Wastewater treatment system and method using reusable technology

Abstract

The present invention relates to a system and method for reducing contaminants in wastewater and for electrolyzing wastewater and other reactants. A unique flow-through approach is implemented where separate streams of oxidant and reductant can be introduced into the electrolytic cell (100) with minimal mixing due to laminar flow. By-products can be easily separated from the outlets from both the anode chamber (101) and cathode chamber (102) by cost-effective separators and gases can be returned to the electrolytic cell as needed to destroy contaminants.

Description

[Technical field]

[0001] The present invention relates to systems and methods for wastewater treatment and electrolytic conversion of reactants into liquid and gas based value added products, more particularly, the present invention relates to systems and methods for reducing contaminants such as persistent chemical oxygen demand, inorganic and organic contaminants in wastewater, sewage, medical waste, scrubber water and industrial waste. [Background technology]

[0002] In modern cities, the current population has developed various ways to obtain a certain level of comfort in their daily lives. To satisfy the comforts of modern lifestyles, the production of food (crops, livestock, processed foods) and industry (hydrocarbons, pharmaceuticals, electronics) has increased, as well as the development of new synthetic products (xenobiotics). Unfortunately, these activities to satisfy conveniences are accompanied by agricultural, industrial, and urban waste, much of which ends up being discharged (treated or untreated) into the environment (air, soil, water). Organic wastes can generally be utilized or reused for other treatments, such as composting and methane production. However, some inorganic and synthetic compounds are persistent or non-biodegradable. Persistent pollutants, including hydrocarbons, pesticides, some personal care products, nanomaterials, and various types of toxins, are increasing and attracting attention due to their adverse effects on natural and human environments, persistence, and biological amplification. Therefore, effective cleanup of these pollutants in the environment is crucial to re-establish the health of ecosystems. Because the pollutants are persistent, traditional cleanup techniques (such as bioremediation or classical physical and chemical processes) either lack the ability to effectively and rapidly clean them up or produce undesirable by-products.

[0003] Since ancient times, the combination of alum and aeration has been the most tried method for treating organic pollutants. In recent years, activated carbon and microorganisms have become known as a method for treating sewage and wastewater, reducing the Chemical Oxygen Demand (COD).

[0004] However, they have drawbacks such as low efficiency, poor recyclability, toxicity, and a narrow range of applications.

[0005] Please refer to the following documents.

[0006] Siamak Azimi Maleki's paper is about the photocatalytic degradation of ethylene dichloride (EDC) wastewater in a batch photocatalytic reactor using titanium dioxide (TiO2) / graphene hybrid as catalyst. The main advantage of this structure using graphene as a support for titanium dioxide is that it greatly enhances the electron transfer.

[0007] KR20200089088 relates to a wastewater treatment method including a first step of performing a pulse electrolysis process on wastewater containing a nickel-cyanide complex to decompose the nickel-cyanide complex into nickel and cyanide ions, a second step of filtering and recovering the nickel precipitated in the wastewater, and a third step of decomposing the cyanide ions contained in the wastewater from which the nickel has been recovered into carbon dioxide and nitrogen through an oxidation reaction.

[0008] US10486992B2 relates to the use of activated carbon in a membrane bioreactor. A membrane bioreactor (MBR) has a membrane that constitutes a support structure. A feed unit supplies a sorbent, such as powdered activated carbon (PAC), to the MBR. The PAC is maintained at a concentration in the mixed liquor of 200 mg / L or more. The mixed liquor containing the sorbent particles is recirculated through the MBR at a flow rate at least twice the feed flow rate. Air bubbles are fed to scouring the membrane during at least a portion of the permeation step. The sorbent particles are present in the mixed liquor and in contact with the membrane. The bioaugmentation product can be immobilized on PAC or other carriers and added to the MBR or other bioreactor.

[0009] AU2020104239A4 relates to a method and apparatus for purifying medical wastewater in general hospitals using graphene.

[0010] CN104176797B is a system related to an apparatus and method for electrochemically treating a kind of organic wastewater that is difficult to decompose, and has devised a kind of SPE electrolytic oxidation sewage treatment electrolysis cell of "zero pole span" similar to solid polymer electrolyte fuel cell technology. This device utilizes an ion exchange membrane to separate the anode chamber and the cathode chamber, and compresses the end plate (titania dimensionally stable) anode, ion exchange membrane, and (nickel) anode to form a "zero pole span" SPE electrolysis sewage treatment electrolysis cell. In this device, electrolysis is carried out, and the wastewater is electrooxidized to generate anode, and the organic matter in water and ammonia nitrogen is mineralized and decomposed; the cathode chamber passes through the tap water (or wastewater), and the cathode release of hydrogen is recycled.

[0011] Despite the widespread use of activated carbon and microorganisms in the treatment of industrial waste and sewage, it is clear that their durability is limited and that harmful chemicals may leach out. To counter such claims, reusable and robust platforms and materials for reducing COD in wastewater are the need of the hour.

[0012] The information disclosed in the Background section is intended to enhance understanding of the general background of the present invention and should not be construed as an admission or in any way suggesting that this information forms prior art already known to those skilled in the art. Summary of the Invention

[0013] The present invention seeks to overcome the problems encountered in the prior art and discloses a system and method that can effectively reduce persistent COD by providing a stabilized and non-toxic antibacterial system that produces useful by-products. The bacterial load is also controlled, as radical species with biocidal properties are generated by oxidation-reduction reactions carried out at the electrodes. The clear filtrate is often separated together with the solid sludge. The method can also be used for the electrosynthesis of industrial products.

[0014] In an exemplary embodiment, the present invention discloses an electrolysis system for reducing pollutants in wastewater treatment and electrosynthesis of reactants, the system is composed of an electrolysis chamber having an anode chamber and a cathode chamber with inlet and outlet ducts, an electrolysis chamber having one anode electrode and one cathode electrode, the composition of the electrodes is non-sacrificial carbon, resin and catalyst, the entire electrode surface is exposed to allow maximum current flow and high reactant flow, and at least one membrane separating the anode chamber and the cathode chamber prevents mixing of reactants in the two chambers.

[0015] In one embodiment, the anode electrode is a carbon-based electrode made of graphene, graphite, resin and catalyst produced by hot pressing or cold pressing, and the cathode electrode is made of graphene, natural graphite flakes purified by dilute sulfuric acid process, resin, catalyst, stainless steel or sandwiched stainless steel. Furthermore, the electrode is made of 95-100% graphite, less than 1% graphene, 0-1% catalyst, optionally 0-30% resin, optionally 0-10% insulator, and optionally includes a steel frame. Graphite is used as an electrode due to its electrical conductivity. Due to its anisotropy, graphite can carry out chemical reactions by intercalating reactant molecules between the graphene layers. Such reactions are called intercalation.

[0016] In a preferred embodiment, the electrodes are impregnated with Teflon to enhance mechanical strength, and the anode and cathode electrodes are used interchangeably depending on the type of waste treatment or electrosynthesis reaction. In one embodiment, at least one of the electrodes is a porous electrode, which increases the electrode surface area and therefore the flux of reactants.

[0017] In another embodiment, the catalyst is selected from the group consisting of platinum group metals (PGM metals) and transition metals such as copper, ruthenium, palladium, platinum, silver, zinc, molybdenum, graphene, CNTs, etc. Additionally, the particulate resin is selected from the group consisting of synthetic resins, pumice, artificial pellets, phenolic resins, phenol formaldehyde resins, and ultra-high molecular weight polyethylene.

[0018] In one embodiment, the membrane for separating the anode and cathode compartments is selected from ion exchange membranes, reverse osmosis membranes, and combinations thereof, with varying pore sizes depending on the desired wastewater treatment and by-products to be separated.

[0019] In a preferred embodiment, the present invention discloses a method for wastewater treatment and electrosynthesis of reactants, comprising the steps of: (a) adding wastewater or reactant solutions to an electrolytic cell or reaction chamber, the electrolytic cell consisting of dimensionally stable graphene anodes and cathodes in at least one anode chamber and at least one cathode chamber; (b) electrolyzing and oxidizing / reducing wastewater to reduce contaminants while continuously introducing a strong electrolyte into the electrolytic cell to reduce the current / speed up the reaction, where oxidation and reduction are performed simultaneously in two cells on demand; (c) introducing flow into the cells by sparger or gas turbulence; (d) recovering by-products generated during the treatment step, where one of the by-products is at least a gas for further action. Furthermore, the strong electrolyte for driving the reaction in the electrolytic cell is selected from the group consisting of sodium sulfate, sodium chloride, potassium chloride, potassium hydroxide and combinations thereof, and the energy source is plug-in or solar energy to maintain the voltage in the system. This is indeed the case for energy generation and waste treatment using renewable resources.

[0020] In one embodiment, the process is anchored by continuously recirculating wastewater through a recirculation conduit connected to the reactor by a recirculation pump, bubbling the by-products back into the chamber for faster electrochemical processes.Furthermore, controlled oxidation and reduction reactions can be carried out simultaneously in the two chambers.

[0021] In one embodiment, the electrolysis process for wastewater treatment is an electro-oxidation and reduction process that uses non-sacrificial carbon electrodes selected for their ability to generate hydroxyl radicals and other secondary oxidants.

[0022] In an exemplary embodiment, the present invention discloses a method for the treatment of wastewater and the reduction of persistent COD, comprising a step of immersing the system in the wastewater. In this system, hydrogen gas is generated on the cathode and collected by a gas absorption unit. Two special electrodes are separated by a suitable distance and a membrane separator. The bottom of the electrode assembly is fitted with a receptacle for collecting the sludge. Such multiple electrode systems are subject to the present invention in various forms and numbers. The removal of COD can use electrolytes but also flow setups. An impeller is introduced into the system to generate turbulence, speed up the reaction process and also introduce special processes.

[0023] In one embodiment, the present invention discloses a method of wastewater treatment where the system is immersed in a wastewater tank or where wastewater is added to a chamber containing the system.

[0024] In a preferred embodiment, the present invention discloses a system and method for reducing persistent COD that can mitigate the levels of persistent COD and pollutants in wastewater from sewage, industrial and hospital waste.

[0025] In another preferred embodiment, the present invention further discloses a system / composition and method for reducing persistent pollutants including hydrocarbons, pesticides, some personal care products, non-substances, and various types of toxins, inhibiting microbial growth, and preventing unpleasant odors.

[0026] The foregoing summary is illustrative and is not intended to be in any way limiting. In addition to the exemplary aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. [Brief description of the drawings]

[0027] However, it should be noted that the attached drawings show only typical embodiments of the present invention, and therefore should not be considered as limiting its scope, since the present invention may admit of other equally effective embodiments. The detailed description is described with reference to the attached figures. In the figures, the leftmost digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to refer to similar features and components. Some embodiments of systems or methods according to embodiments of the present invention will now be described, by way of example, with reference to the attached figures.

[0028] FIG. 1 shows (a) a schematic diagram of an electrochemical flow mode wastewater treatment system according to one embodiment of the present invention and (b) a top view of the system showing parallel electrodes covering the chamber faces or suspended from the lid.

[0029] The figures depict embodiments of the present invention for purposes of example only. Those skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure set forth herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Because this is a patent document, the general broad rules of interpretation should be applied. Everything described and shown is an example of the subject matter of the claims appended hereto. The specific structural and functional details disclosed herein are merely for the purpose of illustrating how to make and use the examples. Several different embodiments and methods not specifically disclosed herein may be included within the scope of the claims. Thus, the claims may be embodied in many alternative forms and should not be interpreted as being limited to only the examples described herein.

[0031] As used in this disclosure, the terms "comprises," "comprising," or other variations are intended to cover a non-exclusive inclusion, such that a device, apparatus, system, assembly, or method consisting of a list of components or a sequence of steps does not include only those components or steps, but may include other components or steps not expressly listed or inherent to such apparatus, assembly, or device. In other words, the use of "comprises" or "comsing" one or more elements or steps in a system, device, or process does not, absent additional constraints, exclude the presence of other elements or additional elements or additional steps in the system, device, or process.

[0032] Rather, an exclusive modifier such as "only" or "singular" may preclude the presence or addition of other subjects in the modifier. The use of permissive terms such as "may" or "can" reflects optionality such that the modifier is not necessarily present, while the absence of a permissive term does not reflect compulsion. In listing items in the exemplary embodiments, conjunctions and inclusive terms such as "and," "together," and "or" include, without excluding, all combinations of one or more of the listed items. The use of "etc." is defined as "et cetera" and indicates the inclusion of all other elements belonging to the same group of the preceding item in any "and / or" combination(s). The modifiers "first," "second," "another," and the like may be used herein to describe various items, but do not limit the modified items to any order. These terms are used only to distinguish one element from another. When there is an ordinal number such as "second" or higher, there must simply be that many elements, without necessarily any difference or other relationship between those elements.

[0033] When an element is referred to as being "connected," "coupled," "resting," "mounted," "fixed," or the like, to other elements, there may be a direct connection to the other elements, or there may be intervening elements present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted similarly (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.).

[0034] As used herein, singular forms such as "a," "an," and "the" are intended to include both the singular and the plural unless the context expressly dictates otherwise. Indefinite articles such as "a" and "an" introduce or refer to any modified term, whether previously introduced or not, while definite articles such as "the" refer to the same term previously introduced. Relative terms such as "almost," "more," and terms of degree such as "approximately," "substantially," reflect a 10% variation in the modified value, or the full range of imprecision that achieves the functionality of the modified term, as would be understood by one of ordinary skill in the art in the technical context. Precision and non-variation are expressed by opposing terms such as "exactly."

[0035] The structures and operations described below may occur in a different order than that described and / or noted in the figures. For example, two operations and / or figures shown in succession may in fact be performed simultaneously or in the reverse order depending on the functionality / acts involved. Similarly, individual operations within the exemplary methods described below may be performed iteratively, individually, or sequentially to provide a loop or other sequence of operations apart from the exact operations described below. Any embodiment or method having the features and functionality described below, in any workable combination, should be presumed to be within the scope of the exemplary embodiments.

[0036] The inventors have recognized that despite the widespread use of available tertiary treatments such as chemical oxidation, ultrafiltration, and membranes, persistent COD is not adequately reduced and operating costs are very high. Furthermore, media and membranes for selective removal of by-products from treatment systems are not commercially available, resulting in revenue loss. Furthermore, physical filtration assemblies are unable to effectively remove gas molecules (<0.001 μm), and removal of toxic gases is essential for industrial and commercial applications. Thus, there remains a need for novel methodologies that are not only environmentally friendly but also economical and provide superior results for reducing persistent COD in such applications, along with effective removal of by-products. To overcome these problems, the inventors have developed the exemplary embodiments and methods described below to address these and other problems recognized by the inventors, with unique solutions enabled by the exemplary embodiments.

[0037] The present invention relates to a system and method for reducing contaminants in wastewater treatment, including hydrocarbons, pesticides, nanomaterials, and various types of toxins in wastewater from industry, sewage, and electrosynthesis of reactants.

[0038] Please refer to FIG. 1 showing (a) a schematic diagram of a wastewater treatment system in electrochemical flow mode and (b) a top view of the same showing parallel electrodes covering the chamber surface or suspended from the lid, according to an embodiment of the present invention. The system includes at least a chamber (100) containing electrodes. The system also includes at least one anode (105) and at least one cathode electrode (106) configured in at least one anode chamber (101) and at least one cathode chamber (102), respectively. Furthermore, the system includes at least a solar cell or plug-in power supply (107) for powering the electrolyzer. In this system, hydrogen gas is generated at the cathode and collected by a gas absorption unit. The two special electrodes are separated by a suitable distance and an impermeable membrane (109) separator. A receptacle is attached to the bottom of the electrode assembly to collect the sludge. Multiple such electrode systems of various forms and numbers are subject to the present invention. The removal of COD can use an electrolyte, but can also use a flow setup. An impeller is introduced into the system to generate turbulence and speed up the reaction process. The type of electrodes is a particular feature of the system, and the electrodes are prepared by hot and cold pressing processes for electrode stability and high current. High-purity graphite electrodes are employed for higher conductivity and faster electron transfer. Also, the anode and cathode chambers need to be separated to extract by-products and gases. If the by-products are two gases, the mixing of the two chambers may cause the gases to mix. In one embodiment, two separate anode and cathode chambers are used depending on the required processing to efficiently separate the cathode and anode streams of the waste liquid and proceed with different reactions.

[0039] The chambers comprise at least one inlet (103a) for the inflow of wastewater with oxidizing components for the anode chamber (101) of the electrolysis chamber (100), at least one inlet (103b) for the inflow of wastewater with reducing components for the cathode chamber (102) of the electrolysis chamber (100), at least one outlet (104a) for the outflow of purified water with a first type of dissolved gas (e.g. oxygen) from the anode chamber (101) of the electrolysis chamber (100) and at least one outlet (104b) for the outflow of purified water with a second type of dissolved gas (e.g. oxygen) from the cathode chamber (102) of the electrolysis chamber (100). Purified water with a first type of dissolved gas, such as oxygen, flows out of the anode chamber (101) of the electrolysis chamber (100), and purified water with a second type of dissolved gas, such as hydrogen, flows out of the cathode chamber of the electrolysis chamber (100). The flow-through design has separate inlets to the anode and cathode compartments on the bottom shroud and separate outlets at opposite ends of the top, ensuring laminar flow of the catholyte and anolyte respectively, allowing efficient heat dissipation from ion exchange and reactions at the electrodes while preventing over-mixing of the fluids.

[0040] The membrane is a thin-film composite type, with a polyamide (PA) active layer (~50-100 nm thick) supported on an asymmetric polysulfone support (~30-60 μm thick).

[0041] The present invention further relates to a system with electrodes made of graphene, high purity graphite and resin. The overall electrical conductivity of the mixture is very high. Special catalysts embedded in the electrodes allow for special reactions. Furthermore, the electrodes can be pressed by hot or cold processes. In another embodiment, inert polymer powders such as Teflon and PVDF are added to the electrode composition to produce corrosion-resistant electrodes. In one embodiment, coal tar pitch, produced from controlled distillation of coal tar, is used as a binder in the manufacture of electrodes. For solid pitch, the material is melted at a temperature 80°C above its softening point (about 105°C). The molten pitch is useful for fusing and graphitizing the electrodes. This enhances and adjusts the electrical conductivity to allow for efficient redox reactions. Furthermore, the present invention discloses a method for treating wastewater and reducing refractory COD, which includes the step of immersing the system in wastewater. In this system, hydrogen gas is generated at the cathode and collected in a gas absorption unit. The two special electrodes are separated by a suitable distance and a membrane separator. A sludge collection container is attached to the bottom. Various configurations and numbers of such electrode systems are within the scope of this invention. The removal of COD can be done using an electrolyte or a flow setup. The hydrogen gas released in turn is collected in a tank and an impeller is introduced into the system to create turbulence and speed up the reaction process.

[0042] The non-sacrificial electrode is comprised of 95 to 100% graphite, less than 1% graphene, 0 to 1% catalyst, optionally 0 to 30% resin, and optionally 0 to 10% corrosion-inhibiting polymer.

[0043] The electrodes are separated by the membrane separator at a suitable distance of 1 cm to 20 cm to allow maximum current to be utilized without compromising the safety of the electrodes touching and the heat generated not being dissipated.

[0044] In general, challenging industrial wastewater treatment applications often do not have functional COD reduction mechanisms, such as metal finishing, food and beverage, oil and gas produced water, fraction flowback, and mine discharge. There is also a need to find cost-effective ways to reuse treated wastewater to lower operational costs, such as reuse of industrial wastewater for boiler feedwater, custom-built high-performance wastewater treatment systems for challenging wastewaters like oily wastewaters and effluents containing high amounts of suspended solids. The first treatment step consists of filtration and ultrafiltration (UF), which can remove emulsified organics and suspended solids down to low micron levels. The second stage of the integrated process is where current technologies are responsible for further removal of dissolved organic and inorganic compounds in particular. Finally, the clarified wastewater is suitable for discharge or reuse.

[0045] In one embodiment, the system is an open system and this method does not involve the generation of sludge. However, if sludge is generated during the process, this sludge can be removed from the chamber. In one embodiment, the electrodes are in the lid of the chamber and the lid can be easily removed to clean the chamber. In a closed electrolysis system, heat is generated and the hydrogen released as a by-product can lead to an explosion. However, as it is an open system, the heat is sufficiently dissipated and the released hydrogen gas can be separated and stored as a by-product and used for further processes.

[0046] In one embodiment, the electrodes are heated to form porous electrodes, which increases the surface area of ​​the electrical conversion process. Different electrode compositions result in different types of wastewater treatment and reaction efficiencies. In one embodiment, pressed or conventional electrodes can be used in the system. The electrodes are made of 70% pure graphite with 1% Cu+30% resin+1-5% graphene. Furthermore, the anode and cathode electrodes can be the same or different depending on the desired reaction and by-products. The electrode surface area of ​​the electrolysis cell affects the reaction rate. Increasing the electrode surface area increases the reaction rate of the electrolysis cell. It also increases the current flowing through the electrodes.

[0047] In one embodiment, the electrolytic conversion system (oxidation and reduction) of scrubber water is saturated with corrosive gases such as CO2, SOX, and NOX, which are typically absorbed in alkaline water. This wastewater, scrubber water, can be converted into useful products such as formic acid + methanol (CO2), SOX (sulfides, bisulfides, sulfates), etc., which can be utilized as valuable materials in the construction industry.

[0048] In one embodiment, wastewater is treated by electrolytic oxidation (EO). Electrolytic oxidation, also known as anodic oxidation or electrochemical oxidation, is a process used for wastewater treatment, mainly for industrial wastewater. It is a type of advanced oxidation process in which anode and cathode electrodes are connected to a power source and a specific voltage is applied. When sufficient supporting electrolyte is provided to the system, strong oxidizing species are formed, which interact with and decompose the pollutants. Since the necessary reactive species are generated at the anode surface, no external chemical addition is required (in contrast to other processes such as in-situ chemical oxidation). The cathode electrode is mainly composed of stainless steel plate, platinum mesh, and carbon felt electrodes. When a voltage is applied to the electrodes, oxygen evolution intermediates, especially hydroxyl radicals, are generated near the anode. Hydroxyl radicals are known to have the highest redox potential, allowing the degradation of many persistent organic compounds.

[0049] In embodiments, electro-oxidation can occur either directly by hydroxyl radicals generated at the anode surface, or by an indirect process where oxidants such as chlorine, hypochlorous acid, hypochlorite, or hydrogen peroxide / ozone are formed at the electrode by the following reaction: 2Cl - → Cl 2 + 2e - Cl 2 + H 2 O → HOCl + H+ + Cl- HOCl → H + + OCl - H 2 O → *OH + H + + e - 2 *OH → H 2 O 2 H 2 O 2 → O 2 + 2H + + 2e - O 2 + *O→ O

[0050] Oxidation occurs when species such as active chlorine species are generated anodically from chloride ions to destroy pollutants. In so-called mediated electro-oxidation, metal ions are oxidized on the anode from a stable state to a more reactive valence state, which can then directly attack pollutants and generate hydroxyl free radicals to promote their destruction.

[0051] In one embodiment, the method is a zero-sludge process, i.e., no sludge is formed during the oxidation process, no chemical inputs are required, and negligible sludge generation occurs, making it a viable sole treatment process for highly difficult-to-treat wastewaters.

[0052] In one embodiment, the wastewater is treated by electroreduction, also known as cathodic reduction or electrochemical reduction. The redox reagent is generated electrically by either an anodic or cathodic process, one of which is O 2 or H generated at the cathode by air supply 2 O 2 The iron catalyst is also regenerated on the cathode surface. Other techniques such as flocculation based on dissolution of iron-impregnated anodes (peroxidative flocculation (PC)), ultrasonic dissolution of heterogeneous catalysts supplying Fe2+ (heterogeneous electro-Fenton) and bioremediation (bio-electro-Fenton) are also of interest. 2 O 2 It can also promote electrochemical generation by oxygen reduction reactions in acidic and alkaline media. O 2 (g) + 2H + + 2e---->H 2 O2 O 2 (g) + H 2 O+2e---->HO 2 - + OH

[0053] H 2 O 2 When is electrogenerated cathodically in an undivided cell without pH control, the process is H 2 O 2 This is called anodic oxidation (AO) (AO-H 2 O 2 The anode adsorbs OH and H 2 O 2 , H.O. 2 (When Cl is present, it is produced by active chlorine). On the other hand, AO-H 2 O 2 When carried out at an acidic pH (~3.0) and in the presence of iron ions (added or already present in the wastewater), the Fenton reaction is achieved in the solution, producing homogeneous OH, hence the EF technique. Supported or chelated iron catalysts have also been used to extend the working pH range or cathodes favorable for continuously regenerating Fe2+ from the reaction, and comparable decomposition efficiencies have been achieved by PC and EF, indicating that it is a suitable scheme. Here, a graphite-based dimensionally stable electrode is specially impregnated with iron. Fe2+ ​​+ H 2 O 2 ---->Fe3+ + OH- + OH- Fe3+ + e- ----> Fe2+ Fe2+ ​​+ 2e----> Fe

[0054] In an exemplary embodiment, the present invention discloses an electrolysis system for reducing pollutants in wastewater treatment and electrolytic synthesis of reactants, comprising: an electrolysis chamber having at least one anode chamber, at least one cathode chamber, at least one inlet for introducing wastewater into the electrolysis chamber, and at least one outlet duct for discharging by-products of electrolysis; at least one anode and at least one cathode configured in the electrolysis chamber, wherein the composition of each of the at least one anode and at least one cathode is non-sacrificial carbon, resin, and catalyst; the entire surfaces of the anode and cathode are exposed to allow maximum current to pass through to promote the flow of reactants, and at least one membrane separating the anode and cathode chambers prevents mixing of reactants in the two chambers; a flow is introduced into the electrolysis chamber to accelerate the reaction rate, and a recirculation pump is connected between the electrolysis chamber and a recirculation conduit for recirculating the wastewater. The at least one anode chamber and the at least one cathode chamber each have at least one anode electrode and at least one cathode electrode configured to expose a maximum surface area of ​​the electrode for maximum current flow. The planar electrodes may cover the entire planar area of ​​the chamber or may be suspended from a lid. Additionally, the system includes at least a solar cell or plug-in power source for powering the electrolytic cell.

[0055] In one embodiment, the anode electrode is a carbon-based electrode made of graphene, graphite, resin and catalyst produced by hot or cold pressing, and the cathode electrode is made of graphene, natural graphite flakes purified by a dilute sulfuric acid process, resin, catalyst, stainless steel or sandwiched stainless steel, further comprising an electrode made of 95-100% graphite, less than 1% graphene, 0-1% catalyst, optionally 0-30% resin, and optionally 0-10% insulator, and the electrode is optionally housed in a steel frame.

[0056] In a preferred embodiment, the electrodes are impregnated with Teflon to enhance mechanical strength, and the anode and cathode electrodes are used interchangeably depending on the type of waste treatment or electrosynthesis reaction. In one embodiment, at least one of the electrodes is a porous electrode, which increases the electrode surface area and therefore the flux of reactants.

[0057] In another embodiment, the catalyst is selected from the group consisting of platinum group metals (PGM metals) and transition metals such as copper, ruthenium, palladium, platinum, silver, zinc, molybdenum, graphene, CNTs, etc. Additionally, the particulate resin is selected from the group consisting of synthetic resins, pumice, artificial pellets, phenolic resins, phenol formaldehyde resins, and ultra-high molecular weight polyethylene.

[0058] In one embodiment, the membrane (109) for separating the anode and cathode compartments is selected from ion exchange membranes, reverse osmosis membranes, and combinations thereof, with varying pore sizes depending on the desired wastewater treatment and by-products to be separated.

[0059] In another embodiment, the anode and cathode chambers are equipped with at least one inlet duct and one outlet duct for controlling the oxidation and reduction reactions in the anode and cathode chambers.

[0060] In a preferred embodiment, the present invention discloses a method for wastewater treatment and electrosynthesis of reactants, comprising the steps of: (a) adding wastewater or reactant solution to an electrolytic cell or reaction chamber, the electrolytic cell being composed of dimensionally stable graphene anodes and cathodes in at least one anode chamber and at least one cathode chamber; (b) electrolyzing and oxidizing / reducing wastewater to reduce contaminants while continuously introducing a strong electrolyte into the electrolytic cell to reduce the current and thus accelerate the reaction rate, the oxidation and reduction being performed simultaneously in two cells on demand; (c) introducing flow into the cells by sparger or gas turbulence; (d) recovering by-products generated during the treatment step, one of the by-products being at least gas for further action. Furthermore, the strong electrolyte for promoting the reaction in the electrolytic cell is selected from the group consisting of sodium sulfate, sodium chloride, potassium chloride, potassium hydroxide and combinations thereof, and the energy source is plug-in or solar energy to maintain the voltage in the system.

[0061] In one embodiment, the process is fixed by continuously recirculating wastewater through a recirculation conduit connected to said reactor by a recirculation pump and bubbling the by-products back into the chamber for faster electrochemical processing.

[0062] In another embodiment, a cathodic current density of about 20-500 A / m2 is applied to the reactor, the gas from the wastewater is purified gas by a filter, and the separation of the outlet gas and liquid is performed by a headspace mechanism. Headspace analysis allows the detection of volatile substances in liquid or solid samples and minimizes column contamination. In this analysis, a small amount of sample is placed in a vial sealed with a septum, and the sample vial is equilibrated at an appropriate elevated temperature.

[0063] In one embodiment, the electrolysis process for wastewater treatment is an electro-oxidation and reduction process that uses non-sacrificial carbon electrodes selected for their ability to generate hydroxyl radicals and other secondary oxidants.

[0064] Working Example

[0065] Example 1: An experiment was carried out to monitor COD in both the anode and the cassolute compartments separated by an ionic membrane. The reactions at the anode included oxygen evolution, diffusion, oxidation of electrolytes, oxidation of water and radical coupling. The reactions at the cathode included reduction reactions, which break down reducible substances into simpler, usable components. This dual action broke down many complex molecules into simpler, usable by-products. A dramatic reduction in COD was observed in both compartments. After about an hour of reaction, a portion of the sludge separated and could be filtered. The results of the special device for reducing refractory COD are shown in Table 1.

[0066] Table 1: Results [Table 1]

[0067] Example 2: Green hydrogen production with reduction of industrial water use: An experiment was conducted to treat industrial wastewater and measure its COD. The industrial wastewater was converted into reusable water by reducing persistent COD that meets the discharge standards. In addition, hydrogen gas was removed from the anode chamber as a by-product.

[0068] In a closed electrolysis system, heat is generated and hydrogen released as a by-product can lead to explosions. However, in an open system, the heat can be managed and the released hydrogen gas can be separated, stored as a by-product and used for further processes. Overall, persistent COD can be significantly reduced and the generated hydrogen gas can be used for energy production. The device can be used repeatedly and requires minimal maintenance for most types of wastewater.

[0069] Example 3: Agricultural chemical wastewater treatment: The chemical oxygen demand of the water before treatment was 2500 ppm. The chemical oxygen demand of the water after one pass was 1200 ppm. There was no chlorine odor without the administration of chemicals, and the growth of microorganisms was also suppressed.

[0070] Example 4: Removal of butylamine from industrial wastewater by electro-oxidation: An experiment was carried out using industrial wastewater containing butylamine, and the COD before and after treatment was calculated. The initial COD before treatment was 4,00,000 ppm. By catalytic oxidation, these were decomposed to NH2, NH3, and NH4SO4, which were converted to butyraldehyde by electro-oxidation, lowering the COD to 1200 ppm (recirculation). In the reduction compartment, only sodium sulfate passed through, and the treatment reduced the persistent COD by 99.7%.

[0071] Example 5: Electroreduction of Carbon Dioxide: For industrial wastewater containing carbon dioxide as a pollutant, carbon dioxide was converted into simple organic fuels and chemicals by the mechanism of electroreduction. The reduction of carbon dioxide in the cathode chamber was accompanied by the oxidation of water at the anode or photoanode, and the carbon dioxide conversion process at low temperature was based on electrocatalysis and photoelectrochemical approaches. This reaction reduced the amount of CO released into the atmosphere. 2 Provided a means to reduce emissions and store renewable energy. 2 The CO released as a by-product was collected in a chamber containing water. 2 is bubbled into a chamber containing wastewater containing KOH and CO 2 The reaction absorbed 1,2-dihydropyridine and released 1,2-dihydropyridine and 1,2-dihydropyridine. The membrane potential applied to the reaction allowed the separation of the different by-products. Table 2

[0072] Table 2: The reactions and potentials assumed in this scheme are as follows: [Table 2]

[0073] Example 6: Na 2 SO 4Addition of 1% Na: Voltage is the driving force behind efficient electrochemical reactions, and for an effective reaction the voltage must be low and the current must be high. To maintain this, an electrochemical system containing 99% pure graphite electrodes as the anode and cathode electrodes was added with 1% Na. 2 SO 4 was added to the electrolyte chamber, 2 SO 4 The addition of 1000 times as much water as the 1000 times as much water was observed to increase the current flow at the same voltage. This resulted in a faster reaction rate. Furthermore, the high flow rate prevented the liquids in the two chambers from intermixing.

[0074] Table 3: Results [Table 3]

[0075] Example 7: Multiple chambers in a row: In an exemplary embodiment, the system can operate multiple chambers in a row to improve the efficiency of the chambers depending on the requirements. 2 SO 4 The experiment was run in an electrochemical setup with two anodic electrodes and two 99% graphite-based electrodes as cathodic electrodes. A current of 22.8 amps was drawn at only 8.1 volts, indicating that the high Na 2 SO 4 It was found that increasing the number of electrodes and the number of chambers increased the reaction rate and further reduced the chemical oxygen demand of the wastewater.

[0076] Pesticide samples were collected using a multi-chamber system (2% Na 2 SO 4 The wastewater was treated with a multi-chamber system (two anode electrodes and two 99% graphite-based cathode electrodes) for reduction of chemical oxygen demand, and the results confirmed the fact that the multi-chamber system results in faster reaction rate and therefore a higher reduction in chemical oxygen demand of the wastewater. The by-products are also different.

[0077] Example 8: Molded and pressed electrodes provided higher efficiency. In one embodiment, the electrodes are molded by hot or cold process. The reduction of COD is faster when the electrochemical system includes molded electrodes compared to conventional electrodes. In an embodiment, the molded cathode electrode provides higher efficiency than the anode as molded electrodes (2% Na with two molded electrodes as anodes and two conventional electrodes as cathode electrodes). 2 SO 4 25 liters) (Table 4).

[0078] [Table 4]

[0079] In an embodiment, a sparger or flow is introduced into the system to increase the efficiency of the system for COD reduction. Of the three transport modes in the system: conduction, convection, and diffusion, convection / flow plays a major role in regulating the efficiency of the water treatment process. It has been observed that increasing the flow rate in the chamber increases the efficiency. (Solution: 2% Na 2 SO 4 , using two molded anode electrodes and two conventional electrodes as cathodes). In one embodiment, high flow rates are possible, preventing flow mixing and current build-up (Table 5), thereby accelerating the reaction rate. In addition to separate chambers for oxidation and reduction, there is the flexibility of multiple electrodes in series covering the entire planar area of ​​the chamber.

[0080] Table 5: Currents in the system with and without flow [Table 5]

[0081] Overall, persistent COD can be significantly reduced, and the hydrogen gas produced can be used for energy generation. The device can be used repeatedly with minimal maintenance for most types of wastewater. It is also easy to clean and maintain, even if sludge is generated. Furthermore, for wastewater treatment, the system can be immersed in a wastewater tank or wastewater can be added to the chamber containing the system, and a solar-power-based current source can be used for the system. This is truly a case of energy generation and waste treatment using renewable resources.

[0082] Potential applications 1. For disinfecting public and private pools, it generates radicals through electrochemical oxidation using electrodes to destroy microorganisms in the water. Compared to other disinfection methods, it does not require the injection of chemicals, has no chlorine smell, and prevents the growth of algae. 2. Ammonia removal in wastewater treatment using electro-oxidation. 3. Electrochemical oxidation at the anode can be applied to decompose various organic pollutants and disinfect drinking water and municipal wastewater. 4. Processing of highly soluble dyes. 5. Decomposition of methyl orange azo dye in a recirculating flow plant system. 6. An innovative approach of combining membrane filtration technologies such as nanofiltration (NF) and microfiltration (MF) with electro-oxidation (EO) treatment as described. 7. EO treatment combined with biological oxidation can be used in separate, combined and integrated ways. 8. Removal of 2,4-dichlorophenol from synthetic wastewater and sulfide from domestic wastewater. 9. Complete COD reduction of azo dyes in sulfate medium at pH 3.0 and photodegradation of intermediates such as the formed Fe(III)-carboxylate complexes. 10. Removal of COD from chlorinated herbicides and removal of COD and colour from textile wastewater using metal impregnated anode and graphite cathode. 11. Removal of harmful gases, methylparaben and TOC from industrial wastewater. 12. Removal of dissolved organic carbon from dye mixtures and winery wastewater. 13. Simultaneous power generation and wastewater treatment by reverse electrodialysis with salt concentration gradient coupled with EF, as well as wind-powered EO process for herbicide removal using BDD electrodes.

[0083] According to the advantages of the present invention compared to existing formulations, the present invention is to provide a major change in the field of wastewater treatment with a cost-effective, reusable and energy-efficient process that lowers the COD for wastewater treatment. For example, metal finishing, food and beverage, oil and gas produced water, fraction flowback, mine wastewater (including treatment of produced water from oil and gas exploration and production, industrial wastewater from metal finishing and textile dyeing industries), etc. There is also a need to find cost-effective ways to reuse treated wastewater to lower operating costs, such as reuse of industrial wastewater for boiler feedwater, or custom-made high-performance wastewater treatment systems for challenging wastes such as oily wastewater or wastewater with high suspended solids. The first treatment step consists of filtration and ultrafiltration (UF), which can remove emulsified organics and suspended solids down to low micron levels. The second stage of the integrated process is where the current technology is responsible for further removal, especially of dissolved organic and inorganic compounds. Finally, the purified wastewater is suitable for discharge or reuse.

[0084] It will be further understood that the functions or structures of multiple components or steps may be combined into a single component or step, or that the functions or structures of one step or component may be split into multiple steps or components. The present invention contemplates all of these combinations. Unless otherwise stated, the dimensions and shapes of the various structures depicted herein are not intended to limit the present invention, and other dimensions and shapes are possible. In addition, while a feature of the present invention may be described in the context of only one of the illustrated embodiments, such a feature may be combined with one or more other features of other embodiments for any given application. It will also be understood from the above that the creation of the unique structures herein and their operation also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and final products resulting from the practice of the methods herein. The use of "consisting of" or "comprising" also contemplates embodiments that "consist essentially of" or "consist of" the referenced features.

[0085] Although embodiments of the present invention have been described in terms that are specific to structural features, it should be understood that the present invention is not necessarily limited to the particular features described. Rather, the particular features and methods are disclosed as embodiments for the present invention. Numerous modifications and adaptations of the systems / components of the present invention will be apparent to those skilled in the art, and therefore, it is intended by the appended claims to cover all such modifications and adaptations that are within the scope of the present invention.

Claims

1. An electrolysis system for the removal of pollutants and electrosynthesis of reactants in wastewater treatment, comprising: An electrolysis chamber (100) having a configuration including at least one anode chamber (101) having a first reactant and at least one cathode chamber (102) having a second reactant, at least one inlet (103a) for introducing wastewater having an oxidizable component into the anode chamber (101) of the electrolysis chamber (100); at least one inlet (103b) for the cathode chamber (102) of the electrolysis chamber (100) for the inflow of wastewater having reducible components, at least one outlet (104a) for discharging purified water having a first type of dissolved gas from the anode chamber (101) of the electrolysis chamber (100); and a configuration including at least one outlet (104b) for discharging purified water containing a second type of dissolved gas from a cathode chamber of the electrolysis chamber (100); the configuration allows for laminar flow of the reactants, the at least one inlet (103) and the at least one outlet (104) being at opposite ends of the electrolysis chamber (100); at least one anode (105) and at least one cathode (106) configured within the electrolysis chamber (100), at least one anode (105) and at least one cathode (106), wherein the at least one anode (105) and the at least one cathode (106) are non-sacrificial electrodes made of carbon, resin, and catalyst, and the entire surface of the anode (105) and the entire surface of the cathode (106) are exposed to maximum current passing therethrough, allowing enhanced flow of the reactants; at least one membrane (109), semi-permeable to allow the passage of water molecules but to block most of the dissolved salts, organic matter and bacteria, said membrane separating the anode chamber (101) from the cathode chamber (102) and avoiding intermixing of the reactants in the two chambers (101, 102); the at least one outlet (104) configured to collect reusable water, the flow of which is introduced into the electrolysis chamber (100) to accelerate the reaction rate; A recirculation conduit is connected to the electrolysis chamber with at least an energy source (107) and a recirculation pump (108) for recirculating the wastewater.

2. 2. A system for wastewater treatment and electrolytic synthesis of reactants according to claim 1, comprising: The anode is a carbon-based electrode made of graphene, graphite, resin and catalyst produced by hot or cold pressing.

3. 3. A system for wastewater treatment and electrolytic synthesis of reactants according to claim 2, comprising: The catalyst is selected from the group consisting of platinum group metals (PGM metals) and transition metals such as copper, ruthenium, palladium, platinum, silver, zinc, molybdenum, graphene, CNTs, etc.

4. 3. A system for wastewater treatment and electrolytic synthesis of reactants according to claim 2, comprising: The particulate resin is selected from the group consisting of synthetic resin, pumice, and artificial pellets, phenolic resin, phenol formaldehyde resin, ultra-high molecular weight polyethylene, and coal tar pitch.

5. 2. A system for wastewater treatment and electrolytic synthesis of reactants according to claim 1, comprising: The cathode is made of graphene, natural graphite flakes refined by a dilute sulfuric acid method, a resin, a catalyst, stainless steel, or a sandwich of stainless steel.

6. 2. A system for wastewater treatment and electrolytic synthesis of reactants according to claim 1, comprising: The electrodes are impregnated with Teflon to increase their mechanical strength, and the anode and cathode are used interchangeably depending on the type of waste treatment or electrosynthesis reaction.

7. 2. A system for wastewater treatment and electrolytic synthesis of reactants according to claim 1, comprising: At least one of the anode and the cathode is porous.

8. 2. A system for wastewater treatment and electrolytic synthesis of reactants according to claim 1, comprising: The at least one inlet duct and one outlet duct are capable of controlling the oxidation and reduction reactions in the anode and cathode chambers.

9. A system for wastewater treatment according to claim 1, The membrane for separating the anode and cathode chambers is selected from ion exchange membranes, reverse osmosis membranes, and combinations thereof, with variable pore sizes of less than 1 micron, depending on the desired wastewater treatment and by-products to be separated.

10. A system for wastewater treatment according to claim 1, The membrane is a thin film composite type in which the active layer is a polyamide (PA) active layer (~50-100 nm thick) supported on an asymmetric polysulfone support (~30-60 μm thick).

11. A system for wastewater treatment according to claim 1, The non-sacrificial electrode is comprised of 95-100% graphite, less than 1% graphene, 0-1% catalyst, optionally 0-30% resin, and optionally 0-10% corrosion-inhibiting polymer.

12. A system for wastewater treatment according to claim 1, The electrodes are separated by the membrane separator at an appropriate distance of 1 cm to 20 cm so that maximum current can be utilized without compromising the safety of the electrodes touching and the heat generated cannot be dissipated.

13. A system for wastewater treatment according to claim 1, The energy source is plug-in or solar energy to maintain the voltage of the system.

14. 1. A method for the treatment of wastewater and electrosynthesis of reactants, comprising the steps of: (a) adding water to be treated to an electrolytic cell chamber, said electrolytic cell being comprised of dimensionally stable graphene anodes and cathodes in at least one anode chamber and at least one cathode chamber; (b) electrolyzing and oxidizing / reducing the wastewater by continuously introducing a strong electrolyte into the electrolytic cells to reduce the current, whereby oxidation and reduction are performed simultaneously in the anode and cathode cells according to the demand of the by-products; (c) introducing a flow into the chamber, the flow being introduced by a sparger or gas turbulence to accelerate the reaction rate; and (d) recovering the by-products, one of which is at least a gas, and the produced gas is recycled to the electrolyzer for faster electrochemical processes.

15. 15. A method for wastewater treatment according to claim 14, comprising: The process is accelerated by continuously recirculating wastewater through a recirculation conduit connected to the reactor by a recirculation pump.

16. 15. A method for wastewater treatment according to claim 14, comprising: The strong electrolyte for reducing current and accelerating reaction rates in the electrolytic cell is selected from the group consisting of sodium sulfate, sodium chloride, potassium chloride, potassium hydroxide, and combinations thereof.

17. 15. A method for wastewater treatment according to claim 14, comprising: In the step (b), about 20-500 A / m 2 is applied to the electrolytic cell.

18. 15. A method for wastewater treatment according to claim 14, comprising: The gases are purified from the waste water by a filter and separation of the exit gases and liquid is achieved by a headspace mechanism.

19. 15. A method for wastewater treatment according to claim 14, comprising: The anode and cathode consist of non-sacrificial carbon electrodes selected for their ability to generate hydroxyl radicals and other secondary oxidants.

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