A ferroelectrically coupled algal-bacterial microbial fuel cell, a preparation method and application thereof, and a wastewater treatment method

Abstract

The application provides a ferroelectrolysis coupled algal-bacterial microbial fuel cell and a preparation method and application thereof and a wastewater treatment method, and belongs to the technical field of wastewater treatment. The IE-MFC (ferroelectrolysis coupled algal-bacterial microbial fuel cell) comprises an anode chamber, a cathode chamber and a ferroelectrolysis chamber arranged in sequence, the anode chamber and the cathode chamber are separated by a proton exchange membrane, the cathode chamber and the ferroelectrolysis chamber are separated by a cation exchange membrane, and the surface of the anode is fixed with an anaerobic microbial membrane; and the surface of the cathode is fixed with a synechococcus. The application introduces a ferroelectrolysis and algal-bacterial symbiotic system, a microelectric field generated internally can stimulate and strengthen the metabolic activity of microorganisms, the biological metabolism of algal bacteria and the synergistic effect of the electric field decompose sulfamethoxazole, and at the same time, ferrous ions are generated in situ by ferroelectrolysis, and the ferrous ions trigger the generation of hydroxyl radicals with strong oxidizability by combining with oxygen generated by the photosynthesis of synechococcus in the cathode area, so that the mineralization of refractory intermediates is realized, and a three-synergistic degradation mechanism of "biodegradation-microelectric field-ferroelectrolysis" is formed.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an iron electrolysis coupled algae-microorganism fuel cell, its preparation method and application, and a wastewater treatment method. Background Technology

[0002] Sulfamethoxazole (SMX), a widely used sulfonamide antibiotic, has become a focal point of environmental science and public health concerns regarding its residues and removal from the environment. It primarily enters urban wastewater treatment systems through pharmaceutical industrial wastewater, medical wastewater, livestock farming emissions, and human metabolites, ultimately remaining partially in the aquatic environment. Exhibiting clear ecotoxicity, it accumulates through the food chain, disrupting the balance of higher trophic levels of fish and even the entire aquatic ecosystem. Furthermore, it promotes the development and spread of antibiotic resistance genes within the ecosystem, leading to antibiotic resistance in environmental microorganisms. This not only threatens human health but also poses potential harm to ecosystems, constituting a series of potentially far-reaching hazards.

[0003] Faced with this challenge, traditional urban wastewater treatment processes (such as conventional activated sludge processes) have limited removal capacity, thus necessitating the reliance on more efficient and targeted advanced treatment technologies. Current research and applications mainly focus on advanced oxidation processes and bioaugmentation treatment methods.

[0004] Advanced oxidation processes (AOPs) generate highly reactive oxidizing species such as hydroxyl radicals or sulfate radicals in water through ozone, persulfate, photocatalysis, or electrochemistry. These radicals can non-selectively attack and break down the stable structures of SMX, such as benzene rings and sulfonamide bonds, mineralizing it into carbon dioxide, water, and inorganic ions, achieving complete degradation and avoiding secondary pollution. This technology is highly efficient and thorough, but the equipment investment and operating energy consumption are relatively high. Bioenhanced treatment involves adding specific, domesticated, and screened highly efficient degrading strains to the biological treatment system, or optimizing the microbial community structure, to enhance the system's biodegradation capacity for SMX. Although this method has lower operating costs and is environmentally friendly, the inherent antibacterial properties of SMX inhibit the growth of ordinary microbial communities, resulting in a slow and unstable biodegradation process. It also has stringent requirements for operating conditions (such as temperature, pH, and sludge age), posing significant challenges for large-scale engineering applications.

[0005] In conclusion, the environmental risks of SMX should not be underestimated. Effective treatment of its wastewater requires comprehensive consideration of water quality characteristics, treatment requirements, and economic costs to ensure water environment safety and public health. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide an iron electrolysis coupled algae-microorganism fuel cell, its preparation method and application, and a wastewater treatment method. The iron electrolysis coupled algae-microorganism fuel cell of this invention achieves efficient degradation of SMX through the combined effects of biodegradation, micro-electric field, and iron electrolysis.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides an iron electrolysis coupled algae-microorganism fuel cell, comprising: The anode chamber, cathode chamber, and iron electrolysis chamber are arranged in sequence. The anode chamber and cathode chamber are separated by a proton exchange membrane, and the cathode chamber and iron electrolysis chamber are separated by a cation exchange membrane. The iron electrolysis chamber is equipped with a top cover. The anode chamber is equipped with an anode, and an anaerobic microbial film is fixed on the surface of the anode; The cathode chamber is equipped with a cathode, and the surface of the cathode is fixed with Algae; The anode and cathode are connected by titanium wire.

[0008] Preferably, the anode chamber is provided with an anode chamber inlet and an anode chamber outlet.

[0009] Preferably, the outlet of the anode chamber is connected to the cathode chamber via a one-way check valve.

[0010] Preferably, the cathode chamber is provided with a cathode chamber outlet.

[0011] Preferably, the titanium wire is connected to a resistor, and the anode, cathode, titanium wire, and resistor form a closed circuit.

[0012] This invention also provides a method for preparing the iron electrolysis coupled algae-bacterial microbial fuel cell described in the above technical solution, comprising the following steps: Anaerobic bacteria were inoculated onto the anode electron collector, and Algae were inoculated onto the cathode electron collector. Then, biofilms were attached to obtain the anode and cathode, respectively. The anode, cathode, anode chamber, cathode chamber, ferroelectrolysis chamber, proton exchange membrane, cation exchange membrane, and titanium wire are assembled to obtain the ferroelectrolysis coupled algae-microorganism fuel cell.

[0013] The present invention also provides the application of the iron electrolysis coupled algae-bacteria microbial fuel cell described in the above technical solution in the field of wastewater treatment, wherein the wastewater contains antibiotics.

[0014] This invention also provides a wastewater treatment method, utilizing the iron electrolysis coupled with an algae-bacterial microbial fuel cell described in the above technical solution, comprising the following steps: Wastewater is introduced into the anode chamber, and elemental iron and an inorganic acid solution are added to the iron electrolysis chamber. The wastewater contains sulfamethoxazole.

[0015] Preferably, the inorganic acid solution includes a sulfuric acid solution for degradation, and the concentration of the sulfuric acid solution is 0.002~0.75 g / L.

[0016] Preferably, the ratio of elemental iron to sulfuric acid solution is 0.5~2.0g:20mL.

[0017] This invention provides an iron electrolysis coupled algae-microorganism fuel cell (IE-MFC), comprising: an anode chamber, a cathode chamber, and an iron electrolysis chamber arranged sequentially, wherein the anode chamber and the cathode chamber are separated by a proton exchange membrane (PEM), and the cathode chamber and the iron electrolysis chamber are separated by a cation exchange membrane, and the iron electrolysis chamber is provided with a top cover; an anode is provided in the anode chamber, and an anaerobic microbial membrane is fixed on the surface of the anode; a cathode is provided in the cathode chamber, and algae are fixed on the surface of the cathode; the anode and the cathode are connected by titanium wires.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention relates to an integrated and innovative water treatment technology: an iron electrolysis-coupled algae-microorganism fuel cell. It introduces an iron electrolysis and algae-microorganism symbiotic system into a traditional microbial fuel cell. The internally generated micro-electric field stimulates and enhances the metabolic activity of the microorganisms. The synergistic effect of the algae-microorganisms' biometabolism and the electric field decomposes sulfamethoxazole. Simultaneously, ferrous ions are generated in situ through iron electrolysis. These ions react with oxygen produced by the photosynthesis of algae in the cathode area, triggering the generation of highly oxidizing hydroxyl radicals, thus mineralizing recalcitrant intermediate products. This forms a three-way synergistic degradation mechanism of "biodegradation-micro-electric field-iron electrolysis." This invention constructs a complete material cycle chain: the anode degrades organic matter to generate electricity; the cathode algae produce oxygen and absorb nutrients such as carbon, nitrogen, and phosphorus; and the cyclical iron ions participate in catalytic reactions, forming a highly efficient and synergistic pollutant removal network. This three-way synergistic treatment mechanism effectively addresses the bioinhibition of antibiotics and overcomes the limitations of low efficiency in traditional biological treatment methods. Furthermore, the operating cost is significantly lower than advanced oxidation processes that require continuous chemical dosing, and it produces low sludge and has good environmental compatibility.

[0019] This invention provides a green solution for treating antibiotic-containing wastewater by combining pollutant degradation, energy recovery, and resource reuse, offering a sustainable development direction in the field of deep treatment of recalcitrant organic wastewater. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the iron electrolysis coupled algae and bacteria microbial fuel cell described in this invention; Figure 2 The graph shows the degradation rate of SMX as a function of the initial concentration of SMX. Figure 3The graph shows the degradation rate of SMX as a function of HRT. Figure 4 The graph shows the degradation rate of SMX as a function of sulfuric acid solution concentration. Figure 5 The graph shows the change in SMX degradation rate with the amount of iron filings added. In the diagram: 1 is the anode chamber, 2 is the cathode chamber, 3 is the iron electrolysis chamber, 4 is the proton exchange membrane, 5 is the anode, 6 is the cathode, 7 is the titanium wire, 8 is the resistor, 9 is the anode chamber inlet, 10 is the anode chamber outlet, 11 is the one-way check valve, 12 is the cathode chamber outlet, and 13 is the cation exchange membrane. Detailed Implementation

[0021] This invention provides an iron electrolysis coupled algae-microorganism fuel cell, comprising: The anode chamber, cathode chamber, and iron electrolysis chamber are arranged in sequence. The anode chamber and cathode chamber are separated by a proton exchange membrane, and the cathode chamber and iron electrolysis chamber are separated by a cation exchange membrane. The iron electrolysis chamber is equipped with a top cover. The anode chamber is equipped with an anode, and an anaerobic microbial film is fixed on the surface of the anode; The cathode chamber is equipped with a cathode, and the surface of the cathode is fixed with Algae; The anode and cathode are connected by titanium wire.

[0022] Figure 1 This is a schematic diagram of the structure of the iron electrolysis coupled algae-microorganism fuel cell described in this invention, wherein: 1 is the anode chamber, 2 is the cathode chamber, 3 is the iron electrolysis chamber, 4 is the proton exchange membrane, 5 is the anode, 6 is the cathode, 7 is the titanium wire, 8 is the resistor, 9 is the anode chamber inlet, 10 is the anode chamber outlet, 11 is the one-way check valve, 12 is the cathode chamber outlet, and 13 is the cation exchange membrane. The following is a detailed description... Figure 1 The iron electrolysis coupled algae and bacteria microbial fuel cell of the present invention will be described.

[0023] In this invention, the anode chamber is preferably provided with an anode chamber inlet and an anode chamber outlet.

[0024] In this invention, the outlet of the anode chamber is connected to the cathode chamber via a one-way check valve.

[0025] In this invention, the cathode chamber is provided with a cathode chamber outlet.

[0026] In this invention, the titanium wire is connected to a resistor, and the anode, cathode, titanium wire, and resistor form a closed circuit.

[0027] In this invention, the resistor is preferably 1KΩ.

[0028] In this invention, both the anode and the cathode preferably include an electron collector, which is preferably a carbon felt, and the carbon felt is preferably 4×10×0.3cm in size.

[0029] In this invention, the anaerobic microorganisms in the anaerobic microbial membrane are preferably derived from the anaerobic bacterial solution in the anaerobic pool of a sewage treatment plant; the *Echinochloa spp.* are preferably purchased from the Freshwater Algae Bank of the Chinese Academy of Sciences (National Aquatic Germplasm Bank Freshwater Algae Bank, FACHB), with the number FACHB-994.

[0030] In this invention, the anode generates electricity by degrading organic matter, while algae in the cathode produce oxygen and absorb nutrients such as carbon, nitrogen, and phosphorus. Iron ions cycle and participate in the catalytic reaction, forming a highly efficient and synergistic pollutant removal network. This three-way synergistic treatment mechanism effectively addresses the bioinhibition of antibiotics and overcomes the limitations of low efficiency in traditional biological treatment methods. Simultaneously, the system's operating cost is significantly lower than advanced oxidation processes that require continuous chemical dosing, and it produces low sludge production and exhibits good environmental compatibility.

[0031] This invention also provides a method for preparing the iron electrolysis coupled algae-bacterial microbial fuel cell described in the above technical solution, comprising the following steps: Anaerobic bacteria were inoculated onto the anode electron collector, and Algae were inoculated onto the cathode electron collector. Then, biofilms were attached to obtain the anode and cathode, respectively. The anode, cathode, anode chamber, cathode chamber, ferroelectrolysis chamber, proton exchange membrane, cation exchange membrane, and titanium wire are assembled to obtain the ferroelectrolysis coupled algae-microorganism fuel cell.

[0032] In this invention, the proton exchange membrane and cation exchange membrane are preferably pretreated before use. The pretreatment preferably includes immersing the proton exchange membrane and cation exchange membrane in a 5wt% NaCl solution for 24 hours, and then washing them with distilled water 4 to 5 times.

[0033] In this invention, the carbon felt is preferably pretreated before use. The pretreatment includes soaking it in a 1mM HCl solution for 24 hours, then soaking it in deionized water and rinsing it 4-5 times, and finally drying it in a 105°C oven for later use.

[0034] In this invention, the supernatant is discarded after the bacterial solution from the anaerobic tank of a sewage treatment plant has been settled for 30 minutes. The remaining material is then mixed with wastewater, and the resulting mixed bacterial solution is used for anode inoculation.

[0035] In this invention, the wastewater treatment plant is preferably a domestic wastewater treatment plant.

[0036] In this invention, the volume ratio of the remaining material to the wastewater is preferably 0.3:1.

[0037] In this invention, the wastewater preferably contains 475 mg / L glucose, 649 mg / L sodium acetate, 88 mg / L KH2PO4 and 593 mg / L NH4Cl.

[0038] In this invention, 250 mL of Alternaria solani culture medium (SE medium) in the logarithmic growth phase is preferably used for cathode inoculation.

[0039] After the anode and cathode inoculation are completed, the present invention preferably places the obtained device in an incubator, maintains the temperature at 25°C and the light cycle at 12h, and performs the membrane attachment.

[0040] In this invention, the preferred time for the film to attach is 7 to 10 days, specifically 7, 8, 9 or 10 days.

[0041] The present invention also provides the application of the iron electrolysis coupled algae-bacteria microbial fuel cell described in the above technical solution in the field of wastewater treatment, wherein the wastewater contains antibiotics.

[0042] In this invention, the iron electrolysis coupled algae-microbial fuel cell is preferably started up before use. The start-up preferably includes the following steps: using a peristaltic pump to pump simulated wastewater into the anode chamber inlet at a flow rate of 0.15~0.2mL / min, the effluent is discharged into the cathode chamber for further treatment through the anode chamber outlet and a one-way check valve, and the cathode chamber effluent is finally discharged from the cathode chamber outlet. The start-up is completed when the load output voltage stabilizes at 400mV or above after 8~9 days.

[0043] In this invention, the simulated wastewater preferably contains 475 mg / L glucose, 649 mg / L sodium acetate, 88 mg / L KH2PO4 and 593 mg / L NH4Cl.

[0044] This invention also provides a wastewater treatment method, utilizing the iron electrolysis coupled with an algae-bacterial microbial fuel cell described in the above technical solution, comprising the following steps: Wastewater is introduced into the anode chamber, and elemental iron and an inorganic acid solution are added to the iron electrolysis chamber for degradation. The wastewater contains sulfamethoxazole.

[0045] In this invention, the inorganic acid solution includes a sulfuric acid solution, and the concentration of the sulfuric acid solution is preferably 0.002~0.75 g / L, specifically 0.002, 0.01, 0.05, 0.25, 0.5 or 0.75 g / L.

[0046] In this invention, the preferred ratio of elemental iron to sulfuric acid solution is 0.5~2.0g:20mL, specifically 0.5g:20mL, 1.0g:20mL, 1.5g:20mL or 2.0g:20mL.

[0047] In this invention, the elemental iron preferably includes iron filings.

[0048] In this invention, the hydraulic retention time (HRT) of the degradation is preferably 6 to 72 hours, specifically 6, 12, 24, 48 or 72 hours.

[0049] In this invention, the concentration of sulfamethoxazole in the wastewater is preferably 20~100 μg / L, specifically 20, 40, 60, 80 or 100 μg / L.

[0050] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0051] Example 1 preparation Figure 1 The iron electrolysis coupled algae-microbe fuel cell structure shown includes the following steps: The proton exchange membrane and cation exchange membrane were immersed in 5 wt% NaCl solution for 24 h, and then rinsed 4 times with distilled water. The anode carbon felt and cathode carbon felt were pre-soaked in 1 mM HCl solution for 24 h, then soaked and rinsed 4 times with deionized water, and dried in an oven at 105 ℃ for later use. The carbon felt had a size of 4 × 10 × 0.3 cm.

[0052] After settling the anaerobic bacterial solution from a domestic wastewater treatment plant for 30 minutes, the supernatant was discarded. This supernatant was then mixed with wastewater at a 30% volume ratio (containing 475 mg / L glucose, 649 mg / L sodium acetate, 88 mg / L KH₂PO₄, and 593 mg / L NH₄Cl). 250 mL of this mixed bacterial solution was used for anode inoculation. *Echinochloa spp.* was purchased from the Freshwater Algae Culture Bank of the Chinese Academy of Sciences (FACHB-994). 250 mL of *Echinochloa spp.* culture medium (SE) during its logarithmic growth phase was used for cathode inoculation. The apparatus was placed in an incubator at 25°C with a 12-hour photoperiod, and biofilm formation was completed in 7 days.

[0053] Start-up: Simulated wastewater (containing 475 mg / L glucose, 649 mg / L sodium acetate, 88 mg / L KH2PO4, and 593 mg / L NH4Cl) is pumped into the anode chamber inlet at a flow rate of 0.15 mL / min using a peristaltic pump. The effluent from the anode chamber is discharged into the cathode chamber for further treatment through the anode chamber outlet and a one-way check valve. The effluent from the cathode chamber is finally discharged from the cathode chamber outlet. Start-up is complete when the load output voltage stabilizes above 400 mV after 8 days.

[0054] After startup, single-factor optimization experiments were conducted. The effects of different initial SMX concentrations, HRT, sulfuric acid solution concentration in the iron electrolysis chamber, and iron addition on SMX degradation by IE-MFC are shown in [reference needed]. Figures 2-5 The iron filings used were 40 mesh. The preparation method of the iron filings is as follows: wash them twice with dilute sulfuric acid while stirring to remove the surface oxide layer, and then filter and collect them with filter paper.

[0055] When HRT=12h, the degradation of SMX by IE-MFC with respect to the initial concentration of SMX is as follows: Figure 2 As shown, the sulfuric acid solution concentration in the iron electrolysis chamber was 0.002 g / L, 20 mL, and the amount of iron added was 1.0 g. With the increase of the initial concentration, the degradation rate of SMX by IE-MFC continued to increase. When the initial concentration reached 60 μg / L, the degradation rate reached the maximum value of 68%. With the further increase of the initial concentration, the degradation rate decreased.

[0056] When the SMX concentration was 60 μg / L, the sulfuric acid solution concentration in the iron electrolysis chamber was 0.002 g / L, 20 mL, and the added iron amount was 1.0 g, the degradation of SMX with changes in HRT was as follows: Figure 3 As shown, with continuous extension of HRT, the degradation gradually tended to stabilize at 48h, with a degradation rate of 77%.

[0057] Further optimization of iron electrolysis parameters was performed by adding 1.0 g of iron filings and 20 mL of dilute sulfuric acid solution (0.002~0.75 g / L) to the electrolysis chamber, with an SMX concentration of 60 μg / L and an HRT of 48 h. Figure 4 It can be seen that the degradation rate of SMX is the highest, at 83%, when the concentration of sulfuric acid solution in the iron electrolysis chamber is 0.05 g / L.

[0058] Under the conditions of sulfuric acid solution concentration of 0.05 g / L and 20 mL, the amount of iron filings added was varied, with no iron added as a control, and the SMX concentration added was 60 μg / L, with an HRT of 48 h. According to... Figure 5 It can be seen that the degradation rate of SMX increases significantly after the addition of iron, with a degradation rate of 83% when 1.0g of iron is added; the optimal degradation rate is achieved when 1.5g of iron is added, with a degradation rate of 86%. This indicates that the Fe produced by the corrosion of iron filings... 2+ It enters the cathode chamber and reacts with H under micro-electric field and aerobic conditions. + The hydroxyl radicals formed by the reaction non-selectively attack and break the stable structures of sulfamethoxazole, such as the benzene ring and sulfonamide bond, further enhancing SMX degradation and achieving the combined effects of biodegradation, micro-electric field and iron electrolysis.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wastewater treatment method, characterized in that, The method of using an iron electrolysis coupled with an algae-microbe fuel cell includes the following steps: Wastewater is introduced into the anode chamber, and elemental iron and inorganic acid solution are added to the iron electrolysis chamber for degradation. The wastewater contains sulfamethoxazole. The inorganic acid solution includes a sulfuric acid solution with a concentration of 0.05 g / L; The ratio of elemental iron to sulfuric acid solution is 1.5g:20mL; The iron electrolysis coupled algae-microbial fuel cell is specifically: The anode chamber, cathode chamber, and iron electrolysis chamber are arranged in sequence. The anode chamber and cathode chamber are separated by a proton exchange membrane, and the cathode chamber and iron electrolysis chamber are separated by a cation exchange membrane. The iron electrolysis chamber is equipped with a top cover. The anode chamber is equipped with an anode, and an anaerobic microbial film is fixed on the surface of the anode; The cathode chamber is equipped with a cathode, and the surface of the cathode is fixed with Algae; The anode and cathode are connected by titanium wire; The proton exchange membrane and cation exchange membrane are pretreated before use. The pretreatment includes immersing the proton exchange membrane and cation exchange membrane in a 5wt% NaCl solution for 24 hours and then washing them with distilled water 4 times. The iron element is iron filings that pass through a 40-mesh screen. The iron filings are prepared as follows: they are washed twice with dilute sulfuric acid by stirring to remove the surface oxide layer, and then collected by filtration through filter paper. The anode chamber is provided with an anode chamber inlet and an anode chamber outlet, and the anode chamber outlet is connected to the cathode chamber through a one-way check valve.

2. The wastewater treatment method according to claim 1, characterized in that, The cathode chamber is equipped with a cathode chamber outlet.

3. The wastewater treatment method according to claim 1, characterized in that, The titanium wire is connected to the resistor, and the anode, cathode, titanium wire and resistor form a closed circuit.

4. The wastewater treatment method according to claim 1, characterized in that, The preparation method of the iron electrolysis coupled algae-microbial fuel cell includes the following steps: Anaerobic bacteria were inoculated onto the anode electron collector, and Algae were inoculated onto the cathode electron collector. Then, biofilms were attached to obtain the anode and cathode, respectively. The anode, cathode, anode chamber, cathode chamber, ferroelectrolysis chamber, proton exchange membrane, cation exchange membrane, and titanium wire are assembled to obtain the ferroelectrolysis coupled algae-microorganism fuel cell.

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