Spatial orientation channel anode, bioelectrochemical system and sewage recycling application thereof

Abstract

The invention provides a spatial orientation channel anode, a preparation method thereof, a bioelectrochemical system and application. The spatially oriented channel anode comprises a carbon skeleton, the carbon skeleton is provided with pore channels, and the pore channels extend in a single direction. When the carbon skeleton anode is applied to a bioelectrochemical system, the growth area of microorganisms on the surface of the anode can be effectively increased, and the carbon skeleton anode has an efficient current collection effect and is beneficial to improving the electrochemical activity of the carbon skeleton anode. After the bioelectrochemical system is started, the directional channel loaded with microorganisms can form a micro-channel reactor, the degradation effect of pollutants when sewage flows through is enhanced, and the chemical energy conversion and in-situ self-driven resource recovery efficiency of the sewage is improved. Meanwhile, the bioelectrochemical system can be used as a desalination system, a concentration system and a desalination-concentration composite system, and the effects of removal of ionic substances in sewage, recovery of nitrogen and phosphorus resources, synchronous comprehensive purification and the like are achieved.

Description

Technical Field

[0001] The present invention relates to the field of bioelectrochemistry, and specifically, to a spatial directional channel anode, a bioelectrochemical system and its sewage resource application, and more specifically, to a spatial directional channel anode and its preparation method, a bioelectrochemical system and its application in sewage purification and resource recovery. Background Art

[0002] In response to the national "dual carbon" call, the development of clean and low-carbon sewage treatment technology has become one of the important research directions in the field of environment. The bioelectrochemical system can use the special electroactive microorganisms at the anode to purify sewage and recover energy and resources. It is a promising sewage resource and energy technology. The bioelectrochemical system can convert the chemical energy in sewage into electrical energy. An efficient anode is an important prerequisite for realizing sewage purification and energy conversion in the bioelectrochemical system. A good anode should provide a more suitable living space for microorganisms, and at the same time have efficient electron conduction ability and effective spatial mass transfer process. Therefore, designing the spatial structure of the anode and accelerating the electron transfer process of the anode are of great significance for strengthening the anode performance and improving the bioelectrochemical sewage production capacity process. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to some extent. To this end, one object of the present invention is to provide a spatially oriented channel anode, which has the advantage of efficient current collection.

[0004] In one aspect of the present invention, the present invention provides a spatial directional channel anode. According to an embodiment of the present invention, the spatial directional channel anode includes a carbon skeleton, the carbon skeleton has a pore channel, and the pore channel extends in a single direction. Thus, the formation of the pore channel effectively improves the spatial structure inside the anode and increases the specific surface area of ​​the anode. When it is applied to a bioelectrochemical system, it can effectively increase the growth area of ​​microorganisms on the anode surface. The carbon skeleton anode has the effect of efficient current collection, and the unidirectional extension of the pore channel is conducive to the directional transmission of electrons and protons generated by microorganisms on the spatial directional channel anode, thereby helping to improve its electrochemical activity. Moreover, after starting the bioelectrochemical system, the directional channel loaded with microorganisms can constitute a microfluidic reactor, which can enhance the degradation effect of pollutants when sewage flows through, and can improve the chemical energy conversion of sewage and the efficiency of in-situ self-driven resource recovery.

[0005] According to an embodiment of the present invention, the spatially oriented channel anode further comprises a doped metal, and the doped metal is attached to the surface of the carbon skeleton. Optionally, the doped metal comprises a transition metal.

[0006] In another aspect of the present invention, the present invention provides a method for preparing the aforementioned spatial directional channel anode. According to an embodiment of the present invention, the method for preparing the spatial directional channel anode comprises: mixing a polymer powder with a first solvent and adjusting it to be acidic to obtain a cross-linked polymer solution; placing the cross-linked polymer solution in a mold with a metal base for freeze drying to obtain an aerogel having a spatial directional channel; pyrolyzing the aerogel to obtain the spatial directional channel anode. Thus, the above preparation method can effectively form a unidirectionally extending pore channel in the carbonized carbon skeleton, thereby effectively improving the spatial structure inside the anode and increasing the specific surface area of ​​the anode. When it is applied to a bioelectrochemical system, it can effectively increase the growth area of ​​microorganisms on the anode surface. The carbon skeleton anode has the effect of efficient current collection, which is conducive to the directional transmission of electrons and protons generated by microorganisms on the spatial directional channel anode, thereby helping to improve its electrochemical activity. Moreover, after starting the bioelectrochemical system, the directional channel loaded with microorganisms can constitute a microfluidic reactor, enhance the degradation effect of pollutants when sewage flows through, and improve the chemical energy conversion of sewage and the efficiency of in-situ self-driven resource recovery.

[0007] According to an embodiment of the present invention, at least one of the following conditions is met: the mass concentration of the polymer in the cross-linked polymer solution is 0.25% to 5%; the polymer includes at least one of chitosan, sodium alginate, and polyvinyl alcohol; the temperature of the pyrolysis treatment is 600°C to 1200°C, and the insulation time is 1 to 4 hours; the heating rate of the pyrolysis treatment is 2 to 10°C / min.

[0008] According to an embodiment of the present invention, the preparation method further comprises: adding a metal salt and / or a metal-based ZIF precursor to the cross-linked polymer solution.

[0009] According to an embodiment of the present invention, based on the total mass of the polymer, the mass concentration of the metal salt in the cross-linked polymer solution is 0.1% to 5%; and / or, based on the total mass of the polymer, the mass concentration of the metal-based ZIF precursor in the cross-linked polymer solution is 0.1% to 2%, and / or, the method for preparing the metal-based ZIF precursor includes: dissolving zinc nitrate and a metal salt in a second solvent to obtain a first mixed solution; dissolving 2-methylimidazole in a third solvent to obtain a second mixed solution; mixing the first mixed solution and the second mixed solution with stirring, and centrifuging to obtain the metal-based ZIF precursor.

[0010] In another aspect of the present invention, the present invention provides a bioelectrochemical system. According to an embodiment of the present invention, the bioelectrochemical system includes: an anode unit, the anode unit includes at least one of the aforementioned spatial directional channel anodes, and the surface of the spatial directional channel anode is attached with electroactive microorganisms; an electrolyte; a cathode unit, the cathode unit is arranged in a columnar shape around the outside of the anode unit. In this way, the anode of the bioelectrochemical system has a large area of ​​microorganism attachment, the carbon skeleton anode has an efficient power collection effect, and after starting the bioelectrochemical system, the directional channel loaded with microorganisms can form a microfluidic reactor, enhance the degradation effect of pollutants when sewage flows through, and improve the chemical energy conversion of sewage and the in-situ self-driven resource recovery efficiency.

[0011] According to an embodiment of the present invention, the bioelectrochemical system further comprises: an ion exchange membrane, the ion exchange membrane comprising at least one layer of anion exchange membrane and at least one layer of cation exchange membrane, the ion exchange membrane being arranged in a columnar shape around the anode unit and the cathode unit.

[0012] According to an embodiment of the present invention, the anode unit includes a plurality of the spatially directional channel anodes, and the anode unit satisfies one of the following conditions: a plurality of the spatially directional channel anodes are arranged in series through conductive wires; a plurality of the spatially directional channel anodes are arranged in parallel through conductive wires; the anode unit includes a plurality of parallel anode combinations, each of the anode combinations includes a plurality of the spatially directional channel anodes arranged in series; the spatially directional channel anodes are cylindrical.

[0013] According to an embodiment of the present invention, the cathode unit and / or the ion exchange membrane are cylindrical.

[0014] In another aspect of the present invention, the present invention provides a desalination system. According to an embodiment of the present invention, the desalination system includes the aforementioned bioelectrochemical system, wherein the ion exchange membrane includes a layer of anion exchange membrane and a layer of cation exchange membrane, the anion exchange membrane is cylindrically arranged around the anode of the spatial directional channel and is arranged close to the anode of the spatial directional channel, and the cation exchange membrane is cylindrically arranged around one side of the cathode unit. Thus, the desalination system can effectively purify sewage.

[0015] In another aspect of the present invention, the present invention provides a concentration system. According to an embodiment of the present invention, the concentration system includes the aforementioned bioelectrochemical system, wherein the ion exchange membrane includes a layer of anion exchange membrane and a layer of cation exchange membrane, the cation exchange membrane is cylindrically arranged around the anode of the spatial directional channel and is arranged close to the anode of the spatial directional channel, and the anion exchange membrane is cylindrically arranged around one side of the cathode unit. Thus, the concentration system can effectively realize the recovery of resources (such as nitrogen and phosphorus).

[0016] In another aspect of the present invention, the present invention provides a desalination-concentration composite system. According to an embodiment of the present invention, the desalination-concentration composite system includes the aforementioned bioelectrochemical system, wherein the ion exchange membrane includes a multilayer anion exchange membrane and a multilayer cation exchange membrane, and the multilayer anion exchange membrane and the multilayer cation exchange membrane are both cylindrical and sequentially overlapped between the anode and cathode units of the spatial directional channel. Thus, the system can simultaneously achieve the purification of sewage and the recovery of resources, and improve the treatment efficiency of sewage pollutants.

[0017] In another aspect of the present invention, the present invention provides the use of the above-mentioned desalination system, concentration system or desalination-concentration system in sewage purification and resource recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 is a schematic structural diagram of a bioelectrochemical system in one embodiment of the present invention;

[0020] Figure 2 is a schematic structural diagram of a bioelectrochemical system in another embodiment of the present invention;

[0021] Figure 3 is a schematic structural diagram of a bioelectrochemical system in another embodiment of the present invention;

[0022] Figure 4 is a cross-sectional schematic diagram of a bioelectrochemical system in another embodiment of the present invention;

[0023] Figure 5 is a cross-sectional schematic diagram of a bioelectrochemical system in another embodiment of the present invention;

[0024] Figure 6 is a cross-sectional schematic diagram of a bioelectrochemical system in another embodiment of the present invention;

[0025] Figure 7is a schematic structural diagram of an anode unit in another embodiment of the present invention;

[0026] Figure 8 is a schematic structural diagram of an anode unit in another embodiment of the present invention;

[0027] Fig. 9 is a schematic structural diagram of an anode unit in another embodiment of the present invention;

[0028] Fig.10 is a schematic diagram of the operating principle of a bioelectrochemical system in another embodiment of the present invention;

[0029] Fig.11 is a schematic diagram of the operating principle of a bioelectrochemical system in another embodiment of the present invention;

[0030] Fig.12 is a schematic diagram of the operating principle of a bioelectrochemical system in another embodiment of the present invention;

[0031] Fig.13 and Fig.14 is a scanning electron microscope image of the spatially oriented channel anode in Examples 1 to 6;

[0032] Fig.15 is a conductivity test graph of the spatial directional channel anode in Examples 1 to 6;

[0033] Fig.16 It is the electrochemical activity test graph of the spatial directional channel anode in Examples 1 to 6 and the anode in Comparative Examples 1 and 2;

[0034] Fig.17 1 is a bioelectrochemical CV curve diagram of the spatially oriented channel anodes in Examples 1 to 6 and the anodes in Comparative Examples 1 and 2;

[0035] Fig.18 This is a test diagram of the electricity generation performance of the bioelectrochemical system corresponding to the spatially oriented channel anodes in Examples 1 to 6 and the anodes in Comparative Examples 1 and 2;

[0036] Fig.19 It is a test graph of the pollutant removal performance and substrate utilization efficiency of the bioelectrochemical system corresponding to the spatial directional channel anodes in Examples 1 to 6 and the anodes in Comparative Examples 1 and 2;

[0037] Fig. 20 It is a test graph of the change of the current density of the bioelectrochemical system corresponding to the spatial directional channel anode in Examples 1 to 6 and the anode in Comparative Examples 1 and 2 with the organic matter concentration;

[0038] Fig.21 It is a test diagram of the stability of the bioelectrochemical system corresponding to the spatially oriented channel anode in Examples 5 and 6;

[0039] Fig. 22 This is a test diagram of the power generation performance of the bioelectrochemical system corresponding to the spatially oriented channel anode in Examples 6 and 7. DETAILED DESCRIPTION

[0040] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0041] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0042] In one aspect of the present invention, the present invention provides a spatial directional channel anode. According to an embodiment of the present invention, the spatial directional channel anode includes a carbon skeleton, the carbon skeleton has a pore channel, and the pore channel extends in a single direction. Thus, the formation of the pore channel effectively improves the spatial structure inside the anode and increases the specific surface area of ​​the anode. When it is applied to a bioelectrochemical system, it can effectively increase the growth area of ​​microorganisms on the anode surface. The carbon skeleton anode has the effect of efficient current collection, and the unidirectional extension of the pore channel is conducive to the directional transmission of electrons and protons generated by microorganisms on the spatial directional channel anode, thereby helping to improve its electrochemical activity. Moreover, after starting the bioelectrochemical system, the directional channel loaded with microorganisms can constitute a microfluidic reactor, which can enhance the degradation effect of pollutants when sewage flows through, and can improve the chemical energy conversion of sewage and the efficiency of in-situ self-driven resource recovery.

[0043] It should be noted that the above-mentioned “the pore channel extends in one direction” means that the pore channel is a directional channel extending in one direction, that is, the extension of the length of the pore channel is a unidirectional extension.

[0044] In some embodiments of the present invention, the width of the pore channel in the spatial directional channel anode is 1 to 100 microns, such as 1 micron, 5 microns, 10 microns, 20 microns, 30 microns, 40 microns, 50 microns, 60 microns, 70 microns, 80 microns, 90 microns, 100 microns, etc. In this way, the spatial directional channel anode has a good spatial channel while still maintaining good mechanical strength to ensure its structural stability. In some specific embodiments, the width of the pore channel in the spatial directional channel anode is 25 to 600 microns; in other specific embodiments, the width of the pore channel in the spatial directional channel anode is 25 to 35 microns. Among them, the above-mentioned "width dimension" refers to the dimension in the direction perpendicular to the extension direction of the channel in the spatial directional channel anode.

[0045] According to some embodiments of the present invention, the spatially oriented channel anode further includes a doped metal, which is attached to the surface of the carbon skeleton, that is, the doped metal is attached to the outer surface of the carbon skeleton and the inner surface of the internal pore channel. Therefore, the introduction of metal active sites in the carbon skeleton can further enhance the electron transfer efficiency between microorganisms and electrodes, improve the anode performance, and be applied to bioelectrochemical systems to further improve the chemical energy conversion of sewage and the efficiency of in-situ self-driven resource recovery.

[0046] According to some embodiments of the present invention, the doping metal includes a transition metal. Thus, the transition metal has high reactivity, can better improve the reactivity of the anode, and has low cost and stable properties. In some specific embodiments, the doping metal includes but is not limited to at least one of iron, manganese, and cobalt.

[0047] In some embodiments of the present invention, there is no special requirement for the form in which the doped metal is attached to the surface of the carbon skeleton, as long as the doped metal can be effectively attached to the surface of the carbon skeleton to improve the anode activity. In some embodiments, the doped metal can be attached to the surface of the carbon skeleton in the form of monodispersed atoms; in other embodiments, the doped metal is attached to the surface of the carbon skeleton in the form of metal oxides or metal nanoparticles.

[0048] In another aspect of the present invention, the present invention provides a method for preparing the aforementioned spatial directional channel anode. According to an embodiment of the present invention, the method for preparing the spatial directional channel anode comprises:

[0049] S100: mixing the polymer powder with the first solvent and adjusting the solvent to be acidic to obtain a cross-linked polymer solution.

[0050] In some embodiments of the present invention, the polymer includes at least one of chitosan, sodium alginate, and polyvinyl alcohol. The above polymers are easy to carbonize, have low cost, and are widely available. In some embodiments, the first solvent may be water.

[0051] In some embodiments of the present invention, the mixture of the polymer powder and the first solvent is adjusted to be weakly acidic, such as pH 5 to 7, which facilitates polymer cross-linking under weakly acidic conditions and thus helps form a carbon skeleton. In some specific embodiments, the pH can be adjusted by a buffer or a weak acid (such as acetic acid).

[0052] According to an embodiment of the present invention, the mass concentration of the polymer in the cross-linked polymer solution is 0.25% to 5%, such as 0.25%, 0.3%, 0.5%, 1.0%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. Thus, a better mechanical strength can be obtained, which is conducive to the colonization of microorganisms and the formation of microchannels (or pore channels) inside the carbon skeleton. If the concentration of the polymer is relatively low, the internal skeleton of the obtained carbon skeleton anode is too loose, resulting in relatively poor mechanical strength; if the concentration of the polymer is relatively high, the carbon skeleton structure will be relatively too dense, which is not conducive to the colonization of microorganisms and the formation of internal microchannels. In some more specific embodiments, based on the total mass of the polymer, the mass concentration of the metal salt in the cross-linked polymer solution is 2% to 5%. In some specific embodiments, the polymer can be chitosan, and the mass concentration of the polymer in the cross-linked polymer solution is 0.5% to 4%.

[0053] According to some embodiments of the present invention, a metal-doped spatially oriented channel anode may be further prepared, and the specific preparation method may include the following two cases:

[0054] In some embodiments, a metal salt is added to the cross-linked polymer solution. In this way, a spatially oriented channel anode with a doped metal attached to the surface of the carbon skeleton can be prepared. The introduction of metal active sites in the carbon skeleton can further enhance the electron transfer efficiency between microorganisms and electrodes, improve the anode performance, and be applied to bioelectrochemical systems to further improve the chemical energy conversion of sewage and the efficiency of in-situ self-driven resource recovery.

[0055] In some specific embodiments, the metal salt is a transition metal salt, which may include at least one of metal nitrates and metal acetates. Further, in some specific embodiments, based on the total mass of the polymer, the mass concentration of the metal salt in the cross-linked polymer solution is 0.1% to 5%, such as 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, etc., which is conducive to the attachment of the doped metal to the surface of the carbon skeleton. If the concentration of the metal salt is relatively low, the loading amount of the doped metal on the surface of the carbon skeleton is relatively small, and the enhancement of the electron transfer efficiency between the microorganism and the electrode is relatively weak. If the concentration of the metal salt is relatively high, it will cause a waste of raw materials.

[0056] In other embodiments, a metal-based ZIF precursor is added to the cross-linked polymer solution. In this way, a spatially oriented channel anode with a doped metal attached to the surface of the carbon skeleton can be prepared. The introduction of metal active sites in the carbon skeleton can further enhance the electron transfer efficiency between microorganisms and electrodes, improve the anode performance, and be applied to bioelectrochemical systems to further improve the chemical energy conversion of sewage and the efficiency of in-situ self-driven resource recovery.

[0057] In some specific embodiments, the metal is a transition metal, and the transition metals that can be used include iron, manganese, cobalt, etc. The organic ligand used in the metal-based ZIF precursor is 2-methylimidazole. Further, in some specific embodiments, based on the total mass of the polymer, the mass concentration of the metal-based ZIF precursor in the cross-linked polymer solution is 0.1% to 2%, such as 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, etc., so that it is conducive to the attachment of the doped metal to the surface of the carbon skeleton. If the concentration of the metal-based ZIF precursor is relatively low, the loading amount of the doped metal on the surface of the carbon skeleton is relatively small, and the enhancement of the electron transfer efficiency between the microorganism and the electrode is relatively weak. If the concentration of the metal-based ZIF precursor is relatively high, it will cause a waste of raw materials.

[0058] In some embodiments of the present invention, the preparation method of the metal-based ZIF precursor includes: dissolving zinc nitrate and a metal salt in a second solvent to obtain a first mixed solution; dissolving 2-methylimidazole in a third solvent to obtain a second mixed solution; mixing the first mixed solution and the second mixed solution, stirring, and centrifuging to obtain a metal-based ZIF precursor.

[0059] In this step, the metal salt includes at least one of metal acetylacetonate, metal nitrate, and metal acetate; the second solvent and the third solvent are at least one of methanol and water, respectively.

[0060] S200: placing the cross-linked polymer solution in a mold with a metal base for freeze drying to obtain an aerogel with spatially oriented channels. In the freeze drying process, the freezing process can induce the directional and orderly growth of ice crystals in the solid polymer (the growth direction is from the surface of the base to the direction away from the base), and then through the drying process, the directional and orderly pore channels in the polymer skeleton are formed as the ice crystals are removed.

[0061] In some embodiments of the present invention, a cross-linked polymer solution is placed in a mold, which may be a mold having a polytetrafluoroethylene sidewall and a brass base. The good thermal conductivity of metallic brass in liquid nitrogen can induce the production of directional growth of ice crystals. Furthermore, there are no special requirements for the shape of the mold, and those skilled in the art can set it according to the requirements for the shape of the anode. In some specific embodiments, a cylindrical mold is used, so that a cylindrical spatial directional channel anode can be prepared, which can facilitate the preparation of a cylindrical bioelectrochemical system. A more uniform self-generated electric field can be generated in the cylindrical bioelectrochemical system, and better power generation performance and organic matter removal effect can be obtained compared to a square bioelectrochemical system.

[0062] In some embodiments, there are no special requirements for the specific conditions of freeze-drying, and those skilled in the art can flexibly set them according to actual needs and other actual conditions. For example, freeze-drying can be performed at -200°C to -20°C.

[0063] In the embodiments of the present invention, the addition of the above metal salts and metal-based ZIF precursors will not affect the directional growth process of ice crystals.

[0064] S300: The aerogel is subjected to pyrolysis treatment to obtain a spatially oriented channel anode. In this way, the polymer skeleton is effectively carbonized by pyrolysis treatment to obtain a carbon skeleton.

[0065] According to some embodiments of the present invention, the temperature of the pyrolysis treatment is 600°C to 1200°C, such as 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1100°C, 1200°C, etc., and the insulation time is 1 to 4 hours, so that sufficient carbonization of the polymer can be effectively achieved.

[0066] In some embodiments, the heating rate of the pyrolysis treatment is 2-10° C. / min.

[0067] According to an embodiment of the present invention, the above-mentioned preparation method can effectively form a unidirectionally extending pore channel in the carbonized carbon skeleton, thereby effectively improving the spatial structure inside the anode and increasing the specific surface area of ​​the anode. When it is applied to a bioelectrochemical system, it can effectively increase the growth area of ​​microorganisms on the anode surface. The carbon skeleton anode has the effect of efficient current collection, and is conducive to the directional transmission of electrons and protons generated by microorganisms on the spatial directional channel anode, thereby helping to improve its electrochemical activity. Moreover, after starting the bioelectrochemical system, the directional channel loaded with microorganisms can form a microfluidic reactor, which can enhance the degradation effect of pollutants when sewage flows through, and can improve the chemical energy conversion of sewage and the efficiency of in-situ self-driven resource recovery.

[0068] In another aspect of the present invention, the present invention provides a bioelectrochemical system. According to an embodiment of the present invention, referring to Figure 1 and Figure 2 The bioelectrochemical system includes: an anode unit, the anode unit includes at least one spatial directional channel anode 10 as described above, and the surface of the spatial directional channel anode 10 is attached with electroactive microorganisms (not shown in the figure); an electrolyte; a cathode unit 20, the cathode unit 20 is cylindrically arranged around the outside of the anode unit 20. In this way, the anode of the bioelectrochemical system has a large area of ​​microorganisms, so that the carbon skeleton anode has a high-efficiency current collection effect, and after starting the bioelectrochemical system, the directional channel loaded with microorganisms can form a microfluidic reactor, which can enhance the degradation effect of pollutants when sewage flows through, and can improve the chemical energy conversion of sewage and the efficiency of in-situ self-driven resource recovery.

[0069] The bioelectrochemical system (BES) combines electrochemical and biological principles and utilizes the physiological metabolic process of microorganisms on electrodes to achieve wastewater treatment and energy and resource recovery. When the bioelectrochemical system is working, microorganisms oxidize organic matter on the anode to produce electrons and protons. The electrons are transferred to the cathode through the external circuit, and the protons migrate to the cathode, and finally a reduction reaction occurs on the cathode.

[0070] According to some embodiments of the present invention, referring to Figures 3 to 6 The bioelectrochemical system further includes: an ion exchange membrane, which includes at least one anion exchange membrane 32 and at least one cation exchange membrane 31, and the ion exchange membrane is arranged in a columnar shape around the anode unit 10 and the cathode unit 20. Thus, the electric field between the anode and cathode drives the ions to migrate through the corresponding ion exchange membrane, thereby achieving the desalination / resource recovery effect.

[0071] According to some embodiments of the present invention, referring to Figure 1 , Figure 6 and Figure 7 The spatial directional channel anode 10 is cylindrical, and further, the ion exchange membrane and / or cathode unit 20 is cylindrically arranged around the spatial directional channel anode 10. Therefore, a more uniform self-generated electric field can be generated in the cylindrical bioelectrochemical system, and better power generation performance and organic matter removal effect can be obtained compared with the square bioelectrochemical system.

[0072] In some embodiments, the bioelectrochemical system further comprises a closing cover 40, such as Figure 2 As shown, the closed cover plate 40 closes both sides of the cylindrical cathode unit 20, thereby obtaining a closed space defined by the closed cover plate 40 and the cathode unit. In some examples, the closed cover plate 40 can be made of organic glass.

[0073] In some embodiments, the bioelectrochemical system further comprises a closing cover 40, such as Figure 3 As shown, the closed cover plate 40 closes both sides of the cylindrical cathode unit 20, thereby obtaining an anode space defined by the closed cover plate 40 and the ion exchange membrane pair, a cathode space defined by the closed cover plate 40, the ion exchange membrane pair and the cathode unit 20, and a space between the ion exchange membrane pairs. The sewage first enters the anode space and then the cathode space, and the space between the ion exchange membrane pairs uses pure water or NaCl solution as the initial recovery liquid. In some examples, the closed cover plate 40 can be organic glass.

[0074] According to some embodiments of the present invention, the anode unit includes a plurality of spatial directional channel anodes, and the plurality of spatial directional channel anodes may be arranged in series and / or in parallel, and specifically may include the following three situations:

[0075] In some embodiments, reference Figures 1 to 7 , multiple spatial directional channel anodes 10 are connected in series through conductive wires 50. There is no limit on the number of spatial directional channel anodes 10 connected in series, and those skilled in the art can flexibly select according to actual needs. Figures 1 to 7 The example only takes 3 and 5 spatially oriented channel anodes 10 connected in series as an example.

[0076] In other embodiments, referring to Figure 8 , multiple spatial directional channel anodes 10 are arranged in parallel through the conductive wires 50. Among them, there is no limit on the number of parallel spatial directional channel anodes 10, and those skilled in the art can flexibly select according to actual needs. Figure 8 The example in which three spatially oriented channel anodes 10 are connected in parallel is merely taken.

[0077] In some other embodiments, reference Fig. 9 The anode unit includes a plurality of parallel anode combinations 100 (i.e., a plurality of anode combinations 100 are arranged in parallel through conductive threads 50), and each anode combination 100 includes a plurality of spatially oriented channel anodes 10 arranged in series. In this way, the multi-stage series anode configuration is further coupled to design a parallel anode configuration. The anode unit of this configuration can greatly improve the sewage treatment capacity of the system and has good practical application prospects. Among them, there is no limit on the number of spatially oriented channel anodes 10 in the anode combination 100, and those skilled in the art can flexibly choose according to actual needs. Moreover, the number of spatially oriented channel anodes 10 in different anode combinations 100 can be the same or different. Fig. 9 The example in which each anode assembly 100 includes three spatially oriented channel anodes 10 connected in series and three anode assemblies 100 connected in parallel is taken as an example.

[0078] In another aspect of the present invention, the present invention provides a desalination system. According to an embodiment of the present invention, referring to Figure 3 , Figure 4 and Fig.10 The desalination system includes the aforementioned bioelectrochemical system, wherein the ion exchange membrane includes a layer of anion exchange membrane 32 and a layer of cation exchange membrane 31, the anion exchange membrane 32 is cylindrically arranged around the spatial directional channel anode 10, and relative to the cation exchange membrane 31, the anion exchange membrane 32 is arranged close to the spatial directional channel anode 10; the cation exchange membrane 31 is cylindrically arranged around the side of the anion exchange membrane 32 away from the spatial directional channel anode 10, that is, relative to the anion exchange membrane 32, the cation exchange membrane 31 is arranged close to the cathode unit 20. Thus, the desalination system can drive the cations to migrate through the cation exchange membrane and the anions to migrate through the anion exchange membrane by the electric field between the cathode and the anode, thereby effectively realizing the removal of ionic substances and achieving the desalination effect.

[0079] According to some embodiments of the present invention, the desalination system can be used to remove organic matter and ionic substances from sewage, as follows:

[0080] In some embodiments, the desalination system is used to remove organic matter from sewage, and the inlet substrate of the desalination system can be acetate, glucose matrix or municipal sewage. In some embodiments, the current output of the desalination system is set to about 20-50 mA, and after treatment, the COD (chemical oxygen demand) of the effluent can be reduced to below 50 mg / L, the TN (total nitrogen) of the effluent from the desalination room is about below 15 mg / L, the ammonia nitrogen of the effluent is below 5 mg / L, and the TP (total phosphorus) of the effluent is below 0.5 mg / L.

[0081] In other embodiments, the desalination system is used to remove ionic substances (such as sodium chloride). When the NaCl concentration of the influent water in the desalination chamber (the enclosed space defined by the closed cover plate 40 and the ion exchange membrane pair) of the desalination system is about 10-30 g / L, the desalination rate can reach 60-70%.

[0082] In some embodiments of the present invention, the desalinated water produced by the desalination system can be used as industrial boiler feed water to ensure safe and stable operation of the boiler and improve energy utilization efficiency.

[0083] According to an embodiment of the present invention, the material of the cation exchange membrane may be a sulfonic acid type polymer material, and the material of the anion exchange membrane may be a quaternary amine type polymer material.

[0084] In another aspect of the present invention, the present invention provides a concentration system. Figure 3 , Figure 5 and Fig.11The concentration system includes the aforementioned bioelectrochemical system, wherein the ion exchange membrane includes a layer of anion exchange membrane 32 and a layer of cation exchange membrane 31, the cation exchange membrane 31 is cylindrically arranged around the spatial directional channel anode 10, and relative to the anion exchange membrane 32, the cation exchange membrane 31 is arranged close to the spatial directional channel anode 10; the anion exchange membrane 32 is cylindrically arranged around the cation exchange membrane 31 on the side away from the spatial directional channel anode 10, that is, relative to the cation exchange membrane 31, the anion exchange membrane 32 is arranged close to the cathode unit 20. Therefore, the concentration system can drive the cations to migrate through the cation exchange membrane and the anions to migrate through the anion exchange membrane through the electric field between the cathode and the anode, thereby effectively realizing the recovery of ionic substances (such as nitrogen and phosphorus), thereby achieving the purification of sewage and the concentration of resource substances.

[0085] According to some embodiments of the present invention, the concentration system can be used to remove organic matter from sewage and recover ionic substances, as follows:

[0086] In some embodiments, the concentration system is used to remove organic matter from sewage, and the inlet substrate of the concentration system can be acetate, glucose matrix or municipal sewage. In some embodiments, the current output of the concentration system is set to about 20-50 mA, and after treatment, the COD (chemical oxygen demand) of the effluent can be reduced to below 50 mg / L, the TN (total nitrogen) of the effluent from the desalination room is about below 15 mg / L, the ammonia nitrogen of the effluent is below 5 mg / L, and the TP (total phosphorus) of the effluent is below 0.5 mg / L.

[0087] In other embodiments, the concentration system is used for concentrated recovery of ionic substances (such as nitrogen and phosphorus). The concentrations of TN (total nitrogen), ammonia nitrogen and TP (total phosphorus) in the recovered liquid using the concentration system are approximately 1.2-2.0 times, 1.2-2.0 times or even 2-3 times the concentrations in the original sewage, respectively, achieving effective nutrient enrichment and concentration, and achieving the purpose of resource recovery. In some embodiments of the present invention, the recovered liquid produced by the concentration system is rich in nitrogen and phosphorus substances, which can be used for irrigation and fertilization of flowers and vegetation, effectively promoting plant growth.

[0088] In another aspect of the present invention, the present invention provides a desalination-concentration composite system. Figure 6 and Fig.12 The desalination-concentration composite system includes the aforementioned bioelectrochemical system, wherein the ion exchange membrane includes a multilayer anion exchange membrane 32 and a multilayer cation exchange membrane 31, and the multilayer anion exchange membrane 32 and the multilayer cation exchange membrane 31 are both cylindrical and sequentially overlapped and arranged between the spatial directional channel anode 10 and the cathode unit 20. Thus, the system can simultaneously achieve the purification of sewage and the recovery of resources, and improve the treatment efficiency of pollutants.

[0089] The desalination-concentration composite system is based on the aforementioned desalination system and concentration system and embeds multiple groups of anion and cation exchange membrane pairs. The alternatingly arranged anion exchange membranes 32 and cation exchange membranes 32 respectively form multiple desalination and concentration chambers (desalted water is obtained in the desalination chamber, and concentrated liquid is obtained in the concentration chamber). Whenever an electron passes through the external circuit of the system, a pair of anions and cations in each chamber will migrate to the outside / inside of the membrane, thereby doubling the desalination / concentration rate of the system.

[0090] In some embodiments of the present invention, 2 to 10 pairs of anion and cation exchange membranes can be embedded in the desalination-concentration composite system. In some specific embodiments, after 2 to 10 pairs of anion and cation exchange membranes are embedded in the desalination-concentration composite system, the average desalination rate of the cycle can reach 100 mg / h-200 mg / h, and the average electron utilization efficiency can reach 450%-800%.

[0091] According to some embodiments of the present invention, by adopting a stacked configuration in a desalination-concentration composite system, the desalination and concentration effects of the desalination-concentration composite system are expected to be further improved, thereby broadening its application scope to the fields of agricultural fertilizer processing, finished desalted water production, etc.

[0092] In another aspect of the present invention, the present invention provides the use of the above-mentioned desalination system, concentration system or desalination-concentration system in sewage purification and nitrogen and phosphorus recovery.

[0093] Example

[0094] The method for preparing a spatially oriented channel anode comprises:

[0095] 10 mmol of zinc nitrate hexahydrate and 5 mmol of iron (III) acetylacetonate were dissolved in 100 mL of methanol to obtain a first mixed solution, 80 mmol of 2-methylimidazole was dissolved in 100 mL of methanol solution to obtain a second mixed solution, the first mixed solution and the second mixed solution were mixed, stirred continuously for 1 hour and then allowed to stand overnight, and centrifuged and dried to obtain a Fe-ZIF precursor;

[0096] Chitosan powder, water and acetic acid were mixed and stirred for 24 h, and then 0.2 g of Fe-ZIF precursor (or no Fe-ZIF precursor) was added to obtain a cross-linked polymer solution;

[0097] The cross-linked polymer solution is placed in a cylindrical mold with a polytetrafluoroethylene side wall and a brass base (i.e., the prepared anode is cylindrical, corresponding to a cylindrical bioelectrochemical system) for freeze drying, ice crystals grow in a directional and orderly manner during the freezing process, and the ice crystals are removed during the drying process, and then spatially directional and orderly pore channels are obtained, namely, spatially directional channel aerogel;

[0098] The aerogel with spatial directional channels was pyrolyzed at 1000°C for 2 hours at a heating rate of 5°C / min in an argon atmosphere to obtain an iron-doped spatial directional channel anode, which was recorded as Fe-NDCF-x (x is the ratio of polymer in the cross-linked polymer solution), and the spatial directional channel anode without the introduction of iron elements was recorded as DCF-x. The diameter of the spatial directional channel anode is 3 cm and the thickness is 0.5 cm.

[0099] In Examples 1 to 6, the polymer mass concentration in the cross-linked polymer solution and the doping metal conditions can be seen in Table 1.

[0100] Table 1

[0101]

[0102] Comparative Example 1

[0103] Graphite plate (GP) was used as the anode of the bioelectrochemical system.

[0104] Comparative Example 2

[0105] Carbon felt (CF) was used as the anode of the bioelectrochemical system.

[0106] The spatial directional channel anodes obtained in Examples 1 to 6 were subjected to performance tests as follows:

[0107] Scanning electron microscope:

[0108] The surfaces of the spatially oriented channel anodes obtained in Examples 1 to 6 were respectively scanned by electron microscope. The scanning electron microscope images and EDS energy spectrum images can be referred to as Fig.13 (a) to (f) in Fig.13 It can be seen that the surface of the spatially oriented channel anode is a uniform pore distribution structure, indicating that the directional induction of the pore channel is successful, and with the increase of the polymer solution concentration, the internal structure of the spatially oriented channel anode becomes denser.

[0109] The vertical cross-sections of the spatially oriented channel anodes obtained in Examples 1 to 6 were respectively scanned by electron microscope. The scanning electron microscope images and EDS energy spectrum images can be referred to as Fig.14 (a) to (f) in Fig.14 It can be seen that the cross-section of the spatially oriented channel electrode is lamellar.

[0110] Moreover, by Fig.13 (b), (d) and (f) in Fig.14 As can be seen from (b), (d) and (f) in the figure, the addition of Fe-ZIF precursor to the cross-linked polymer solution successfully achieved the attachment of metal to the carbon skeleton surface.

[0111] Electrochemical performance:

[0112] The conductivity of the spatially oriented channel anodes obtained in Examples 1 to 6 was tested respectively. The test results can be found in Fig.15 ; Electrochemical activity tests were performed on the spatially oriented channel anodes obtained in Examples 1 to 6 and the anodes in Comparative Examples 1 and 2, and the test results can be found in Fig.16 .

[0113] Fig.15 It can be shown that the Fe-NDCF-3 anode has the best conductivity. With the increase of the mass concentration of the polymer, the carbon skeleton inside the anode becomes denser, forming more pore channels, thereby improving the conductivity of the anode, and the introduction of iron can further improve the conductivity.

[0114] like Fig.16 As shown, the Fe-NDCF-3 anode has the best electrochemical activity, and its redox current density is the highest, which is far superior to the electrochemical activity of the anodes in Comparative Examples 1 and 2. The maximum oxidation current density of the Fe-NDCF-3 anode is 128.6 A / m 2 , is a DCF-3 anode (maximum oxidation current density is 58.9A / m 2 ), indicating that the introduction of metal active sites effectively enhances the electrochemical activity of the spatially oriented channel anode. In contrast, the redox activity of the oriented channel anode prepared from the precursor solution with a lower polymer concentration is relatively low. The maximum oxidation current density of the Fe-NDCF-2, DCF-2, Fe-NDCF-1, and DCF-1 anodes is 74.5 A / m 2 , 5.7A / m 2 , 11.6A / m 2 and 0.5A / m 2 It can be seen that the formation of a conductive skeleton inside the carbon-based skeleton anode can effectively promote the electrocatalytic activity of the electrode.

[0115] The specific capacitance of different anodes was calculated by CV curves, such as Fig.16 (b) in the figure shows that as the polymer concentration increases, a conductive skeleton gradually forms inside the anode, and the specific capacitance of the anode is significantly improved. The specific capacitance of the Fe-NDCF-3 anode is 2.5 times and 68 times higher than that of the Fe-NDCF-2 anode and the Fe-NDCF-1 anode, and the specific capacitance of the DCF-3 anode is 5.4 times and 153 times higher than that of the DCF-2 anode and the DCF-1 anode. The specific capacitance of the Fe-NDCF-3 anode is twice that of the DCF-3 anode.

[0116] The internal resistance of each anode is measured by EIS test, such as Fig.16(c) and (d) in Figure 2 show that the charge transfer resistance accounts for the main part. As the conductive skeleton gradually forms, the internal resistance of the anode decreases significantly. The charge transfer resistance of the DCF-1 anode is 826.5Ω, the charge transfer resistance of the DCF-2 anode is 55.2Ω, the charge transfer resistance of the DCF-3 anode is 15.5Ω, and the charge transfer resistance of the Fe-NDCF-3 anode is 8.9Ω, which is the lowest.

[0117] Electrochemical performance of the anode after loading microorganisms:

[0118] In Examples 1 to 6 and Comparative Examples 1 and 2, microorganisms are loaded on the anode surface to obtain an anode biofilm, which is a mixed bacterial biofilm with electroactive microorganisms such as Geobacter as an important component. The bioelectrochemical activity test of each bioanode loaded with microorganisms is performed to obtain a CV curve, and the test results can be referred to Fig.17 Therefore, the Fe-NDCF-3 bioanode has the best substrate oxidation intensity, and its maximum oxidation current reaches 31.5A / m 2 , is the maximum oxidation current of DCF-3 (19.1A / m 2 ), while the maximum oxidation current of Fe-NDCF-2 bioanode was 21.7 A / m 2 , is the maximum oxidation current of DCF-2 (12.5A / m 2 ), the maximum oxidation current of Fe-NDCF-1 bioanode reached 18.3 A / m 2 , is the maximum oxidation current of DCF-1 (7.7A / m 2 ) is 2.4 times.

[0119] Polarization curve test:

[0120] The anodes in Examples 1 to 6 and Comparative Examples 1 and 2 were respectively assembled to obtain a bioelectrochemical system without an ion exchange membrane, such as Figure 1 As shown, the simulated influent uses 1g / L sodium acetate as a substrate, the electrolyte is phosphate buffer (PBS), and 5.0mL / L vitamin solution and 12.5mL / L mineral solution are added to maintain the growth of microorganisms. The cathode is an air cathode, which includes a carbon black diffusion layer, an activated carbon carbon black composite catalytic layer, and a stainless steel mesh collector. The anode biofilm is a mixed bacterial biofilm with electroactive microorganisms such as Geobacter as an important component. The external resistance of the bioelectrochemical system was adjusted from 5000Ω to 2Ω step by step, and stabilized for 20 minutes respectively. The output voltage and anode potential were recorded to obtain the polarization curve. The test results can be referred to Fig.18 .

[0121] The power generation performance of the anode bioelectrochemical system with different spatial directional channels can be obtained through polarization curves. The test results can be referred to Fig.18 The maximum power density of the bioelectrochemical system of Fe-NDCF-3 anode reached 3018±133mW / m 2 , is the maximum power density of the bioelectrochemical system with DCF-3 anode (2130±105mW / m 2 ), the maximum power density of the bioelectrochemical system of the Fe-NDCF-2 anode and the maximum power density of the bioelectrochemical system of the Fe-NDCF-1 anode were approximately 1979±124 mW / m 2 and 1228±100mW / m 2 , respectively, compared with the BES of DCF-2 anode (1516±77mW / m 2 ) and BES of DCF-1 anode (571±28mW / m 2 ) increased by about 31% and 115%. At the same time, the maximum current density of the bioelectrochemical system of Fe-NDCF-3 anode is 20.5A / m 2 , which has obvious advantages in all bioelectrochemical systems, while the maximum current density of the bioelectrochemical system with DCF-1 anode is only 2.3A / m 2 .

[0122] Testing of pollutant removal performance and substrate utilization efficiency of bioelectrochemical system:

[0123] The anodes in Examples 1 to 6 and Comparative Examples 1 and 2 were respectively assembled to obtain a bioelectrochemical system without an ion exchange membrane, such as Figure 1 and Figure 2 As shown, the simulated influent uses 1g / L sodium acetate as a substrate, the electrolyte is phosphate buffer (PBS), and 5.0mL / L vitamin solution and 12.5mL / L mineral solution are added to maintain the growth needs of microorganisms. The cathode is an air cathode, which includes a carbon black diffusion layer, an activated carbon carbon black composite catalytic layer, and a stainless steel mesh collector. The anode biofilm is a mixed bacterial biofilm with electroactive microorganisms such as Geobacter as important components.

[0124] The obtained bioelectrochemical system was tested for pollutant removal performance and substrate utilization efficiency. The test results can be referred to Fig.19 .Depend on Fig.19 As shown in (a), the COD degradation effect in Fe-NDCF-3BES is significantly better than that in other bioelectrochemical systems. At the end of the cycle, the effluent COD is about 32 mg / L, and the organic matter is effectively removed. The first-order kinetics fitting of the organic matter degradation in all bioelectrochemical systems is shown in Figure 2. Fig.19 In (b) and (c), the organic matter removal rate constant of Fe-NDCF-3BES is 0.23±0.01h -1Compared with Fe-NDCF-2BES (0.20±0.02h -1 ) and Fe-NDCF-1BES (0.17±0.01h -1 ) were 15% and 35% higher, respectively, and the degradation performance of organic matter was better than that of the corresponding control anode. Fig.19 In (d), the Coulombic efficiencies of DCF-1BES, Fe-NDCF-1BES, DCF-2BES, Fe-NDCF-2BES, DCF-3BES, and Fe-NDCF-3BES are 27%, 31%, 34%, 50%, 50%, and 74%, respectively, indicating that the bioelectrochemical activity of the spatially oriented channel anode is improved with the compactness of the internal carbon skeleton, while promoting the conversion of organic matter into electrical energy.

[0125] The relationship between the current density and the organic matter concentration in different bioelectrochemical systems is analyzed, such as Fig. 20 As shown, the Fe-NDCF-3 bioanode can produce a higher current density than the control at the same organic matter concentration, especially in the low organic matter concentration region below 200 mg / L, indicating that it has the optimal conversion efficiency of organic matter to electrical energy.

[0126] Stability test:

[0127] The anodes in Examples 5 (DCF-3) and 6 (Fe-NDCF-3) were assembled to obtain bioelectrochemical systems without ion exchange membranes, such as Figure 1 and Figure 2 As shown, the simulated influent uses 1g / L sodium acetate as a substrate, the electrolyte is phosphate buffer (PBS), and 5.0mL / L vitamin solution and 12.5mL / L mineral solution are added to maintain the growth needs of microorganisms. The cathode is an air cathode, which includes a carbon black diffusion layer, an activated carbon carbon black composite catalytic layer, and a stainless steel mesh collector. The anode biofilm is a mixed bacterial biofilm with electroactive microorganisms such as Geobacter as important components.

[0128] The stability of the obtained bioelectrochemical system under long-term continuous operation was evaluated. Fig.21 As shown in the long-term current density curve, Fe-NDCF-3BES and DCF-3BES both maintained a relatively stable current output during continuous operation, indicating that these bioelectrochemical systems have good operating stability.

[0129] Example 7

[0130] The difference from Example 6 is that the cathode unit is arranged in a square shape on the opposite side of the anode unit, that is, the obtained bioelectrochemical system is square.

[0131] The power generation performance of the cylindrical bioelectrochemical system and the square bioelectrochemical system were tested respectively. Fig. 22 As shown, it can be seen that the power density of the cylindrical bioelectrochemical system is better than that of the square bioelectrochemical system, indicating that the cylindrical bioelectrochemical system has a better conversion efficiency of organic matter into electrical energy.

[0132] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0133] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0134] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A spatially oriented channel anode, characterized in that: The invention comprises a carbon skeleton having pore channels, and the pore channels extend in a single direction.

2. The spatially oriented channel anode according to claim 1, characterized in that: Also includes a doping metal, wherein the doping metal is attached to the surface of the carbon skeleton, Optionally, the doping metal comprises a transition metal.

3. A method for preparing the spatially oriented channel anode according to claim 1 or 2, characterized in that: include: Mixing the polymer powder with the first solvent and adjusting the solvent to be acidic to obtain a cross-linked polymer solution; Placing the cross-linked polymer solution in a mold with a metal base for freeze drying to obtain an aerogel with spatially oriented channels; The aerogel is subjected to pyrolysis treatment to obtain the spatially oriented channel anode.

4. The method according to claim 3, characterized in that: At least one of the following conditions is met: The mass concentration of the polymer in the cross-linked polymer solution is 0.25% to 5%; The polymer includes at least one of chitosan, sodium alginate and polyvinyl alcohol; The temperature of the pyrolysis treatment is 600°C to 1200°C, and the holding time is 1 to 4 hours; The heating rate of the pyrolysis treatment is 2 to 10°C / min.

5. The method according to claim 3 or 4, characterized in that: Also includes: Metal salts and / or metal-based ZIF precursors are added to the cross-linked polymer solution.

6. The method according to claim 5, characterized in that Based on the total mass of the polymer, the mass concentration of the metal salt in the cross-linked polymer solution is 0.1% to 5%; and / or, based on the total mass of the polymer, the mass concentration of the metal-based ZIF precursor in the cross-linked polymer solution is 0.1% to 2%, And / or, the method for preparing the metal-based ZIF precursor comprises: dissolving zinc nitrate and a metal salt in a second solvent to obtain a first mixed solution; dissolving 2-methylimidazole in a third solvent to obtain a second mixed solution; The first mixed solution and the second mixed solution are mixed and stirred, and centrifuged to obtain the metal-based ZIF precursor.

7. A bioelectrochemical system, characterized in that: include: An anode unit, the anode unit comprising at least one spatially oriented channel anode according to claim 1 or 2, and electroactive microorganisms are attached to the surface of the spatially oriented channel anode; Electrolytes; The cathode unit is in a columnar shape and is arranged around the outer side of the anode unit.

8. The bioelectrochemical system according to claim 7, characterized in that: Also includes: The ion exchange membrane comprises at least one layer of anion exchange membrane and at least one layer of cation exchange membrane. The ion exchange membrane is arranged in a columnar shape around the anode unit and the cathode unit.

9. The bioelectrochemical system according to claim 8, characterized in that: The anode unit comprises a plurality of spatially oriented channel anodes, and the anode unit satisfies one of the following conditions: A plurality of the spatially oriented channel anodes are arranged in series via conductive wires; A plurality of the spatially oriented channel anodes are arranged in parallel via the conductive wires; The anode unit comprises a plurality of parallel anode assemblies, each of which comprises a plurality of spatially oriented channel anodes arranged in series; The spatially oriented channel anode is cylindrical.

10. The bioelectrochemical system according to claim 8, characterized in that: The cathode unit and / or the ion exchange membrane are cylindrical.

11. A desalination system, characterized in that: A bioelectrochemical system comprising any one of claims 8 to 10, wherein the ion exchange membrane comprises an anion exchange membrane and a cation exchange membrane, the anion exchange membrane is cylindrically arranged around the spatial directional channel anode and is arranged close to the spatial directional channel anode, and the cation exchange membrane is cylindrically arranged close to one side of the cathode unit.

12. A concentration system, characterized in that: A bioelectrochemical system comprising any one of claims 8 to 10, wherein the ion exchange membrane comprises an anion exchange membrane and a cation exchange membrane, the cation exchange membrane is cylindrically arranged around the spatial directional channel anode and is arranged close to the spatial directional channel anode, and the anion exchange membrane is cylindrically arranged close to one side of the cathode unit.

13. A desalination-concentration composite system, characterized in that: A bioelectrochemical system comprising any one of claims 8 to 10, wherein the ion exchange membrane comprises a multilayer anion exchange membrane and a multilayer cation exchange membrane, and the multilayer anion exchange membrane and the multilayer cation exchange membrane are both cylindrical and overlapped in sequence between the spatially oriented channel anode and cathode units.

14. Use of the desalination system according to claim 11, the concentration system according to claim 12 or the desalination-concentration system according to claim 13 in sewage purification and resource recovery.

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