incorporation of CDI, MCDI, i-CDI cells or similar desorption cells into the FPC system involves providing a waste stream and desorbing the waste stream from the CDI, MCDI, i-CDI and similar desorption cells. Control of the relevant cells in the FPC system to accommodate is required. CCC and EDC are types of FPC.

[0030] "FPC parameters" are: (i) physical adsorption; (ii) capacitive adsorption; (iii) electrochemical pH adjustment; ( _iv ) electrochemical peroxide ( _H2O2 ) generation and (v) electrodeposition (e.g., electroplating, electrophoretic deposition); (vi) electrochemical oxidation or reduction; (vii) deposition; (viii) pore size profile, (ix) electrode treatment, (x) Means electrode spacing and (xi) user-selected values in FPC for flow-by vs. flow-through vs. carbon block cell designs. One or more FPC parameters are selected or "tuned" to remove target species from the flow-through based on empirical data for a given input water chemistry.

[0031] "Halide derivative" means a molecule or compound that contains a halide.

[0032] "HE" means high efficiency mesoporous carbon. Electrodes made of HE carbon have a predominantly mesoporous structure with a nominal surface area of about 380 m ² /g. HE has a formulation of greater than 98% mesoporous carbon and the balance macroporous carbon. HE is formulated using the pore size profile method disclosed in US Provisional Patent Application No. 62/702,286, which is incorporated herein.

[0033] A "hybrid system" includes at least one FPC (CCC or EDC) and at least one other type of water purification cell, such as a peroxide cell, CDI, MCDI, i-CDI, or non-electrochemical cell. Or means a water purification system containing a filter. The minimum configuration for a hybrid system is serial (FPC feeding other cell types or vice versa). Larger systems may be serial only or may have serial paths in parallel (to increase throughput).

[0034] "Immobilization" means adsorption of a target species to an FPC electrode without subsequent desorption to a clarified output stream.

[0035] "Input stream" means a liquid, typically water, containing various ions and metals that is fed through the inlet to the cell.

[0036] "KN" means microporous carbon sold as Kynol® available from American Kynol, Inc. (Pleasantville, NY). Electrodes made of KN carbon have a microporous structure and a nominal surface area of about 1800 m ² /g.

[0037] "Metal" is defined by the Pourbaix diagram of As, Se, Pb, Ni, Zn, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb , Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb , Dy, Ho, Er, Tm, Yb, and Lu.

[0038] "Metal derivative" means a molecule or compound containing a metal or metalloid.

[0039] "Metal speciation" means different chemical forms ("species") of a metal in a given environment. For example, As(III) and As(V) are arsenic species that can coexist in aqueous solutions at a given pH.

[0040] "NHE" means normal hydrogen electrode.

[0041] "Output stream" means the liquid that has passed through the FPC and contains a lower molar concentration of the target species than the input stream.

[0042] "Parallel system architecture" means FPCs (and optionally other types of cells and filters) connected in parallel, i.e., each FPC (and optionally other types of cells and filters) outputs provide the system output. The parallel system architecture can be fixed or include multiple FPCs, process controllers, interconnecting lines, sensors, and valves located in lines and cells.

[0043] "Physisorption" means physical entrapment of a target species in the electrode pores.

[0044] "PMD" means pore size, which is the diameter of the pores at the carbon electrode surface. The pores may be dead-end or through-channels within the carbon electrode and typically have variable channel diameters.

[0045] "Point of entry" or "POE" means the location where a water supply supplies water to a water distribution system in a residential, commercial/industrial building, or other structure.

[0046] "Point of use" or "POU" means a location where water is dispensed from a water distribution system to a consumer, beverage dispenser, kitchen appliance, or other end use.

[0047] "Polarity" means either positive or negative polarity of a DC voltage.

[0048] A "pore size profile" is made according to the pore size profile method disclosed in US Provisional Patent Application No. 62/702,286 and US Patent Application No. 16/417,574, which are incorporated herein. It also refers to the volume ratio(s) of microporous, mesoporous, and macroporous carbon in the electrode. Generally speaking, the larger the average pore size, the longer the service life of the electrode and the higher the permeability of the electrode to flow-through. Average pore size is controlled by the ratio of microporous, mesoporous, and macroporous carbon used to make a given carbon electrode.

[0049] A "Pourbaix diagram" (also called a potential/pH diagram, E _H -pH diagram, or pE/pH diagram) shows the possible stable (equilibrium) phases of an aqueous electrochemical system. Dominant ionic boundaries are represented by lines. As such, the Pourbaix diagram can be read like a standard state diagram with a different set of axes. Like state diagrams, Pourbaix diagrams do not address reaction rates or rate effects. For soluble species, Pourbaix diagram lines are usually drawn for concentrations of 1M or ^10-6M . Additional lines may be drawn for other densities.

[0050] The "Pourbaix operating region" relates the pH at a given electrode in the FPC and the applied E to the Pourbaix diagram to select the immobilization of the target species at a given water chemistry. means that

[0051] "Pure", in reference to an electrode, means not surface modified. For example, Spectracarb™ electrodes are pure as supplied by the manufacturer.

[0052] A "process controller" monitors sensors placed within a system of FPCs (and optionally other types of cells and filters) to Process control sampling the input, through, and/or output flow and FPC (and optionally other types of cells and filters) conditions in a water purification system containing multiple other types of water purification cells or filters A computer that operates an application. The process controller actuates valves in lines interconnecting the source of aqueous solution to be treated, the FPC (and optionally other types of cells and filters), and the system outlet, thereby activating the various FPCs (and optionally other types of cells and filters) can be configured in series, series-parallel, or parallel system architectures. Based on the sensor data, the process controller can dynamically adjust the FPC parameters of the FPCs in the system (and optionally other cells and filters in the system as well).

[0053] "Cleaning" means removing one or more target species from a flow-through. Purification includes metals for which Pourbaix diagrams exist (e.g., As, Pb, Ni, Zn, Al, Cr, Mn, Fe, and Cu), halides (e.g., Cl, Br, chloramines), organics, and biological compounds. including removal of

[0054] A "wound cell design" is one in which the continuous separator and porous carbon-based electrode material are physically spirally wound to provide multiple, primarily flow-by, flow channels through the porous carbon electrode. It refers to the FCP cell design in which the cylinder with which it is created is created. To manufacture a wound cell, sheets of anode material, separator material, and cathode material are laminated and then rolled to form a cylinder. Current collectors are usually attached to the anode and cathode at multiple points to reduce electrical losses.

[0055] "SC" means microporous carbon sold as Spectracarb™ available from Engineered Fibers Technology, LLC (Shelton, Conn.). Electrodes made of SC carbon have a microporous structure and a nominal surface area of about 1900 m ² /g.

[0056] "SCE" means saturated calomel electrode, which is a standard reference electrode commonly used as a reference electrode, eg, in cyclic voltammetry.

[0057] "Serial system architecture" means FPCs (and optionally other types of cells and filters) connected in series, ie, the outlet of a first FPC feeds the inlet and the second FPC and the outlet of the second FPC feeds the inlet and the third FPC, and so on. A series system architecture can be fixed or include multiple FPCs (and optionally other types of cells and filters), process controllers, sensors, interconnecting feed lines, and outlets on one FPC and inlets on a second FPC. It can also include a valve placed in the supply line between the

[0058] "Series-parallel system architecture" means a system in which FPCs (and optionally other types of cells and filters) can be connected in series or in parallel. A series-parallel system architecture can be fixed or include multiple FPCs (and optionally other types of cells and filters), process controllers, interconnecting feed lines, sensors, and outlets of one FPC and a second FPC. It can also include a valve located in the supply line to and from the inlet, which is actuated by the process controller. A typical series-parallel system architecture includes multiple ranks of a given series of cells, thereby similarly processing the through-flow with the increased throughput provided by multiple serial paths.

[0059] "SHE" means standard hydrogen electrode.

[0060] A "shift" is an intentional or unintentional chemical or electrochemical modification of an electrode surface using the methods disclosed in US Provisional Patent Application No. 62/702,286, incorporated herein. By quality (eg, electrochemical oxidation by applied potential or voltage), it is meant to change the potential (also called "position") of the _EPZC of the electrode.

[0061] "Seed" means a molecule, compound, or particulate in a water stream or adsorbed to a cell electrode.

[0062] "Speciation" means the distribution of an element between defined chemical species within a system or FPC. For example, uncharged metal particles, metal ions, and metal complexes of a given metal can coexist in a solution or suspension at a given pH, and their distribution changes as the pH changes. obtain.

[0063] A "stacked cell design" is one in which separate pieces of separator and porous carbon-based electrode material are stacked layer-by-layer to provide multiple, primarily flow-by, flow-through cells through and/or near the porous carbon electrode. We mean an FCP cell design that creates a cylinder with channels. Current collectors are usually attached to the anode and cathode at multiple points to reduce electrical losses. FIG. 23 shows a stacked cell design.

[0064] "Surface charge enhanced surface" means an electrode surface to which a surface charge has been imparted by chemical or electrochemical methods.

[0065] A "system" is a plurality of interconnected FPCs (and optionally other types of cells and filters) controlled either manually or by a process controller.

[0066] "Target metal" means the species or species of a given metal or metal derivative to be removed using CCC.

[0067] "Target speciation" refers to the number of ionic states or It means one of complex formation.

[0068] "Target species" means a molecule, compound, or microparticle to be removed using FPC. A “target species” is not only a molecule, compound or microparticle that is detected in the input stream to the FPC (also called “identified as a species in the Pourbaix diagram”), but also a molecule, compound or microparticle that contains the FPC Also includes one or more intermediates and final reaction products created in

[0069] "Through-flow" means a liquid stream being processed within a cell. Stated another way, through flow means the liquid flow within the cell and between the inlet to the cell and the outlet from the cell.

[0070] "Treat" means providing an input stream to an operating FPC or system containing FPCs and recovering a clarified output stream.

[0071] "Treated electrode" means an electrode that has undergone an electrode surface modification disclosed herein.

[0072] "TDS" means total dissolved solids. A common operational definition is that solids must be small enough to withstand filtration through filters with 2 micron pores.

[0073] "Untreated electrode" means an electrode that has not undergone the electrode surface modification disclosed herein, ie, a pure carbon electrode.

[0074] "Voltage" and "potential" are synonymous herein. Voltage is direct current (“DC”) unless otherwise specified.

[0075] A "waste stream" passes through a CDI, MCDI, i-CDI cell, reverse osmosis, ion exchange, or other water purification cell that cycles between adsorption and desorption to remove ions at a higher molar concentration than the input stream. means the liquid it contains. A deionization cell, such as a capacitive deionization cell, can be used in the system containing the FPC. FPC has no waste stream. The output stream from the FPC is purified water. A system containing a deionization cell that periodically desorbs molecules provides (i) a purified output stream from the deionization cell operating in adsorption combined with the FPC output stream, and (ii) desorption It has a waste stream from a deionization cell operating under conditions.

(Related technology)
[0076] Toxic metals, especially lead, in drinking water and crop irrigation water are a major global health problem. This problem, and its impact on health, go largely unreported until a crisis occurs when the water in the municipal water system becomes toxic due to lead contamination. Last year, at least 18 million Americans were at risk of drinking lead-contaminated water. Over 5,000 public water systems were in violation of federal lead regulations. Elevated blood lead levels in children cause irreversible neurological and behavioral deficits and have been associated with reduced IQ and lifelong achievement, even at low levels. The US Environmental Protection Agency ("EPA") emphasizes that there is no safe level of lead exposure. Most commonly used filters for residential point-of-use/point-of-entry (POU/POE) lead reduction, such as filters using zeolites and ion exchange, are inadequate. They have a limited useful life, lack substantial lead specificity, and are expensive.

[0077] FIG. 1 shows locations in the United States with dangerously high lead levels in municipal drinking water and the incidence of elevated blood lead levels in US infants, where infants are susceptible to permanent brain injury, They are at risk of seizures, coma, and even death from lead poisoning. The Natural Resources Defense Council (“NRDC”) recently released the EPA's Lead and Copper Regulation (https://www.epa.gov/dwreginfo/lead-and-), a federal standard for monitoring lead and copper levels in water. We found 5,363 public water systems that violated the copper-rule. The NRDC report also found 1,110 water systems that exceeded the action level for lead (15 ppb in at least 10 percent of homes tested). Together, these systems serve approximately 4 million people. The EPA is considering revising the 1991 Lead and Copper Regulations to make the regulations more stringent, and EPA officials have announced an ambitious 10-year plan for the EPA to "declare war on lead." It said it was working on a strategy, describing lead in drinking water as "one of the greatest environmental threats we face as a nation."

[0078] A 2018 test of a municipal water system in Flint, Michigan showed a lead level of 13,000 ppb, which is 866 times the EPA action level for lead in drinking water. People are becoming more aware and concerned about water quality in their homes, schools, and communities. Public school water bottles in New York, California, Ohio, and Illinois far exceeded the 15 ppb action level in testing. Despite corrosion control measures taken by public water authorities to minimize the risk of lead leaching from pipes from older infrastructure into drinking water systems, lead concentrations in drinking water are generally rising nationwide. there is The most effective way to eliminate lead from drinking water is to replace lead lines, at an estimated cost of $30 billion. A better POU/POE device for drinking water could be a much simpler and cost effective solution. The problem of lead contamination is not adequately addressed as existing solutions are overwhelmed by high cost, poor efficacy, and/or short device lifetimes.

[0079] Lead removal devices currently on the market lack lead specificity and device life is limited by the total filtered water volume, regardless of lead concentration. Over time, the pressure drop across the filter becomes so large that even if the adsorbent in the filter is not completely depleted, water cannot flow through it, rendering it useless.

[0080] Chlorine and/or chloramines are routinely added to US drinking water supplies as disinfectants to control microbial growth. While microbial removal is beneficial for human consumption, chlorine and/or chloramines contribute to the unpleasant taste and odor of tap water. Therefore, it is desirable to remove chlorine and chloramines prior to final use. Chlorine is more volatile than chloramines and can be easily removed with a typical consumer filter pitcher. However, removal of chloramines requires specially formulated filters containing activated carbon (catalytic carbon). The presence of chlorine and/or chloramines is also detrimental to water purification processes that rely on polymeric membranes such as reverse osmosis (RO). Most membranes are not resistant to these disinfectants and degrade upon exposure, causing irreversible damage and costly RO membrane replacement. Drinking water and other waters used in thermoelectric plants and other industrial processes (“process water”) should contain chlorine, chloramines, and other halides (especially bromine and iodine) to reduce corrosion and contamination of process systems. ), as well as halide derivatives. A solution to the technical problem of removing both chlorine and chloramines from water sources by reducing the use of activated carbon filters without damaging RO membranes would not only reduce water purification costs, but also improve drinking water quality. Improves water and process water quality. Oxidation of water pollutants as a water purification process is usually performed using hydrogen peroxide or ozone. Oxidation of certain water pollutants promotes further decomposition and eventual destruction of the pollutant without further intervention.

[0081] The technical problems to be solved are: (i) more efficient and cheaper purification devices for producing purified water, especially devices that remove soluble and insoluble lead in drinking water to less than 15 ppb; (ii) the purification device is readily scalable for residential, urban, commercial and industrial use; Applicants have developed a Faradic Porous Cell (“FPC”) that solves this technical problem by aggregation of target species. Remove chlorine, other halides, chloramine disinfectants, and other halide derivatives from water using a novel electrodehalogenation technology, referred to herein as an Electrodehalogenation Cell (“EDC”) A first species; and a second species that uses a novel capacitive coagulation technology, referred to herein as a capacitive coagulation cell (“CCC”), to remove metals, metal derivatives, and particulate metals. Two types of FPC are disclosed herein. Applicant's Faradic porosity technology is significantly more effective at purifying water than commonly used processes such as chemical coagulation, ion exchange, and adsorbents. EDC solves the technical problem of reducing the cost and increasing the efficiency of removing chlorine, chloramines, and other halides and halide derivatives from drinking and process waters. CCC solves the technical problem of reducing the cost and improving the efficiency of removing metals, metal derivatives and particulate metals from drinking water and process water.

Map of counties with water systems violating EPA lead and copper regulations (left), produced by the National Resources Defense Council, and the number of cases in children with high blood lead levels in 2012 (right). Schematic of part of the CCC core. The schematic shows two pairs of electrodes (anode and cathode for each pair) within the CCC core. A CCC typically has more than 10 pairs of electrodes. Comparison of lead removal between applicant's CCC device and a commercially available prior art POU device. Applicant's CCC, indicated as "PTW" in FIG. 2, tested various municipal water chemistries whose lead content exceeded EPA action levels. Applicant's CCC outperformed all prior art devices. Pourbaix diagram of lead (Pb) in a carbonate solution showing the Pourbaix operating region for lead species removal at the intersection of E applied to the anode and cathode and the resulting pH near each electrode. Aggregation mechanism for lead (Pb) removal, showing pathways for lead species formation and immobilization of Pb species. Pourbaix diagram for hypochlorite (Debiemme-Chouvy, Catherine & Hua, Y & Hui, F & Duval, Jean-Luc & Cachet, H. (2014). "Electrochemical treatments using tin oxide anode to prevent biofou ling" errata [Electrochimica Acta56/ 28 (2011) 10364-10370].Electrochimica Acta.121.461.10.1016/j.electacta.2014.01.130.). Pourbaix diagram for hypobromite (supra). Pourbaix diagram for monochloramine (NH ₂ Cl) (www.sedimentaryores.net/Pipe%20Scales/Chlorine-chloramine.html). Commercially available microporous carbon [Spectracarb (SC) and Kynol (KN)], mainly mesoporous carbon [Calgon (CG)], mesoporous carbon [carbon xerogel (CX )], as well as the charge passed when using our high efficiency (HE) carbon electrode. The order of carbon type in the legend is also the order of the starting specific charge (y-axis) traces passed, except that CX is the lower y-axis value than HE. Potential distribution for kynol electrodes in a four-electrode setup in 4.3 mM NaCl, with pure kynol as anode and cathode, Pt as counter electrode, and standard calomel electrode (SCE) as reference. Voltage was applied from 1.6V to 0.8V in steps of 0.2V and back to 1.6V. E _0,avg represents the open circuit voltage of the system. Figures 8a-e are cyclic at a scan rate of 0.5 mV/s in 4.3 mM NaCl using carbon as the working electrode, Pt-coated Ti as the counter electrode, and a standard calomel electrode (SCE) as a reference. Voltamograms (CV) are shown. CVs were collected using carbon electrodes (various types as shown) placed in the electrolyte and held at constant voltage for the same experimental period. The voltage applied between the anode and cathode was ramped up and then ramped down at the scan rate and the current response was recorded as CV. In addition to the CV of a pure (0h) electrode, each plot shows the results of an accelerated oxidation study (3h and 6h traces) performed after using the electrode for 3 and 6h at a constant applied potential of 2.0V. indicates Figure 8a shows the CV for the microporous SC. After 3 hours of electrochemical oxidation, the E _PZC was shifted to the right, indicating the formation of covalent bonds between the oxygen-containing functional groups and the carbon surface of the carbon electrode. After 6 hours, the potential of zero charge (E _pzc ) no longer exists and the current drops significantly, indicating pore collapse. The same trend is observed in Fig. 8b for microporous KN. Figure 8c shows the CV for CG, which is predominantly mesoporous carbon. After 3 and 6 hours of electrochemical oxidation, the E _PZC is shifted to the right, but the current is maintained due to the uncollapsed pores. Figures 8d and 8e, mesoporous CX and mesoporous HE, respectively, show the same trends observed for CG in Figure 8c, but HE has a higher electrochemically active surface area than CX. In comparison, the 3 hour and 6 hour time points exhibit a larger area within the CV plot and therefore achieve a larger current response. The pore size of CX is ten times larger than that of HE, which is related to electrode stability and ultimate lifetime. However, the larger the pore size of CX, the much smaller the surface area than HE. Bench-scale capacitive coagulation device. SEM micrograph and EDX mapping showing final state of immobilized lead species. Carbon (C), lead (Pb), and oxygen (O) are mapped in the bottom three panels and are represented by the brightest contrast in their corresponding grayscale images. In the corresponding gray scale of the photograph, carbon electrodes are shown in black and copper in gray. A color photograph of the EDX mapping is available. Experimental breakthrough curves for a prior art charcoal packed column (panel a) and applicant's CCC device (panels b and c). The left y-axis is normalized to the initial lead concentrations: (a) 126 ppb, (b) 296 ppb, and (c) 10,000 ppb. The right y-axis shows the total Pb removed in mg per processed volume. DO reduction at 1.2V. DO reduction generates hydrogen peroxide, a strong oxidant. Pourbaix diagram for Pb (Schock, M.R., Hyland, R.N., and Welch, M.M. (2008). Occurrence of contaminant accumulation in lead pipe scales from domestic drinking-water dist Ribution systems.Environ 42(12), pages 4285-4291). Pourbaix diagrams for Cu showing removal methods: (a) copper hydroxide [Cu(OH) ₂ ] formation and (b) copper electrodeposition or electroplating [Cu _(s) ] (https://commons .wikimedia.org/wiki/File:Cu-pourbaix-diagram.svg). Pourbaix diagram for Ni (Ciesielczyk, F., Bartczak, P., Wieszczycka, K., Siwinska-Stefanska, K., Nowacka, M., and Jesionowski, T. (2013). Adsorption of Ni(II) from model solutions using co-precipitated inorganic oxides. Adsorption. 19, pp. 423-434). Pourbaix diagram for Fe (https://commons.wikimedia.org/wiki/File:Pourbaix_Diagram_of_Iron.svg). Pourbaix diagram for Mn (https://commons.wikimedia.org/wiki/File:Mn_pourbaix_diagram.png). Pourbaix diagram for Al (https://corrosion-doctors.org/Corrosion-Therdynamics/Potential-pH-diagram-aluminum.htm). Pourbaix diagram for Zn (https://commons.wikimedia.org/wiki/File: Zn-pourbaix-diagram.svg). Schematic of EDC device in stacked cell design. The feed (influent, or input stream) enters the bottom of the device, travels through an annular space near the walls of the cell housing, and then flows centrally over the electrode surface into axial channels. and then discharged (effluent or output stream) through the axial channel to the FPC outlet. Feed spacers are optional; feed spacers (shown in Figures 23 and 29) are additional layers of material between the anode and cathode and are optional to create a larger flow path for through flow. Can be added by choice. Applied voltage and transient current as a function of volume processed at flow rates of 300-500 ml/min for EDC experiments performed with Calgon as both electrodes. The current spikes at about 1500 and about 1600 gallons are due to noise (inadvertent physical movement of electrical leads) and are negligible. At about 1800 gallons, operation was switched from applying a constant voltage to applying a constant current of about 0.2 A, observed as a straight line. The voltage decay seen in this condition (the voltage reads negative, but the total cell voltage increases with constant current) is a result of the application of constant current. Subsequent switching was also constant current, but the voltage soon reached the cutoff value and the system behaved as if it were constant voltage in nature. Copper deposition at an applied potential of 1.2V occurs (a) on the cathode and (b) not on the anode. Carbon electrodes are shown in black and copper in gray in the grayscale equivalent of the photograph. A color photograph of copper deposited on the cathode is available. Rust-colored Fe oxide deposits on the separator on the cathode surface after the experiment. In the grayscale equivalent of the photograph, the carbon electrode is shown in black and the iron as a gray deposit on the white separator. A color photograph of the copper deposit on the cathode is available. Scanning electron microscopy (SEM) micrographs of (a) carbon cloth with white precipitates and (b) cloth showing Pb crystals. EDX mapping of the Pb crystal from Figure 27 confirming that the crystal is lead oxide by the presence of both lead and oxygen. Carbon (C), lead (Pb), and oxygen (O) are mapped in the right three panels and are represented by the brightest contrast in their corresponding grayscale images. A color photograph of the EDX mapping is available. Schematic of a wound cell design in which a continuous separator and a porous carbon-based electrode material are physically spirally wound to create a cylinder with multiple, primarily flow-by flow passages through the porous carbon electrode. figure. EDC experiments performed with Kynol as both electrodes. Figure 2 shows the concentration of total chlorine in the feed and product streams and the applied voltage as a function of volume treated at a flow rate of 500 ml/min. EDC experiments performed with Kynol as both electrodes. Figure 2 shows the concentration of free chlorine in the feed and product streams and the applied voltage as a function of volume treated at a flow rate of 500 ml/min. EDC experiments performed with Kynol as both electrodes. Figure 2 shows the concentration of chloramines in the feed and product streams and the applied voltage as a function of volume processed at a flow rate of 500 ml/min. EDC experiments performed with Kynol as both electrodes. Figure 2 shows the removal rate of total chlorine, free chlorine, chloramines and peroxides and applied voltage after treatment of tap water with EDC as a function of treated volume at a flow rate of 500 ml/min. EDC experiments performed with oxidized Kynol as one electrode and Fuel Cell Earth as the other electrode. Concentration of total chlorine in feed and product streams and applied voltage as a function of volume treated at flow rates of 300-500 ml/min. EDC experiments performed with oxidized kynor as one electrode and fuel cell ground as the other electrode. Concentration of free chlorine in feed and product streams and applied voltage as a function of volume treated at flow rates of 300-500 ml/min. EDC experiments performed with oxidized kynor as one electrode and fuel cell ground as the other electrode. Concentration of chloramines in feed and product streams and applied voltage as a function of volume processed at flow rates of 300-500 ml/min. EDC experiments performed with oxidized kynor as one electrode and fuel cell ground as the other electrode. Removal rate of total chlorine, free chlorine, chloramines and peroxides after EDC treatment of tap water as a function of treated volume and applied voltage. EDC experiments performed with Calgon as both electrodes. Concentration of total chlorine in feed and product streams and applied voltage as a function of volume treated at flow rates of 300-500 ml/min. EDC experiments performed with Calgon as both electrodes. Concentration of free chlorine in feed and product streams and applied voltage as a function of volume treated at flow rates of 300-500 ml/min. EDC experiments performed with Calgon as both electrodes. Concentration of chloramines in feed and product streams and applied voltage as a function of volume processed at flow rates of 300-500 ml/min. EDC experiments performed with Calgon as both electrodes. Removal rate of total chlorine, free chlorine, chloramines and peroxides after EDC treatment of tap water as a function of treated volume and applied voltage.

[Summary of Invention]
[00123] To increase the efficiency of removing metal and halide contaminants from water using electrochemical devices that typically operate under a constant applied potential, Applicants have proposed capacitive adsorption, near the cell electrodes. Or combine the faradic reaction above and electrode pore size profiling to create a new type of electrochemical device, the faradic porous cell. A primary consideration in Faradic porous cells is the selection of carbon-based materials that can undergo reactions and change pH over time at both the anode (carbon oxidation by water) and cathode (dissolved oxygen reduction). and use. Carbon materials with suitable porosity and bulk material properties can induce these reactions over extended periods of time, thereby allowing targeted reactions with incoming components (target species) to be removed from aqueous solutions. .

[00124] The next design consideration is the spacing between the anode and cathode. Decreasing the spacing can increase the reaction rate while maintaining electrical isolation between the electrodes, limiting the residence time required to achieve a certain "react and immobilization" process. . Electrode spacing is typically less than 1 mm and must not cause anode-cathode shorting or unacceptable pressure drop in the FPC (with consequent increase in residence time and decrease in flow rate). , preferably as close as possible. Preferred electrode spacing is less than 1 mm, preferably less than 200 microns, more preferably less than 50 microns, most preferably less than 20 microns.

[00125] Some of the target species adsorb to the electrode either by physical entrapment ("physisorption") or by electrical attraction ("capacitive adsorption"). Other species of target species are starting materials for reactions (typically oxidations) that directly or indirectly create new species of target species immobilized on the electrode. Immobilization removes the target species from solution. The potentials applied to the anode and cathode are selected based on the Pourbaix diagram of the target species in the input stream, given the spacing between the electrodes and the properties of the corresponding carbon electrode material. Examples of FPC parameters for various target species are shown in Table 1. For example, to remove copper, immobilization to electrodes by plating can occur at potentials ranging from about 0.3 V to -0.4 V versus NHE in the pH range of 0-14. In addition, at potentials above 0 V versus NHE and pH values above 4, deposition in the form of copper hydroxide (Cu(OH) ₂ ) can occur at the anode (see Figure 17). A total cell potential of about 0.4 V is desirable for copper removal in Faradic porous cells.

[00126] Other target species can be removed by similar mechanisms but in different voltage regimes. For example, lead deposition can arise from the pH and potential generated at the electrode surface. At potentials more negative than about -0.4 V versus NHE and in the pH range of 0-14, lead can plate as a solid at the cathode. Deposition at the anode can also occur as PbO ₂ if the pH is kept above 1.5 and potentials above 0.5 V versus NHE are used (FIG. 16). Finally, oxidation from H ₂ O ₂ occurring at the cathode can also cause deposition of the target species. The rate of dissolved oxygen (“DO”) reduction near the cathode depends on the oxidation of cathode carbon, for example, by oxidative shift of the _EPZC at the cathode or as a result of in situ use.

[00127] The Pourbaix diagram for materials can be used to define the pH and voltage required to remove the target species of interest in a Faradic porous cell. A Faradic porous cell contains a series of porous carbon anodes and cathodes, typically a reduced cathode (negative E _PZC with a positive surface charge) and a pure anode (where the anode becomes positive during use). E _PZC shift (suffer (negative surface charge))) and is actuated by applying a small voltage, eg, 1.2 V, across the electrodes. A schematic diagram of a CCC embodiment of the FPC is shown in FIG. An aqueous input stream to be purified is introduced into the FPC through an inlet to the cell, electrodes in the FPC are immersed in the water stream, and target species are removed from the flow-through. After removal of target species at the FPC, the flow-through exits the cell through an outlet for use, storage, or further processing. The electrodes of the cell are connected to a power supply capable of applying E+ or E- to a given electrode. The core advances of FPC are the precise matching of the E+ applied to the cell anode and the E− applied to the cell cathode, the pore size profile of the electrode materials, and the selected Pourbaix operating area, which This improves purification efficiency and improves cost/benefit. The Pourbaix diagram operating region shows seeding based on applied E and pH. In FPC, seeding is driven by potentials E+ and E− applied to the electrodes. Using electrodes with optimized pore mouth distribution (“PMD”) profiles and maintaining FPC operation in the selected Pourbaix operating regime removes target species far beyond conventional adsorption occurring on untreated electrodes. increases.

[00128] Preferred average pore sizes range from 0.8 nm to 50 nm, with a more preferred average pore size range from 2 nm to 20 nm. The applied potential causes redox reactions (e.g., plating, oxidation, reduction, peroxidation, etc.) of the target species on the carbon electrodes, altering the local pH regions at the anode (acidic) and cathode (basic). drive the faradic reaction in . The combination of target species reaction and pH change is controlled by the applied potential. The applied E is typically a constant voltage and reaches a near constant current at steady state. Generally speaking, the applied voltage determines what Faradic reactions occur within the FPC. FPC removes target species from the flow-through without the use of treated (i.e., shifted E _PZC ) electrodes, whereas the use of treated electrodes results in less target species removal for certain water chemistries. increases. Using the treated electrodes, the working voltage window (potential difference between the E _PZC at the anode and the E _PZC at the cathode) is typically in the range of 0.3V to 1.23V.

[00129] The FPC invention can be used to target species (e.g., lead, iron, manganese, cadmium, chromium, chlorine, chloramines, etc.) by optimizing electrode porosity, applied E, and Pourbaix actuation area. It combines adsorption (both physical and capacitive) and immobilization (also called coagulation) of the adsorbed target species. (ii) capacitive adsorption; (iii) electrochemical pH adjustment and target species _{immobilization} ; (iv) electrochemical peroxide ( _H2O2 ) generation; (v) electrodeposition (e.g. (vi) electrochemical oxidation or reduction; (vii) deposition; (viii) pore size profile; (ix) electrode treatment, (x) electrode spacing, and (xi) flow-by pair Optimization of the flow-through versus carbon block cell design depends on the target species, the input stream water chemistry, and the through-stream water chemistry.

[00130] Reduction occurs only at the cathode of the FPC. Electrochemical reduction is usually described as a potential applied to the cell. The voltage distribution between the anode and cathode occurs spontaneously based on the amount of voltage applied, the material properties of the electrodes, and the chemistry of the aqueous solution.

[00131] An embodiment of the present invention relates to metal ions or particulate metals for which Pourbaix diagrams exist, such as As, Se, Pb, Ni, Zn, Al, Sc, Ti, V, Cr, Mn, Fe, Co. , Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ce, Pr, Nd , Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu from the input stream by one or more of the following methods, each of which is a CCC parameter: A capacitive coagulation system and method using multiple capacitive coagulation cells: (i) physisorption; (ii) capacitive adsorption; (iii) electrochemical pH control and metal immobilization; (v) _{electrodeposition} (e.g., electroplating, electrophoretic deposition) _; (vi) electrochemical oxidation or reduction; (vii) deposition; (viii) pore size. Profile; (ix) electrode treatment, (x) electrode spacing, and (xi) flow-by vs. flow-through vs. carbon block cell design. CCC can remove lead from water to produce water with lead concentrations below 15 ppb, the EPA action level for drinking or irrigation water.

[00132] Compared to prior art devices, Applicants' CCC has a high specificity for lead and other metals, removing both dissolved and particulate lead and other metals, and takes less time than days or weeks. , have device lifetimes that can be measured in years, and use low-cost materials. Applicant's CCC combines electrochemistry with carbon materials to create a system that is not saturated, polluted, or inhibited by other constituents in water such as iron, volatile organic compounds (VOCs), particulate matter and natural organic matter (NOM). It achieves its long life and efficiency by providing The lifetime of Applicant's device is several times longer than the prior art of carbon filtration, ion exchange filtration, zeolite adsorbents, and reverse osmosis (RO).

[00133] In CCC, a combination of optimized PMD, applied E, chemical and electrochemical manipulations facilitate immobilization (coagulation) of lead on carbon electrodes. Adsorbed lead is permanently removed from the solution (Fig. 13). This methodology is readily adaptable and applicable to the treatment of iron, manganese, cadmium, chromium, and other metals and metal derivatives. "Tuning" the CCC is primarily based on (ii) analyzing and selecting the operating region in the Pourbaix diagram of the target species, and (i) selecting the voltage applied between the CCC anode and cathode. and (iii) choosing a pore size profile for the CCC carbon electrode that maximizes the removal of the target species. The effluent from the CCC can be used without further treatment or sent to one or more EDC, CCC, or prior art water purification cells for further removal of other target species. can. Conditioning can optionally be further optimized by electrode treatments.

[00134] Metal speciation and chemistry can be exploited to selectively remove lead (and other target metals) from water with high efficacy and selectivity regardless of water chemistry. can. Through this operation, Applicant's CCC can (i) electrochemically, chemically, and physically remove lead and other target species from drinking water sources, currently requiring and input stream conditions. and (ii) more efficient, inexpensive and scalable devices for purifying drinking and process waters, especially soluble and solve the technical problem of providing a device that removes insoluble lead to less than 15 ppb. Adjustment of the pH of the input stream may be necessary to improve aggregation of the target species, especially for metal removal.

[00135] In EDC embodiments of FPC technology, EDC parameters are "tuned" to remove other non-metal target species such as chlorine, chloramines, and other halides and halide derivatives from the EDC influent. be done. "Tuning" the EDC is primarily based on (ii) analyzing and selecting the operating region in the Pourbaix diagram of the target species, and (i) selecting the voltage applied between the EDC anode and cathode. and (iii) choosing a pore size profile for the EDC carbon electrode that maximizes the removal of the target species. The effluent from the EDC can be used without further treatment or sent to one or more EDC, CCC, or prior art water purification cells for further removal of other target species. can. Conditioning can optionally be further optimized by electrode treatments. Device features and advantages are listed below and in Tables 2 and 3 of the drawings.

[00136] EDC or CCC optionally use treated anodes and cathodes made of carbon in which the Epzc of one or both electrodes is shifted compared to the Epzc of the pure electrodes. Shifting the Epzc of an electrode can change the rate of reaction that occurs (either positively or negatively). Whether to shift anodic only, cathodic only, or both types of electrodes, and how much Epzc shift to use depends on the input water chemistry and the target species.

[00137] Carbon electrodes are superior to metal electrodes in avoiding or reducing electrolysis or water decomposition when a high potential of 3V is applied to the electrodes. Applied potentials above 1.23 V (“overpotentials”) can cause electrolysis of water, which produces hazardous hydrogen gas. Metal electrodes can cause the generation of hydrogen gas below 2V. In contrast, carbon electrodes can withstand higher applied voltages while avoiding substantial water electrolysis.

[00138] EDC's inventiveness is due to (i) the reduction in power consumption required to reduce chlorine and chloramines (sources of taste and odor) due to specific carbon electrodes and applied voltages, (ii) on-demand or continuous processing (iii) a highly scalable and simple design that enables significantly lower cost POU/POE devices and lower cost urban, commercial and industrial large scale systems; (iv) similar performance to conventional carbon blocks (e.g. activated carbon/activated charcoal) but requiring significantly less carbon; (v) similar free chlorine removal performance at much shorter residence times; (vi) use less carbon, (vii) longer electrode life, especially for chlorine and chloramine removal, (viii) finer control over specific removal rate and output water quality, (ix) target species. (x) the ability to adjust the cost/benefit of FPC through the choice of carbon for the FPC electrode;

Detailed Description of Preferred Embodiments
[00139] During the capacitive charging process, a constant current or voltage is used to charge the electrode surface for energy storage, desalination, or other useful capacitive techniques. Electrode charging and subsequent discharging are often performed over thousands of cycles over a range of voltages and currents, depending on the intended application. Carbon electrodes made of activated carbon (i) have a large specific surface area, resulting in a large capacitance, and (ii) add functional groups to, among other things, scavenging metals and other target species, energy These capacity-based charge and discharge processes are often employed because of the opportunity for surface modification that improves storage and deionization (eg, desalination of seawater or brackish water). Activated carbon is a form of carbon that has been treated to have a large number of small, low volume pores that increase the surface area available for adsorption or chemical reactions. FPC can be used in wastewater, cooling water, laundry wastewater, water to be purified for human consumption, water to be purified for agriculture, water to be purified for horticulture, water to be purified for food use, softening sea water to be purified for human consumption; water to be purified for laboratory use; brackish water to be purified for human consumption or agricultural use; can be used to purify water to be purified.

[00140] Pore size distribution in carbon electrodes is an important FPC parameter that has been overlooked in conventional water purification techniques.

[00141] The electrode properties are shown in Table 4. The electrode supplier is listed in the first column of Table 4. Pore size, or pore diameter (“PMD”), is critical in maintaining charge passing through and is directly related to EDC electrode lifetime. PMD is commonly used as representative of the diameter of the relevant pore channels in carbon electrodes. FIG. 9 shows the effect of PMD on the stability of passing charge. After repeated cycles of application of voltage or potential followed by reverse voltage or potential (or short or open circuit of anode(s) and cathode(s)), the pore channel (and even the pore mouth) ) may "collapse" (more precisely, the pores are clogged). The pore mouth becomes "covered" and/or the pore channel becomes "closed", reducing the surface area of the carbon (especially the diameter and length of the pore channel) so that the pores are no longer effective. ceases to function effectively. A "covered" pore mouth blocks access to the interior of the pore. Pore mouth roofing and pore channel collapse cause poor electrode performance and eventual failure of prior art cells.

[00142] In FPC, the target species is ionized, charged, or partially charged due to the asymmetric distribution of electrons in the chemical bond, because of the applied potential, the carbon It can be attracted to the electrode, which creates a driving force that brings the target species closer to (or in contact with) the carbon electrode. Non-ionic and uncharged species of the target species can impinge on the electrode surface. Contact with the electrode surface can result in multiple pathways to immobilization of the target species. An alkaline environment can be electrochemically produced by controlling large local pH fluctuations, which, for example, produces insoluble metal oxides, deposits near or on the electrode, and deposits on the electrode fines. trapped in the pores. Faradic reactions, such as oxygen reduction reactions at the cathode, can produce hydrogen peroxide, which can diffuse out of the electrode and oxidize target metal molecules in close proximity. Hydrogen peroxide performs indiscriminate oxidation. The higher the local concentration of target species closer to the electrode, the higher the statistical probability that hydrogen peroxide will oxidize the target species. Other faradic reactions, such as direct electron transfer (reduction or oxidation) between the target species and the electrode may also occur. When the target species is attracted to the electrode surface, the carbon electrode either (1) transfers electron(s) from the electrode to the target species to reduce the target species and cause it to deposit on the electrode, or (2) Transfer electron(s) from the target species to the carbon electrode to oxidize the target species to either an insoluble oxide or hydroxide, or a reaction that can be immobilized by an additional electron transfer reaction or pH adjustment. It can be made into a high quality seed. Deposited and electrically attracted species are trapped in the electrode pores.

[00143] The actual pore size and volume within an activated carbon depends on a given pore shape, tortuosity (usually associated with changes in pore diameter), and channel length. Based on micrographs of activated charcoal, depending on the activation and/or synthesis procedure, the pores within activated charcoal can be tubular channels, polygonal channels, spheroidal chambers, surface slits, and the like. Channels and chambers can be "dead-end" or "through" (i.e., a channel or chamber having two surface emergences, also called "pore mouths", with channel continuity between the two pore mouths). . The pores in activated carbon are generalized as being tubular channels having an average pore channel diameter (hereinafter "pore channel diameter") and average pore size. Measuring the actual pore channel diameters of the billions of pores that rarely have a constant pore channel diameter in a mass of activated carbon is a very difficult task and is not reported here. As a generalization, the pore channel diameter is assumed to be the same as the pore diameter.

[00144] The diameter of the pore mouth, i.e., the opening of the pore to the electrolyte, has a significant impact on its pore utilization for adsorption and multi-cycle performance in capacitive coagulation; , the influence is dominant. Larger pore diameters (and thus pore mouth surface areas) provide significant contact area between the pore channels and the electrolyte. A small pore size has a more limited contact area (ie, "pore mouth surface area"). Pore size is defined by IUPAC as microporous, mesoporous, and macroporous pore sizes of less than 2 nm, 2-50 nm, and greater than 50 nm, respectively. The lifetime of an adsorption medium has a direct correlation with the pore size present on the surface of the material. The concept and effects of "pore pore roofing", also called pore mouth plugging, after repeated cycles of adsorption and desorption using activated carbon electrodes are described below. After repeated FPC polarity reversal cycles, the pore mouth "roofs" or "closes" and the pore channel "collapses" so that the pore surface area becomes more efficient for trapping and adsorbing target species. ceases to function.

[00145] Applicants' devices incorporating capacitive coagulation technology remove soluble (dissolved) and insoluble (particulate) lead species from sample tap water spiked with lead concentrations up to about 300 ppb, well beyond EPA action levels. was removed until it fell below Efficient lead removal was demonstrated even at lead concentrations as low as 5 ppb in the input stream, well below action levels. Prototype devices have achieved greater than 90% and often greater than 99% specificity for lead removal over other components commonly found in tap water, such as calcium (Ca ²⁺ ). Applicant's capacitive coagulation invention was able to achieve this performance in hard alkaline water, where lead species tend to form complexing species that are difficult to remove with commercial off-the-shelf products. CCC can also unexpectedly remove both soluble (dissolved) and insoluble (particulate) lead, arsenic, nickel, and copper species.

[00146] Applicant's capacitive coagulation invention, in one embodiment for lead removal, provides one gallon per minute (gpm) provides a POU/POE water purification device capable of meeting NSF/ANSI 53 and 61 certification with a minimum flow rate of . In addition, the device is (i) highly specific for target metals such as arsenic, lead, nickel, copper, cadmium, lead, manganese, mercury, and radioactive metals, which is better than state-of-the-art solutions ( ii) reliable, (iii) efficient, and (iv) long lasting. Applicant's capacitive coagulation cell removes soluble and insoluble lead to less than 15 ppb, making it a more efficient, less expensive cell suitable not only for residential use but also for scaling up to higher throughput systems. , to realize a highly scalable water purification device. Although the detailed examples below focus on lead removal using a capacitive coagulation cell, adjustment of the CCC parameters allows the CCC to be "tuned" for any other metal for which a Pourbaix diagram exists. or metal derivatives such as arsenic, cadmium, manganese and mercury, also Se, Ni, Zn, Al, Sc, Ti, V, Cr, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru , Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm , Yb, and Lu can be eliminated.

[00147] In the direct comparison shown in Figure 3, Applicant's CCC compares with commercially available POU/POE water purification devices such as Brita® Longlast™ and Brita® PUR. Filter, as well as Calgon GAC filter material. Brita® Long Last™ Pitcher Filters have shown dramatically different performance when tested on two different days based on changes in the chemistry of the water supplied by the Lexington, Kentucky Municipal Water System. Met. This different performance highlights the need for more reliable devices that perform well in the changing water chemistries that occur daily. Applicant's invention outperformed the Brita® Long Last™ device in both cases.

[00148] Soluble lead ions adsorb to carbon electrodes by physical and/or chemisorption, a process that has been well documented (J. Chem. Technol. Biotechnol. 2002, 77, 458-464). Kadirvelu, K.; Kanmani, P.; Senthilkumar, P.; Subburam, V. and Carbon. Walczyk, M.), under applied potential, undergoes further electroadsorption to the cathode. Adjustment of pH can also be utilized to control lead speciation in tap water. At an actuation voltage of 1.2 V (as shown in FIG. 4), the potential distribution across the device yields +0.9 V at the anode and −0.3 V at the cathode, with pH varying between the electrodes and an overall A neutral pH is produced. However, while the overall pH remains relatively constant, there are significant pH fluctuations (also called "plugs") from acidic at pH 2 to alkaline at pH 10, and the acid/base chemistry at the electrode surface is make a big difference. By relating the voltage and pH at each electrode to the Pourbaix diagram, the operating conditions can be selected to obtain the desired lead species formation in a given water chemistry (Fig. 4, where DIC is dissolved inorganic carbon). A similar approach to manipulating pH has been used to remove boric acid using capacitive deionization (CDI). Electrochimica Acta. 2011, 56, pp. 248-54, Avraham, E.; Noked, M.; Soffer, A.; Aurbach, D.; For most residential and commercial applications, the input stream pressure is less than 60 psi, and electrode porosity typically avoids a drop of more than 20 psi at the FPC outlet compared to the inlet pressure.

[00149] In CCC, during operation, there are multiple mechanisms of action for lead removal: physical and electrochemical adsorption, pH regulation resulting in acid/base chemistry, and electrical adsorption to produce lead oxide and other insoluble species. Chemical/chemical oxidation occurs simultaneously. The effects of applied potential and H ₂ O ₂ evolution on lead removal from tap water were verified by experimental data. As shown in Table 5, some lead physisorption occurs on the carbon electrode at open circuit. For shorts, there is a slight improvement in lead removal, but the most dramatic results occur at an applied voltage of 1.2 V, dropping the lead concentration to nearly 0 ppb. In the CCC used in the experiments, "feed" is the input stream and "processed" is the output stream.

[00150] In FIG. 4, the Pourbaix diagram for lead (Pb) in aqueous carbonate solution shows the Pourbaix operating region for lead species removal at the CCC at the intersection of E applied to the anode and cathode. . In the flow-through cell, FIG. 2 shows that the starting pH range of the cathode is acidic (pH 2-3), while the starting pH range of the anode is basic (pH 9-10). . In the flow-through cell design (FIG. 2), these pH regions are the result of reactions occurring at the electrode surface, resulting in pH fluctuations of 2-10. In FIG. 4, Pb ²⁺ is in solution equilibrium in the mostly white region (approximately pH 7) between the darker PbO ₂ (s) and Pb(s) regions. However, in the solution closest to the anode and cathode, Pb ²⁺ either (i) becomes reactive or (ii) becomes immobilized as other Pb species. FIG. 5 shows the reaction mechanism by which Pb is removed from solution. In the flow-through cell, in the alkaline (pH 9-pH 10) region near the anode (at 0.9 V applied E, generated from the pH generated at the cathode), Pb ²⁺ is PbCO ₃ −2Pb(OH) ₂ , 2Pb (OH) ₂ and immobilized as PbO ₂ (adsorbed to the anode). In the alkaline region near the anode, Pb ²⁺ also forms ionic compounds and lead hydroxides (as shown in the middle box of FIG. 5), which are then oxidized to PbO _{2 ,} Pb ₃ O ₄ , and Pb (OH) ₂ and these reaction products are then immobilized (adsorbed). Also, in the flow-through cell, hydrogen peroxide generated at the cathode by reduction of dissolved oxygen and combined with the acidic pH (pH 2-pH 3) generated at the anode at an applied E of −0.4 V is a strong oxidant. is. Hydrogen peroxide diffuses into the flow-through including the region near the anode where it oxidizes the lead species in the intermediate reactions described above. This removes the immobilized lead species from the solution. Additional lead species are more likely to be immobilized by reaction with hydrogen peroxide generated by oxygen reduction at the cathode (“peroxide cell”). Water Research. 2017, 120, pp. 229-237, Tang, W.; He, D.; Zhang, C.; Kovalsky, P.; Waite, T.; D. In a hybrid system, an FPC can be used in series with a peroxide cell to achieve increased lead removal.

[00151] In EDC, a cascade of chemical-electrochemical-chemical-electrochemical reactions occur to decompose free chlorine and chloramines. pH and actuation voltage are correlated via the Pourbaix diagram for the target species. Examples for hypochlorite, hypobromite, and monochloramine are given below and shown in Figures 6, 7 and 8, respectively. Based on the pH and potential distribution at each electrode, target species formation can be controlled by selecting the pH and applied voltage. This calibration process determines and controls which species are decomposed at which voltage for a given influent water chemistry. In FIGS. 6-8, the y-axis is the standard hydrogen electrode (SHE) voltage applied between the anode and cathode, and the x-axis is pH.

[00152] Referring to FIG. 6, at anode potentials of less than 1.5 V versus NHE and total cell potentials of less than 2.5 V applied across the anode and cathode, the electrochemically generated hydrogen peroxide Reacts with "free chlorine" in solutions with a pH greater than 7. Direct electrochemical reduction of hypochlorous acid (HOCl) and hypochlorite ions (OCl ⁻ ) from a carbon cathode converts them to free chloride ions and water. The chloride ions are then capacitively adsorbed (immobilized). There is no upper limit to the pH (e.g., _H2O2 can be used to dechlorinate the effluent from a caustic/chlorine odor scrubber), but in practice _the is preferably pH 8.5.

[00153] Referring to Figure 7, Pourbaix diagram for hypochlorite, anodic potential below 1.2 V vs NHE, cathodic potential above -1.0 V vs NHE, and At total cell potentials of less than 2.2 V applied across the electrochemically generated hydrogen peroxide reacts with "free bromine" in solutions with a pH greater than 7. Direct electrochemical reduction of hypobromite (HOBr) and hypobromite ions (OBr ⁻ ) from a carbon cathode converts them to free chloride ions and water. The bromide ions are then capacitively adsorbed (immobilized).

[00154] Referring to Figure 8, which is a Pourbaix diagram for monochloramine, an anodic potential of less than 1.4 V vs. NHE, a cathodic potential of greater than -1.0 V vs. NHE, and a At total cell potentials below 2.4 V, the direct electrochemical transformation of chloramines under acidic conditions produces ammonium salts. Electrochemically generated hydrogen peroxide (at the EDC cathode) reacts directly with chloramines to produce a mixture of products: chloride ions, nitrite ions, protons (acids), and water. Chloramines react with electrochemically generated hydrogen peroxide to produce ammonia, which 1) reacts with electrochemically generated hydrogen peroxide to produce nitrogen and hydrogen gases and water, or 2. ) reacts further with acids to give ammonium salts in two ways. Chloramines also react directly with electrochemically generated acids in a cascade process to produce trichloramines, which are converted to hypochlorous acid in water.

[00155] EDCs typically operate at a total cell potential of less than 3.0 V applied across the anode and cathode. Depending on the target species and input water chemistry, the total cell potential below 3.0V applied across the anode and cathode in the EDC is typically between 1.0V and 3.0V.

[00156] As shown in Figure 9, the active surface area of SC, KN, and CG carbon electrodes decreases with exposure to cycles of applied voltage. The specific charge passing through of CX is stable over cycling, but lower than the other carbons tested. In contrast, Applicants' HE electrode formulated with PMD performs better than the other electrodes and maintains superior performance after about 220 cycles. In SC, KN, CG, and CX electrodes, oxide groups form on the surface, causing pore roofing and pore collapse, leading to increased resistance (bulk oxidation). Alternatively, oxide groups may form a resistive oxide layer (surface oxidation). In both scenarios, according to Ohm's law, it is necessary to increase the applied voltage to maintain the same amount of current and compensate for this increase in resistance: V=IR, where V is the voltage (V ), I is the current (A), and R is the resistance (Ω).

[00157] Figure 10 shows that at a given applied voltage, a potential distribution exists between the anode and cathode in the CCC. The voltage is divided between the electrodes, but may not be equal. For example, if 1.6V is applied to the FPC, the cathode can be −0.9V vs SCE and the anode can be +0.7V vs SCE (FIG. 10). This, in turn, affects the operating parameters of the FPC and the frequency of polarity switching performed in each cycle of operation in the EDC. Active surface area, carbon material, and applied voltage, among others, affect the potential distribution. The Epzc of the electrode affects the distribution of E applied during the first use of the electrode, and the potential distribution changes slightly. Balancing the faradic kinetics at the anode and cathode ultimately stabilizes the potential distribution.

[00158] The accelerated oxidation studies shown in Figure 11 demonstrate the effect of pore "collapse and roofing" observed in microporous carbon. This highlights that mesoporous carbon can handle large applied voltages while maintaining charge efficiency and avoiding pore collapse and roofing effects. Careful selection of PMDs used in FPC devices can greatly improve device reliability and lifetime, thereby reducing water treatment costs.

[00159] A bench-scale CCC system is shown in FIG. Capacitive coagulation systems achieve lead removal selectivities greater than 50% relative to non-metallic ions. In a CCC tuned (using the CCC parameters) to remove lead (“lead removal CCC”), lead removal can approach 100%. In one embodiment of the lead-removing CCC, various oxygen-based surface groups were added to the electrodes, and at a CCC operating voltage of 1.2 V, lead was reduced to less than 15 ppb in all cases for a tap water input stream of about 50 ppb. Lead removal is achieved. Using carboxyl-functionalized electrodes (also referred to as treated electrodes) as described in US Provisional Patent Application No. 62/702,286, incorporated herein, the lead removal CCC reduces the concentration of lead in the output stream to down to 0.05 ppb, which corresponds to a removal efficiency of 99.9%.

[00160] Confirmed by ICP-MS and calculated as percent removal of species, the removal selectivity for dissolved lead ^was : It was consistently above 99% (Table 6). Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analyzes of the filtered electrode confirming lead immobilization are shown in FIG.

[00161] To further study the effect of applied potential on lead removal, lead-spiked tap water was filtered with no applied potential (passive filtration/physisorption) through a packed column filled with activated carbon. A comparison was made with CCC (active filtration/capacitive coagulation) operated at 1.2V. The same amount of carbon and flow rate was used for both experiments. The breakthrough curves for these studies are shown in FIG. The packed column initially adsorbed lead as indicated by a sharp drop in concentration, but began to saturate after only about 0.3 L of water passed through the carbon. In contrast, the CCC was able to filter 5 gallons of water to a staggering 10,000 ppb, maintain performance, and consistently remove lead at concentrations below 2 ppb. This is extrapolated to an estimated device capacity of 1 g or more of lead removed per gram of carbon electrode. The prototype device shown in FIG. 9 produced a total capacity of over 500 g of lead, which corresponds to a theoretical volumetric capacity of approximately 8.8 million gallons assuming an input stream concentration of 150 ppb lead. Other factors also affect the CCC performance of the POU configuration, resulting in a predicted CCC volumetric capacity of 100,000 gallons. In contrast, current POU filters have a volumetric capacity of only about 1,500 gallons.

[00162] In addition, dissolved oxygen (DO) dropped to about 10% of saturation, which corresponds to less than 1 ppm DO and _1.25 ppm _H2O2 after filtration at an applied potential of 1.2V. was measured (Fig. 15). These observations reveal that lead removal is affected by _a combination of potential and _H2O2 generation. The Pourbaix diagram of FIG. 4 highlights how sensitive lead speciation is to small changes in water chemistry, such as pH and voltage fluctuations. The combination of these mechanisms produces the observed advantages of capacitive coagulation used in CCC.

[00163] To test the limits of Applicants' CCC device, tap water with lead concentrations as low as 5 ppb and as high as 10,000 ppb were treated with CCC. An applied voltage of 1.2 V resulted in successful lead removal in all cases (Table 7). Even at very dilute conditions where passive filtration consisting of equilibrium-based adsorption is difficult, the active filtration process of capacitive coagulation is excellent, with selectivities greater than 99% (Table 6).
Important improvements in CCC device performance over prior art devices:
99.9% lead removal >99% selectivity maintained down to about 5 ppb lead Developed active lead filtration system (capacitive coagulation)
permanent lead removal

[00164] Higher throughput CCC systems are created by adding more capacitive coagulation cells and/or by using larger electrodes in each cell. These large systems achieve lead removal efficiencies of 150 ppb to 10 ppb or less at flow rates of 1 gpm and above.

[00165] Preferred applied for removal of Al, Ag, Au, Br, Cl, Co, Cu, Fe, Hg, Ir, Mn, Pb, Pd, Pt, Ni, Zn, and chloramines using FPC E is shown in Table 1.

[00166] The CCC system removes lead to below EPA action levels even when the input stream has various combinations of lead content, water hardness, alkalinity, disinfectant, and pH. The chemistry of the water affects the speciation of lead (eg, the chemistry of the municipal water supply varies daily, and the effect is shown in Figure 4 above). Currently, there is no single device that can handle all forms of lead. Prior art devices typically use physical trapping at higher pH and zeolitic media at lower pH. In contrast, CCC can remove all forms (species) of lead commonly found in drinking water sources.

[00167] Various operating parameters are considered depending on the type of water. Corrosion of internal materials is a common concern in electrochemical-based systems, but little evidence of corrosion has been observed in FPC systems. The internal parts are designed and materials are chosen to be extremely robust, stable and inert to electrolytic and chemical corrosion. In one embodiment of the present invention, the FPC system is designed to switch to an open circuit or small potential when not in use after on/off operation or if lead leaching is found due to the addition of chloramines. An inexpensive carbon block prefilter is added to remove chloramines. An optional post-filter is added if it is discovered that small pieces of carbon cloth have fallen off over time.

[00168] Operational adjustments for specific water chemistries. Analysis of a typical input stream supplied to a given FPC device allows for adjustments to optimize operating parameters for specific water chemistries (adjustments include physical and electrical lead to optimize chemisorption, pH control, and oxidation to lead oxide and other insoluble species). Typical operating parameters are adjusted as follows:

[00169] Operating Voltage. To obtain the potential distribution, a three-electrode set-up is used with the cathode, anode, and a standard calomel electrode (SCE) as a reference. The potential at each electrode is recorded for open circuits, short circuits, and up to a voltage of 1.4 V in 0.2 V steps. pH and actuation voltage are correlated via the Pourbaix diagram. Lead species formation can be controlled by selecting the applied voltage based on the pH and potential distribution at each electrode. This calibration process determines and controls which lead species will deposit at which voltage for a given input stream water chemistry.

[00170] Oxygen reduction and _{H2O2 evolution} . Oxygen reduction at the cathode generates H ₂ O ₂ which can react with lead species to promote the formation of lead oxide. An applied voltage of 1.2 V significantly reduces DO and 1.25 ppm H ₂ O ₂ is measured in filtered water. The actuation voltage is controlled to amplify this reaction and maximize lead removal. Experiments were run with open circuits, short circuits, and a maximum voltage of 1.4 V in 0.2 V increments, where pH, DO, and H ₂ O ₂ concentrations at the outlet typically remove lead below EPA action levels. .

[00171] Carbon conductivity. FPC devices typically use medium conductivity microporous carbon (carbon B in Table 8). To elucidate the effect of capacitive solidification on lead removal, a comparative study of carbons with different properties in Table 8 was performed.

_[ 00172] CCC lead removal techniques include: (i) physisorption; (ii) capacitive adsorption; (iii) electrochemical pH adjustment and metal immobilization; (iv) electrochemical peroxide ( _H2O2 ) generation; (v) electrodeposition (e.g., electroplating, electrophoretic deposition); (vi) electrochemical oxidation; (vii) deposition; (viii) pore size profile, (ix) electrode treatment, (x) Dependent on electrode spacing and (xi) flow-by vs. flow-through vs. carbon block cell design. A combination of these factors, or a cascade of these factors, causes speciation and immobilization of target species that are trapped in the pore network of the carbon electrode, resulting in a clarified effluent. It is essential that the carbon electrode be electrically conductive. Higher conductivity carbon materials result in more uniform current distribution across the electrode, typically leading to increased H ₂ O ₂ generation and a more efficient lead removal process. Pore size and surface area are related to the adsorption capacity and tortuosity of the material. Pore size and surface area also affect H ₂ O ₂ generation in FPC devices.

[00173] POU/POE device design. The POU/POE FPC product design parameters are: (1) device residence time and size specified to achieve a flow rate of 1.5 gpm; and (2) processing at least 150 gallons of water at 1.5 gpm. effective lead removal defined by a reduction in dissolved lead levels from 150 ppb to less than 10 ppb and a removal selectivity of greater than 90% for non-metallic divalent ions.

[00174] Water residence time: Residence time is a measure of the average time (volume/flow rate) that a volume of water stays in the device. In other words, it is the time required to filter a given amount of water. The internal volume of the device and the flow rate determine the residence time. For a bench-scale CCC device, a flow rate of 20 ml/min and a residence time of 5 minutes typically gives the desired removal. The residence time at the flow rate at which performance peaks is chosen as a design specification and the device is sized appropriately.

[00175] Pressure drop: The pressure drop across the FPC device becomes increasingly important with increasing flow rates. A pressure drop of less than 20 psi is considered acceptable and below the normal inlet water pressure of about 45 psi for residential and urban buildings.

[00176] Ultimate capacity of FPC devices. NSF/ANSI certification requires lead levels to be reduced from 150 to 10 ppb, and POU systems on the market are rated to treat up to 120 gallons of water. This means that about 1 gallon of water per gram of carbon is treated for the pitcher system and about 1.6 gallons of water per gram of carbon is treated for the under-sink system. One embodiment of the CCC device can process 2 gallons of water at 1.5 gpm and lead levels from 150 ppb to 10 ppb or less. The ultimate capacity of the system is obtained from the lead removal curve. Pressure drop problems typically occur after removing more than 1 g of lead per gram of FPC carbon electrode. Embodiments of the CCC for POU/POE use may include lead sensors and/or pressure drop sensors to alert the user to device replacement.

[00177] FPC replacement threshold range for various embodiments. Generally, CCCs are exchanged when target metal concentrations in the output stream exceed the relevant threshold levels, e.g. the Lead and Copper Rule (https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations)). The threshold level (also called sorption capacity) can be specified by the agency or selected by the user. Municipal and industrial wastewater discharge limits are different from potable water limits. Metal concentration thresholds are typically higher. Effluent guidelines exist for various industries (https://www.epa.gov/eg).

[00178] FPC regeneration. Instead of replacing the FPC, some FPCs regenerate (e.g., desorb adsorbed metal ions and particles from the CCC electrode in CCCs when the metal concentration in the FPC output stream rises above a threshold level). can be) removed. One method of CCC regeneration is to flush the cell with acid to dissolve the solidified metal and regenerate the electrodes. During this "acid regeneration" step, the output stream is sent to a vessel where a highly concentrated waste stream is collected for further processing. After the acid regeneration step, the CCC is flushed with water until the output stream reaches pH 7 (or other target pH), after which normal CCC operation (i.e., removal of metal ions and particles from the flow-through) is performed. resumed. Another method of CCC regeneration is by electrolysis or electrochemical regeneration in acidic solutions. Electrolytic (also called electrochemical) regeneration converts metal oxides to soluble metal ions, which are washed out of the CCC with water and collected in a waste container. Electrolysis is an electrochemical reaction that requires the application of an external voltage to promote non-spontaneous reactions. Any insoluble metal species formed on the electrodes can be dissolved into solution using a small voltage, typically 5 V or less, applied across the CCC. CCC regeneration can also be a sequence of acid regeneration followed by electrolysis or vice versa.

[00179] Multiple FPCs in series, each targeting the same or different species. Multiple FPCs connected in series (outlet to inlet), tuned to remove the same target species, continuously increase the target species concentration with a single pass of the input stream through the series-connected FPCs. Acts to reduce (achieving the same level of target species removal as running a single cell in batch mode multiple times). By adjusting the FPC parameters of multiple cells connected in series, e.g., the pH of the flow-through and the voltage applied to the cell electrodes of a given cell, to different FPC and EDC parameters, in some cases, 1 Each pass in series allows each cell to remove a different target species from the pass-through. A Pourbaix diagram showing speciation of a target species at a given voltage and pH best illustrates the concept of "cell series." Pourbaix diagrams for lead (FIG. 16) and copper (FIG. 17) are used to illustrate the immobilization of different metals in the CCC series. The horizontal dashed line represents the applied voltage, which can be moved along the vertical axis. The vertical dashed line represents pH, which can be shifted along the horizontal axis. The areas where these lines intersect represent the metallic species present at these conditions. The operating conditions illustrated in Figures 16 and 17a were to immobilize (adsorb to the CCC electrode) Pb and Cu as _PbO2(s) (Figure 16) and Cu(OH) _2(s) (Figure 17), respectively. of metals from the feed stream. At the operating conditions illustrated in Figure 17b, Cu is electrodeposited or electroplated on the electrodes as Cu _(s) . Pourbaix diagrams for nickel, iron, manganese, aluminum and zinc are also included (FIGS. 18-22). A similar approach of manipulating applied voltage and pH can be used to remove these metals. The operating conditions chosen to form the insoluble species may differ for each target species, and there are several possibilities for a given target species, depending on the species formation illustrated in the Pourbaix diagram. obtain.

[00180] As explained below, using the Pourbaix diagrams shown in FIGS. selected for removal from the influent. Applied voltages and electrochemical pH adjustments can be selected by one skilled in the art to remove a given species of target element or complex. Copper is removed by CCC by electrodeposition, hydroxide deposition, and/or oxidation to copper oxide.

[00181] FPC control system. FPC parameters for a given FPC are monitored and controlled using a computer system that monitors and/or controls various sensors, interfaces, valves, and peripherals, commonly referred to as a process control computer (also called a process controller). ) and are generally associated with continuous or semi-continuous production activities associated with materials, such as chemicals and petroleum, whether in liquid, solid, or gas phase. The process control computer allows FPC parameters to be applied to one or more FPCs in the system and to change the path of the flow through, eg, to convert a serial system architecture to a series-parallel system architecture.

[00182] Extension of FPC design to other target species for which Pourbaix diagrams exist. In addition to Pb, Ni, Zn, Al, Cu, Fe, Mn, Cl, Br, and chloramines, the FPC parameters and systems and methods disclosed above can be used for As, Se, Sc, Ti, V, Cr, Co , Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ce, Pr, Nd, Pm, Sm , Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and the removal of metal and halide species identified in the Pourbaix diagram for other halides.

[00183] [Example]
[00184] EDC performance tests were performed to verify the removal of total chlorine, free chlorine, chloramines, and peroxides ( _H2O2 ) using carbon electrodes and _voltages below 3.0V. Measurements were made using analytical test kits. Experiments were performed using a flow-by-cell design and 14 pairs of electrodes in alternating series anode-cathode-anode-cathode (a variable number of repetitions of anode-cathode) anode-cathode (FIG. 23). In the flow-by design shown in FIG. 23, the input flow travels through an annular space near the wall of the cell vessel, then flows over the electrode surface toward the center into the axial channel and then through the axial channel. and discharged to the FPC outlet. A positive voltage is applied to the anode and a negative voltage is applied to the cathode. To ensure that all electrodes degrade at the same rate and extend the life of the EDC device, the polarity of the voltage applied to a given electrode is periodically switched (each anode to cathode, each cathode to anode ). An example is shown in FIG. The interval between polarity switching for a given EDC can be set arbitrarily (e.g., every hour) or one or more EDC parameters, e.g. current threshold, voltage threshold, current reduction at constant voltage It can also be set based on rate, rate of current reduction at constant voltage, rate of voltage reduction at constant current, rate of voltage reduction at constant current, total volume processed, and concentration of target species in the EDC effluent. Preferred polarity switching points are (i) the rate of decrease in current at constant applied voltage, (ii) the rate of increase in voltage at constant applied current, (iii) the total volume treated, and (iii) is the concentration of the target species. Depending on the target species, the rate of decrease or increase may be detected before an increase in concentration of the target species in the effluent is detected, and vice versa (V vs. concentration of the target species in the effluent is plotted). See figure below). Three types of carbon were investigated. Table 4 shows electrode characteristics.

[00185] Capacitive solidification experiments were performed to test Cu removal using 16 pairs of carbon electrodes (~13 g of carbon). The cathode was pure SC and the anode was SC oxidized with nitric acid. The FPC was operated with a short circuit (0V). 1 L of feed solution of about 100 ppm Cu[Cu(NO ₃ ) ₂ ] in direct injected (“DI”) H ₂ O was processed at a flow rate of 20 ml/min. The sample was analyzed by inductively coupled plasma (ICP) using an optical emission spectrometer (OES) and the results in Table 9 show that about 1/3 of the Cu was removed in one pass.

[00186] Capacitive solidification experiments were performed to test Cu removal using 12 pairs of carbon electrodes (~10 g of carbon). Both cathode and anode were pure SC. The FPC was operated with a potential of 1.2 V applied to the cathode. 18.5 L of a feed solution of about 50 ppm Cu[Cu(NO ₃ ) ₂ ] and about 50 ppm Ca(CaCl ₂ ) in DIH ₂ O was processed at a flow rate of 20 ml/min. During operation, Cu is plated onto the cathode from solution and is shown as a grayish deposit in Figure 25a.

[00187] Flow-by capacitive coagulation experiments were performed using 14 pairs of carbon electrodes (approximately 30 g of carbon) to test Cu removal. The cathode was KN oxidized with nitric acid and the anode was pure carbon. The FPC was operated at applied potentials of 0.8, 1.0 and 1.2V. 1.5 L of feed solution of about 2 ppm Cu[Cu(NO ₃ ) ₂ ] in tap H ₂ O was processed at a flow rate of 100 mL/min. Samples were taken before and after cell filtration and the Cu ²⁺ concentration was measured by ICP-OES. Approximately 78% Cu removal was achieved for all conditions tested (Table 10).

[00188] Flow-by capacitive coagulation experiments were performed using 14 pairs of carbon electrodes (approximately 30 g of carbon) to test Cu removal at low pH. The cathode was KN oxidized with nitric acid and the anode was pure carbon. The FPC was operated at 1.2V. 1.5 L of feed solution of about 10 ppm Cu[Cu(NO ₃ ) ₂ ] in tap H ₂ O was processed at a flow rate of 100 mL/min. The pH was adjusted to _2.8 using concentrated _H2SO4 . Samples were taken before and after cell filtration and the Cu ²⁺ concentration was measured by ICP-OES. Cu was removed very effectively (Table 11) with 99.8% removal.

[00189] A flow-by capacitive coagulation experiment was performed using 14 pairs of carbon electrodes (~30 g of carbon) to test Ni removal. The cathode was KN oxidized with nitric acid and the anode was pure carbon. The FPC was operated at applied potentials of 0.8, 1.0 and 1.2V. 1.5 L of feed solution of about 50 ppm Ni[Ni(Cl) ₂ ] in tap H ₂ O was processed at a flow rate of 100 mL/min. Samples were taken before and after cell filtration and the Ni ²⁺ concentration was measured by ICP-OES. A maximum rejection of about 63% was achieved at 1.2V (Table 12).

[00190] Capacitive coagulation experiments were performed using 16 pairs of carbon electrodes (approximately 14 g of carbon) to test Fe removal. The cathode was pure SC and the anode was SC oxidized with nitric acid. The cell was operated with a short circuit (0V). 18.5 L of feed solution of 100 ppm Fe[Fe(Cl) ₃ ] or 25 ppm FeCl ₃ in DIH ₂ O was treated at a flow rate of 20 ml/min. The concentration of Fe steadily decreased with treatment and the ICP-OES results are shown in Table 13. For high concentration experiments (100 ppm Fe), Fe oxides formed at the cathode as a rust-colored deposit on the separator, shown as a grayish deposit (FIG. 26).

[00191] A flow-by capacitive coagulation experiment was performed using 14 pairs of carbon electrodes (approximately 30 g of carbon) to test Fe removal. The cathode was KN oxidized with nitric acid and the anode was pure carbon. The FPC was operated at applied potentials of 0.8, 1.0 and 1.2V. 1.5 L of feed solution of about 15 ppm Fe[Fe(Cl) ₃ ] in tap H ₂ O was processed at a flow rate of 100 mL/min. Samples were taken before and after cell filtration and the Fe ³⁺ concentration was measured by ICP-OES. Approximately 99.9% Fe removal was achieved for all conditions tested (Table 14).

[00192] Flow-by capacitive coagulation experiments were performed using 14 pairs of carbon electrodes (approximately 30 g of carbon) to test Mn removal. The cathode was KN oxidized with nitric acid and the anode was pure carbon. The FPC was operated at applied potentials of 0.8, 1.0 and 1.2V. 1.5 L of feed solution of about 20 ppm Mn[Mn(SO ₄ )] in tap H ₂ O was processed at a flow rate of 100 mL/min. Samples were taken before and after cell filtration and the Mn ²⁺ concentration was measured by ICP-OES. About 99.8% Mn removal was achieved at 1.2 V (Table 15).

[00193] Flow-by capacitive coagulation experiments were performed using 14 pairs of carbon electrodes (approximately 30 g of carbon) to test Al removal. The cathode was KN oxidized with nitric acid and the anode was pure carbon. The FPC was operated at applied potentials of 0.4, 0.8 and 1.2V. 1.5 L feed solution with about 30 ppm Al from a wastewater sample was processed at a flow rate of 100 mL/min. Samples were taken before and after cell filtration and the Al ³⁺ concentration was measured by ICP-OES. About 99.9% Al removal was achieved at 0.4 V (Table 16).

[00194] A flow-by capacitive coagulation experiment was performed using 14 pairs of carbon electrodes (approximately 30 g of carbon) to test Zn removal. The cathode was KN oxidized with nitric acid and the anode was pure carbon. The FPC was operated at applied potentials of 0.4, 0.8 and 1.2V. 1.5 L of feed solution of about 35 ppm Zn[Zn(Cl ₂ )] in tap H ₂ O was processed at a flow rate of 100 mL/min. Samples were taken before and after cell filtration and the Zn ²⁺ concentration was measured by ICP-OES. About 40.8% Zn removal was achieved at 1.2 V (Table 17).

[00195] To investigate the physisorption of Pb on pure and oxidized kynol, a packed column was filled with about 5 g of carbon and 1 L, 20 ml of _DIH2O with about 100 ppm of Pb [Pb( _NO3 ) ₂ ]. /min flow rate. The results in Table 18 provide evidence that Pb is physically adsorbed on carbon. In addition, after filtration, there was a significant amount of white precipitate on the pure Kynol electrode (Fig. 27), which was confirmed to be lead oxide by Energy Dispersive X-ray Spectroscopy (EDX) (Fig. 27). 28).

[ ₀₀₁₉₆ ] Flow-through capacitive using 1 L feed solution of ~50 ppb Pb[Pb( _NO3 ) ₂ ] in tap H2O, 12 pairs of pure carbon electrodes (~10 g) and a flow rate of 20 mL/min Coagulation studies showed Pb removal to well below federal action levels of 15 ppb in a single pass (Tables 19 and 20). The cell was operated with a short circuit (0V) and applied potentials of 0.8 and 1.2V. Pb was spiked several times to test the removal. The experiments in Table 20 were performed at 1.2 V using a pure anode and a cathode oxidized with nitric acid. Samples were taken before and after filtration through the cell and Pb ²⁺ concentrations were measured with an ANDalyze handheld sensor and/or inductively coupled plasma mass spectroscopy (ICP-MS). "\" in the table means "not measured".

[00197] 1.5 L feed solution of about 5 to about 275 ppb Pb[Pb(NO ₃ ) ₂ ] in tap H ₂ O, 14 pairs of carbon electrodes (about 30 g), pure anode and oxidized with nitric acid Flow-by capacitive coagulation experiments using the cathode and a flow rate of 100 mL/min also showed Pb removal to well below the federal action level of 15 ppb in a single pass (Table 21). The cell was operated with an applied potential of 1.2V. Samples were taken before and after cell filtration and Pb ²⁺ concentrations were measured with ANDalyze handheld sensors and/or ICP-MS. The results revealed that Pb was permanently removed from the solution.

[00198] Flow-through capacitive coagulation using 1 L of feed solution of ~50 ppb Pb[Pb( _NO3 ) ₂ ] in tap _H2O , 12 pairs of carbon electrodes (~10 g), and a flow rate of 20 mL/min. Experiments were performed at open circuit voltage (OCV), short circuit (0 V), and applied potentials from 0.4 to 1.4 V in 0.2 V steps. Various oxygen-containing surface groups and carbons with different properties were tested. Samples were taken after one pass through the cell and the Pb ²⁺ concentration was measured with an ANDalyze handheld sensor and/or ICP-MS.

[00199] The experimental results in Table 22 are for a pure anode and a cathode oxidized with citric acid. Pb was removed by OCV and short circuit, but was removed more effectively under applied potential. Best results were obtained at 1.2 V, with 92% Pb removal.

[00200] The experimental results in Table 23 are for a pure anode and a cathode oxidized with nitric acid. The measured Pb concentration is below the spiked value of about 50 ppb. The pH was close to 9 and was likely free of insoluble Pb species as measured. An orange deposit was also observed on the last piece of pure carbon (anode) and was found around the filter paper.

[00201] The experimental results in Table 24 are for a pure anode and a cathode oxidized in an oven at 340°C for 72 hours. Pb removal was observed at short and 1.2V. Dissolved oxygen (DO) was also monitored throughout the experiment and decreased with applied voltage, suggesting that oxygen is being reduced to _H2O2 (Table 25) _.

[00202] Three carbons were tested: Kynor, Zorflex, and Fulcell Earth. These properties are listed in Table 26. Results using Zoflex are shown in Tables 27 and 28. DO decreased with applied voltage and lead removal improved.

[00203] Results using Kynol are shown in Tables 18-24 and Tables 29, 32 and 36 below. For the results shown in Table 29, only OCV, short circuit, and applied potential of 1.2V were tested. Even with a starting concentration of about 10 ppb, lead removal to very low levels was achieved and the DO concentration dropped below 6% at 1.2V. SEM/EDX confirmed Pb deposition on the electrodes (FIG. 13).

[00204] Fuelcell ground (www.fuelcellstore.com) is a graphite cloth and is highly conductive. The results are shown in Tables 30 and 31. In both cases there was no measurable current due to the very small surface area. When the cell was disassembled after the first experiment (Table 30), there was an orange deposit on all filter papers regardless of location within the cell. The experiment was repeated using pure carbon for both the anode and cathode, and samples were taken after the 3-hour repetition instead of one pass (Table 31). In this case, no lead was removed for an open circuit, some was removed for a short, and much more was removed for an applied potential of 1.2V. DO remained unchanged regardless of applied potential and H ₂ O ₂ was measured to be 0 ppm at 1.2V. Pb removal may not occur by reaction with _H2O2 , but by pH fluctuations at _the electrode surface.

[00205] The same series of experiments were conducted with Pb mixed into synthetic tap water (Tables 32 and 33). This water contained no carbonate and the concentrations of other ionic species were similar to our tap water. Pb removal was observed at OCV and short, with slightly more removal at 1.2V. DO concentrations were low throughout the experiment.

[00206] A breakthrough curve for a packed column of pure or nitric acid oxidized carbon (about 5 g) was obtained and ₁ L of tap H2O with Pb[Pb( _NO3 ) ₂ ] of about 150 ppb at 20 mL/min. Flow filtered (Tables 34 and 35). In this case, Pb removal is occurring by physisorption (passive filtration) rather than capacitive adsorption and coagulation by our device (active filtration). The initial Pb concentration drops dramatically, but both carbons quickly saturate and become ineffective after about 0.3 L of water. Under the conditions tested, pure carbon appears to be more effective at physisorbing lead compared to oxidized carbon. To determine when the flow-through embodiment of the FPC device saturates, 12 pairs of electrodes (approximately 10 g) were used to process 5 gallons of water in one pass at 1.2 V at 20 mL/min. Sustained performance was obtained for 5 gallons of water treated (Table 36). The lead concentration remained low after filtration, while the calcium (Ca ²⁺ ) concentration remained nearly constant, demonstrating a selectivity to lead of greater than 99%. This experiment was repeated using a flow-by device, using 14 pairs of electrodes (approximately 30 g) and processing 5 gallons of water at 1.2 V at 100 mL/min in one pass (Table 37). Pb removal was maintained for the total volume passed, even from extremely high starting Pb concentrations.

[ ₀₀₂₀₇ ] Flow-by capacitive using 1.5 L feed solution of ~150 ppb Pb[Pb( _NO3 ) ₂ ] in tap H2O, 14 pairs of carbon electrodes (~30 g), and a flow rate of 300 mL/min. Coagulation experiments were performed at an applied potential of 1.2 V (Table 38). Samples were taken before and after one pass through the cell and the Pb ²⁺ concentration was measured with an ANDalyze handheld sensor. Samples processed were at the detection limit of the sensor.

[00208] 1.5 L of a feed solution of about 150 ppb Pb[Pb( _NO3 ) _{2 ]} in tap _H2O at pH 2.83 adjusted with concentrated _H2SO4 , 14 pairs of carbon electrodes (about 30 g), and flow-by capacitive coagulation experiments with a flow rate of 100 ml/min were performed at an applied potential of 1.2 V (Table 39). Samples were taken before and after one pass through the cell and the Pb ²⁺ concentration was measured with an ANDalyze handheld sensor. Samples processed were below the detection limit of the sensor.

[00209] A flow-by capacitive coagulation experiment using 1.5 L of feed solution of a wastewater sample from a Pb-acid battery manufacturer with Pb of ~150 ppb, 14 pairs of carbon electrodes (~30 g), and a flow rate of 100 ml/min was performed by: The applied potential was 1.2 V (Table 40). Samples were taken before and after one pass through the cell and the Pb ²⁺ concentration was measured with an ANDalyze handheld sensor. The effluent was well below the assigned Pb emission limit of 0.6 ppm.

[00210] 1.5 L feed solution of about 150 ppb Pb[Pb( _NO3 ) _{2 ]} in tap H2O, about 14 g carbon electrode, pure anode and nitric acid oxidized cathode, and 50, 100, and a wound cell design for capacitive coagulation experiments with a flow rate of 200 ml/min, all showing Pb removal to less than the federal action level of 15 ppb in a single pass (Table 41). The cell was operated with an applied potential of 1.2V. Samples were taken before and after cell filtration and the Pb ²⁺ concentration was measured with an ANDalyze handheld sensor.

[00211] In a capacitive coagulation experiment using 1.5 L of feed solution with about 50 ppb Pb [Pb( _NO3 ) _{2 ]} and 2.5 ppm Pb in tap water H2O and about 10 ppm Cu in tap water. A wound cell design was used. Pb removal was below the federal action level of 15 ppb for low concentrations and below 1 ppm for high concentrations (Table 42). Cu removal was over 99% (Table 43). A schematic diagram of a wound cell is shown in FIG.

[00212] A series cell architecture was used for capacitive coagulation experiments using a 2.5 ppm solution of Pb[Pb( _NO3 ) ₂ ] in tap _H2O and approximately 30 g of carbon electrodes at 1.2 V. Five consecutive gallons of water were processed and concentrations were consistently less than 48 ppb (Table 44).

[00213] The carbon block was used in capacitive coagulation experiments with 1.5 L feed solution of ~50 ppb Pb[Pb( _NO3 ) _{2 ]} in tap H2O (Table 45). Pb removal was below the federal action level of 15 ppb.

[00214] Industrial wastewaters containing multiple metal species, Cu, Fe, and Mn at concentrations in the ppm range, were used for flow-by capacitive coagulation experiments. Flow rates of 0.5, 1.0, and 1.5 L/min were tested at 1.2V. Cu was reduced by over 98%, Fe by over 14%, and Mn by over 87% (Table 46).

[00215] Reverse osmosis (RO) concentrates containing multiple metal species, Cu, Fe, and Mn at concentrations in the ppb range, or brines, were used for flow-by capacitive coagulation experiments. Flow rates of 0.1, 0.5, and 1.0 L/min were tested at 1.2V. Cu over 99%, Fe over 99% and Mn over 74% reduction (Table 47).

[00216] Total chlorine and free chlorine were measured before and after treatment with EDC conditioned for chlorine removal. Chloramine was estimated from the difference between total chlorine and free chlorine. Greater than 99% free chlorine removal and up to 99% chloramine removal were obtained. A voltage of less than 3.0 V was applied to the cell during operation. Flow rates of 100-500 ml/min were tested. A total of about 210 gallons of water was treated before performance degradation was observed due to charge loss strictly due to pore collapse.

[00217] When V>0, oxidized kynol (nitric acid treatment) was used as the anode and pure kynol was used as the cathode, and when V<0, the electrodes were switched. The total chlorine in the feed (influent) and product (effluent) streams is shown in FIG. A clear reduction in total chlorine in the effluent was observed. Figures 31 and 32 show the concentration of free chlorine and chloramine in the feed and product streams, respectively. Figure 33 shows the % removal for each disinfectant. Greater than 99% free chlorine removal and about 80% chloramine removal were obtained. Up to 100% peroxide removal was also achieved after treatment with EDC.

[00218] Oxidized Kynol (nitric acid treatment) was used as the cathode and fuel cell ground as the anode. The total chlorine in the feed and product streams is shown in FIG. A clear reduction in total chlorine in the effluent was observed at an applied voltage of 2.0V. Figures 35 and 36 show the concentrations of free chlorine and chloramines in the feed and product streams, respectively. Figure 37 is the % removal for each disinfectant. Greater than 99% free chlorine removal and about 40% chloramine removal were obtained. About 60% peroxide removal was also achieved after treatment with EDC.

[00219] When V>0, oxidized Calgon (nitric acid and electrochemical treatment) was used as anode and pure Calgon cathode, and when V<0, the electrodes were switched. The total chlorine in the feed and product streams is shown in FIG. A clear reduction in total chlorine in the effluent was observed. Figures 39 and 40 show the concentrations of free chlorine and chloramines in the feed and product streams, respectively. Figure 41 shows the % removal for each disinfectant. Up to 96% free chlorine removal and about 57% chloramine removal were obtained. About 57% peroxide removal was also achieved after treatment with EDC.

[wrap up]
[00220] In summary, the FPC invention is an electrochemical device for purifying an aqueous solution comprising at least one carbon-based anode and at least one carbon-based cathode, the anode and cathode each being Epzc-shift free. pure electrodes) are alternately arranged in a container, said container having at least one inlet for supplying an aqueous solution to the container and at least one outlet for discharging a purified output from the container. A separator is positioned between each electrode, and a power source with associated wiring provides a constant DC voltage or current to the carbon-based electrodes to remove at least one target species to be removed. An aqueous solution containing is shown in the Pourbaix diagram of at least one target species, and the at least one is a DC voltage that agglutinates the target species to the electrodes. Aggregation of at least one target species is caused by oxidation of the target species in a pH region of less than 4 near at least one anode. Alternatively, aggregation of at least one target species is caused by oxidation of the target species in a pH region of less than 4 near at least one anode and oxidation in a pH region of greater than 10 near at least one cathode. It arises from the production of agents. The power supply is controlled by the process controller or manually. The materials from which the electrodes are made have high water permeability and include activated carbon cloth, mixtures of microporous and mesoporous activated carbons, mixtures of mesoporous and macroporous activated carbons, and microporous and mesoporous activated carbons. It is selected from the group consisting of mixtures of macroporous activated carbons. The thickness of the separator is selected from the group consisting of the ranges 1 nm-100 microns, 2 nm-50 microns, 2 nm-30 microns, 1-100 microns, 1-50 microns, and 1-30 microns. The DC voltage used to achieve faradic immobilization is selected from the group consisting of less than 0.6V, less than 1.2V, and less than 2.0V. The electrodes may optionally be separated by an impermeable insulator, in which case the flow-through flows only through the porous electrodes to reach the exhaust channel, or through the permeable It may be separated by a separator, in which case the flow-through flows by the electrodes and through the separator to the exhaust channel. An ion exchange membrane can optionally cover at least one anode, at least one cathode, or both electrodes. The zero charge potential of the at least one carbon-based electrode can be shifted by a mechanism selected from the group consisting of cathodic reduction, cathodic oxidation, anodic reduction, and anodic oxidation. The spacing between electrodes is selected from the group consisting of less than 1 mm, less than 200 microns, less than 50 microns, and less than 20 microns. The FPC cell design can be wound or laminated.

[00221] The anode in the FPC is 0% to 30% microporous activated carbon containing carbon with a conductivity value greater than 10 S/cm and 70% to 100% mesoporous activated carbon. 2.0-10 nm average pore size achieved with a pore size profile of 0%-20% macroporous activated carbon and 80%-100% mesoporous activated carbon with conductive It can have an average pore size selected from the group consisting of 2.5 to 10 nm achieved using a mesoporous activated carbon pore size profile with a modulus value greater than 10 S/cm. The cathode in the FPC is 0%-30% microporous activated carbon containing carbon with a conductivity value greater than 10 S/cm and 70%-100% pores of the mesoporous activated carbon. 2.0-10 nm average pore size achieved using the aperture profile and 0%-20% macroporous activated carbon and 80%-100% mesoporous activated carbon with conductivity values of It can have an average pore size selected from the group consisting of 2.5 to 10 nm, an average pore size achieved with a mesoporous activated carbon pore size profile of greater than 10 S/cm.

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Claims (15)

An electrochemical device for purifying an aqueous solution, comprising:
At least one carbon-based anode and at least one carbon-based cathode (each said anode and cathode being a pure electrode with no EPZC shift) are alternately arranged in a container, said container containing an aqueous solution. and at least one outlet for discharging purified output from said vessel, a separator disposed between each electrode and having associated wiring. a power source supplying a DC constant voltage or constant current to the carbon-based electrode;
an aqueous solution containing at least one target species to be removed is pumped through the inlet and past or through the electrode to an exhaust channel leading to the at least one outlet;
wherein said DC voltage applied to said at least one anode and said DC voltage applied to said at least one cathode are related to the Pourbaix diagram of said at least one target species, capacitive adsorption, faradic immobilization, and a DC voltage that causes the at least one target species to aggregate to the electrode by a mechanism selected from the group consisting of both capacitive adsorption and faradic immobilization, wherein the aggregation of the at least one target species comprises: A device caused by oxidation of said target species in a pH region of less than 4 near said at least one anode . said aggregation of said at least one target species is caused by oxidation of said target species in a pH region of less than 4 near said at least one anode, said oxidation greater than 8 near said at least one cathode; 2. The device of claim 1, resulting from the generation of oxidants in the pH range. 3. The device of claim 1, wherein the power supply is controlled by a process controller or manually. The materials from which the electrodes are made include activated carbon cloth, mixtures of microporous and mesoporous activated carbons, mixtures of mesoporous and macroporous activated carbons, and microporous, mesoporous and macroporous activated carbons. 2. The device of claim 1, selected from the group consisting of mixtures of activated carbons. 1. The thickness of said separator is selected from the group consisting of the ranges of 1 nm to 100 microns, 2 nm to 50 microns, 2 nm to 30 microns, 1 to 100 microns, 1 to 50 microns, and 1 to 30 microns. devices described in . 2. The device of claim 1, wherein the DC voltage used to achieve faradic immobilization is selected from the group consisting of less than 0.6V, less than 1.2V, and less than 2.5V. 2. The device of claim 1, wherein the electrodes are separated by an impermeable insulator, and through-flow flows only through the electrodes before reaching the exhaust channel . 2. The device of claim 1, wherein the electrodes are separated by a permeable separator, and a flow-through flows by the electrodes and through the separator to the exhaust channel. 2. The device of claim 1, wherein an ion exchange membrane covers the at least one anode, the at least one cathode, or both electrodes. 2. The device of claim 1, wherein the zero charge potential of the at least one carbon-based electrode is shifted by a mechanism selected from the group consisting of cathodic reduction, cathodic oxidation, anodic reduction, and anodic oxidation. . at least one carbon-based anode comprising:
With a pore size profile of 0% to 30% microporous activated carbon containing carbon with a conductivity value greater than 10 S/cm and 70% to 100% mesoporous activated carbon an average pore size of 2.0-10 nm achieved,
0% to 20% macroporous activated carbon and 80% to 100% mesoporous activated carbon, where conductivity values are achieved using mesoporous activated carbon pore size profiles greater than 10 S/cm 2. The device of claim 1, having an average pore size selected from the group consisting of an average pore size of 2.5-10 nm. at least one carbon-based cathode comprising:
With a pore size profile of 0% to 30% microporous activated carbon containing carbon with a conductivity value greater than 10 S/cm and 70% to 100% mesoporous activated carbon an average pore size of 2.0-10 nm achieved,
0% to 20% macroporous activated carbon and 80% to 100% mesoporous activated carbon, where conductivity values are achieved using mesoporous activated carbon pore size profiles greater than 10 S/cm 2. The device of claim 1, having an average pore size selected from the group consisting of an average pore size of 2.5-10 nm. 2. The device of claim 1, wherein the spacing between electrodes is selected from the group consisting of less than 1 mm, less than 200 microns, less than 50 microns, and less than 20 microns. 3. The device of claim 1, wherein the cell design is wound, laminated, or carbon block. The average pore mouth distribution range is 0 to 50 nm, and the target species and FPC parameters are
Manganese with FPC parameters of 0 to 1.2 V anode voltage range, cathode voltage less than -1.1, and working voltage of 1.2 V;
iron with FPC parameters in the anode voltage range of 0-1.2V, the cathode voltage of less than -0.5V, and the working voltage range of 0.4-1.2V;
Cobalt with FPC parameters anodic voltage range above 0V and cathodic voltage below -0.5V;
Nickel with FPC parameters 0-1.0V anode voltage range, cathode voltage less than -0.4V, and working voltage 1.2V;
Copper with FPC parameters anodic voltage above 0V, cathodic voltage below 0V, and working voltage range of 0.8-1.2V;
zinc with FPC parameters greater than 0 V anode voltage, less than -0.8 V cathode voltage, and a working voltage range of 0.8-1.2 V;
Aluminum with FPC parameters anode voltage above 0V, cathode voltage below -1.3V, and working voltage of 0.4V;
Lead with FPC parameters anode voltage above 0.5V, cathode voltage below -0.4V, and working voltage of 1.2V;
Palladium with FPC parameters anodic voltage above 0 V and cathodic voltage below 0 V;
Silver with FPC parameters anodic voltage above 0V and cathode below 0V;
Iridium with FPC parameters anode voltage above 0.4V and cathode voltage below 0V;
platinum with FPC parameters anodic voltage above 0V and cathodic voltage below 0V;
gold with FPC parameters anodic voltage above 0.8V and cathodic voltage below 0V;
Mercury with FPC parameters anodic voltage above 0.3V and cathodic voltage below 0V;
chlorine whose FPC parameters are less than 1.5 V anodic potential versus NHE and less than 2.5 V total cell potential applied across the anode and cathode;
Bromine whose FPC parameters are anodic potential less than 1.2 V vs NHE, cathodic potential greater than −1.0 V vs NHE, and total cell potential less than 2.2 V applied across the anode and cathode; and FPC The group consisting of chloramines whose parameters are anodic potential less than 1.4 V vs. NHE, cathodic potential greater than -1.0 V vs. NHE, and total cell potential less than 2.4 V applied across the anode and cathode. 2. The device of claim 1, selected from:

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