CN113880231B

CN113880231B - Electrode stack and electrode stack array for bioelectrochemical system

Info

Publication number: CN113880231B
Application number: CN202111177780.3A
Authority: CN
Inventors: 朱洪光; 武齐; 潘芳慧; 王友保; 吴可佳; 王伯文; 刘雪钰
Original assignee: Shanghai Linhai Ecological Technology Co ltd; Tongji University
Current assignee: Shanghai Linhai Ecological Technology Co ltd; Tongji University
Priority date: 2021-10-09
Filing date: 2021-10-09
Publication date: 2023-05-30
Anticipated expiration: 2041-10-09
Also published as: CN113880231A

Abstract

The invention provides an electrode stack and an electrode stack array of a bioelectrochemical system, the electrode stack comprises an electrode stack box body and electrode plates, a first accommodating space is formed in the electrode stack box body, a reactant to be processed is accommodated in the first accommodating space, the reactant to be processed can be liquid or gas, one or more groups of electrode plates are sequentially arranged in the first accommodating space at intervals and are submerged in the reactant to be processed, the polarities of the opposite sides of two adjacent electrode plates are the same, the electrode stack realizes an industrialized system of a cathode and anode multi-compartment in the bioelectrochemical system, provides structural support for the large-scale application of the bioelectrochemical system, is convenient to install and detach, can flexibly move and combine the scene for the bioelectrochemical system where various needs are located, and has a compact structure and low price.

Description

Electrode stack and electrode stack array for bioelectrochemical system

Technical Field

The invention relates to the field of bioelectrochemistry, in particular to an electrode stack and an electrode stack array of a bioelectrochemical system.

Background

The shortage of energy and environmental pollution are still the troublesome problems faced by the current world, and the sustainable development of society and environment can be promoted by developing renewable energy and realizing the recycling of waste. The bioelectrochemical system (Bioelectrochemical Systems, BES) has been found to be a system for degrading waste while recovering biomass and other value-added chemicals. The basic principle is that electrons are released by oxidation reaction of dehydrogenase system of electrically reinforced microorganism and electrons are obtained by reduction reaction of reductase system. BES has multiple functions of synchronously realizing energy recovery, resource recovery, sewage treatment and the like, and is a novel technology with wide application prospect. At the anode, the electrogenesis microorganism takes the anode as an electron acceptor, and the organic matters are oxidatively degraded, so that the growth metabolism is maintained. In this process, the released protons and electrons are transferred to the cathode, and the reduction reaction is completed at the cathode. The potential difference between the anode and the cathode is the circuit terminal voltage, or the output voltage, or the input voltage. In the process of degrading organic matters, compared with the traditional physicochemical method and biological method, BES has the characteristics of short reaction path, controllable reaction condition, weak side reaction and the like.

The earliest BES emerged in the concept of microbial fuel cells (Microbial Fuel Cell, MFC). The initial prototype of MFC, see the study by the botanicist Potter professor at university of dalafo, uk, at 1910, found that he oxidized yeast on the Pt electrode of half-cell using e.coli (e.coli) as microbial catalyst to obtain output current. Later, MFC devices featuring electricity generation were developed with an electricity generation power density of from the initial 0.01mW/m ² The power density of (C) rises to 4000mW/m nowadays ² The method improves the efficiency by nearly 5 orders of magnitude. At present, although the utilization of MFC to produce electricity has incomparable advantages, the MFC device is still at laboratory scale level because the existence of a proton exchange membrane between an anode chamber and a cathode chamber in a double chamber leads to large internal resistance and low output power of the MFC, and oxygen of a cathode in a single chamber easily enters the anode chamber through an electrode to influence the activity of anaerobic microorganisms, reduce the recovery rate of electrons and energy and influence the coulomb efficiency and power output.

In 2005, the professor Burce Logan at the state university of pennsylvania, usa, extended the range of application of MFC, found that energy recovered from organics through the bioanode could inherently drive the cathodic hydrogen evolution reaction, thereby greatly reducing the energy consumption of electrolytic hydrogen production, which technology was initially referred to as bioelectrochemical assisted microbial reactors, and later changed to microbial cells (Microbial Elecotrolysis Cell, MEC). To this end, BES has evolved from MECs that are primarily hydrogen production by electrolysis. At present, MEC hydrogen production is still in a laboratory research stage, and various membranes are needed in MEC as barriers for reducing hydrogen loss although MEC has the advantages of high hydrogen production purity, high energy utilization rate and the like, and the mass production of zymophyte causes substrate loss, accumulation of organic acid causes system pH reduction, influences the production of electrogenesis bacteria, and causes hydrogen production rate reduction and the like.

In addition, BES has been combined with modern sensing technologies to develop bioelectrochemical sensors (Environmental Monitoring Bioelectrochemical Sensor, EMBES) based on environmental monitoring, using on-site rapid monitoring and continuous on-line analysis, which has become a hot spot in recent years of research. EMBES began in 1975 as a chemically modified electrode that was able to selectively perform the desired reactions and provide faster electron transfer rates, driving the development of electrochemical analytical chemistry. EMBES refers to a sensor that uses biological materials (such as enzymes, antigens, antibodies, hormones, etc.) or organisms themselves (cells, organelles, tissues, etc.) as sensing elements, and electrodes (solid electrodes, ion selective electrodes, etc.) as transduction elements, and outputs in response to current and potential signals. On the one hand, the electrode is used as an electron donor or acceptor, so that the electron transfer mechanism and metabolic process of a biological system can be simulated, and thermodynamic and kinetic parameters can be measured; on the other hand, the specificity of biological reaction, the sensitivity of an electroanalysis method and the real-time detectability are utilized to prepare the bioelectrochemical sensor, so that a powerful means is provided for detecting biomass.

BES can be used for generating electricity and hydrogen, and can be used in the sewage treatment field, such as COD removal, denitrification, desulfurization, dechlorination, azo dyeing and decoloration and the like, and valuable additional products such as methane production, alkali production, saccharide synthesis and the like.

However, in the past such BES, which is aimed at enhancing the efficiency of biological reactions with respect to the generation of electricity or hydrogen, was not separately divided from MFCs or MECs, and researchers sometimes used MFC terminology, and sometimes MEC terminology. In 2020, university of homography Zhu Hongguang teaches teams posting papers in the journal of ACS Omega, and also is accustomed to extending MEC terms during manuscript. While anonymous manuscript specialists clearly propose that MEC should only be used in the case of hydrogen production in electrolytic cells, other terms are more appropriate for expression in order to avoid confusion advice. After the professor team admitted the expert to propose an electrically enhanced bioreactor (Electroenhanced Bioreactor, EEB), the paper was published in a record.

The EEB proposal marks the perfection of BES classification system, namely BES can be divided into four classes: MFC targets electricity production, MEC targets hydrogen production, EMBES targets environmental monitoring, EEB targets improved biological reaction efficiency. Among them, specific enhancement target forms of EEB may be various, such as wastewater treatment targeting denitrification, electrically enhanced bioenergy conversion targeting methanogenesis, bio-fermentation engineering targeting active organic products, etc.

No matter the BES which aims at generating electricity, hydrogen and improving the efficiency of biological reaction, engineering application is limited in laboratory research at present, and the main reason is that efficient low-cost biological reaction electrodes for industrial scale application cannot be developed. The earlier reported papers and patents are mostly bar-shaped or sheet-shaped electrodes in a small scale, are immersed in a reactor at a certain distance, have long distance between a cathode and an anode, have low proton transfer efficiency, and have most of noble metals as the electrodes, and have high cost. Recently, there have been reports that graphite fiber brush electrodes, carbon fiber felt electrodes, pt/Fe electrodes, copper mesh tin plated electrodes, palladium nano carbon powder carbon cloth composite electrodes, and the like, which are being paid attention to, are not capable of realizing large-scale industrial applications, although they have relative stability, conductivity, biocompatibility, and the like. For example, patent document CN203922843U discloses a microbial electrolytic cell device integrating organic sewage treatment and methane production, comprising a microbial electrolytic cell housing 1, wherein an anode electrode 8 and a cathode electrode 4 are arranged in the microbial electrolytic cell housing 1, the cathode electrode 4 and the anode electrode 8 are respectively connected with a low potential end and a high potential end of an external direct current stabilized power supply 6 through a titanium wire 5 and a titanium wire 7, a water inlet pipe 9 is arranged on the side surface of the lower end of the microbial electrolytic cell housing 1, the water inlet pipe 9 is connected with a water distributor 10, a sludge discharge pipe 11 and a valve 12 are arranged at the bottom end of the microbial electrolytic cell housing 1, a drain pipe 2 is arranged on the side surface of the upper end of the microbial electrolytic cell housing 1, and a gas collecting pipe 3 is arranged at the top end of the microbial electrolytic cell housing 1.

In order to break through the bottleneck of BES large-scale industrialized application, a new product needs to be designed to promote the industrialized development and engineering application of BES.

Disclosure of Invention

In view of the drawbacks of the prior art, an object of the present invention is to provide an electrode stack and an electrode array for a bioelectrochemical system.

The electrode stack of the bioelectrochemical system provided by the invention comprises an electrode stack box body and an electrode plate;

the electrode pile box body is internally provided with a first accommodating space, the first accommodating space accommodates a reactant to be processed, one or more groups of electrode plates are sequentially arranged in the first accommodating space at intervals and submerged in the reactant to be processed, and the polarities of the opposite sides of two adjacent electrode plates are the same.

Preferably, the number of the electrode plates is an odd number.

Preferably, a detachable support frame is arranged on the electrode stack box body, and the support frame comprises a support backrest, a bottom frame and a lifting rod;

the bottom frame is arranged at the bottom of the first accommodating space, the supporting backrest is arranged on the bottom frame and used for supporting the electrode plates, the bottom of the lifting rod is connected with the bottom frame, and the top of the lifting rod is upwards extended to the outside of the electrode stack box body.

Preferably, the electrode plate comprises an anode plate, a cathode plate, an insulating structure and a support body;

the anode sheet, the insulating structure and the cathode sheet are sequentially stacked to form a stacked structure, the periphery of the insulating structure extends outwards from the inner side of the anode sheet and the inner side of the cathode sheet respectively and wraps the edge part of the outer side of the anode sheet and the edge part of the outer side of the cathode sheet respectively to form an anode wrapping edge and a cathode wrapping edge, and the support body wraps the stacked structure circumferentially and two ends of the support body are clamped on the anode wrapping edge and the cathode wrapping edge respectively;

the anode plate and the cathode plate are both in a pole piece structure, the pole piece structure comprises a conducting layer and a stainless steel net arranged on the outer side surface of the conducting layer, and the insulating structure is a permeable structure so that protons are allowed to pass through the insulating structure;

and the stainless steel nets on the anode plate and the cathode plate after being electrified form an equipotential surface.

Preferably, the insulating structure comprises a first insulating layer, and the anode and cathode bags Bian Junyou are formed by wrapping the edge parts of the first insulating layer; or alternatively

The insulation structure comprises a first insulation layer and a second insulation layer, wherein the anode wrapping is formed by wrapping the edge of the first insulation layer, and the cathode wrapping is formed by wrapping the edge of the second insulation layer.

Preferably, the conductive layer is a permeable porous structure, including carbon felt or carbon cloth;

the insulation structure adopts industrial non-woven fabrics or geotextiles;

the supporting body is made of a corrosion-resistant sheet-shaped waterproof material, and the cross section of the supporting body is of a C-shaped structure.

Preferably, the anode sheet and the cathode sheet are respectively provided with an anode electrode column and a cathode electrode column;

one end of the anode electrode column is arranged on the stainless steel mesh of the anode sheet, and the other end of the anode electrode column penetrates through the first insulating layer and is connected with the anode of an external power supply;

one end of the cathode electrode column is arranged on the stainless steel mesh of the cathode plate, and the other end of the cathode electrode column penetrates through the second insulating layer and is connected with a negative electrode of an external power supply;

the anode electrode column and the cathode electrode column are stainless steel electrode columns;

the stainless steel electrode column is of a T-shaped structure of a stainless steel sheet welded stainless steel column.

Preferably, the anode sheet and the cathode sheet are of matched continuous concave-convex fluctuation structures or are of flat plate structures along the length or width direction.

Preferably, a pH electrode is disposed between the first insulating layer and the second insulating layer.

According to the invention, an electrode stack is provided, comprising a plurality of electrode stacks of the bioelectrochemical system arranged in an array.

Compared with the prior art, the invention has the following beneficial effects:

1. the electrode stack realizes an industrialization system of the anode and cathode multiple compartments in the bioelectrochemical system, provides structural support for large-scale application of sewage treatment, is convenient to install and disassemble, has good flexibility, can be flexibly moved and put into a water body to be treated to treat sewage or realize the effect of other bioelectrochemical systems, and has a compact structure and low price.

2. According to the invention, by adopting the electrode stack, a plurality of relatively independent circulating areas formed by the cathode area and the anode area are formed, the electron transfer path is shortened, the problem of electron transfer in the process of adverse oxidation-reduction reaction caused by overlarge distance between electrode plates applied to pilot scale and field industrialized biochemical reaction tanks is solved, the reactions of high-efficiency oxidative decomposition of sewage organic matters, reduction and denitrification of denitrifying bacteria and the like are realized, and a stable and reliable product is provided for microbial electrochemistry in large scale.

3. The electrode plate is adopted, so that the area of the electrode can be increased, the distance between the electrodes is shortened, the electron transfer rate between the anode and the cathode is accelerated, meanwhile, the carbon felt has large surface area, microorganisms are attached, the oxidation-reduction reaction of the sewage organic matters is promoted, and the efficient removal of the sewage organic matters is achieved.

4. The double-electrode plate structure provided by the invention has the advantages of compact structure, large surface area, good stability and low preparation cost, can be applied to BES industrialization scale with electricity generation, hydrogen generation and improvement of biological reaction efficiency as main targets, is beneficial to the industrialized development of bioelectrochemistry, can realize electrochemical bioaugmentation of sewage biological treatment and anaerobic methanation, and is applied to methane generation of bioelectrochemistry consumed carbon dioxide.

5. The arrangement of the stainless steel net plays three roles simultaneously, on one hand, the stainless steel net plays a role of a supporting framework of the conducting layer, on the other hand, the stainless steel net is tightly pressed on the surface of the carbon felt, and a plurality of honeycomb-like 'sink chambers' with regular or irregular structures are formed by the meshes and the carbon felt, so that microorganisms can be beneficial to stay in the sink chambers for reaction; on the other hand, the stainless steel mesh forms an 'equal voltage surface' on the surface of the carbon felt, the current density is uniform, and a precondition is provided for the electrode stack and the large-scale sewage treatment design of the electrode stack array on the premise of not influencing the reaction efficiency.

6. The conductive layer and the insulating layer are respectively made of carbon felt and industrial non-woven fabrics, can be repeatedly used, are not easy to be degraded by microorganisms, and are low in cost.

7. The anode sheet and the cathode sheet can adopt a matched continuous concave-convex structure, so that the external surface area of the electrode is greatly increased, microorganisms have more attachment spaces, and the reaction efficiency is improved.

8. The electrode adopts a stainless steel mesh and carbon felt composite sheet structure to replace noble metal wire structures such as titanium and the like, has large electrode surface area, large bioelectrochemical reaction range and low price, and has obvious advantages compared with the noble metal wire electrode such as titanium and the like.

9. The invention can be made into movable sewage treatment equipment, can be applied to various sewage treatment scenes, has wide application range and good universality, and can be customized according to practical application space.

10. The invention adopts a detachable installation mode, is convenient for maintenance and repeated use, and has long service life.

Drawings

Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:

FIG. 1 is a schematic perspective view of an electrode stack according to the present invention;

FIG. 2 is a schematic top view of an electrode stack according to the present invention;

FIG. 3 is a schematic view of the structure of the support backrest and the electrode plates in the present invention;

FIG. 4 is a schematic top view of an electrode stack of the present invention, showing the positional relationship of the support back and the electrode plates;

FIG. 5 is a schematic view of the structure of an electrode plate according to the present invention;

FIG. 6 is a schematic view of the structure of the anode sheet and the cathode sheet of the present invention in a flat plate structure;

FIG. 7 is a schematic view of the structure of the anode sheet and the cathode sheet in the present invention in a matched wavy configuration;

FIG. 8 is a schematic view of the structure of the anode and cathode sheets of the present invention in the form of matching continuous trapezoids and inverted trapezoids;

FIG. 9 is a schematic perspective view of an electrode array according to the present invention;

FIG. 10 is a schematic diagram of the structure of the electrode array according to the present invention in a plan view;

FIG. 11 is a schematic view of the structure of the electrode plates of the electrode array of the present invention in a wave structure;

fig. 12 is a schematic structural view of the electrode plate in the electrode stack according to the present invention when the electrode plates are arranged in a continuous trapezoid or inverted trapezoid.

The figure shows:

cathode edge 10 of first insulating layer 1

Conductive layer 2 electrode stack case 100

First accommodation space 101 of stainless steel mesh 3

Support 4 anode region 102

Second insulating layer 5 cathode region 103

Anode electrode column 6 supports backrest 104

Cathode electrode column 7 chassis 105

pH electrode 8 lifting bar 106

Anode edge 9 electrode plate 200

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.

Example 1:

the invention provides an electrode stack of a bioelectrochemical system, which comprises an electrode stack box body 100 and electrode plates 200, wherein a first accommodating space 101 is formed in the electrode stack box body 100, a reactant to be processed is accommodated in the first accommodating space 101, one or more groups of electrode plates 200 are sequentially arranged in the first accommodating space 101 at intervals and are submerged in the reactant to be processed, and the polarities of the opposite sides of two adjacent electrode plates 200 are the same. As shown in fig. 2, the anode side of the electrode plate 200 forms an anode region 102, the cathode side of the electrode plate 200 forms a cathode region 103, and the anode region 102 has an oxygen oxidation reaction and an oxygen-deficient reduction reaction of the cathode region 103.

The reactant to be treated can be liquid or gas, in the practical application of sewage treatment, the reactant to be treated is sewage to be treated, and the reactant to be treated is often doped with suspended activated sludge flocs, suspended micro-particle biological carriers and the like, and in the specific design, the electrode stack box body 100 can adopt a hollow structure, and the reactant to be treated naturally flows into the electrode stack box body 100; or the electrode stack case 100 is provided with a water inlet and a water outlet which are respectively communicated with the first accommodating space 101, and the water inlet and the water outlet are respectively used for flowing the reactant to be treated into and out of the first accommodating space 101, and according to the actual application scenario, the power of water flow provided by a water pump can be used for enabling the sewage to be treated in the electrode stack case 100 to flow when necessary. The electrode stack has good flexibility, can be flexibly moved and placed into a water body to be treated for sewage treatment, and realizes industrialization of a bioelectrochemical system.

In the invention, as shown in fig. 1 and 3, a detachable support frame is provided on the electrode stack case 100, the support frame includes a support backrest 104, a bottom frame 105 and a lifting rod 106, the bottom frame 105 is arranged at the bottom of the first accommodating space 101, the support backrest 104 is mounted on the bottom frame 105 and is used for supporting the electrode plate 200, the bottom of the lifting rod 106 is connected with the bottom frame 105, the top of the lifting rod 106 extends upwards and to the outside of the electrode stack case 100, the lifting rod 106 is preferably made of stainless steel, the bottom frame 105 and the support backrest 104 can be lifted from the electrode stack case 100 by operating the top of the lifting rod 106 and the electrode plate 200 can be lifted from the electrode stack case 100 together, so as to realize a detachable and maintainable structure, and greatly improve the practicability of the product.

Further, in this embodiment, as shown in fig. 3 and 4, the support backrest 104 preferably adopts a plurality of L-shaped backrests, and each two L-shaped backrests are arranged oppositely so as to form a second accommodating space between the two L-shaped backrests, the electrode plate 200 is installed in the second accommodating space in a matching manner, the underframe 105 can be made by using a frame base, for example, using a profile or a pipe fitting, etc. in a vertical arrangement manner in a transverse and longitudinal welding manner, the underframe 105 is used as a support for the bottom of the electrode plate 200, the two L-shaped backrests are used as a support for the side surface of the electrode plate 200, and the electrode plate 200 can be easily taken out from the two L-shaped backrests when maintenance is required, so that maintenance and replacement are convenient.

The electrode plate 200 comprises an anode plate, a cathode plate, an insulating structure and a supporting body 4, wherein the anode plate, the insulating structure and the cathode plate are sequentially laminated to form a stacked structure, the periphery of the insulating structure extends outwards from the inner side of the anode plate and the inner side of the cathode plate respectively and wraps the outer side of the anode plate and the outer side of the cathode plate respectively to form an anode wrapping 9 and a cathode wrapping 10, the supporting body 4 wraps the stacked structure circumferentially and two ends of the supporting body are clamped on the anode wrapping 9 and the cathode wrapping 10 respectively to form an insulating cavity closed structure, and the supporting body 4 has an insulating cavity closed function and also has an integral fixing function of the double electrode plates.

The anode plate and the cathode plate are both in a pole piece structure, and the pole piece structure comprises a conductive layer 2 andstainless steel mesh 3 arranged on the outer side of the conductive layer 2, the insulating structure being a permeable structure such that the insulating structure allows protons (H ⁺ ) By means of a preferably thin permeable structure, the protons (H ⁺ ) Through the adoption of the method, the distance between the anode and the cathode is greatly shortened, and the proton transfer rate is increased, so that the reaction efficiency of the system is improved; meanwhile, a proton exchange membrane is not required to be arranged between the cathode chamber and the anode chamber, the two sides of a single compartment are both the anode or the cathode, and the ion systems in the two compartments can be isolated by means of electrophoresis and reactance of the electrodes.

The stainless steel nets 3 on the anode plate and the cathode plate after being electrified form an equal voltage surface, the stainless steel nets are preferably stainless steel wire nets, the stainless steel nets 3 can ensure that microorganisms attached to the conductive layer 2 at all positions have current required by a bioelectrochemical system, and the structure of the double-electrode plate is beneficial to large-size design.

The stainless steel net 3 is used as a conductor in bioelectrochemistry, the stainless steel net 3 plays a role of supporting a framework of the conductive layer 2, meanwhile, the stainless steel net 3 is tightly pressed on the surface of the carbon felt, and a plurality of honeycomb-like 'sink chambers' with regular or irregular structures are formed by meshes of the stainless steel net 3 and the carbon felt, so that microorganisms are beneficial to staying in the sink chambers and not being washed away by water flow, and microbial reaction is beneficial to. The invention can realize multiple functions, not only can realize electricity generation and hydrogen production, but also can realize electrically enhanced biological reactions, such as biosynthesis of electrically enhanced valuable substances, such as methane production, alkali production, saccharide synthesis and the like, such as sewage treatment by an electrically enhanced biological method, such as COD removal, denitrification, desulfurization, dechlorination, azo dye decolorization and the like.

The conductive layer 2 is a porous structure, and comprises a carbon felt or carbon cloth, wherein the carbon felt or carbon cloth can be subjected to specific chemical modification so as to selectively perform required reactions and provide a faster electron transfer rate, and the carbon felt is also called a carbon fiber felt, is made of carbon fibers, has broad adsorption spectrum, and has large capacity and low price, and the carbon felt or the carbon cloth is used as a carrier in microbial reactions. The insulation structure is made of industrial non-woven fabrics or geotextiles, the non-woven fabrics are made of polyester fiber (polyester fiber) materials, and the insulation structure is manufactured through a needling process and can be made into different thicknesses, handfeel, hardness and the like. The industrial non-woven fabric has the characteristics of water permeability, corrosion resistance, flexibility, thinness, flame retardance, no toxicity, no smell, low price, cyclic utilization and the like, so that the industrial non-woven fabric is water permeable, breathable, not easy to be degraded by microorganisms, durable in use, and has the characteristics of water permeability, air permeability and insulativity.

The support body 4 clamps the four-side sealed insulating anode binding 9 and the cathode binding 10 and seals the thin-layer permeable insulating structure between the anode and the cathode electrode plates to form a sealed thin-layer permeable insulating structure body, and the insulating structure body is insulating and can not cause the electrodes to realize circuit communication by means of the insulator, so that short circuit can be prevented; the industrial non-woven fabric or geotextile body in the insulating structure body is thin and has good permeability, and protons can directionally diffuse in the solution through a permeable system in the bioelectrochemical reaction to form a pseudo-semiconductor channel; short distance, reduced resistance, and maintained continuous reaction path. Meanwhile, the whole insulating structure body is a closed reaction passage, so that external impurity particles can be reduced from entering competing protons, loss during passing through a reaction medium is reduced, the external reaction medium can be prevented from entering a proton movement channel, the effective reaction duty ratio is ensured, and side reactions are reduced.

Meanwhile, the closed structure reduces the entry and diffusion of protons into the reaction medium, avoids the interference and damage of pH change caused by proton migration to the microbial reaction environment, and maintains the continuous and stable system environment.

In this embodiment, the support body 4 adopts stainless steel sheet or other waterproof materials with corrosion-resistant slice to make into the sealed insulating chamber and the cross section is C shape structure, and C shape structure has certain elasticity, can realize the elasticity centre gripping to anode plate and negative pole piece, is difficult for rustting, realizes the stability of structure, and support body 4 is through right the centre gripping that positive pole bordures 9, negative pole bordure 10 realizes the seal fixed to the stacked structure, makes the bipolar plate structure wholly form closed passageway structure, reduces the proton and loses when passing through the reaction medium, avoids outside reaction medium to get into proton motion passageway, guarantees reaction efficiency.

In practical application, the resistance of the insulation structure is larger than a set threshold value, so that short circuit between the anode sheet and the cathode sheet can be prevented, the cathode and anode isolation function is achieved, the insulation structure has the characteristic that the resistance distribution is uniform everywhere, and the stability of microbial electrochemical reaction is ensured.

Further, the resistivity of the insulating material is typically 10 ¹⁰ ～10 ²² Omega.m, the threshold value in the present invention can be set to 10 ¹⁰ Omega.m. The insulating structure can isolate charged conductors with different potentials, so that current can circulate according to a certain path, the potential distribution of an electric field is improved, and the effect of protecting the conductors is achieved. If the external voltage is U, the input current is I, and the area of the conductive layer is S, the resistance r=u/(i×s) per square meter. For this purpose, two resistance states are produced, namely the resistance R when no bioelectrochemical reaction takes place _a While the bioelectrochemical reaction effectively occurs with a resistance R _b R is then _a >>R _b ，>>I.e. more than two orders of magnitude apart.

In practical application, the size of the insulating structure is larger than the sizes of the conductive layer 2 and the stainless steel net 3, and one end of the insulating structure extends to the outer side surface of the stainless steel net 3 and wraps the end parts of the conductive layer 2 and the stainless steel net 3, namely the end parts of the conductive layer 2 and the stainless steel net 3 form a wrapping edge.

Specifically, the insulation structure comprises a first insulation layer 1 and a second insulation layer 5, the anode wrapping 9 is formed by wrapping the edge of the first insulation layer 1, the cathode wrapping 10 is formed by wrapping the edge of the second insulation layer 5, and then the surrounding insulation wrapping structure is formed, so that the situation of short circuit between the cathode and the anode is effectively avoided.

Specifically, the anode sheet and the cathode sheet are respectively provided with an anode electrode column 6 and a cathode electrode column 7, one end of the anode electrode column 6 is arranged on the stainless steel net 3 of the anode sheet, the other end of the anode electrode column 6 passes through the first insulating layer 1 and is connected with the positive electrode of an external power supply, one end of the cathode electrode column 7 is arranged on the stainless steel net 3 of the cathode sheet, the other end of the cathode electrode column 7 passes through the second insulating layer 5 and is connected with the negative electrode of the external power supply, and the anode electrode column 6 and the cathode electrode column 7 are preferably welded on the stainless steel net 3 so as to provide stable current for the reaction of microorganisms.

The anode electrode column 6 and the cathode electrode column 7 are stainless steel electrode columns, in this embodiment, the stainless steel electrode columns are T-shaped structures of stainless steel sheets welded to the stainless steel columns, the stainless steel sheets are welded to the stainless steel mesh 3, and the stainless steel columns extend to the first insulating layer 1 to be externally connected with an electrode of an external power supply.

In this embodiment, as shown in fig. 6, the anode sheet and the cathode sheet are both in a flat plate structure along the length or width direction, and in order to make the whole device react more stably, a pH electrode 8 is disposed between the first insulating layer 1 and the second insulating layer 5, and the pH electrode 8 is used for measuring the pH in the electrode plate in the reaction process.

In actual manufacturing, as shown in fig. 5, first, the lower layer of the anode sheet or the cathode sheet is an industrial non-woven fabric, the middle layer is a carbon felt, the upper layer is a welded stainless steel wire mesh, the length and width dimensions of the carbon felt and the welded stainless steel wire mesh of the aspect ratio of the industrial non-woven fabric of the lower layer are long, and the anode sheet or the cathode sheet is covered by the industrial non-woven fabric of the lower layer. Secondly, combining the anode sheet with the anode sheet, wherein the middle layer is two layers of non-woven fabrics, welding a stainless steel wire mesh on the outermost layer of the anode sheet or the cathode sheet, and fixing the anode sheet and the cathode sheet by using a stainless steel sheet with the wrapping width shorter than that of the industrial non-woven fabrics as a support body 4. And (3) carrying out dislocation welding on the anode sheet and the cathode sheet to obtain stainless steel electrode posts for the wiring posts of the positive and negative electrode leads of the electrodes. And a pH electrode 8 is added between the industrial non-woven fabrics, and the pH change in the electrode plate is monitored in real time in the reaction process.

Further, the double electrode plate of the invention forms H when the anodic oxidation reaction occurs ⁺ To the cathode, so that the pH electrode 8 shows acidity slightly less than 7, too low or too high a pH is detrimental to the redox reaction of the microorganism. If the acidity is too low, irreversible damage is caused to the electrogenic bacteria; too high alkalinity can inhibit the activity of denitrifying microorganisms and electrogenic microorganisms. As another example, the pH can be straightThe activity of denitrifying bacteria, electrogenesis bacteria and denitrifying enzyme are affected, and the electron generation, transmission and denitrification capacity in the bioelectrochemical system are further affected.

The pH range of the bioelectrochemical system is preferably alkaline and neutral, and the condition is critical to the biological denitrification process. The pH in different bioelectrochemical systems can be influenced by specific experimental conditions such as inoculated microorganisms, matrixes, electrode materials and the like, so that the optimal pH ranges of different bioelectrochemical system reactors can be different to a certain extent. In addition, the oxidation-reduction reaction of the anode and the cathode of the bioelectrochemical system is carried out, which may cause the phenomena of peracid of the anode and overbase of the cathode, and is unfavorable for the activity of microorganisms. In actual operation, an aeration device is added at the bottom of the double electrode plates to realize anode aeration, the anode aeration is carried out, the cathode is not aerated, and air flow drives water flow to circulate, so that the solution of the anode and the cathode is in an exchange and uniform mixing state, and the acidity of the anode and the alkalinity of the cathode are neutralized, so that the pH value of the solution of the bioelectrochemical system is not too low or too high; adding weak acid substances such as ammonium salt, bicarbonate and the like into the bioelectrochemical system, and maintaining the pH of the whole system by utilizing the migration action of an electric field inside the bioelectrochemical system.

The invention also provides an electrode pile array, which comprises a plurality of electrode piles of the bioelectrochemical system which are arranged in an array, as shown in fig. 9 and 10, a plurality of groups of electrode piles are arranged in an array to form the electrode pile array, so that the expansion capacity of the bioelectrochemical system is greatly improved, and the industrialization of a reaction device is realized.

The electrode stack box body can be displayed in a plurality of groups on a large-scale reaction tank body, and a stack array form is formed on the reaction tank body, so that engineering application is realized.

Example 2:

this embodiment is a preferable example of embodiment 1.

In this embodiment, the number of the electrode plates 200 is equal to the number of the anode regions 102 and the cathode regions 103 formed by an odd number, and a plurality of independent spaces formed by the anode regions 102 and the cathode regions 103 are formed in the electrode stack, and the distances between the anode regions 102 and the cathode regions 103 are adjusted according to the reaction effect, so that the electron transfer path can be shortened, the high-efficiency oxidative decomposition of organic matters and the reduction reaction of related microorganisms are realized, and a stable and reliable product is provided for the large-scale development and engineering application of the electrochemical system.

The width of each single electrode plate 200 is 0.8m, the length is 1.8m, the distance between two adjacent electrode plates 200 is 0.18m, an electrode stack formed by combining 9 electrode plates 200 is designed, a supporting backrest 104 is designed, the cross section of the supporting backrest 104 is of an L-shaped structure, the bottom end is welded on a bottom frame 105, the top end is a free end, a cuboid space is formed between the two L-shaped supporting backrest 104, and the electrode plates 200 are installed in the cuboid space.

In this embodiment, the anode sheet and the cathode sheet are in a matched continuous concave-convex structure along the length or width direction, and are pressed in an acute wave tooth shape. If the wavy anode plate and cathode plate self-riveting structure shown in fig. 7 is adopted, and then, for example, the trapezoid and inverted trapezoid continuous anode plate and cathode plate self-riveting structure shown in fig. 8 is adopted, the specific surface area of the double electrode plates can be greatly increased, and the reaction efficiency is improved.

In this embodiment, the anode electrode columns 6 and the cathode electrode columns 7 in the dual-electrode plate structure are arranged in a staggered manner, so that contact between adjacent electrode plate columns can be effectively prevented. When in use, the water treatment device can be connected in parallel to form a large-area bioelectrochemical sewage treatment system.

Example 3:

this embodiment is a modification of embodiment 1.

In this embodiment, the insulating structure includes a first insulating layer 1, the anode bordure 9 and the cathode bordure 10 are formed by wrapping the edges of the first insulating layer 1, and in actual manufacturing, the first insulating layer 1 adopts a thinner structure, and the periphery of the first insulating layer 1 is cut into two layers to realize the bordure of the cathode and the anode.

Further, the isolation between the anode sheet and the cathode sheet is realized only by one first insulating layer 1, and the effect in the invention can also be realized.

Taking sewage treatment denitrification as an example, the working principle of the invention is as follows:

as shown in fig. 1 and 5, in the male partA large amount of electrochemical active ammonia oxidizing bacteria and nitrite oxidizing bacteria are adhered to meshes of a carbon felt on a pole piece and a stainless steel net 3, a large amount of denitrifying bacteria are adhered to meshes of the carbon felt on a cathode piece and the stainless steel net 3, and a porous honeycomb-like 'sink' formed by the carbon felt and the stainless steel net 3 can enable microorganisms to stay on the surface of the carbon felt and not to be easily washed away by water flow and the like, so that when treated sewage passes through an anode piece, the electricity-generating microorganisms adhered to the surface metabolize organic matters in the sewage to generate CO ₂ 、H ⁺ Electrons, H ⁺ And electrons migrate to the cathode, and autotrophic denitrifying bacteria attached to the surface of the cathode sheet under the assistance of electricity obtain electrons, and NO ₂ ^- 、NO ₃ ^- Reduction to N ₂ 。

The main ammoxidation and nitration reactions on the anode sheet are as follows:

NH ₄ ⁺ +2H ₂ O→NO ₂ ^- +8H ⁺ +6e

NO ₂ ^- +H ₂ O→NO ₃ ^- +2H ⁺ +2e

the denitrification reaction on the cathode sheet is as follows:

NO ₃ ^- +2e+2H ⁺ →NO ₂ ^- +H ₂ O

NO ₂ ^- +e+2H ⁺ →NO+H ₂ O

2NO+2e+2H ⁺ →N ₂ O+H ₂ O

N ₂ O+2e+2H ⁺ →N ₂ +H ₂ O

proved by experiments, the invention is used for denitrification treatment of low C/N wastewater, when the low voltage is added with 0.7V, the C/N of the inlet water is 3, and the TN removal rate reaches 87.10 percent

Taking methane as an example, the working principle of the invention is as follows:

as shown in FIG. 1, a large amount of electrochemically active methanogens are adhered to the meshes of a carbon felt and a stainless steel net 3 on a cathode sheet, a large amount of electrogenic microorganisms are adhered to the meshes of the carbon felt and the stainless steel net 3 on an anode sheet, and a porous honeycomb-like sink is formed by the carbon felt and the stainless steel net 3The chamber can ensure that microorganisms stay on the surface of the carbon felt and are not easy to be washed away by water flow and the like, and when the treated sewage passes through the anode plate, the organisms in the electrogenesis microorganisms metabolism sewage attached on the surface generate CO ₂ 、H ⁺ Electrons, H ⁺ And electrons migrate to the cathode, and the electroactive methanogens attached to the surface of the cathode sheet under electrical assistance capture CO ₂ Catalytic CO ₂ 、H ⁺ Electrons are converted to methane.

Cathode substrate oxidation reaction, wherein the substrate is used as an electron donor; the cathodic substrate reduction reaction, the substrate acting as an electron acceptor, is specifically as follows:

CO ₂ +H ₂ O→HCO ₃ ^- +H ⁺ ；

HCO ₃ -+9H ⁺ +8e ^- →CH ₄ +H ₂ O。

the electron transfer path is electron transfer through cytochrome C or other reducing proteins, electron transfer through nanowires with electrical conduction, electron transfer through electron shuttles secreted by microorganisms themselves, and the like.

In the description of the present application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements being referred to must have a specific orientation, be configured and operated in a specific orientation, and are not to be construed as limiting the present application.

The foregoing describes specific embodiments of the present invention. It is to be understood that the invention is not limited to the particular embodiments described above, and that various changes or modifications may be made by those skilled in the art within the scope of the appended claims without affecting the spirit of the invention. The embodiments of the present application and features in the embodiments may be combined with each other arbitrarily without conflict.

Claims

1. An electrode stack of a bioelectrochemical system, characterized by comprising an electrode stack box (100) and an electrode plate (200);

the electrode stack box body (100) is internally provided with a first accommodating space (101), a reactant to be processed is accommodated in the first accommodating space (101), one or more groups of electrode plates (200) are sequentially arranged in the first accommodating space (101) at intervals and are submerged in the reactant to be processed, and the polarities of the opposite sides of two adjacent electrode plates (200) are the same;

the electrode plate (200) comprises an anode plate, a cathode plate, an insulating structure and a supporting body (4);

the anode sheet, the insulating structure and the cathode sheet are sequentially stacked to form a stacked structure, the periphery of the insulating structure extends outwards from the inner side of the anode sheet and the inner side of the cathode sheet respectively and wraps the outer side edge of the anode sheet and the outer side edge of the cathode sheet respectively to form an anode wrapping edge (9) and a cathode wrapping edge (10), and the support body (4) wraps the periphery of the stacked structure and two ends of the support body are clamped on the anode wrapping edge (9) and the cathode wrapping edge (10) respectively;

the anode plate and the cathode plate are both in a pole piece structure, the pole piece structure comprises a conductive layer (2) and a stainless steel net (3) arranged on the outer side surface of the conductive layer (2), and the insulating structure is a permeable structure so that protons are allowed to pass through the insulating structure;

the stainless steel nets (3) on the anode plate and the cathode plate after being electrified form an equipotential surface;

the conductive layer (2) is of a permeable porous structure and comprises carbon felt or carbon cloth;

the insulating structure adopts industrial non-woven fabrics or geotextiles.

2. The electrode stack of the bioelectrochemical system according to claim 1, characterized in that the number of electrode plates (200) is an odd number.

3. The electrode stack of the bioelectrochemical system according to claim 1, characterized in that a detachable support frame is arranged on the electrode stack box body (100), and the support frame comprises a support backrest (104), a bottom frame (105) and a lifting rod (106);

the bottom frame (105) is arranged at the bottom of the first accommodating space (101), the supporting backrest (104) is arranged on the bottom frame (105) and used for supporting the electrode plates (200), the bottom of the lifting rod (106) is connected with the bottom frame (105), and the top of the lifting rod (106) is upwards and extends to the outside of the electrode pile box body (100).

4. The electrode stack of the bioelectrochemical system according to claim 1, characterized in that said insulating structure comprises a first insulating layer (1), said anode (9) and cathode (10) bordures being formed by the edge portion of said first insulating layer (1); or alternatively

The insulation structure comprises a first insulation layer (1) and a second insulation layer (5), wherein the anode wrapping (9) is formed by wrapping the edge of the first insulation layer (1), and the cathode wrapping (10) is formed by wrapping the edge of the second insulation layer (5).

5. The electrode stack of a bioelectrochemical system according to claim 1, characterized in that said support (4) is made of a sheet-like watertight material having corrosion resistance and has a C-shaped cross section.

6. The electrode stack of the bioelectrochemical system according to claim 4, characterized in that the anode sheet and the cathode sheet are respectively provided with an anode electrode column (6) and a cathode electrode column (7);

one end of the anode electrode column (6) is arranged on the stainless steel net (3) of the anode sheet, and the other end of the anode electrode column (6) penetrates through the first insulating layer (1) and is connected with the anode of an external power supply;

one end of the cathode electrode column (7) is arranged on the stainless steel net (3) of the cathode plate, and the other end of the cathode electrode column (7) penetrates through the second insulating layer (5) and is connected with a negative electrode of an external power supply;

the anode electrode column (6) and the cathode electrode column (7) are stainless steel electrode columns;

7. The electrode stack of claim 1, wherein the anode and cathode sheets are of matched continuous relief structures or are each of flat plate structures along the length or width direction.

8. Bioelectrochemical system electrode stack according to claim 4, characterized in that a pH electrode (8) is arranged between the first insulating layer (1) and the second insulating layer (5).

9. An electrode stack array comprising a plurality of bioelectrochemical system electrode stacks of any of claims 1 to 8 arranged in an array.