A method and device for synchronous ethanol production by electrically enhanced separation membrane water treatment

Abstract

The present invention discloses a method and device for synchronous ethanol production by electrically enhanced separation membrane water treatment. The coupling of MES technology and anaerobic wastewater treatment technology can not only effectively improve the sewage treatment effect of anaerobic membrane organisms, but also is expected to achieve the emission reduction and resource utilization of CO2 generated in situ in the anaerobic wastewater treatment system.

Description

Technical Field

[0001] The invention belongs to the field of environment and relates to a method and device for synchronous ethanol production through electric enhanced separation membrane water treatment. Background Art

[0002] As a highly efficient wastewater treatment process, the anaerobic membrane bioreactor (AnMBR) can produce CH4 energy gas while releasing CO2. In recent years, the number of sewage treatment plants has increased year by year with the sewage load, and the large amount of CO2 that comes with it has become a significant source of greenhouse gases that cannot be ignored. However, CO2 is also a very extensive renewable resource. The carbon atoms in the CO2 molecule are in the highest oxidation state, that is, the lowest energy state. The process of converting inorganic CO2 into organic energy substances requires a large amount of energy and reducing power. Therefore, developing green renewable resources based on CO2, partially replacing fossil energy and petrochemical products, and achieving greenhouse gas emission reductions is one of the important strategic goals for achieving sustainable development.

[0003] Microbial electrosynthesis (MES) is an effective technology for reducing CO2 and producing valuable extracellular carbon products without producing harmful byproducts. It relies on the stimulation of exogenous electrons on microorganisms to make them exhibit unique metabolic reactions and complete "unbalanced" metabolism. In this process, electrical energy is used to drive the biocathode for carbon fixation. Electroactive microorganisms obtain electrons from the solid electrode through electrocatalysis for CO2 reduction, thereby achieving carbon-containing products (C 2+ ) production, such as C 2+ Acid and C 2+ Therefore, coupling MES technology with anaerobic wastewater treatment technology is expected to achieve the reduction and resource utilization of CO2 generated in situ in anaerobic wastewater treatment systems.

[0004] Currently, only a few studies on the use of MES to recycle CO2 have demonstrated on a laboratory scale the use of pure cultures or mixed microbial communities to directly introduce carbon dioxide gas into the electrosynthesis system or to add bicarbonate to the electrosynthesis culture medium to supply the raw materials for electrosynthesis. For example, patent publication number CN103881905B discloses an embedded bioelectrosynthesis system, which mainly consists of an anaerobic oxidation reactor, a bioelectrosynthesis reactor, a culture medium circulation control system, a power supply, and an external circuit. The bioelectrosynthesis reactor is composed of a conductive reactor wall, a diaphragm, and an anode from the inside out. The conductive reactor wall also serves as the cathode of the reactor. The culture medium circulation control system is used to control and adjust the pH value, temperature, CO2 concentration, etc. of the culture medium.

[0005] However, in such public documents, carbon dioxide gas is directly blown into chamber 2 through a conduit connected to a carbon dioxide cylinder (for example, the Chinese invention patent application with publication number CN103881905B adopts this method) or the raw material for electrosynthesis is supplied by adding bicarbonate to the electrosynthesis culture medium. However, one of the main purposes of bioelectrosynthesis is to reduce carbon dioxide emissions, so the method of directly adding bicarbonate does not meet the needs of practical applications; and for the raw material supply method of directly introducing carbon dioxide through a connection to a carbon dioxide cylinder, there is a problem that the raw material supply amount is difficult to control, especially online control, and mass transfer of carbon dioxide to the electrode reaction zone is also a problem faced by this feeding method in improving the efficiency of bioelectrosynthesis.

[0006] Moreover, the above-mentioned method is actually difficult to couple with the wastewater treatment process to achieve direct treatment of the large amount of CO2 that accompanies the sewage treatment process. Summary of the Invention

[0007] 1. Problem to be solved

[0008] The purpose of the present invention is to provide a microbial electrosynthesis coupled with the existing anaerobic membrane biological water treatment process, which can simultaneously achieve enhanced water treatment effect, in-situ CO2 emission reduction and C 2+ A device and method for increasing alcohol production.

[0009] 2. Technical solution

[0010] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0011] A first aspect of the present invention provides a device for electrically enhanced separation membrane water treatment and simultaneous ethanol production, the device comprising:

[0012] Reactor and power supply,

[0013] The reactor is a two-chamber reactor, comprising a chamber 1 and a chamber 2, wherein the chambers 1 and 2 are separated by a cation exchange membrane;

[0014] An electrode is provided in the chamber 1, and the electrode is connected to the power supply via a wire, serving as the anode of the device;

[0015] The second chamber is provided with a membrane separation component and filled with anaerobic sludge.

[0016] in,

[0017] The membrane of the membrane separation assembly is externally connected to the power supply through a wire and serves as the cathode of the device. The cathode is in contact with the anaerobic sludge.

[0018] According to any embodiment of the first aspect of the present invention, the second chamber is further provided with a reference electrode, and the reference electrode is externally connected to the power supply through a wire.

[0019] According to any embodiment of the first aspect of the present invention, the membrane comprises any one or more of a tubular membrane, a hollow fiber membrane or a flat membrane, and has electrical conductivity.

[0020] According to any embodiment of the first aspect of the present invention, the membrane separation assembly comprises a membrane and a fixing member for the membrane, wherein the fixing member has an opening;

[0021] The opening is connected to a pipe to realize water outlet of the second chamber.

[0022] According to any embodiment of the first aspect of the present invention, the device further comprises a hydraulic drive system and a gas collection system, wherein the hydraulic drive system is used to drive the flow of the liquid in the reactor;

[0023] The gas collection system is used to collect the gas discharged from the reactor.

[0024] According to any embodiment of the first aspect of the present invention, the second chamber is further provided with a liquid inlet, a liquid outlet and an air outlet;

[0025] The hydraulic drive system is respectively connected to the liquid inlet and / or liquid outlet of the second chamber;

[0026] The liquid inlet of the second chamber is in communication with the opening of the fixing member;

[0027] The gas outlet is in communication with the gas collection system.

[0028] According to any embodiment of the first aspect of the present invention, the chamber 1 is further provided with a liquid inlet, a liquid outlet and an air outlet;

[0029] The hydraulic drive system is respectively connected to the liquid inlet and the liquid outlet of the chamber 1;

[0030] The gas outlet is in communication with the gas collection system.

[0031] According to any embodiment of the first aspect of the present invention, the hydraulic drive system includes a drive pump and a pipeline;

[0032] The driving pump is connected to the liquid inlet and / or liquid outlet of the second chamber through a pipeline;

[0033] The driving pump is communicated with the liquid inlet and / or liquid outlet of the first chamber through a pipeline.

[0034] According to any embodiment of the first aspect of the present invention, a pressure sensing system is provided on the pipeline of the hydraulic drive system.

[0035] A second aspect of the present invention provides a method for synchronous ethanol production by water treatment using an electrically enhanced separation membrane, comprising:

[0036] 1) Adding anolyte into chamber 1;

[0037] 2) inoculating anaerobic sludge in chamber 2; and bringing the cathode into contact with the anaerobic sludge;

[0038] 3) The water to be treated is introduced into the second chamber, and voltage is applied to the anode and cathode to carry out the reaction.

[0039] According to any embodiment of the second aspect of the present invention, in step 3), the voltage is (-1.0 V) to (-3.0 V) (representing negative 1 V to negative 3 V).

[0040] According to any embodiment of the second aspect of the present invention, the anolyte comprises 40-50 mg / L of Na2HPO4 and 20-30 mg / L of KH2PO4.

[0041] According to any embodiment of the second aspect of the present invention, the usage amount of the anaerobic sludge is 3000-6000 mg / L.

[0042] According to any embodiment of the second aspect of the present invention, the water body to be treated includes sewage to be treated; the sewage to be treated includes domestic sewage, commercial sewage or industrial wastewater.

[0043] According to any embodiment of the second aspect of the present invention, the water to be treated includes components including buffer, glucose, and trace elements.

[0044] According to any embodiment of the second aspect of the present invention, the water to be treated includes 0.01-0.04 g / L MgCl2·6H2O, 0.001-0.015 g / L CaCl2, 3-6 g / L Na2HPO4, 1-3 g / L KH2PO4, 1-2 mL / L trace elements, 0.5-5 g / L glucose, and 0.5-1.5 g / L NaHCO3.

[0045] According to any embodiment of the second aspect of the present invention, the chemical oxygen demand concentration of the water to be treated is 500-6000 mg / L.

[0046] According to any embodiment of the second aspect of the present invention, in step 3), the reaction temperature is 25-30° C.; and the hydraulic retention time of the water to be treated in chamber 2 is 24-36 hours.

[0047] According to any embodiment of the second aspect of the present invention, in step 3), after the water to be treated enters chamber 2, an anaerobic membrane biological reaction is carried out in chamber 2 to produce CO2;

[0048] The CO2 is reduced under the action of electrons provided by the cathode.

[0049] Beneficial effects

[0050] 1) The electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided by the present invention couples the MES technology with the anaerobic wastewater treatment technology; it can effectively improve the sewage treatment effect of the anaerobic membrane biological treatment, accelerate the electron transfer in the treatment process, promote the degradation of organic matter, and enhance the effluent water quality; the CO2 generated in the anaerobic membrane biological sewage treatment process can successfully become the raw material for microbial electrolysis, realizing the reduction of CO2 to carbon-containing products (C 2+ ) to achieve emission reduction and resource utilization of CO2 generated in situ in anaerobic wastewater treatment systems.

[0051] 2) The electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided by the present invention has a membrane assembly retained in chamber 2. The membrane has the dual functions of a filtration membrane and a biological cathode, which can achieve the following effects: on the one hand, it can reduce sludge loss by intercepting it, and on the other hand, it can alleviate the occurrence of membrane fouling by applying an electrical bias on the membrane surface through electrostatic repulsion;

[0052] On the other hand, by introducing the electric field, the growth of electroactive microorganisms is stimulated and they are enriched on the separation membrane to complete the electron transfer process, thereby enhancing the conversion of organic pollutants, thereby improving treatment efficiency and effluent quality, and recovering energy products from sewage to supplement operating energy consumption.

[0053] 3) In the electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided by the present invention, the cathode (membrane) is in direct contact with the microorganisms, which increases the contact area with the microorganisms and improves the electron transfer efficiency between the microorganisms and the electrode. At the same time, the electrochemical action further assists the microorganisms in improving their treatment efficiency.

[0054] 4) The method for synchronous ethanol production by electrically enhanced separation membrane water treatment using the device provided by the present invention can effectively realize the conversion of carbon dioxide into ethanol by combining with relevant process parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic structural diagram of the electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided in Example 1 of the present invention;

[0056] Figure 2The COD treatment effect of the water body to be treated by using the electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided in Example 1 of the present invention;

[0057] FIG3( a ) shows the ethanol production effect of the water to be treated by using the electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided in Example 1 of the present invention;

[0058] FIG3( b ) shows the effect of producing acetic acid on the water to be treated by using the electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided in Example 1 of the present invention;

[0059] FIG3( c ) shows the propionic acid production effect of the water to be treated using the electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided in Example 1 of the present invention;

[0060] FIG3( d ) shows the isobutyric acid production effect of the water to be treated using the electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided in Example 1 of the present invention;

[0061] FIG3(e) shows the effect of producing isovaleric acid on the water to be treated by the electrically enhanced separation membrane water treatment and simultaneous ethanol production device provided in Example 1 of the present invention;

[0062] FIG4( a ) is a surface image of the cathode (i.e., membrane) after the operation of Example 1 is completed;

[0063] FIG4( b ) is a surface image of the cathode (i.e., membrane) after hydraulic cleaning at the end of the operation of Example 1;

[0064] FIG5( a ) is a surface image of the cathode (i.e., membrane) after the operation of Comparative Example 1 is completed;

[0065] Figure 5(b) is a surface image of the cathode (i.e., membrane) after hydraulic cleaning at the end of the operation of Comparative Example 1;

[0066] In the picture:

[0067] 100. Reactor; 110. Chamber 1; 111. Anode; 112. Anode gas outlet; 113. Anode liquid outlet; 114. Anode liquid inlet; 115. Anode liquid inlet storage tank; 116. Anode liquid outlet storage tank; 120. Chamber 2; 121. Cathode; 122. Cathode gas outlet; 123. Cathode liquid outlet; 124. Cathode liquid inlet; 125. Cathode liquid inlet storage tank; 126. Cathode liquid outlet storage tank; 130. Cation exchange membrane; 140. Reference electrode; 150. Membrane separation assembly; 151. Membrane; 152. Fixing member; 160. Anaerobic sludge;

[0068] 200, power supply;

[0069] 300. Hydraulic drive system; 310. Drive pump; 320. Pipeline; 321. Pressure sensing system;

[0070] 400. Gas collection system. DETAILED DESCRIPTION

[0071] The present disclosure may be more readily understood by reference to the following description in conjunction with the accompanying drawings and examples, all of which constitute a part of this disclosure. It should be understood that the present disclosure is not limited to the specific products, methods, conditions, or parameters described and / or illustrated herein. Further, the terms used herein are for the purpose of describing specific embodiments by way of example only and are not intended to be limiting unless otherwise indicated.

[0072] It should also be understood that, for the sake of clarity, certain features of the present disclosure may be described herein in the context of separate embodiments, but may also be provided in combination with each other in a single embodiment. That is, unless clearly incompatible or specifically not included, each separate embodiment is considered to be combinable with any other embodiment, and the combination is considered to represent another different embodiment. Conversely, for the sake of simplicity, various features of the present disclosure described in the context of a single embodiment may also be provided individually or in any sub-combination. Finally, although a particular embodiment may be described as part of a series of steps or part of a more general structure, each step or sub-structure itself may also be considered to be an independent embodiment.

[0073] Unless otherwise indicated, it should be understood that each individual element in a list and each combination of individual elements in that list will be interpreted as a different embodiment. For example, a list of embodiments expressed as "A, B, or C" should be interpreted to include embodiments "A," "B," "C," "A or B," "A or C," "B or C," or "A, B, or C."

[0074] In this disclosure, the singular forms of the articles "a," "an," and "the" also include the corresponding plural reference, and a reference to a specific value includes at least that specific value unless the context clearly dictates otherwise. Thus, for example, a reference to "a substance" is a reference to at least one of that substance and equivalents thereof.

[0075] Terms including ordinal numbers such as "first" and "second" may be used to explain various components or fluids, but these components and fluids are not limited by these terms. Therefore, without departing from the teachings of the present disclosure, these terms are only used to distinguish the component / fluid from another component / fluid.

[0076] When items are described by using the conjunction terms "... and / or..." etc., the description should be understood to include any one and all combinations of one or more of the associated listed items.

[0077] In general, the use of the term "about" indicates an approximate value that can vary depending on the desired properties obtained by the disclosed subject matter and will be interpreted in a context-dependent manner based on function. Therefore, one of ordinary skill in the art will be able to interpret a certain degree of difference on a case-by-case basis. In some cases, the number of important figures used when expressing a particular value can be a representative technique for determining the difference allowed by the term "about". In other cases, a gradient in a range of values ​​can be used to determine the range of differences allowed by the term "about". Further, all ranges in this disclosure are inclusive and combinable, and reference to a value stated in a range includes every value within that range.

[0078] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; and the terms used herein include any and all combinations of one or more of the associated listed items.

[0079] The device for electrically enhanced separation membrane water treatment and simultaneous ethanol production provided by the present invention comprises: a reactor 100, a power supply 200, a hydraulic drive system 300, and a gas collection system 400;

[0080] As the hydraulic drive system 300, its function is to provide driving force for the circulation / movement of the liquid in the device; based on this, the hydraulic drive system is generally composed of a drive pump 310 and a pipeline 320; preferably, a pressure sensing system 321 is provided on its pipeline 320, such as a pressure sensor or a vacuum pressure gauge.

[0081] The gas collection system 400 mainly functions to store gas. For this purpose, the gas collection system may include, for example, a gas collection bag.

[0082] The reactor 100 is a two-chamber reactor, comprising a chamber 110 and a chamber 2 120 , wherein the chamber 110 and the chamber 2 120 are separated by a cation exchange membrane 130 ;

[0083] An electrode is provided in the chamber 110, and the electrode is connected to the power supply 200 via a wire as the anode 111 of the device; in addition, an anode gas outlet 112 is provided at the top of the chamber 1, an anode liquid outlet 113 is provided at the side, and an anode liquid inlet 114 is provided at the bottom, and the anode liquid inlet 114 is connected to the anode liquid storage tank 115 through a hydraulic drive system 300; the anode liquid outlet 113 is connected to the anode liquid storage tank 116 through a hydraulic drive system 300; the anode gas outlet 112 is connected to the gas collection system 400 located at the anode.

[0084] The material of the anode 111 is required to have good conductivity, for example, stainless steel, titanium, etc.; the specific form of the electrode can be a mesh or sheet, such as a stainless steel mesh, titanium mesh, titanium sheet, etc.

[0085] The second chamber 120 is provided with a reference electrode 140 and a membrane separation assembly 150, and is filled with anaerobic sludge 160. The reference electrode 140 is connected to the power source 200 via a wire, and the membrane 151 of the membrane separation assembly 150 is connected to the power source 200 via a wire, serving as the cathode 121 of the device. The cathode 121 is in contact with the anaerobic sludge 160. Furthermore, the upper portion of the second chamber 120 is provided with a cathode gas outlet 122 and a cathode liquid outlet 123, and the bottom portion is provided with a cathode liquid inlet 124. The cathode liquid inlet 124 is connected to a cathode liquid storage tank 125 via a hydraulic drive system 300. The cathode liquid outlet 123 is connected to a cathode liquid storage tank 126 via a hydraulic drive system 300. The cathode gas outlet 122 is connected to a gas collection system 400 located at the cathode.

[0086] The "membrane separation component 150" includes a membrane 151 and a fixing member 152 for the membrane. The fixing member 152 has an opening 153, and the opening 153 is connected to the cathode liquid outlet 123 at the upper part of the chamber 2 120 through a pipe to realize water outlet from the chamber 2 120.

[0087] In fact, the membrane separation component 150 is arranged in the chamber 2 120 and is filled with anaerobic sludge 160, which constitutes the basic structure of the anaerobic membrane separation reactor. On this basis, the membrane 151 of the membrane separation component 150 is connected to the power supply 200 through a wire as the cathode 121 of the device, providing a structural basis for the process coupling of the anaerobic membrane separation reaction and the microbial electrosynthesis. Furthermore, the membrane 151 of the membrane separation component 150 actually has both the screening and interception functions of the anaerobic membrane biological reaction and the electron transfer function of the microbial electrosynthesis. In addition, the introduction of the electric field on the membrane surface can stimulate the growth of microorganisms in the anaerobic sludge 160 in the chamber 2 120, including the growth of electroactive microorganisms, and enrich the electron transfer process on the membrane 151 serving as the "cathode 121", thereby strengthening the conversion of organic pollutants, thereby improving the treatment efficiency and effluent water quality, and recovering energy products from the sewage to supplement the operating energy consumption. Based on this, the membrane 151 of the membrane separation assembly 150 must first meet the requirements of electrical conductivity, and secondly, must have as large a specific surface area as possible, and have a sufficiently large electrode area within the second chamber 120. Therefore, the material of the membrane 151 serving as the cathode 121 may include, for example, conductive materials (e.g., conductive carbon materials, metal materials, conductive polymer materials), supported conductive materials (e.g., supported metal materials, supported carbon materials), and conductive mixed matrix materials (e.g., metal-doped polymer materials, carbon-doped polymer materials). The specific form of the electrode may include, for example, a tubular membrane, a hollow fiber membrane, or a flat membrane.

[0088] In addition, as the device for the simultaneous production of ethanol by electrically enhanced separation membrane water treatment, temperature control devices can be added to, for example, the reactor 100, the cathode / anode liquid inlet water storage tanks 125 / 115, the cathode / anode liquid outlet water storage tanks 126 / 116, and the connecting pipe 320 with the hydraulic drive system 300 according to the reaction temperature conditions.

[0089] The method provided by the present invention for performing electrically enhanced separation membrane water treatment and simultaneous ethanol production using the device includes:

[0090] 1) preparing an anolyte comprising 40-50 mg / L of Na2HPO4 and 20-30 mg / L of KH2PO4; storing the anolyte in an anode liquid inlet storage tank 115; and adding the anolyte to chamber one 110 through an anode liquid inlet 114 at the bottom of chamber one 110 via a hydraulic drive system 300;

[0091] 2) Anaerobic sludge 160 is inoculated into chamber 2 120, and the cathode 121 is immersed in the sludge reaction zone and the sludge suspension zone, directly contacting the anaerobic sludge 160; the cathode 121 is in direct contact with the microorganisms, which increases the contact area with the microorganisms and improves the electron transfer efficiency between the microorganisms and the electrode. At the same time, the electrochemical action further assists the microorganisms in improving their treatment efficiency.

[0092] 3) The water to be treated is stored in the cathode liquid inlet storage tank 125, and the mixed and degassed water to be treated is introduced into the second chamber 120 through the cathode liquid inlet 124 at the bottom of the second chamber 120 via the hydraulic drive system 300. The chemical oxygen demand concentration of the water to be treated is 500-6000 mg / L, and the water to be treated is required to contain components such as buffer and glucose;

[0093] As used herein, a "buffer pair" refers to two chemical substances that react to counteract hydrogen ions or hydroxyl ions in a solution, thereby maintaining the pH of the solution constant; examples thereof include phosphate buffer pairs, citric acid buffer pairs, carbonate buffer pairs, acetate buffer pairs, barbituric acid buffer pairs, and Tris (tris(hydroxymethyl)aminomethane)) buffer pairs.

[0094] Furthermore, the schematic water body to be treated contains: 0.01-0.04 g / L MgCl2·6H2O, 0.001-0.015 g / L CaCl2, 3-6 g / L Na2HPO4, 1-3 g / L KH2PO4, 1-2 mL / L trace elements, 0.5-5 g / L glucose, and 0.5-1.5 g / L NaHCO3; and the amount of the water body to be treated needs to ensure that the amount of the anaerobic sludge is 3000-6000 mg / L.

[0095] The main purpose of the trace elements described herein is to provide elements such as sodium, cobalt, zinc, and manganese. Based on this, the trace elements include EDTA-2Na, CoCl2 (or its hydrate CoCl2·6H2O), CuSO4 (or its hydrate CuSO4·5H2O), NiCl (or its hydrate NiCl·6H2O), H3BO4, ZnSO4 (or its hydrate ZnSO4·7H2O), MnCl2 (or its hydrate MnCl2·6H2O), Na2MoO4 (or its hydrate Na2MoO4·2H2O), and Na2WO4 (or its hydrate Na2WO4·2H2O). The content ranges for reference are as follows: 15-20 mg / L EDTA-2Na, 0-0.5 mg / L CoCl2 (or its hydrate CoCl2·6H2O), 0-0.5 mg / L CuSO4 (or its hydrate CuSO4·5H2O), 0-0.5 mg / LNiCl (or its hydrate NiCl·6H2O), 0-0.1 mg / L H3BO4, 0.4-1 mg / L ZnSO4 (or its hydrate ZnSO4·7H2O), 0-0.5 mg / L MnCl2 (or its hydrate MnCl2·6H2O), 0-0.5 mg / L Na2MoO4 (or its hydrate Na2MoO4·2H2O), 0-0.5 mg / LNa2WO4 (or its hydrate Na2WO4·2H2O).

[0096] Turn on the power supply 200 and apply voltage to the anode 111 and cathode 121 to initiate a reaction. The voltage is generally -1.0-3.0 V. The reaction temperature is 25-30° C. The hydraulic retention time of the water to be treated in the second chamber 120 is 24-36 hours.

[0097] After the water to be treated enters the second chamber 120, an anaerobic membrane biological reaction is carried out in the structure / environment provided by the second chamber 120 to produce CO2; the cathode 121 can effectively enrich the electroactive microorganisms and generate electron transfer between the microorganisms, so that the generated CO2 is converted by the electroactive microorganisms enriched on the surface of the cathode 121 using the electrons to produce the target product ethanol and acetic acid and other gases. The gases enter the gas collection system 300 through the gas outlet of the cathode 121 at the upper part of the second chamber 120 for storage;

[0098] The treated water body, after separation by the membrane 151 of the cathode 121, passes through the opening of the fixing part 152, the pipe connected to the opening 152, and the cathode liquid outlet 123 at the top of the chamber 2 120, and enters the cathode liquid storage tank 126 under the action of the hydraulic drive system 300.

[0099] Example 1

[0100] Electrically enhanced separation membrane water treatment and simultaneous ethanol production device:

[0101] like Figure 1 As shown, the device consists of a reactor 100, a power source 200, a hydraulic drive system 300 and a gas collection system 400;

[0102] The hydraulic drive system 300 is composed of a drive pump 310 and a pipeline 320, and a vacuum pressure gauge is provided on the pipeline 320; and the gas collection system 400 is a gas collection bag.

[0103] The anode 111 is a titanium sheet used as an electrode and is connected to the positive electrode of the power supply;

[0104] The cathode 121 is a tubular film composed of carbon nanotubes, and the tubular film is fixed to the fixing member 152 by a conductive sealant.

[0105] The operating process parameters of this embodiment are as follows:

[0106] 1) Adding anolyte to chamber 110; the anolyte consists of 44 mg / L Na2HPO4 and 25 mg / L KH2PO4;

[0107] 2) inoculating anaerobic sludge into chamber 2 120 and placing the cathode 121 in direct contact with the anaerobic sludge;

[0108] The water to be treated introduced into chamber 2 120 has been pre-mixed and degassed, and its chemical oxygen demand concentration is 1000±50 mg / L. The water to be treated includes 0.04 g / L of MgCl2·6H2O, 0.015 g / L of CaCl2, 6 g / L of Na2HPO4, 3 g / L of KH2PO4, 1 mL / L of trace elements, 0.47 g / L of glucose, and 1.5 g / L of NaHCO3. The amount of water to be treated introduced must ensure that the amount of anaerobic sludge is 6000 mg / L.

[0109] Table 1. Specific composition of trace elements used in this embodiment

[0110] trace substances Content (mg / L) EDTA-2Na 18.76 <![CDATA[CoCl2·6H2O]]> 0.3 <![CDATA[CuSO4·5H2O]]> 0.32 <![CDATA[NiCl·6H2O]]> 0.24 <![CDATA[H3BO4]]> 0.018 <![CDATA[ZnSO4·7H2O]]> 0.54 <![CDATA[MnCl2·6H2O]]> 1.24 <![CDATA[Na2MoO4·2H2O]]> 0.28 <![CDATA[Na2WO4·2H2O]]> 0.1

[0111] 3) Turn on the power supply 200 and apply voltage to the anode 111 and cathode 121 to initiate a reaction; the voltage is -1.0 V; the reaction temperature is 25±2° C.; and the hydraulic retention time of the water to be treated in the second chamber 120 is 36 hours.

[0112] During operation, water enters the second chamber 120 and is filtered out by the membrane separation assembly 150 . The liquid level in the second chamber 120 is kept balanced and the chamber operates at a constant flux by adjusting the speed of the inlet and outlet water driving pumps.

[0113] During operation, the anode 121 partially electrolyzes to produce H + After passing through the cation exchange membrane 130, the CO2 produced by the anaerobic microorganisms at the bottom of the cathode 111 can be further converted into CO2 by the electroactive microorganisms enriched on the membrane 151 of the cathode 121 using electrons to produce gas containing the target product ethanol, ultimately achieving the multiple goals of water treatment and energy conversion.

[0114] Comparative Example 1

[0115] This comparative example utilizes the apparatus described in Example 1;

[0116] The difference is that in the specific operation of the solution of this comparative example, the power supply is not turned on.

[0117] The two groups of reactions in Example 1 and Comparative Example 1 were run simultaneously:

[0118] 1) Observe the change of transmembrane pressure difference by installing a vacuum pressure gauge on the pipeline connected to the cathode liquid outlet 123 of the second chamber 120. The larger the transmembrane pressure difference, the more serious the fouling resistance of the membrane 151.

[0119] As shown in FIG4 , the final results indicate that, during constant flux operation, the rising trend of the transmembrane pressure difference in Example 1 is significantly slowed down, and the pollutants attached to the membrane surface as shown in FIG4 (a) are also easier to clean, and the membrane surface after washing (as shown in FIG4 (b)) can basically return to its initial state. The above indicates that the electric field can slow down the clogging of membrane pores and make the pollution reversible.

[0120] As shown in FIG5 , after the surface of the separation membrane of the comparative example 1 was completely contaminated (as shown in FIG5 (a)), some pollutants could not be removed after simple hydraulic cleaning (as shown in FIG5 (b)), and the separation membrane failed to recover to its original state.

[0121] 2) measuring the chemical oxygen demand and volatile fatty acid content in the outlet water of each chamber 2 120 (the outlet water of Example 1 is the outlet water R1, and the outlet water of Comparative Example 1 is the outlet water R2);

[0122] like Figure 2 As shown, the COD intensity of the influent to R1 and R2 was maintained at 500 mg / L, with the COD concentration of the effluent from R1 after membrane filtration being approximately 22.56 mg / L. Meanwhile, multiple data sets showed that the effluent COD was 0 mg / L. In R2, the average effluent COD content was 41.59 mg / L.

[0123] Overall, the system complies with the GB18918-2002 effluent discharge standard.

[0124] 3) As shown in FIG. 3 , the product conditions of each chamber 2 120 and the ethanol concentration in the liquid were measured to observe the effect of the electric field on the operation of the entire system. The average gas production concentration in Example 1 was approximately 22.56 mg / L, and four multi-carbon products, acetic acid, propionic acid, isobutyric acid, and isovaleric acid, appeared relatively stably in the reactor system enhanced at -1.0 V.

[0125] Among them, as shown in Figure 3(b), the maximum acetic acid can reach 230 mg / L; as shown in Figure 3(c), the maximum propionic acid can reach 248 mg / L; and as shown in Figures 3(d) and (e), the maximum production of isobutyric acid and isovaleric acid can reach 9.98 mg / L and 14.52 mg / L respectively; at the same time, as shown in Figure 3(a), the ethanol produced can reach 7.05 mg / L.

[0126] In the product of Comparative Example 1, only acetic acid was detected in the effluent, with a maximum concentration of 96.65 mg / L. Propionic acid and isovaleric acid were detected on four and five days, with maximum concentrations of 40.2 mg / L and 6.36 mg / L, respectively. No ethanol was detected. Overall, the product yield was low.

[0127] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for synchronous ethanol production by electrically enhanced separation membrane water treatment, characterized in that: The treatment is carried out using an electrically enhanced separation membrane water treatment device with simultaneous ethanol production; The device comprises a reactor (100) and a power source (200); The reactor (100) is a two-chamber structure, comprising a chamber 1 (110) and a chamber 2 (120), wherein the chamber 1 (110) and the chamber 2 (120) are separated by a cation exchange membrane (130); An electrode is provided in the chamber 1 (110), and the electrode is externally connected to the power supply via a wire, serving as an anode (111) of the device; The second chamber (120) is provided with a membrane separation component (150) and is filled with anaerobic sludge (160). in, The membrane (151) of the membrane separation assembly (150) is externally connected to the power source via a wire, serving as the cathode (121) of the device, and the cathode (121) is in contact with the anaerobic sludge (160); Including steps: 1) adding anolyte to chamber 1 (110); 2) inoculating anaerobic sludge (160) into the second chamber (120); and bringing the cathode (121) into contact with the anaerobic sludge (160); 3) introducing the water to be treated into the second chamber (120), and applying a voltage in the range of -1.0 V to -3.0 V to the anode (111) and the cathode (121) to carry out the reaction; After the water to be treated enters chamber two (120), an anaerobic membrane biological reaction is carried out under the structure provided by chamber two (120) to produce CO2; the cathode (121) enriches the electroactive microorganisms and generates electron transfer with the microorganisms, so that the generated CO2 is converted by the electroactive microorganisms enriched on the surface of the cathode (121) using electrons to produce the target product ethanol and acetic acid gas.

2. The method for synchronous ethanol production by electrically enhanced separation membrane water treatment according to claim 1, characterized in that: The membrane (151) includes any one or more of a tubular membrane, a hollow fiber membrane and a flat membrane, and has electrical conductivity.

3. The method for synchronous ethanol production by water treatment using electrically enhanced separation membrane according to claim 1, characterized in that: The membrane separation assembly (150) comprises a membrane (151) and a fixing member (152) for the membrane (151), wherein the fixing member (152) has an opening; The opening is connected to a pipe to enable water to flow out of the second chamber (120).

4. The method for synchronous ethanol production by electrically enhanced separation membrane water treatment according to claim 3, characterized in that: The device further comprises a hydraulic drive system (300) and a gas collection system (400), wherein the hydraulic drive system (300) is used to drive the flow of liquid in the reactor (100); The gas collection system (400) is used to collect the gas discharged from the reactor (100).

5. The method for synchronous ethanol production by electrically enhanced separation membrane water treatment according to claim 4, characterized in that: The second chamber (120) is also provided with a liquid inlet, a liquid outlet and an air outlet; The hydraulic drive system (300) is respectively connected to the liquid inlet and / or liquid outlet of the second chamber (120); The liquid inlet of the second chamber (120) is in communication with the opening of the fixing member (152); The gas outlet is in communication with the gas collection system (400).

6. The method for simultaneous ethanol production by water treatment using electrically enhanced separation membranes according to claim 5, characterized in that: The chamber 1 (110) is also provided with a liquid inlet, a liquid outlet and an air outlet; The hydraulic drive system (300) is respectively connected to the liquid inlet and the liquid outlet of the chamber 1 (110); The gas outlet is in communication with the gas collection system (400).

7. The method for synchronous ethanol production by electrically enhanced separation membrane water treatment according to claim 5, characterized in that: The hydraulic drive system (300) includes a drive pump and a pipeline; The driving pump is connected to the liquid inlet and / or liquid outlet of the second chamber (120) through a pipeline; The driving pump is connected to the liquid inlet and / or liquid outlet of the chamber 1 (110) through a pipeline.

8. The method for simultaneous ethanol production by water treatment using electrically enhanced separation membranes according to any one of claims 1 to 7, characterized in that: In step 2), the amount of the anaerobic sludge is 3000-6000 mg / L.

9. The method for simultaneous ethanol production by water treatment using electrically enhanced separation membranes according to claim 8, characterized in that: The water body to be treated has: Chemical oxygen demand of 500-6000 mg / L; Ingredients including buffer and glucose.

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