CN113880231A

CN113880231A - Bioelectrochemical system electrode stack and electrode stack array

Info

Publication number: CN113880231A
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: 2022-01-04
Anticipated expiration: 2041-10-09
Also published as: CN113880231B

Abstract

The invention provides an electrode stack and an electrode stack array of a bioelectrochemical system, wherein the electrode stack comprises an electrode stack box body and electrode plates, a first accommodating space is arranged in the electrode stack box body, a reactant to be treated is accommodated in the first accommodating space, the reactant to be treated can be liquid or gas, one or more groups of the electrode plates are sequentially arranged in the first accommodating space at intervals and submerged in the reactant to be treated, and the polarities of the opposite sides of the two adjacent electrode plates are the same.

Description

Bioelectrochemical system electrode stack and electrode stack array

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 world today, and the sustainable development of society and environment can be promoted only by developing renewable energy and realizing the resource utilization of waste and sewage. Research shows that a Bioelectrochemical system (BES) is a system for degrading waste and simultaneously recovering biomass energy and other chemical products with added values. The basic principle is a metabolic process of electrically strengthening electrons released by an oxidation reaction of a dehydrogenase system of a microorganism and electrons obtained by a reduction reaction of a reductase system. BES has multiple functions of synchronously realizing energy recovery, resource recovery, sewage treatment and the like, and is a new technology with wide application prospect. At the anode, the electrogenesis microorganism takes the anode as an electron acceptor to oxidize and degrade organic matters and maintain growth and metabolism. In the 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, BES has the characteristics of short reaction path, controllable reaction conditions, weak side reactions and the like compared with the traditional physical chemical method and biological method.

The earliest BES used Microbial Fuel cells (Microbial Fue)l Cell, MFC) concept emerged. The initial prototype of MFC, as studied by the professor Potter of the university of dala bun, england, 1910, found that he oxidized yeast on the half-cell Pt electrode using escherichia coli (e. Later, MFC devices featuring electricity generation were developed with power generation power densities from the first 0.01mW/m²The power density of the power is increased to 4000mW/m²And the improvement is nearly 5 orders of magnitude. At present, although the power generation of the MFC has incomparable advantages, the MFC device is still at a laboratory scale level because the existence of a proton exchange membrane between an anode chamber and a cathode chamber in a double chamber results in large internal resistance and low output power of the MFC, and oxygen of a cathode in a single chamber easily penetrates through an electrode to enter the anode chamber 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 Burce Logan professor at Pennsylvania State university in the United states expanded the application range of MFC, and found that the energy recovered from organic matter by the bioanode could inherently drive the hydrogen evolution reaction at the cathode, thereby greatly reducing the energy consumption for electrolytic hydrogen production, and this technology was initially referred to as a bioelectrochemical assisted Microbial reactor (bioelectrochemistry) and was later changed into a Microbial Cell (MEC). To this end, BES was developed with MEC based on electrolytic hydrogen production. At present, MEC hydrogen production is still in a laboratory research stage, although MEC hydrogen production has the advantages of high purity, high energy utilization rate and the like, various membranes are needed in MEC to serve as barriers for reducing hydrogen loss, substrate loss is caused by mass production of zymophyte, the pH of a system is reduced due to accumulation of organic acid, production of electrogenic bacteria is influenced, and the hydrogen production rate is reduced.

In addition, BES is combined with modern sensing technology, and an Environmental Monitoring-based Bioelectrochemical Sensor (EMBES) is developed, and is a hot spot of research in recent years by applying on-site rapid Monitoring and continuous on-line analysis. EMBES started from a chemically modified electrode in 1975, which was able to selectively perform the reactions one desires to expect and provides a faster electron transfer rate, driving the development of electrochemical analytical chemistry. The EMBES refers to a sensor which takes biological materials (such as enzymes, antigens, antibodies, hormones and the like) or organisms (cells, organelles, tissues and the like) as sensitive elements, takes electrodes (solid electrodes, ion selective electrodes and the like) as transduction elements, and responds to output by current and potential signals. On 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 bioelectrochemical sensor is prepared by utilizing the specificity of biological reaction and the sensitivity and real-time detection of an electroanalytical method, and a powerful means is provided for the detection of biological substances.

BES can be used in the fields of sewage treatment such as removal of COD, denitrification, desulfurization, dechlorination, azo dyeing and decoloring, and production of valuable additional products such as methanogenesis, alkali production, carbohydrate synthesis and the like, in addition to electricity and hydrogen production.

However, in the past such electrically enhanced bioreaction efficiency enhancing BES, which is targeted to produce electricity or hydrogen, was not separately identified from MFC or MEC, and researchers sometimes used MFC terminology and sometimes MEC terminology. In 2020, the university of Tongji, Zhuhongguang professor, posted papers in ACS Omega journal, which was also used to extend MEC terminology during the manuscript review. While the anonymous manuscript reader clearly suggested that MEC should only be used in the case of cell hydrogen production, other terms are more appropriate to avoid confusion. The article is recorded and published after the acceptance of experts by the group of professor zhu suggested the introduction of Electrically Enhanced Bioreactors (EEBs).

The introduction of EEB marks the perfection of the BES classification system, i.e., BES can be divided into four categories: MFC aims at electricity production, MEC aims at hydrogen production, EMBES aims at environmental monitoring, and EEB aims at improving biological reaction efficiency. Among them, the specific target forms of enhancement of EEB may be various, such as wastewater treatment targeting denitrification, electrically enhanced bioenergy conversion targeting methanogenesis, biological fermentation engineering targeting active organic products, and the like.

BES, which mainly aims at generating electricity and hydrogen and improving the biological reaction efficiency, is currently in the laboratory research stage, and the engineering application is limited, mainly because a high-efficiency low-cost biological reaction electrode for industrial scale application cannot be developed. The early reported papers and patents are mostly small-scale rod-shaped or sheet-shaped electrodes, which are immersed in a reactor at a certain distance, the distance between the cathode and the anode is long, the proton transfer efficiency is low, and the electrodes are mostly noble metals, so the cost is high. Recently, graphite fiber brush electrodes, carbon fiber felt electrodes, Pt/Fe electrodes, copper mesh tinned electrodes, palladium nano carbon powder carbon cloth composite electrodes and the like which are concerned are reported to have relative stability, conductivity, biocompatibility and the like, but cannot realize large-scale engineering application. For example, patent document CN203922843U discloses a microbial electrolysis cell apparatus integrating organic sewage treatment and methane production, comprising a microbial electrolysis cell housing 1, an anode electrode 8 and a cathode electrode 4 are arranged in a microbial electrolysis cell shell 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 voltage 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 electrolysis cell shell 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 electrolysis cell shell 1, a water discharge pipe 2 is arranged on the side surface of the upper end of the microbial electrolysis cell shell 1, a gas collection pipe 3 is arranged at the top end of the microbial electrolysis cell shell 1, however, the electrode used in the design has small surface area, small electrolysis space, high price, non-compact integral structure and unreasonable structural design.

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

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide an electrode stack of a bioelectrochemical system and an electrode stack array.

The invention provides an electrode stack of a bioelectrochemical system, which comprises an electrode stack box body and an electrode plate;

the electrode stack box body is internally provided with a first accommodating space which 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 odd.

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

the bottom frame is arranged at the bottom of the first accommodating space, the supporting backrest is installed on the bottom frame and is 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 faces upwards and extends to the outside of the electrode stack box body.

Preferably, the electrode plate comprises an anode sheet, a cathode sheet, 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 respectively extends outwards from the inner side of the anode sheet and the inner side of the cathode sheet and respectively wraps the edge of the outer side of the anode sheet and the edge of the outer side of the cathode sheet to form an anode wrapping edge and a cathode wrapping edge, the supporting body is wrapped around the circumference of the stacked structure, and two ends of the supporting body are respectively clamped on the anode wrapping edge and the cathode wrapping edge;

the anode sheet and the cathode sheet both adopt a sheet structure, the sheet structure comprises a conductive layer and a stainless steel net arranged on the outer side surface of the conductive layer, and the insulating structure is a permeable structure so as to allow protons to pass through the insulating structure;

and after the anode sheet and the cathode sheet are electrified, the stainless steel nets on the anode sheet and the cathode sheet respectively form equal voltage surfaces.

Preferably, the insulating structure comprises a first insulating layer, and the anode wrapping edge and the cathode wrapping edge are both formed by wrapping the edge part of the first insulating layer; or

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

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

the insulation structure adopts industrial non-woven fabric or geotextile;

the supporting body is made of a stainless steel sheet or other corrosion-resistant sheet-shaped waterproof materials, 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 sheet, and the other end of the cathode electrode column penetrates through the second insulating layer and is connected with the negative electrode of an external power supply;

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

the stainless steel electrode column is a T-shaped structure formed by welding a stainless steel sheet and a stainless steel column.

Preferably, the anode sheet and the cathode sheet are in a matched continuous concave-convex structure or are in a flat plate structure along the length direction or the width direction.

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

The electrode stack array provided by the invention comprises a plurality of electrode stacks of the bioelectrochemical system, which are arranged in an array.

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

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

2. According to the invention, the electrode stack is adopted to form a plurality of relatively independent circulation areas consisting of the cathode area and the anode area, so that the electron transfer path is shortened, the problem that the distance between the application electrode plates of the pilot-scale and on-site industrialized reaction tank is too large, and the electron transfer in the oxidation-reduction reaction process is not favorable is solved, the high-efficiency reactions of the oxidation decomposition of organic matters in sewage, the reduction denitrification of denitrifying bacteria and the like are realized, and a stable and reliable product is provided for the large-scale microbial electrochemistry.

3. The invention can increase the area of the electrodes, shorten the distance between the electrodes, accelerate the electron transfer rate between the anode and the cathode by adopting the electrode plates, and simultaneously, the carbon felt has large surface area and is attached with microorganisms, thereby promoting the oxidation-reduction reaction of organic matters in the sewage and obtaining the high-efficiency removal of the organic matters in the sewage.

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 which mainly aims at generating electricity and hydrogen and improving the biological reaction efficiency, is beneficial to the industrialization development of bioelectrochemistry, and particularly can realize the electrochemical biological enhancement of sewage biological treatment and anaerobic methanation and be applied to methane production of bioelectrochemistry consumed carbon dioxide.

5. The stainless steel net plays three roles simultaneously, on one hand, the stainless steel net plays a role of supporting a framework of the conducting layer, on the other hand, the stainless steel net is tightly pressed on the surface of the carbon felt, and meshes and the carbon felt form a plurality of honeycomb-like 'room' with regular or irregular structures, so that microorganisms can stay in the room to react; 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 premise is provided for the large-scale sewage treatment design of the electrode stack and 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 fabric, can be repeatedly used, are not easily degraded by microorganisms, and have low price.

7. According to the invention, the anode sheet and the cathode sheet can adopt a matched continuous concave-convex fluctuating 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 in the invention adopts a stainless steel mesh and carbon felt composite sheet structure to replace a noble metal wire structure such as titanium and the like, the surface area of the electrode is large, the bioelectrochemical reaction range is large, the price is low, and the electrode has obvious advantages compared with the electrode adopting the noble metal wire 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 the actual application space.

10. The invention adopts a detachable installation mode, is convenient to maintain and repeatedly use and has long service life.

Drawings

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

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 back support and the electrode plate according to 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 backrest 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 structural view of the anode sheet and the cathode sheet of the present invention both having a flat plate structure;

FIG. 7 is a schematic structural diagram of the anode strip and the cathode strip of the present invention in a matched wave structure;

FIG. 8 is a schematic structural diagram of the continuous trapezoid and the inverted trapezoid of the anode strip and the cathode strip in the invention;

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

FIG. 10 is a schematic top view of an electrode stack according to the present invention;

FIG. 11 is a schematic structural view of an electrode plate of the electrode stack of the present invention arranged in a wave structure;

FIG. 12 is a schematic structural view of the electrode plates of the electrode stack array of the present invention in continuous trapezoidal and inverted trapezoidal arrangements.

The figures show that:

cathode edge wrapping 10 of first insulating layer 1

Conductive layer 2 electrode stack case 100

The first receiving space 101 of the stainless net 3

Support 4 anode region 102

Second insulating layer 5 cathode region 103

Anode electrode column 6 supports backrest 104

Bottom frame 105 of cathode electrode post 7

pH electrode 8 lifting rod 106

Anode edge-covered 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 invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling 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 the electrode stack box body 100 is internally provided with a first accommodating space 101, a reactant to be treated is accommodated in the first accommodating space 101, one or more groups of the electrode plates 200 are sequentially arranged in the first accommodating space 101 at intervals and submerged in the reactant to be treated, 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, the anode region 102 has an oxygen oxidation reaction, and the cathode region 103 has an oxygen-deficient reduction reaction.

The reactant to be treated can be liquid or gas, in the practical application of sewage treatment, the reactant to be treated is the sewage to be treated, suspended activated sludge floc, suspended microorganism carriers and the like are often doped in the reactant to be treated, and when the electrode stack box 100 is specifically designed, the electrode stack box 100 can adopt a hollow structure, and the reactant to be treated naturally flows into the electrode stack box 100; or the electrode stack box 100 is provided with a water inlet and a water outlet which are respectively communicated with the first accommodating space 101, the water inlet and the water outlet are respectively used for processed reactants to flow into and out of the first accommodating space 101, and according to an actual application scene, a water pump can be adopted to provide water flow power to enable processed sewage in the electrode stack box 100 to flow if 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 the industrialization of a bioelectrochemical system.

In the invention, as shown in fig. 1 and 3, a detachable support frame is arranged on the electrode stack box 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 is upward and extends to the outside of the electrode stack box 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 box 100 and the electrode plate 200 can be lifted from the electrode stack box 100 together by operating the top of the lifting rod 106, so that a detachable and maintenance structure is realized, and the practicability of the product is greatly improved.

Further, in this embodiment, as shown in fig. 3 and 4, the supporting backrest 104 preferably adopts a plurality of L-shaped backrests, and each two L-shaped backrests are arranged oppositely 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 base frame 105 can be made of a frame base, for example, by welding in a vertical manner using a section bar or a pipe fitting, the base frame 105 serves as a support for the bottom of the electrode plate 200, the two L-shaped backrests serve as supports for the side surfaces of the electrode plate 200, and the electrode plate 200 can be easily taken out from the two L-shaped backrests when maintenance is needed, so as to facilitate maintenance and replacement.

Electrode board 200 includes anode strip, cathode piece, insulation system and supporter 4, anode strip, insulation system, cathode piece stack gradually and form stacked structure, insulation system's periphery is respectively from the inboard of anode strip, the inboard outside extension of cathode piece and respectively to the limit portion in the anode strip outside, the limit portion parcel in the cathode piece outside form the positive pole bordure 9, the negative pole bordure 10, supporter 4 winds stacked structure's circumference parcel and both ends centre gripping respectively are in the positive pole is bordured 9, the negative pole is bordured and is formed insulating chamber enclosed construction on 10, supporter 4 both have insulating chamber enclosed function, have bipolar plate's monolithic fixed function again.

The anode sheet and the cathode sheet both adopt a sheet structure, the sheet structure comprises a conductive layer 2 and a stainless steel mesh 3 arranged on the outer side surface of the conductive layer 2, and the insulation structure is a permeable structure and allows protons (H)⁺) Proton (H) is allowed by preferably a thin permeable structure⁺) By the method, the distance between the anode and the cathode is greatly shortened, the proton transfer rate is increased, and 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 the single compartment are both the anode or the cathode, and the ionic systems in the two compartments can be isolated by virtue of the electrophoresis and reactance action of the electrodes.

The electrified stainless steel meshes 3 of the anode sheet and the cathode sheet form equal voltage surfaces, the stainless steel meshes are preferably stainless steel meshes, the stainless steel meshes 3 can ensure that microorganisms attached to the conductive layer 2 have the current required by the bioelectrochemical system, and the large-size design of the double-electrode plate structure is facilitated.

Stainless steel net 3 is as the conductor in the time of the bioelectrochemistry, and stainless steel net 3 plays the effect to the support skeleton of conducting layer 2, and simultaneously, stainless steel net 3 compresses tightly on the surface of carbon felt, and the mesh of stainless steel net 3 forms "the room of accomodating" of a plurality of regular or irregular structure's similar honeycombs with carbon felt, is favorable to the microorganism to stop in the room of accomodating and not washed away by the rivers, is favorable to the reaction of microorganism. The invention can realize multiple functions, not only can realize electricity generation and hydrogen production, but also can realize electricity-enhanced biological reaction, such as the biosynthesis of electricity-enhanced valuable substances, such as the synthesis of methane, alkali and saccharides, and the like, and such as the sewage treatment by an electricity-enhanced biological method, such as COD removal, denitrification, desulfurization, dechlorination, azo dye decoloration and the like.

The conductive layer 2 is a permeable porous structure and comprises a carbon felt or a carbon cloth, the carbon felt or the carbon cloth can be subjected to specific chemical modification and then can selectively perform required reaction, and provides higher electron transfer rate, the carbon felt is also called a carbon fiber felt, is a felt made of carbon fibers, has broad adsorption spectrum, large capacity and low price, and is used as a carrier for microbial reaction. The insulation structure adopts industrial non-woven fabrics or geotextile, the non-woven fabrics are produced by adopting polyester fiber (polyester fiber) materials, and the insulation structure is manufactured by a needling process and can be made into different thicknesses, handfeels, hardness and the like. The industrial non-woven fabric has the characteristics of water permeability, corrosion resistance, flexibility, light weight, flame retardance, no toxicity, no odor, low price, cyclic utilization and the like, so that the industrial non-woven fabric is water permeable, air permeable, not easy to degrade by microorganisms, durable in use, and has the characteristics of water permeability, air permeability and insulativity.

The support body 4 clamps the enclosed insulating anode edge covering 9 and the cathode edge covering 10 on the periphery and encloses the thin-layer permeable insulating structure between the two electrode plates of the anode and the cathode to form an enclosed thin-layer permeable insulating structure body, and the insulating structure body is insulating, so that the electrodes can not be communicated with each other by virtue of an insulator, and short circuit can be prevented; the industrial non-woven fabric or the geotextile in the insulation structure body has thin body and good permeability, and protons can directionally diffuse in a solution through a permeability system in a bioelectrochemical reaction to form a simulated semiconductor channel; the distance is short, the resistance caused by the resistance can be reduced, and a continuous reaction path is maintained. Meanwhile, the whole insulating structure body is a closed reaction passage, so that the entrance of external foreign particles into competitive protons can be reduced, the loss during the passage of a reaction medium can be reduced, the external reaction medium can be prevented from entering a proton movement channel, the effective reaction ratio can be ensured, and the side reaction can be reduced.

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

In this embodiment, supporter 4 adopts stainless steel sheet or other to have anticorrosive waterproof material of slice to make and forms and seal insulating chamber and cross section and be C shape structure, and C shape structure has certain elasticity, can realize the elasticity centre gripping to positive pole piece and negative pole piece, and is difficult for rustting, realizes the stability of structure, and supporter 4 is through right the centre gripping that positive pole bordured 9, negative pole bordured 10 realizes sealing fixedly to stacked structure, makes the bipolar plate structure form closed access structure on the whole, and loss when reducing proton and passing through reaction medium avoids outside reaction medium to get into proton motion channel, guarantees reaction efficiency.

In practical application, the resistance of the insulating structure is larger than a set threshold value, so that short circuit between the anode sheet and the cathode sheet can be prevented, the effect of isolating the cathode and the anode is achieved, the insulating structure has the characteristic that the resistance at each position is uniformly distributed, and the stability of microbial electrochemical reaction is guaranteed.

Further, the resistivity of the insulating material is typically 10¹⁰～10²²Omega m, the threshold value set in the present invention can be set to 10¹⁰Omega.m. The insulation structure can isolate the electrified conductors with different potentials, so that current can flow according to a certain path, the potential distribution of an electric field is improved, and the function of protecting the conductors is achieved. When the external voltage is U, the input current is I, and the area of the conductive layer is S, the resistance R per square meter becomes U/(I × S). For this purpose, two resistance states are produced, namely the resistance R when the bioelectrochemical reaction does not occur_aAnd the resistance is R when the bioelectrochemical reaction effectively occurs_bThen R is_a>>R_b，>>I.e. by more than two orders of magnitude.

In practical application, the size of the insulating structure is larger than that 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 ends of the conductive layer 2 and the stainless steel net 3, i.e. the ends of the conductive layer 2 and the stainless steel net 3 form a bound edge.

Specifically, the insulating structure comprises a first insulating layer 1 and a second insulating layer 5, the anode wrapping edge 9 is formed by wrapping the edge of the first insulating layer 1, the cathode wrapping edge 10 is formed by wrapping the edge of the second insulating layer 5, and therefore a wrapping structure with the periphery sealed and insulated is formed, and the situation that the cathode and the anode are short-circuited is effectively avoided.

Specifically, anode plate, cathode plate have anode electrode post 6, negative pole electrode post 7 respectively, the stainless steel net 3 at the anode plate is installed to the one end of anode electrode post 6, and the other end of anode electrode post 6 passes first insulating layer 1 and is connected the positive pole of external power source, the one end of negative pole electrode post 7 is installed on the stainless steel net 3 of cathode plate, and the other end of negative pole electrode post 7 passes second insulating layer 5 and is connected the negative pole of external power source, and anode electrode post 6, negative pole electrode post 7 all preferably weld on stainless steel net 3 to provide stable electric current for the reaction of microorganism.

The anode electrode column 6 and the cathode electrode column 7 both adopt stainless steel electrode columns, in this embodiment, the stainless steel electrode columns are T-shaped structures formed by welding stainless steel sheets on a stainless steel net 3, and the stainless steel sheets extend to the outside of the first insulating layer 1 and are connected with electrodes of an external power supply.

As shown in fig. 6, in this embodiment, the anode sheet and the cathode sheet are both flat plate structures along the length direction or the width direction, 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 pH in the electrode plate during 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-width dimension of the length-width ratio carbon felt of the industrial non-woven fabric of the lower layer and the length-width dimension of the welded stainless steel wire mesh are long, and the anode sheet or the cathode sheet is wrapped with the industrial non-woven fabric of the lower layer. And secondly, combining the anode sheet with the edge covered with the stainless steel sheet, wherein the middle layer is two layers of non-woven fabrics, welding the 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 the stainless steel sheet with the edge width shorter than that of the industrial non-woven fabric as a support body 4. And the stainless steel electrode columns are welded on the anode sheet and the cathode sheet in a staggered manner and are used as binding posts for the anode and cathode leads of the electrode. And adding a pH electrode 8 between the industrial non-woven fabrics, and monitoring the pH change in the electrode plate in real time in the reaction process.

Further, the double electrode plate of the present invention forms H when an anodic oxidation reaction occurs⁺And the pH electrode 8 is acidic, and is slightly less than 7, and the pH is not beneficial to the redox reaction of the microorganism. If the acidity is too low, the electrogenic bacteria can be irreversibly damaged; too high alkalinity will inhibit the activity of denitrifying microorganisms and electrogenic microorganisms. In another example, pH can directly affect the activities of denitrifying bacteria, electrogenic bacteria, and denitrifying enzymes, thereby affecting the electron generation, transfer, and denitrification capabilities in the bioelectrochemical system.

The pH range of the biological electrochemical system denitrification is suitable for being alkaline and neutral, and the condition is crucial to the biological denitrification process. The pH in different bioelectrochemical systems is influenced by specific experimental conditions such as inoculated microorganisms, substrates, electrode materials and the like, so that the optimal pH ranges of different bioelectrochemical system reactors have certain differences. In addition, the redox reactions between the cathode and the anode of the bioelectrochemical system may cause the phenomena of over-acid at the anode and over-alkali at the cathode, which are unfavorable to the activity of microorganisms. In actual operation, an aeration device is additionally arranged at the bottom of the double electrode plate to realize anode aeration, and through the anode aeration and the non-aeration of the cathode, airflow drives water flow to circulate, so that the solutions of the anode and the cathode are in an exchange and uniform mixing state, and the pH value of the solution of the bioelectrochemical system is not too low or too high due to the neutralization of the acidity of the anode and the alkalinity of the cathode; weakly acidic substances such as ammonium salt and bicarbonate are added into the bioelectrochemical system, and the pH of the whole system is maintained by utilizing the migration effect of an electric field in the bioelectrochemical system.

The invention also provides an electrode stack array, which comprises a plurality of bioelectrochemical system electrode stacks arranged in an array, as shown in fig. 9 and fig. 10, the electrode stack array is formed by arranging a plurality of groups of electrode stacks in an array, the expansion capability of the bioelectrochemical system is greatly improved, and the industrialization of a reaction device is realized.

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

Example 2:

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

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

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

In this embodiment, the anode electrode posts 6 and the cathode electrode posts 7 in the double-electrode-plate structure are arranged in a staggered manner, so that the contact between the adjacent electrode posts can be effectively prevented. When in use, a plurality of groups of the sewage treatment system can be connected in parallel and used together to form a large-area bioelectrochemical sewage treatment system.

Example 3:

this example is a modification of example 1.

In this embodiment, the insulating structure includes a first insulating layer 1, the anode edge 9 and the cathode edge 10 are both formed by wrapping an edge of the first insulating layer 1, and in actual manufacturing, the first insulating layer 1 is of a thin structure, and the edge of the cathode and the anode is cut into two layers around the first insulating layer 1.

Further, the anode sheet and the cathode sheet are isolated by only one first insulating layer 1, and the effect of the present invention can also be achieved.

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

as shown in figures 1 and 5, a large amount of electrochemical activity ammonia oxidizing bacteria and nitrite oxidizing bacteria are attached to the meshes of the carbon felt on the anode plate and the stainless steel net 3, a large amount of denitrifying bacteria are attached to the meshes of the carbon felt on the cathode plate and the stainless steel net 3, and the porous cellular-like 'room' 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, when the treated sewage passes through the anode plate, the electricity-producing microorganisms attached to the surface metabolize organic matters in the sewage to produce CO₂、H⁺And electrons, H⁺And transferring electrons to the cathode, and under the assistance of electricity, obtaining electrons from autotrophic denitrifying bacteria attached to the surface of the cathode sheet to remove NO₂ ^-、NO₃ ^-Reduction to N₂。

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

NH₄ ⁺+2H₂O→NO₂ ^-+8H⁺+6e

NO₂ ^-+H₂O→NO₃ ^-+2H⁺+2e

the denitrification reaction on the cathode sheet is as follows:

NO₃ ^-+2e+2H⁺→NO₂ ^-+H₂O

NO₂ ^-+e+2H⁺→NO+H₂O

2NO+2e+2H⁺→N₂O+H₂O

N₂O+2e+2H⁺→N₂+H₂O

experiments prove that the low C/N wastewater is denitrified by the method, when the low voltage is applied to 0.7V, the C/N of the inlet water is 3, and the TN removal rate reaches 87.10 percent

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

as shown in figure 1, a large amount of electrochemically active methanogens are attached to the meshes of the carbon felt and the stainless steel net 3 on the cathode plate, a large amount of electrogenic microorganisms are attached to the meshes of the carbon felt and the stainless steel net 3 on the anode plate, and the porous honeycomb-like 'sink chamber' formed by the carbon felt and the stainless steel net 3 can enable the microorganisms to stay on the surface of the carbon felt and not to be easily washed away by water flow and the like, when the treated sewage passes through the anode plate, the electrogenic microorganisms attached to the surface metabolize organic matters in the sewage to generate CO₂、H⁺And electrons, H⁺And the electrons migrate to the cathode, and the electroactive methanogen attached to the surface of the cathode plate captures CO under the assistance of electricity₂Catalyzing CO₂、H⁺And the electrons are converted to methane.

Performing cathode substrate oxidation reaction, wherein the substrate is used as an electron donor; and (3) performing a cathode substrate reduction reaction, wherein the substrate is used as an electron acceptor, and the specific reaction is as follows:

CO₂+H₂O→HCO₃ ^-+H⁺；

HCO₃-+9H⁺+8e^-→CH₄+H₂O。

the electron transfer pathway is electron transfer by cytochrome C or other reductive proteins, electron transfer by electrically conductive nanowires, electron transfer by electron shuttles secreted by the microorganism itself, or the like.

In the description of the present application, it is to 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 those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

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

Claims

1. The electrode stack of the bioelectrochemical system is characterized by comprising an electrode stack box body (100) and an electrode plate (200);

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

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

3. The bioelectrochemical system electrode stack according to claim 1, wherein a detachable support frame is provided on the electrode stack casing (100), and the support frame comprises a support backrest (104), a bottom frame (105) and a lifting bar (106);

the bottom frame (105) is arranged at the bottom of the first accommodating space (101), the supporting backrest (104) is installed on the bottom frame (105) and is 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 upward and extends to the outside of the electrode stack box body (100).

4. The bioelectrochemical system electrode stack according to claim 1, wherein the electrode plates (200) comprise an anode sheet, a cathode sheet, an insulating structure, and a support 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 respectively extends outwards from the inner side of the anode sheet and the inner side of the cathode sheet and respectively wraps the edge of the outer side of the anode sheet and the edge of the outer side of the cathode sheet to form an anode wrapping edge (9) and a cathode wrapping edge (10), the supporting body (4) wraps around the circumferential direction of the stacked structure, and two ends of the supporting body are respectively clamped on the anode wrapping edge (9) and the cathode wrapping edge (10);

the anode sheet and the cathode sheet both adopt a sheet structure, the sheet 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 as to allow protons to pass through the insulating structure;

and equal voltage surfaces are formed on the stainless steel nets (3) on the anode sheet and the cathode sheet after the anode sheet and the cathode sheet are electrified.

5. The bioelectrochemical system electrode stack according to claim 4, wherein the insulating structure comprises a first insulating layer (1), and the anode edge covering (9) and the cathode edge covering (10) are wrapped by the edge of the first insulating layer (1); or

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

6. The bioelectrochemical system electrode stack according to claim 4, characterized in that said conductive layer (2) is a permeable porous structure comprising a carbon felt or a carbon cloth;

the insulation structure adopts industrial non-woven fabric or geotextile;

the supporting body (4) is made of a stainless steel sheet or an anticorrosive flaky impervious material, and the cross section of the supporting body is of a C-shaped structure.

7. The bioelectrochemical system electrode stack according to claim 4, wherein the anode sheet and the cathode sheet have an anode electrode column (6) and a cathode electrode column (7), respectively;

one end of the anode electrode column (6) is arranged on the stainless steel mesh (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 mesh (3) of the cathode sheet, and the other end of the cathode electrode column (7) penetrates through the second insulating layer (5) and is connected with the negative electrode of an external power supply;

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

8. The bioelectrochemical system electrode stack according to claim 4, wherein the anode sheet and the cathode sheet have a continuous concave-convex structure or a flat structure along the length or width direction.

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

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