Electrocoagulation and electrochemical oxidation process for removal of organic contaminants

Abstract

A method of treating contaminated water with organic contaminants and metal species is disclosed. The method includes agglomerating the organic contaminants and the metal species to produce solids, separating the solids, and electrochemically treating the water. Methods including directing contaminated water to an electrocoagulation cell, a solid-liquid separator, and an electrooxidation cell are also disclosed. A system for recovering metals from battery treatment water is also disclosed. The system comprises an electrocoagulation cell, a solid-liquid separator and an electrooxidation cell.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Provisional Application No. 63 / 531,826, entitled “TOC Removal Using Membranes Process and Electrochemical Oxidation Processes,” filed August 10, 2023, under 35 USC §119(e), which is incorporated herein by reference in its entirety for all purposes. Technical Field

[0002] The aspects and embodiments disclosed herein relate to methods for treating water containing at least one organic contaminant. In particular, the aspects and embodiments disclosed herein relate to methods for treating water using electrocoagulation and electrochemical processes. Overview

[0003] According to one aspect, a method for treating contaminated water is provided. The method may include providing contaminated water comprising a first concentration of at least one organic pollutant and a first concentration of a metallic substance. The method may include coagulating the at least one organic pollutant and the metallic substance to produce a solid comprising the at least one organic pollutant and the metallic substance. The method may include separating at least some of the solids from the contaminated water to produce first-treated water and the separated solids. The method may include electrochemically treating the first-treated water with a cathode and an anolyte comprising an anodic oxide material to produce second-treated water having a second concentration of at least one organic pollutant below the first concentration of the at least one organic pollutant and a second concentration of a metallic substance below the first concentration of the metallic substance.

[0004] In some implementations, coagulation involves adding a coagulant to water to produce solids.

[0005] In some implementations, coagulation involves electrochemically treating water with cathodes and anodes containing sacrificial metal materials to produce solids.

[0006] In some implementations, the method also includes recovering metallic substances from the separated solids.

[0007] In some embodiments, the method further includes separating residual solids from the water in the second treatment to produce water and the separated residual solids in the third treatment.

[0008] In some implementations, the method also includes recovering metallic substances from the residual separated solids.

[0009] In some embodiments, the method further includes controlling at least one of the reaction time for coagulation and the reaction time for electrochemical treatment.

[0010] In some implementations, the method further includes adding a flocculant to the contaminated water before separating at least some of the solids from the solids.

[0011] In some embodiments, the contaminated water contains a first concentration of perfluoroalkyl and polyfluoroalkyl substances (PFAS), and the water in the second treatment contains a second concentration of PFAS at a lower concentration than the first concentration of PFAS.

[0012] In some implementations, the contaminated water includes water used in battery treatment.

[0013] In some implementations, the metallic substances include lithium and cobalt.

[0014] In some implementations, the water in the second treatment contains less than 100 ppm of total organic carbon (TOC).

[0015] According to another aspect, a method for treating contaminated water is provided, the contaminated water comprising at least one organic pollutant at a first concentration and a first concentration of a metallic substance. The method may include directing the contaminated water to an electrocoagulation cell having a first cathode and a first anode comprising a sacrificial metal to produce solids comprising at least one organic pollutant and a metallic substance. The method may also include directing the contaminated water and solids to a first solid-liquid separator to produce first-treated water and separated solids. The method may further include directing the first-treated water to an electrooxidation cell having a second cathode and a second anode comprising an anodic oxide material to produce second-treated water having a second concentration of at least one organic pollutant lower than the first concentration of the at least one organic pollutant and a second concentration of a metallic substance lower than the first concentration of the metallic substance.

[0016] In some implementations, the method further includes directing the water from the second treatment to a second solid-liquid separator.

[0017] In some implementations, the method also includes guiding the separated solids to a metal recycling unit.

[0018] In some embodiments, the method further includes controlling at least one of the following: the residence time of contaminated water in the electrocoagulation cell, the residence time of the first-treated water in the electrooxidation cell, and the potential applied to the electrocoagulation cell or the potential applied to the electrooxidation cell.

[0019] According to another aspect, a system is provided for recovering metals from battery-treated water containing at least one organic contaminant and a metallic substance. The system may include an electrocoagulation cell having an inlet fluidly connected to a source of battery-treated water, the electrocoagulation cell including a first cathode and a first anode containing a sacrificial metal. The system may include a first solid-liquid separator having an inlet fluidly connected to an outlet of the electrocoagulation cell, a solid-stage outlet, and a liquid-stage outlet. The system may include an electrooxidation cell having an inlet and an outlet fluidly connected to the liquid-stage outlet, the electrooxidation cell including a second cathode and a second anode, the second anode containing an anodic oxide material.

[0020] In some embodiments, the system further includes a controller operable to generate a control signal that adjusts at least one of the following: the residence time of water in the electrocoagulation cell, the residence time of liquid fractions in the electrooxidation cell, the potential applied to the electrocoagulation cell, or the potential applied to the electrooxidation cell.

[0021] In some implementations, the system also includes a sensor operatively connected to the controller, the sensor being configured to measure at least one of pH, flow rate, conductivity, current density, concentration of at least one organic pollutant, and concentration of at least one metallic substance.

[0022] In some embodiments, the system further includes a second solid-liquid separator having an inlet that is fluidly connected to the outlet of the electro-oxidized cell.

[0023] In some implementations, the system also includes a metal recovery unit located downstream of the solids fraction outlet.

[0024] In some implementations, the sacrificial metal includes aluminum and / or iron.

[0025] In some embodiments, the anodic oxide material is selected from platinum, titanium oxide, mixed metal oxide (MMO) coated size-stable anode (DSA) materials, graphite, graphene, boron-doped diamond (BDD), lead / lead oxide, and combinations thereof.

[0026] In some implementations, the anodic oxide material is of formula Ti n O 2n-1 Titanium oxides, wherein n ranges from 3 to 9, including 3 and 9.

[0027] In some implementations, the sources of battery treatment water include black substance leachate, battery shred water, and / or battery discharge water.

[0028] This disclosure is intended for all combinations of any one or more of the foregoing aspects and / or implementations, as well as combinations with any one or more implementations and any examples set forth in the details. Brief description of the attached diagram

[0029] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures is represented by the same numbers. For clarity, not every component may be labeled in every drawing. In the drawings: Figure 1 It is a block diagram of a system for treating contaminated water according to one implementation scheme; Figure 2 This is a block diagram of a system for treating contaminated water according to another implementation scheme; Figure 3 This is a block diagram of a system for treating contaminated water according to another implementation scheme; Figure 4 This is a block diagram of a system for treating contaminated water according to another implementation scheme; Figure 5 This is a block diagram of a system for treating contaminated water according to another implementation scheme; Figure 6 It is a schematic diagram of a system for treating contaminated water according to one embodiment; and Figure 7 This is a schematic diagram of a system for treating contaminated water according to another implementation scheme. Detailed Explanation

[0030] The transition from fossil fuel-dependent economies to renewable energy-dependent economies has introduced a significant reliance on batteries. The use of rechargeable batteries is rapidly increasing due to their known energy-saving storage capabilities and the high demand for battery-operated electronic devices and energy storage systems, such as electric vehicles (EVs).

[0031] Lithium-ion batteries (LIBs) are an exemplary type of rechargeable battery. Due to their excellent energy density, long lifespan, and discharge capability, LIBs have been widely used in various applications, such as consumer electronics. Recently, LIBs have been extensively used in automotive propulsion because these batteries can provide reliable service for many years and are expected to last approximately 10 years under normal driving conditions. LIBs may subsequently be used for utility-scale energy storage, but will eventually reach the end of their lifespan.

[0032] LIBs typically contain rare and toxic elements such as lithium, cobalt, nickel, manganese, copper, aluminum, and graphite. For example, a LIB usually includes an anode, an electrolyte, and a cathode containing lithium in the form of lithium transition metal oxides. The global availability of these elements is limited. LIBs pose supply chain risks because demand for these elements is projected to exceed supply. Therefore, efficient and cost-effective processes are needed to manage and recycle existing accumulations of waste LIBs and their constituent elements.

[0033] The disposal of waste batteries (LIBs) has caused environmental problems. It is desirable to recover usable materials from batteries and battery processing procedures. Material recycling can reduce the amount of material extracted from the environment's limited supply. Furthermore, by recovering materials from batteries, the negative environmental impacts of mining and processing ores can be reduced (e.g., SOx emissions from sulfide ore smelting, such as sulfide ores that produce copper, nickel, and cobalt).

[0034] Currently, there are two broad types of methods for recycling waste LIBs: leaching methods and combined methods that include calcination and leaching. Typically, leaching methods may include the following steps: crushing or breaking down the battery and / or battery components, leaching with acid, and separating the leached material by precipitation, compounding, and / or extraction. However, leaching methods also involve multiple separation steps that produce complex leachate compositions and generate significant amounts of secondary waste.

[0035] A combined calcination and leaching approach typically includes the following steps: crushing or breaking the battery and / or battery components, calcination, acid leaching, separation of the leached material by precipitation, compounding, and / or extraction. This combined approach generally requires higher energy consumption due to the heat treatment process. Additionally, the recovery rate of electrode materials may be low because some components of the electrode materials may burn into carbon dioxide and other hazardous substances.

[0036] Furthermore, current battery recycling methods involve advanced chemical and mechanical processing systems, which are limited by the complexity of their waste. Some of the biggest challenges of these current processes are optimization and wastewater treatment. Wastewater streams generated by the battery industry contain significant amounts of metal ions, high levels of organic matter, and other suspended solids. In addition, such wastewater streams have been found to contain significant amounts of fluorinated compounds, such as perfluoroalkyl and polyfluoroalkyl substances (PFAS), which are well-known as pollutants that are difficult to remove from wastewater streams. Common PFAS include perfluorooctanoic acid (PFOA) and / or perfluorooctane sulfonic acid (PFOS), but other fluorinated compounds may also be present in battery processing wastewater streams.

[0037] Battery manufacturers and recycling processes often require on-site wastewater treatment systems because they may be unable to meet regulatory emission limits, and municipal wastewater infrastructure may not be able to support such high pollution levels. However, advantageously, the extraction of precious metal ions from battery recycling and manufacturing wastewater streams (often referred to as wastewater extraction) can be achieved through certain water treatment processes that provide successful separation.

[0038] Wastewater streams containing high levels of organic matter are typically treated using the Fenton reaction principle. The Fenton reaction process generally utilizes oxidants such as hydrogen peroxide and ferrous ions to oxidize organic matter under acidic and high-temperature conditions. High degradation rates have been achieved when treating organic matter using the Fenton reaction process. However, a significant solids load is usually generated as a byproduct of the treatment.

[0039] Ultraviolet (UV) light can be used in water treatment systems to break down organic pollutants. For example, UV radiation can convert certain organic pollutants in water into carbon dioxide and water. As another example, UV radiation can convert halogenated compounds into halogenated acids. UV light can be used alone or in combination with another method to destroy organic pollutants.

[0040] Electrochemical oxidation, also referred to herein as electro-oxidation, is another exemplary process that can be used to destroy organic pollutants in water. Electrochemical oxidation can be used to directly and / or indirectly oxidize electron-rich organic compounds by applying a voltage without producing major byproducts or harmful pollutants. Electrochemical oxidation can be carried out in an electrochemical cell having a cathode and / or anode. The cathode and / or anode can be formed in various shapes, such as planar or circular. In at least some embodiments, the cathode and / or anode can be characterized by a foil, mesh, or foam structure, which can be associated with a high active surface area, pore structure, and / or pore distribution, providing sufficient active sites for surface reactions to occur. For example, the cathode and / or anode can have a diameter from 1 cm². 2 Up to 1000 cm 2 The effective area.

[0041] Electrochemical oxidation reactions typically occur on the anode surface. The anode material can be selected as an anodic oxide material that promotes the oxidation of organic pollutants. Exemplary anode materials include platinum, titanium oxide, mixed metal oxide (MMO) coated size-stabilized anode (DSA) materials, graphite, graphene, boron-doped diamond (BDD), or lead / lead oxide. The DSA material can be uncoated or coated with noble metals or metal oxides, such as IrO2, and others.

[0042] Titanium oxide anodes have been found to offer several advantages over organic materials in wastewater streams, such as providing high corrosion resistance, high conductivity, and high electrochemical stability under both acidic and alkaline conditions. Titanium oxide electrode materials can possess properties conforming to the formula Ti... n O 2n-1 Composition of (n=3-10), such as Ti3O5, Ti4O7, Ti5O9, Ti6O 11 And others. An exemplary titanium oxide electrode material is Ti4O7, sometimes referred to as Magneli-phase titanium oxide. Magneli-phase titanium oxide electrodes and electrochemical cells comprising said electrodes are described in International Application Publication No. WO / 2020041712 (filed August 23, 2019, entitled “System and method for electrochemical oxidation of polyfluoroalkyl substances in water”), the disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0043] Another exemplary anode material is platinum, because the current-induced oxidation of platinum is negligible at low current densities. Platinum can be used as a solid conductor or as a coating on another electrode substrate such as titanium. Platinum, graphite, or graphene can be uncoated or coated with anodized materials.

[0044] Electrochemical cells may include a reference electrode, such as one located near the cathode. A reference electrode allows for continuous measurement of the potential of the working electrode, i.e., the cathode, without allowing current to flow through it. Therefore, the use of a reference electrode allows for precise control of the cell voltage in water with a specific conductivity, thus controlling the current that determines the reaction kinetics as described herein, to limit competing reactions.

[0045] Electrochemical oxidation can also be used to remove fluorinated compounds, including perfluoroalkyl and polyfluoroalkyl substances (PFAS). These man-made compounds are very stable and do not readily decompose in the environment. These compounds can also be highly water-soluble because they carry a negative charge when dissolved. The reaction is typically characterized by Kolbe-type oxidation.

[0046] The PFAS destruction reaction begins by applying a sufficient positive voltage to a titanium oxide (e.g., Ti4O7) surface, directly oxidizing carboxylate ions to carboxylate radicals (Equation 1). The carboxylate radicals are then decarboxylated to perfluoroalkyl radicals (Equation 2). Through coupling with hydroxyl radicals generated anoly on the Ti4O7 surface, the perfluoroalkyl radicals are converted to perfluoroalcohols (Equation 3), which are further defluorinated to perfluorocarbonyl fluoride (Equation 4) and finally hydrolyzed as perfluorocarboxylic acids as byproducts by losing one carbon atom in the chain (Equation 5). Reactions 1 through 5 can typically be repeated until all carbon from the PFAS is eventually stripped to inorganic CO2 and H2. + and F - .

[0047]

[0048] The removal of organic pollutants can also involve chemical treatments through coagulation. As used herein, “coagulation” refers to the chemical process in which non-settleable particles become unstable and attract each other to form clumps. Coagulation is a chemical process achieved by altering the charge of the particles, for example, neutralizing the particles to reduce the repulsive forces between them. Coagulation typically alters the chemical properties of the suspension to induce aggregation and sedimentation.

[0049] Coagulation can be achieved by adding coagulants to wastewater. Examples of coagulants typically include inorganic salts of aluminum and iron, such as ferric chloride and ferric sulfate. These salts typically neutralize the charge on particles and hydrolyze to form insoluble precipitates of the particles. Other examples of coagulants include organic coagulants, such as diallyl dimethyl ammonium chloride (DADMAC).

[0050] Alternatively or concurrently, coagulation can be achieved by applying an electric current, referred to herein as electrochemical coagulation or electrocoagulation. The electric current can release ions from the surface of the electrode, which destabilizes suspended and / or dissolved substances in the wastewater suspension. The unstable substances can aggregate to form insoluble precipitates. When the sacrificial metal M is used as the electrode, the electrochemical reactions that occur in the solution are shown in Equations (6)-(9) below, where reactions (6)-(7) occur at the anode and reactions (8)-(9) occur at the cathode.

[0051]

[0052] Exemplary electrodes for electrocoagulation can release aluminum ions and / or iron ions. If an aluminum electrode is used, Al can be generated at the anode. 3+ (aq) ions. If an iron electrode is used, Fe can be generated at the anode. 2+ / Fe 3+Ions. Depending on the pH of the solution, metal cations can further undergo spontaneous reactions to produce hydroxides, hydroxyl oxides, and / or polyhydric hydroxides, which are capable of forming monomeric and polymeric ionic substances. Hydrolysis products have a high affinity for both dispersed and charged particles, causing them to aggregate. Furthermore, the gas generated at the electrodes can induce flotation of precipitated flocs, which can then be separated by filtration.

[0053] It is believed that electrocoagulation and electrochemical oxidation may have a synergistic effect on the removal of organic compounds from wastewater, and thus on the recovery of metal compounds. For example, electrocoagulation can reduce the energy requirements of electrochemical oxidation. Electrocoagulation can also provide the benefit of reducing the amount of dosing agent required to remove organic pollutants from wastewater by eliminating the need for adding chemical coagulants.

[0054] Flocculation can be used in combination with coagulation to generate larger particles for faster sedimentation. As used herein, "flocculation" refers to the physical process in which clumps of particles physically connect to form larger particles and then a precipitate. Flocculation is the physical process of agglomeration. Flocculation can be achieved through physical agitation, such as by mixing.

[0055] Optionally, a flocculant may be added to aid the flocculation process. Flocculants typically provide a basis for sedimented particles to physically adhere and grow into flocs or flakes. Exemplary flocculants include, for example, polymers, such as high molecular weight polymers, medium molecular weight polymers, low molecular weight polymers, and cationic or anionic polymers.

[0056] Therefore, coagulation can be used to bind non-settleable particles together, and flocculants can be added to aggregate small clumps formed by coagulation and form larger clumps. However, flocculation and coagulation do not need to be used together. Coagulation and flocculation can be operated under different conditions. When choosing whether to coagulate, flocculate, or both, the conditions of the suspension to be treated, such as pH, temperature, and composition, can be considered.

[0057] According to one or more embodiments, the systems and methods disclosed herein relate to the removal of organic or fluorinated compounds from contaminated water sources. The systems and methods disclosed herein may also relate to the recovery of target compounds, such as heavy metal compounds, from contaminated water sources. In some embodiments, the water source may be associated with a battery treatment system, such as a battery manufacturing or recycling system or process.

[0058] Therefore, battery treatment water can include battery recycle water and / or battery recovery water. In some embodiments, battery treatment water can include black matter leachate. As part of the recycling process, waste batteries can be broken down into smaller parts by mechanical operations such as crushing or shredding. The residual waste separated from the decomposed batteries is called black matter. The composition of the black matter can vary depending on the source battery (including factors such as the age and condition of the battery), the efficiency of the recycling process, and the generation process. The black matter is then typically dissolved in a solution that usually contains a strong acid or strong base to produce black matter leachate.

[0059] In some embodiments, battery treatment water may include battery breakup water. Battery breakup can be carried out in an inert solution, for example, in a water bath or under continuous or intermittent water showers. The contaminated water from the battery breakup process can be referred to as battery breakup water.

[0060] In some embodiments, battery treatment water may include battery discharge water. During recycling and / or recovery processes, waste batteries can be discharged by exposure to a salt solution. Exemplary salt solutions include aqueous solutions of NaCl, Na₂S, and MgSO₄. The contaminated solution after exposure to waste batteries may be referred to as battery discharge water.

[0061] In some cases, this disclosure may relate to battery handling systems. However, it should be noted that the systems and methods disclosed herein can be similarly used in conjunction with any water source containing organic contaminants. For example, sources of aqueous solutions may be associated with water purification, nuclear power generation, microelectronics manufacturing, semiconductor manufacturing, food processing (including agricultural uses and irrigation), textile manufacturing, paper manufacturing and recycling, pharmaceutical manufacturing, chemical processing, and metal extraction systems or processes. Water sources may be associated with industrial applications, such as the removal of organic contaminants from industrial wastewater. Water sources may be associated with wastewater and / or municipal water treatment.

[0062] Furthermore, while this disclosure generally relates to lithium-ion battery processing and recycling, it should be understood that the systems and methods disclosed herein can be similarly used to process (including manufacture and destroy) or recycle other battery types, such as alkaline batteries, lead-acid batteries, or nickel-cadmium batteries.

[0063] Effluents generated by the systems and methods disclosed herein can meet regulatory emission requirements. In some embodiments, effluents generated by the systems or methods disclosed herein can be collected and used for a variety of applications, including battery manufacturing or recycling, industrial applications, electronics and semiconductor manufacturing, laboratory applications, medical applications, pharmaceutical manufacturing, beverage and food preparation, irrigation water, and agricultural applications.

[0064] In one aspect, a method is provided that can separate and break down high levels of organic matter and dissolved solids from contaminated water sources. The contaminated water can undergo coagulation and filtration processes to separate readily available organic matter and total suspended solids (TSS). Total organic carbon (TOC) can be removed by electrochemical oxidation. The effluent can be treated by optional refining processes, such as membrane filtration.

[0065] While not wishing to be bound by theory, coagulation is believed to improve the removal efficiency of both solids and dissolved organic matter by increasing the molecular weight of suspended organic matter and suspended solids, and thus potentially reducing the operating costs of subsequent TOC removal processes. Compared to the Fenton reaction, coagulation produces smaller solid sludge, which can further reduce operating costs by decreasing the overall volume of sludge treated. Filtration of coagulated solids can reduce the solids loading in subsequent steps. For example, operating costs can also be reduced by decreasing or eliminating TSS loading in the membrane stage and reducing or limiting high levels of TOC before membrane treatment with coagulation.

[0066] Furthermore, electrochemical treatment of water to remove TOC can reduce or eliminate the need for external chemical agents (such as chemical coagulants) and can reduce or eliminate the heating requirements during chemical coagulation. Electrocoagulation and electrooxidation are considered more sustainable methods for reducing TSS and TOC in polluted water.

[0067] The systems and methods disclosed herein can be used to recover metals from contaminated water. For example, the systems and methods disclosed herein can be used to recover metals from battery treatment water, such as battery recirculation water or battery recovery water, e.g., black matter leachate, battery breakup water, and / or battery discharge water. Furthermore, the systems and methods disclosed herein can be used to generate effluents that meet regulatory discharge requirements. In some embodiments, the systems and methods disclosed herein can be used to recover water from battery treatment operations.

[0068] Please refer to the attached diagram for details. Figure 1 This is a block diagram of an exemplary system 1000 for treating contaminated water. Figure 1 An exemplary system 1000 includes a solid-liquid separator 200, a TOC removal unit 300 located downstream of the effluent outlet of the solid-liquid separator 200, and a second solid-liquid separator 400 located downstream of the effluent outlet of the TOC removal unit 300. Contaminated water is directed to the solid-liquid separator 200.

[0069] The upstream solids-liquid separator 200 can be used to separate suspended solids, such as total suspended solids (TSS), from contaminated water. In some exemplary embodiments, the solids-liquid separator 200 can be a bulk particulate filter, such as a filter having a pore size of 50 μm to 200 μm, for example, a filter with a pore size of 50 μm to 100 μm, 100 μm to 150 μm, or 150 μm to 200 μm.

[0070] Downstream of the effluent outlet of the solids-liquid separator 200, the TOC removal unit 300 can remove finer and / or dissolved solids from contaminated water. The TOC removal unit 300 can be any treatment unit capable of reducing TOC in the contaminated water stream. An exemplary TOC removal unit 300 includes an electro-oxidation cell containing a cathode and an anode, a Fenton reagent reactor containing a source of oxidant, and / or a UV radiation unit containing a UV light source. In some embodiments, the TOC removal unit 300 may employ one or more TOC reduction processes.

[0071] The second solid-liquid separator 400 is an optional purification unit located downstream of the effluent outlet of the TOC removal unit 300. Exemplary downstream solid-liquid separation unit 400 includes a nanofiltration unit (NF), a reverse osmosis unit (RO), or a microfiltration unit (MF).

[0072] Figure 2 This is a block diagram of an exemplary system 2000 for treating contaminated water. Figure 2 System 2000 is similar to Figure 1 System 1000, except Figure 2 The system 2000 includes a coagulation unit 100 located upstream of the initial solids-liquid separator 200. Contaminated water is directed to the coagulation unit 100. The coagulation unit 100 can be configured to generate solids, such as solid aggregates, of organic pollutants and metallic substances in the contaminated water. The water containing the formed solids can then be directed to the solids-liquid separator 200 to separate the formed solids.

[0073] In some embodiments, the coagulation unit 100 may be a chemical coagulation unit, including a reactor and a source of coagulant fluidly connected to the reactor. The source of coagulant may add an effective amount of coagulant to the contaminated water to produce solids. In some embodiments, the coagulation unit 100 may be an electrocoagulation cell, including a cathode and an anode. The electrocoagulation cell may be configured to produce solids from electrochemically generated ions.

[0074] Figure 3 This is a block diagram of an exemplary system 3000 for treating contaminated water. Figure 3 System 3000 is similar to Figure 1 System 1000, except Figure 3 System 3000 includes a chemical pretreatment unit 410 located upstream of the refining solids-liquid separator 400. The chemical pretreatment unit 410 may include a source of chemical pretreatment agents fluidly connected upstream of the refining solids-liquid separator 400. In some embodiments, the chemical pretreatment unit 410 may include a source of acid or base for pH adjustment, a source of coagulant and / or flocculant, a source of chlorine, a source of oxidant, a source of UV radiation, and / or an adsorbent.

[0075] Figure 4 This is a block diagram of an exemplary system 4000 for treating contaminated water. Figure 4 System 4000 is similar Figure 1 System 1000, except Figure 4 The system 4000 includes a metal recovery unit located downstream of the solids outlet of the solids-liquid separator 200. The metal recovery unit includes a thickener 220 downstream of the solids outlet of the solids-liquid separator 200 and a filter press 230 downstream of the solids outlet of the thickener 220. Water recovered from the effluents of the thickener 220 and the filter press 230 can be directed upstream to be introduced into the contaminated water inlet stream. The filter cake produced from the filter press 230 can be treated to recover metals.

[0076] Figure 5 This is a block diagram of an exemplary system 5000 for treating contaminated water. Figure 5 System 5000 is similar Figure 4 System 4000, except Figure 5 The system 5000 includes a condensation unit 100 located upstream of the solid-liquid separator 200. Water recovered from the effluents of the thickener 220 and the filter press 230 can be directed upstream of the condensation unit 100 to be introduced into the contaminated water inlet stream.

[0077] Figure 6 This is a schematic diagram of an exemplary system 6000 for treating contaminated water. The exemplary system 6000 includes a source of contaminated water 700 (which may be a battery-treated water treatment system); a coagulation reactor 100 fluidly connected to the source of contaminated water 700 (including a source of coagulant 110 and optionally a source of flocculant 120 fluidly connected thereto); a first solid-liquid separation unit 200 fluidly connected to the coagulation reactor 100; an electro-oxidation cell 300 fluidly connected to the liquid stage outlet of the solid-liquid separator 200, the electro-oxidation cell 300 including a cathode 310a and an anode 310b; a second solid-liquid separation unit 400 fluidly connected to the electro-oxidation cell 300; and a source of a chemical pretreatment agent fluidly connected to the solid-liquid separation unit 400.

[0078] Thickener 220 is located downstream of the solids stage outlet of first solids-liquid separator 200. Filter press 230 is located downstream of the solids stage outlet of thickener 220. Metal recovery is possible from the solids stage. In some embodiments, a metal recovery unit may be located downstream of the solids stage outlet of solids-liquid separator 200, and optionally downstream of the solids stage outlets of thickener 220 and / or filter press 230. The liquid stage produced by thickener 220 and filter press 230 may be directed upstream of condensation reactor 100.

[0079] The electro-oxidation cell 300 may include a fluid recirculation flow to maintain continuous or semi-continuous operation of the system. The electro-oxidation cell 300 may also include a reference electrode 630 positioned to measure the current density within the electro-oxidation cell 300. The materials and positioning (e.g., distance) of the cathode 310a and anode 310b can be selected to control the operation of the electro-oxidation cell 300. The anode 310b may include or be formed from an anodic oxide material. Exemplary anodic oxide materials include platinum, titanium oxide, mixed metal oxide (MMO) coated size-stabilized anode (DSA) materials, graphite, graphene, boron-doped diamond (BDD), lead / lead oxide, and combinations thereof. In some exemplary embodiments, the anode 310b may be a Magneille phase titanium oxide anode. For example, the anodic oxide material may be of formula Ti n O 2n-1 Titanium oxides, wherein n ranges from 3 to 9, including 3 and 9.

[0080] An exemplary system 6000 includes a controller 500 and one or more pumps or valves operatively connected to unit operations within the system 6000, the pumps or valves being positioned to direct water flow through the system 6000. The controller 500 may be operable to generate a control signal that regulates at least one of the residence time of water in the condensation reactor 100 or the electro-oxidation cell 300, or the potential applied to the electro-oxidation cell 300. The controller 500 may be operatively connected to one or more pumps or valves to regulate the residence time.

[0081] The exemplary system 6000 also includes a sensor 600 located at a source 700 of contaminated water to measure the properties of the contaminated water. However, in some embodiments, the sensor 600 may be positioned online downstream of the source 700 of the contaminated water. The exemplary system 6000 also includes a sensor 620 positioned to measure the properties of the effluent. Sensors 600, 620 may include one or more of a pH meter, flow meter, temperature sensor, conductivity sensor, or composition sensor, for example, a composition sensor configured to measure the concentration of one or more contaminants (e.g., organic contaminants, metallic substances, fluorinated compounds, etc.). Sensors 600, 620 and a reference electrode 630 are operatively connected to a controller 500, which may be programmed to generate a control signal that adjusts at least one operating parameter of the system in response to measurements obtained by sensors 600, 620 or the reference electrode 630 located within the electro-oxidation cell 300. Exemplary operating parameters of the system include flow rate (including residence time), pH, temperature, conductivity, current density, etc.

[0082] Figure 7 This is a schematic diagram of an exemplary system 7000 for treating contaminated water. The exemplary system 7000 is similar to... Figure 6 System 6000, except that system 7000 includes an electrocoagulation cell 100a fluidly connected to a source 700 of contaminated water, instead of a coagulation reactor 100, the electrocoagulation cell 100a includes a cathode 110a and an anode 110b. A source 120 of flocculant may be fluidly connected to the electrocoagulation cell 110a or downstream of the electrocoagulation cell 110a (e.g.,...). Figure 7 (As shown in the exemplary implementation).

[0083] The electrocoagulation cell 100a may include a fluid recirculation flow to maintain continuous or semi-continuous operation of the system. The electrocoagulation cell 100a may also include a reference electrode 610 positioned to measure the current density within the electrocoagulation cell 610. The materials and positioning (e.g., distance) of the cathode 110a and anode 110b can be selected to control the operation of the electrocoagulation cell 10a. The cathode 110a and / or anode 110b may include or be formed of a sacrificial metal material. Exemplary sacrificial metal materials include aluminum and / or iron.

[0084] The controller 500 may be operable to generate a control signal that adjusts at least one of the following: the residence time of water in the electrocoagulation cell 110a, or the residence time of water in the electrooxidation cell 300, or the potential applied to the electrocoagulation cell 110a, or the potential applied to the electrooxidation cell 300. In some embodiments, a reference electrode 610 is operatively connected to the controller 500, which may be programmed to generate a control signal for adjusting at least one operating parameter of the system in response to measurements obtained by sensors 600, 620 or reference electrodes 610, 630 located within the electrocoagulation cell 110a and / or the electrooxidation cell 300.

[0085] According to one aspect, a method for treating contaminated water is provided. The method may include providing contaminated water containing a concentration of at least one organic pollutant and a concentration of a metallic substance. The contaminated water may also contain a concentration of at least one fluorinated compound, such as perfluoroalkyl substances and polyfluoroalkyl substances (PFAS). In some embodiments, the contaminated water may be battery treatment water, such as battery recycle water or battery recovery water. Exemplary battery treatment water includes black substance leachate, battery breakup water, or battery discharge water. Therefore, in some embodiments, the metallic substance includes lithium and cobalt. The metallic substance may include lithium, cobalt, nickel, manganese, copper, aluminum, graphite, or combinations thereof.

[0086] In some embodiments, the contaminated water may have a total organic carbon (TOC) concentration of at least about 2,000 ppm. For example, the contaminated water may have a TOC concentration between about 2,000 ppm and 5,000 ppm, such as between 2,000 ppm and 2,500 ppm, 2,500 ppm and 3,000 ppm, 3,000 ppm and 3,500 ppm, 3,500 ppm and 4,000 ppm, 4,000 ppm and 4,500 ppm or 4,500 ppm and 5,000 ppm. The contaminated water may have a total suspended solids (TSS) concentration of at least about 100 ppm, for example, between about 100 ppm and 2000 ppm, such as between 100 ppm and 250 ppm, 250 ppm and 500 ppm, 500 ppm and 750 ppm, 750 ppm and 1000 ppm, 1000 ppm and 1250 ppm, 1250 ppm and 1500 ppm or 1500 ppm and 2000 ppm. The contaminated water may have a concentration of at least about 100 ppm Li, for example, 100 ppm to 1000 ppm Li; at least about 0.1 ppm Mg or Mn, for example, 0.1 ppm to 20 ppm or 1 ppm to 10 ppm Mg or Mn; at least about 10 ppm Ni, for example, 10 ppm to 300 ppm Ni; and / or at least about 50 ppm Al, for example, 50 ppm to 1200 ppm Al. Typically, the lower end of the range can be associated with battery discharge water, while the upper end of the range can be associated with battery breakage water or leachate containing black substances.

[0087] The systems and methods disclosed herein can be used to produce treated water (also referred to herein as effluent) having low concentrations of one or more of organic contaminants, metallic substances, and optionally fluorinated compounds (such as PFAS). In some embodiments, the treated water can meet regulatory discharge requirements. For example, the treated water can have a TOC of less than 100 ppm. In some embodiments, the treated water can have a TOC of less than 75 ppm, less than 50 ppm, less than 25 ppm, or less than 10 ppm. Thus, in some embodiments, the systems and methods disclosed herein can reduce the TOC of contaminated water by at least 90%, at least 95%, at least 98%, at least 99%, at least 99.9%, at least 99.99%, or at least 99.999%.

[0088] In some implementations, the methods disclosed herein can be used to recover at least 90% of a metallic substance (one or more of lithium, cobalt, nickel, manganese, copper, aluminum, graphite or combinations thereof) from contaminated water, for example, recovering at least 90%, at least 95%, at least 98%, at least 99%, at least 99.9%, at least 99.99%, or at least 99.999% of a metallic substance from contaminated water.

[0089] Methods may include reducing suspended solids from contaminated water. Suspended solids can be reduced by coagulating at least one organic pollutant and metallic substance to produce aggregated solids. In some embodiments, coagulation can be achieved by adding an effective amount of at least one coagulant to the contaminated water. In other embodiments, coagulation can be achieved by electrochemically treating the water with a cathode and anode containing sacrificial metal materials to produce solids. Therefore, in some embodiments, methods may include directing contaminated water to an electrocoagulation cell. Methods may include operating the electrocoagulation cell, for example, controlling the potential applied to the anode and cathode to generate ions that produce solids containing organic pollutants and metallic substances.

[0090] In some embodiments, the method may further include flocculating the agglomerated solids to produce larger flocs. Flocculation can be carried out by adding an effective amount of flocculant to the contaminated water. In some embodiments, the flocculant may be added to the contaminated water before or after coagulation. In other embodiments, the flocculant may be added to the contaminated water after coagulation. Flocculation may be carried out in combination with chemical coagulants or electrocoagulation.

[0091] The method may include separating at least some solids from contaminated water to reduce the total suspended solids (TSS) concentration of the contaminated water and produce treated water and separated solids. Therefore, in some embodiments, the method may include directing the contaminated water and solids to a solids-liquid separation unit. The solids-liquid separation unit may be configured to produce a liquid fraction containing treated water with reduced TSS and a solid fraction containing aggregated solids. The liquid fraction may then be processed to reduce TOC, while the solid fraction may be processed to recover metallic substances.

[0092] Therefore, in some embodiments, the method may further include recovering metallic substances from the separated solids. For example, the method may include concentrating the separated solids. The method may include directing the separated solids to a thickener. In some embodiments, the method may further include directing the separated solids to a filter press. The thickener and / or filter press may be configured to further dewater the separated solids and produce a filter cake containing metallic substances. In some embodiments, the method may further include directing the separated solids to a metal recovery unit to recover at least some of the metallic substances for reuse. For example, the method may further include directing dewatered solids (e.g., filter cake) to a metal recovery unit.

[0093] Methods may include reducing the TOC of polluted water. In some embodiments, methods may include reducing the TOC of polluted water through a Fenton reaction, such as by adding an oxidant to the polluted water. Exemplary oxidants include hydrogen peroxide, ozone, oxygen, and persulfate. Methods may also include reducing TOC by exposure to UV light.

[0094] In some embodiments, the method may include reducing TOC by electrochemically treating treated water with a cathode and an anode comprising an anodic oxide material. In some embodiments, two or more methods for reducing TOC may be used. Therefore, in some embodiments, the method may include directing water to an electro-oxidizing cell having a cathode and an anode comprising an anodic oxide material. Exemplary anodic oxide materials include platinum, titanium oxide, mixed metal oxide (MMO) coated size-stabilized anode (DSA) materials, graphite, graphene, boron-doped diamond (BDD), lead / lead oxide, and combinations thereof. In some exemplary embodiments, the anode may be a Magneille phase titanium oxide anode. For example, the anodic oxide material may be of the formula Ti n O 2n-1 Titanium oxides, wherein n ranges from 3 to 9, including 3 and 9.

[0095] The treated water resulting from reduced TSS and TOC can meet regulatory discharge requirements. For example, treated water produced by electrochemical oxidation can meet regulatory discharge requirements. For example, as previously described, the treated water can have a TOC of less than 100 ppm, or less than 75 ppm, less than 50 ppm, less than 25 ppm, or less than 10 ppm.

[0096] In some embodiments, the method may include further refining the treated water. For example, the method may include separating residual solids from the treated water and producing a refined effluent. In some embodiments, the method may include directing the treated water to a solid-liquid separator. Exemplary refining solid-liquid separators include RO, NF, and / or MF separation processes. In some embodiments, metals may also be recovered from the residual solids. The method may optionally include adding a chemical pretreatment agent to the treated water or treating the treated water with a chemical pretreatment agent prior to separating the residual solids. Exemplary chemical pretreatment agents include acids or bases for pH adjustment, coagulants and / or flocculants, chlorine, oxidants, UV radiation, and / or adsorbents.

[0097] The method may include controlling one or more parameters of the treatment process. For example, the method may include controlling the reaction time of coagulation and / or the reaction time of electrochemical oxidation. The method may include controlling at least one of the following: the residence time of contaminated water in the coagulation reactor or electrocoagulation cell, the residence time of the first-treated water in the electrooxidation cell, the potential applied to the electrocoagulation cell, or the potential applied to the electrooxidation cell. Parameters can be controlled through one or more unit operations to reduce reaction time, improve or reduce the removal of TSS and / or TOC from contaminated water, and / or reduce energy use.

[0098] The method may include controlling one or more parameters of the water, such as pH, flow rate, temperature, etc. In some embodiments, the method may include controlling the dosing rate of an agent (such as a coagulant, flocculant, or chemical pretreatment agent). The method may include controlling the dosing rate of an oxidant and / or the intensity of UV light applied to the water.

[0099] In some implementations, the method may include measuring one or more parameters of the treatment process. For example, the method may include measuring one or more of the following: pH, flow rate, temperature, conductivity, current density, or composition, such as the concentration of one or more contaminants (e.g., organic contaminants, metallic substances, or fluorinated compounds). For example, one or more parameters may be measured in contaminated water prior to any treatment. One or more parameters may be measured in the effluent or treated water. One or more parameters may be measured within a unit operation, such as within a condensation reactor, an electrocoagulation cell, or an electrooxidation cell.

[0100] In some embodiments, process parameters can be controlled in response to one or more measurements. For example, the residence time of contaminated water in a coagulation reactor or electrocoagulation cell, the residence time of first-treated water in an electrooxidation cell, the potential applied to the electrocoagulation cell, or the potential applied to the electrooxidation cell can be controlled in response to measurements such as pH, flow rate, temperature, conductivity, current density, or composition. In some embodiments, one or more of pH, flow rate, temperature, dosing rate of agents (such as coagulants, flocculants, chemical pretreatment agents, and / or oxidants), and / or the intensity of applied UV light can be controlled in response to measurements.

[0101] The functionality and advantages of these and other embodiments will be better understood from the following examples. These embodiments are intended to be illustrative in nature and are not intended to limit the scope of the invention.

[0102] The test will assess the reduction of total organic matter (TOC, TSS) in the contaminated water sample. Contaminated water samples may include water from battery treatment or manufacturing processes. The contaminated water sample will contain at least 3500 ppm TOC, at least 100 ppm TSS, and at least 100 ppm Li.

[0103] Contaminated water samples will be treated in various comparative pilot-scale systems, including (1) a coagulation system, (2) a coagulation and electrochemical oxidation system, (3) a coagulation and oxidant dosing (Fenton reaction) system, and (4) a coagulation, electrochemical oxidation, and oxidant dosing system. The coagulation process may include either chemical coagulant or electrochemical coagulation. A filter will be located between the coagulation and downstream processes (electrochemical oxidation and / or oxidant). Electrochemical coagulation and electrochemical oxidation cells will be operated at 8.0 volts. Amperes, conductivity, pH, ORP, and TOC concentrations will be monitored throughout the testing.

[0104] The expected results are as follows: the sample that passes (1) coagulation treatment is expected to have about 2500 ppm TOC, about 5 ppm TSS and about 80 ppm Li; the sample that passes (2) coagulation and electrochemical oxidation treatment is expected to have about 1000 ppm TOC, about 0 ppm TSS and about 2 ppm Li; the sample that passes (3) coagulation and oxidant addition treatment is expected to have about 2250 ppm TOC, about 0 ppm TSS and about 80 ppm Li; and (4) the sample that passes (4) coagulation, electrochemical oxidation and oxidant addition treatment is expected to have about 1500 ppm TOC, about 0 ppm TSS and about 1 ppm Li.

[0105] Therefore, comparative testing is expected to show that, compared with coagulation alone and coagulation with oxidant addition, combining coagulation and electrochemical oxidation will provide superior removal of organic pollutants from water treated by the sample cells.

[0106] It is also anticipated that controlling the pH of the water flow prior to electrochemical oxidation will improve the removal of organic contaminants from the sample. Additionally, increasing the residence time of the cell during electrochemical oxidation can also improve the removal of organic contaminants from the sample. The residence time can be controlled, for example, by increasing it, to produce product water with less than 100 ppm TOC, or even less than 10 ppm TOC.

[0107] The wording and terminology used herein are for descriptive purposes and should not be considered restrictive. As used herein, the term "plurality" refers to two or more items or components. The terms "comprising," "including," "carrying," "having," "containing," and "involving," whether in the written description, claims, or the like, are open-ended terms, meaning "including but not limited to." Therefore, the use of such terms implies coverage of the items listed thereafter and their equivalents, as well as additional items. Regarding claims, only the transitional phrases "consisting of" and "consisting substantially of" are closed or semi-closed transitional phrases, respectively. The use of ordinal terms such as "first," "second," "third," and similar terms modifying claim elements in claims does not, in itself, imply any priority, precedence, or order of one claim element relative to another, or the chronological order in which the actions of the methods are performed, but is merely used as markers to distinguish one claim element having a certain name from another element having the same name (but for the purpose of using ordinal terms).

[0108] Several aspects of at least one embodiment have been described so far; it should be understood that various changes, modifications, and improvements will readily occur to those skilled in the art. Any feature described in any embodiment may be included in or substitute for any feature in any other embodiment. Such changes, modifications, and improvements are intended to be part of this disclosure and are intended to be within the scope of the invention. Therefore, the foregoing description and drawings are by way of example only.

[0109] Those skilled in the art will understand that the parameters and configurations described herein are exemplary, and the actual parameters and / or configurations will depend on the specific application in which the disclosed methods and materials are used. Those skilled in the art will also recognize or be able to determine equivalents of the specific embodiments disclosed using only routine experiments.

Claims

1. A method for treating polluted water, comprising: Provide water contaminated with at least one organic pollutant and a metallic substance at a first concentration; The at least one organic pollutant and the metallic substance are agglomerated to produce a solid containing the at least one organic pollutant and the metallic substance; At least some of the solids are separated from the contaminated water to produce water and separated solids from the first treatment; and The first-treated water is electrochemically treated with a cathode and an anodic material containing an anodic oxide to produce second-treated water, the second-treated water having a second concentration of the at least one organic pollutant lower than the first concentration of the at least one organic pollutant and a second concentration of the metal substance lower than the first concentration of the metal substance.

2. The method of claim 1, wherein coagulation comprises adding a coagulant to the water to produce the solid.

3. The method of claim 1, wherein coagulation comprises electrochemically treating the water with a cathode and an anode containing sacrificial metal materials to produce the solid.

4. The method of claim 1, further comprising recovering the metallic substance from the separated solid.

5. The method of claim 1, further comprising separating residual solids from the water of the second treatment to produce water of the third treatment and residual separated solids.

6. The method of claim 5, further comprising recovering the metallic substance from the residual separated solid.

7. The method of claim 1, further comprising controlling at least one of the reaction time of the agglomeration and the reaction time of the electrochemical treatment.

8. The method of claim 1, further comprising adding a flocculant to the contaminated water prior to separating at least some of the solids from the solids.

9. The method of claim 1, wherein the contaminated water contains a first concentration of perfluoroalkyl substances and polyfluoroalkyl substances (PFAS), and the water treated in the second manner contains a second concentration of PFAS at a lower concentration than the first concentration of PFAS.

10. The method of claim 1, wherein the contaminated water comprises battery-treated water.

11. The method of claim 10, wherein the metallic substance comprises lithium and cobalt.

12. The method of claim 1, wherein the water treated in the second process contains less than 100 ppm of total organic carbon (TOC).

13. A method for treating contaminated water, said contaminated water comprising at least one organic pollutant at a first concentration and a metallic substance at a first concentration, said method comprising: The contaminated water is directed to an electrocoagulation cell having a first cathode and a first anode containing sacrificial metals to produce a solid containing at least one organic pollutant and the metallic substance. The contaminated water and the solids are directed to a first solid-liquid separator to produce water and separated solids after a first treatment. and The water treated in the first step is directed to an electro-oxidation cell having a second cathode and a second anode containing an anodic oxide material to produce water treated in the second step, the water having a second concentration of the at least one organic pollutant lower than the first concentration of the at least one organic pollutant and a second concentration of the metal substance lower than the first concentration of the metal substance.

14. The method of claim 13, further comprising directing the water from the second treatment to a second solid-liquid separator.

15. The method of claim 13, further comprising guiding the separated solids to a metal recovery unit.

16. The method of claim 13, further comprising controlling at least one of the following: the residence time of the contaminated water in the electrocoagulation cell, the residence time of the first treated water in the electrooxidation cell, the potential applied to the electrocoagulation cell, or the potential applied to the electrooxidation cell.

17. A system for recovering metals from battery-treated water containing at least one organic pollutant and a metallic substance, the system comprising: An electrocoagulation cell having an inlet fluidly connected to a source of water treated by the battery, the electrocoagulation cell including a first cathode and a first anode, the first cathode and the first anode comprising sacrificial metal; A first solid-liquid separator has an inlet, a solid-stage outlet, and a liquid-stage outlet that are fluidly connected to the outlet of the electrocondensed cell; and An electro-oxidizing cell having an inlet and an outlet fluidly connected to the liquid fraction outlet, the electro-oxidizing cell including a second cathode and a second anode, the second anode comprising an anodic oxide material.

18. The system of claim 17, further comprising a controller operable to generate a control signal that adjusts at least one of the residence time of water in the electrocoagulation cell, the residence time of liquid fractions in the electrooxidation cell, a potential applied to the electrocoagulation cell, or a potential applied to the electrooxidation cell.

19. The system of claim 18, further comprising a sensor operatively connected to the controller, the sensor being configured to measure at least one of pH, flow rate, conductivity, current density, concentration of the at least one organic pollutant, and concentration of at least one metallic substance.

20. The system of claim 17 further includes a second solid-liquid separator having an inlet fluidly connected to the outlet of the electro-oxidized cell.

21. The system of claim 17 further includes a metal recovery unit located downstream of the solids fraction outlet.

22. The system of claim 17, wherein the sacrificial metal comprises aluminum and / or iron.

23. The system of claim 17, wherein the anodic oxide material is selected from platinum, titanium oxide, mixed metal oxide (MMO) coated size-stable anode (DSA) materials, graphite, graphene, boron-doped diamond (BDD), lead / lead oxide, and combinations thereof.

24. The system of claim 23, wherein the anodic oxide material is of formula Ti n O 2n-1 Titanium oxides, wherein n ranges from 3 to 9, including 3 and 9.

25. The system of claim 17, wherein the source of the battery-treated water includes black substance leachate, battery breakage water, and / or battery discharge water.

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