New method for generating electricity by treating landfill leachate through basic zinc carbonate template porous carbon anode double-chamber MFC
By preparing alkaline zinc carbonate template porous carbon as an anode catalyst, the construction of a dual-chamber MFC was solved, and the existing MFC anode materials were complex and costly were achieved, and efficient power generation and pollutant degradation effects were achieved.
Patent Information
- Application Number
- CN202510488021.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2025-07-22
AI Technical Summary
The existing MFC anode material preparation method is complex and costly, and the power generation capacity and pollutant degradation effect are limited when dealing with actual wastewater.
Porous carbon materials were prepared as an anode catalyst by alkali zinc carbonate template method, and dual-chamber MFC was constructed with carbon cloth matrix, and aging waste leachate was used as matrix to run microbial fuel cells.
Porous carbon materials with high specific surface area and pore volume have been achieved, which significantly improves the power production performance of MFC and the removal rate of COD and ammonia nitrogen in wastewater, and the color of wastewater is also significantly reduced.
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Figure CN120356993A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a new method for generating electricity by treating landfill leachate with a zinc hydroxycarbonate template porous carbon anode dual-chamber MFC, belonging to the technical fields of inorganic environmental materials and wastewater resource utilization. Background Art
[0002] A microbial fuel cell (MFC) is an innovative renewable energy technology that uses the metabolism of microorganisms on organic matter in wastewater to simultaneously achieve the degradation of pollutants and electricity generation. At present, MFC has been widely studied in fields such as municipal sewage, oil-based mud waste liquid, and livestock wastewater. However, the limited electricity generation capacity and pollutant degradation effect of MFC have hindered the further development of its application research. The anode, as the reaction interface between microorganisms and the electrode, is a key parameter affecting the electricity generation and pollutant removal performance of MFC. It generates electrons and protons by oxidizing organic compounds in the anode chamber through a microbial biofilm. The anode material directly affects the electron transfer rate and microbial attachment effect of MFC, thereby affecting the electricity generation and pollutant degradation performance of MFC. Due to good biocompatibility, large specific surface area, and stable performance, carbon-based materials have always been an important topic in the exploration of composite anode materials. Common carbon-based materials include graphene, carbon nanotubes, and porous carbon. Among them, porous carbon materials have been widely used in the field of MFC due to their low price and excellent performance.
[0003] Currently, researchers have prepared porous carbon materials by methods such as activation method, hydrothermal carbonization method, and template method to optimize the performance of porous carbon materials. For example, in the article "Activated carbon derived from rice husk as efficient oxygen reduction catalyst in microbial fuel cell" on pages 2969 - 2975 of Volume 32 of "Electroanalysis" in 2020, the rice husk-based porous carbon prepared by hydrolysis, activation, and rolling has a specific surface area and pore volume of 1809 m 2 / g and 1.198 cm 3 / g. The disadvantages of this method are as follows: (1) The preparation method is complex and costly. The rice husk raw material needs to be treated with concentrated sulfuric acid first and then activated at high temperature; (2) The substrate of the MFC constructed in the article is simulated wastewater rather than actual wastewater, and the degradation effect of the MFC on the pollution indicators in the wastewater after operation is not explored. Another example is the article "Magnesium oxide-templated coal-based porous carbon as a novel anode for high-performance microbial fuel cell treatment" in "Process Safety and Environmental Protection", Volume 195, No. 106764 in 2025. A coal-based porous carbon catalytic material was prepared using MgO as a template in combination with a KOH activator for MFC to treat mixed wastewater, achieving a maximum output voltage of 633 mV and a chemical oxygen demand (COD) removal of 46.1%. However, this method has the following deficiencies: (1) The specific surface area of the prepared porous carbon material is relatively small, only 1149 m 2 / g; (2) The removal efficiency of the coal-based carbon MFC for single wastewater is not clear. Summary of the Invention
[0004] The object of the present invention is to prepare a porous carbon material with low cost and excellent performance for the MFC anode, so that the wastewater can be effectively degraded while generating electricity. The present invention proposes the following methods for the preparation of the porous carbon material for the MFC anode and the assembly and operation of the MFC:
[0005] (1) Preparation of the ash-free anthracite as the carbon source of the porous carbon material
[0006] Place the anthracite coal sample in a mortar, grind it for 30 minutes and then screen it to obtain a coal sample with a mesh size of -200. The coal sample is pickled successively with 4 mol / L hydrochloric acid and 10 wt% hydrofluoric acid. After washing away the excess acid with distilled water, it is placed in a blast drying oven and dried at 50 °C for 12 h to obtain the ash-free anthracite.
[0007] (2) Preparation of the zinc hydroxycarbonate template porous carbon
[0008] Weigh 1 g of deashed anthracite, 3 g of KOH, and 0.5 g of basic zinc carbonate into a 100 mL beaker, add 50 mL of ethanol to form a suspension, ultrasonicate for 30 min, stir magnetically for 2 h, and obtain a black mixture after drying; place the mixture in a tube furnace, under the condition of a heating rate of 5 °C / min, after introducing N2, first heat up to 300 °C for pyrolysis for 30 min, then continue to heat up to 800 °C for activation for 2 h, and after natural cooling to room temperature, wash with 4 mol / L hydrochloric acid and deionized water three times respectively, and vacuum dry at 60 °C to obtain basic zinc carbonate template porous carbon (CPC-ZHC); without using the basic zinc carbonate template agent and replacing the basic zinc carbonate with an equal mass of ZnO, the above method can be used to prepare porous carbon (CPC) and zinc oxide template porous carbon (CPC-ZnO) respectively.
[0009] (3) Pretreatment of carbon cloth substrate
[0010] Cut the carbon cloth into small pieces of 2×3 cm with clean scissors, ultrasonically clean them successively with absolute ethanol and a sulfuric acid-nitric acid mixed solution with a volume ratio of 3:1, then wash them with distilled water, put them into a blast drying oven and dry at 60 °C, and calcine them in a muffle furnace at 300 °C for 4 h to obtain the carbon cloth substrate (CC).
[0011] (4) Preparation of basic zinc carbonate template porous carbon electrode
[0012] Mix 18 mg of basic zinc carbonate template porous carbon, 300 μL of absolute ethanol, 150 μL of ethylene glycol, and 100 μL of 5% Nafion solution, ultrasonically treat for 30 min to obtain a mixed ink, evenly coat the mixed ink onto the carbon cloth substrate with a pipette, and dry in a blast drying oven at 60 °C for 24 h to obtain a basic zinc carbonate template porous carbon catalyst anode.
[0013] Replace the basic zinc carbonate template porous carbon with an equal amount of zinc oxide template porous carbon and porous carbon, and zinc oxide template porous carbon catalyst anode and porous carbon catalyst anode can be obtained. The MFC cathode directly uses the pretreated carbon cloth substrate.
[0014] (5) Construction of CPC-ZHC-MFC system
[0015] Select a double-chamber MFC made of plexiglass, the effective volume of both the anode chamber and the cathode chamber is 800 mL, the two chambers are connected by a flange, and the flange is separated by a proton exchange membrane (Dupont Nafion N117). The cathode and anode form a closed circuit with an external resistor with a resistance value of 1 kΩ through titanium wires, and a data acquisition card is connected in parallel at both ends of the external resistor to record the voltage data during the operation of the MFC.
[0016] (6) Start-up of double-chamber MFC
[0017] Add 500 mL of anodic inoculum (250 mL of anaerobic sludge mixed with 250 mL of 0.1 mol / L phosphate buffer solution) to the anodic chamber of the MFC, add 8.75 mL of nutrients (6.25 mL of trace metal solution mixed with 2.5 mL of vitamin solution) to maintain the growth of microorganisms in the anodic chamber, and add 500 mL of potassium ferricyanide phosphate buffer solution (250 mL of 0.05 mol / L potassium ferricyanide solution mixed with 250 mL of 0.05 mol / L phosphate buffer solution) to the cathodic chamber; when it is observed that the output voltage of the MFC rapidly drops below 50 mV, it is regarded as the completion of the startup of the MFC.
[0018] (7) Operation of a microbial fuel cell with landfill leachate as the substrate
[0019] Replace the anaerobic sludge substrate in the anodic chamber with 500 mL of landfill leachate, and at the same time, replace the cathodic chamber with a new potassium ferricyanide phosphate buffer solution (500 mL). Operate the MFC at room temperature and constant pressure, use a data acquisition instrument to record its output voltage, and measure the chemical oxygen demand (COD), ammonia nitrogen, and chromaticity value of the wastewater before the start of operation and after the end of operation, respectively.
[0020] The present invention adopts the above technical solutions and mainly has the following effects:
[0021] (1) The anodic catalyst of the CPC-ZHC microbial fuel cell prepared by the method of the present invention has a relatively high specific surface area (2323.73 m 2 / g) and pore volume (1.09 cm 3 / g). When degrading with aged landfill leachate as the substrate, it can achieve 41.4% and 54.7% degradation of COD and ammonia nitrogen in the wastewater respectively after one cycle of operation, and at the same time, the chromaticity of the wastewater is reduced from 800 times to 80 times.
[0022] (2) The CPC-ZHC electrode prepared by the present invention can improve the power generation performance when the MFC treats wastewater, and can significantly enhance the power generation performance compared with the CC electrode without the loaded catalyst.
[0023] (3) The anodic catalyst prepared by the present invention can be directly used for the degradation of actual wastewater and has a relatively high application prospect. Description of the Drawings
[0024] Figure 1 X-ray diffraction patterns of CPC, CPC-ZnO, and CPC-ZHC;
[0025] Figure 2 N2 adsorption-desorption curves of CPC, CPC-ZnO, and CPC-ZHC;
[0026] Figure 3 Schematic diagram of a dual-chamber microbial fuel cell device;
[0027] Figure 4 Output voltage variation curves with time for a two-chamber MFC with different anode catalysts;
[0028] Figure 5 Power density curves of a two-chamber MFC with different anode catalysts. Detailed implementation manners
[0029] The present invention will be further described below in conjunction with the detailed implementation manners.
[0030] Example 1
[0031] A method for electricity generation by treating landfill leachate using a zinc hydroxycarbonate template porous carbon anode two-chamber MFC, the specific steps are as follows:
[0032] (1) Preparation of deashed anthracite, the carbon source of the porous carbon material
[0033] Place the anthracite coal sample in a mortar, grind it for 30 min and then screen it to obtain a -200 mesh coal sample; successively pickle the coal sample with 4 mol / L hydrochloric acid and 10 wt% hydrofluoric acid, wash away the excess acid with distilled water, and then place it in a blast drying oven to dry at 50 °C for 12 h to obtain deashed anthracite.
[0034] (2) Preparation of zinc hydroxycarbonate template porous carbon
[0035] Weigh 1 g of deashed anthracite, 3 g of KOH and 0.5 g of zinc hydroxycarbonate and place them in a 100 mL beaker, add 50 mL of ethanol to form a suspension, ultrasonicate for 30 min, stir magnetically for 2 h, and obtain a black mixture after drying; place the mixture in a tube furnace, under the condition of a heating rate of 5 °C / min, after introducing N2, first heat it to 300 °C and pyrolyze for 30 min, then continue to heat it to 800 °C and activate for 2 h, and after natural cooling to room temperature, wash it 3 times with 4 mol / L hydrochloric acid and deionized water respectively, and vacuum dry at 60 °C to obtain zinc hydroxycarbonate template porous carbon (CPC-ZHC); without using the zinc hydroxycarbonate templating agent and replacing zinc hydroxycarbonate with an equal mass of ZnO, the porous carbon (CPC) and zinc oxide template porous carbon (CPC-ZnO) can be prepared respectively by the aforementioned method.
[0036] (3) Pretreatment of the carbon cloth substrate
[0037] Cut the carbon cloth into small pieces of 2×3 cm with clean scissors, ultrasonically clean it successively with absolute ethanol and a sulfuric acid-nitric acid mixed solution with a volume ratio of 3:1, wash it with distilled water again, then put it into a blast drying oven to dry at 60 °C, and calcine it in a muffle furnace at 300 °C for 4 h to obtain the carbon cloth substrate (CC).
[0038] (4) Preparation of the zinc hydroxycarbonate template porous carbon electrode
[0039] 18 mg of zinc carbonate hydroxide template porous carbon, 300 μL of absolute ethanol, 150 μL of ethylene glycol, and 100 μL of 5% Nafion solution were mixed, and the mixture was ultrasonically treated for 30 min to obtain a mixed ink. The mixed ink was evenly coated onto the carbon cloth substrate with a pipette and dried in a forced-air drying oven at 60 °C for 24 h to obtain the zinc carbonate hydroxide template porous carbon catalyst anode. The MFC cathode directly used the pretreated carbon cloth substrate.
[0040] (5) Construction of the CPC-ZHC-MFC system
[0041] A double-chamber MFC made of plexiglass was selected. The effective volumes of both the anode chamber and the cathode chamber were 800 mL. The two chambers were connected by a flange, and the flange was separated by a proton exchange membrane (Dupont Nafion N117). The anode and cathode were connected to an external resistor with a resistance of 1 kΩ through titanium wires to form a closed circuit, and a data acquisition card was connected in parallel at both ends of the external resistor to record the voltage data during the operation of the MFC.
[0042] (6) Start-up of the double-chamber MFC
[0043] 500 mL of anode inoculum (250 mL of anaerobic sludge mixed with 250 mL of 0.1 mol / L phosphate buffer solution) was added to the anode chamber of the MFC, and 8.75 mL of nutrients (6.25 mL of trace metal solution mixed with 2.5 mL of vitamin solution) was added to maintain the growth of microorganisms in the anode chamber. 500 mL of potassium ferricyanide phosphate buffer solution (250 mL of 0.05 mol / L potassium ferricyanide solution mixed with 250 mL of 0.05 mol / L phosphate buffer solution) was added to the cathode chamber. When it was observed that the output voltage of the MFC rapidly dropped below 50 mV, it was considered that the start-up of the MFC was completed.
[0044] (7) Operation of the microbial fuel cell using actual wastewater as the substrate
[0045] The anaerobic sludge substrate in the anode chamber was replaced with 500 mL of wastewater to be treated, and at the same time, a new potassium ferricyanide phosphate buffer solution (500 mL) was put into the cathode chamber. The MFC was operated at room temperature and constant pressure, and a data acquisition instrument was used to record its output voltage. The chemical oxygen demand (COD), ammonia nitrogen, and chromaticity values of the wastewater were measured before and after the operation started.
[0046] Example 2
[0047] A method for generating electricity by treating landfill leachate using a double-chamber MFC with a porous carbon anode, the specific steps are as follows:
[0048] (1) Ash removal treatment of the carbon source of the porous carbon material
[0049] Same as step (1) in Example 1.
[0050] (2) Preparation of zinc carbonate basic template porous carbon
[0051] Same as step (2) in Example 1.
[0052] (3) Pretreatment of carbon cloth substrate
[0053] Same as step (3) in Example 1.
[0054] (4) Preparation of zinc oxide template porous carbon electrode
[0055] Mix 18 mg of zinc oxide template porous carbon, 300 μL of absolute ethanol, 150 μL of ethylene glycol and 100 μL of 5% Nafion solution, and obtain a mixed ink after ultrasonic treatment for 30 min. Apply the mixed ink evenly onto the carbon cloth substrate with a pipette gun and dry it in a blast drying oven at 60 °C for 24 h to obtain a zinc oxide template porous carbon catalyst anode. The MFC cathode directly uses the pretreated carbon cloth substrate.
[0056] (5) Construction of CPC-ZnO-MFC system
[0057] Same as step (5) in Example 1.
[0058] (6) Start-up of dual-chamber MFC
[0059] Same as step (6) in Example 1.
[0060] (7) Operation of microbial fuel cell with actual wastewater as substrate
[0061] Same as step (7) in Example 1.
[0062] Example 3
[0063] A method for electricity generation by a dual-chamber MFC with a porous carbon anode for treating landfill leachate, the specific steps are as follows:
[0064] (1) Ash removal treatment of carbon source of porous carbon material
[0065] Same as step (1) in Example 1.
[0066] (2) Preparation of zinc carbonate basic template porous carbon
[0067] Same as step (2) in Example 1.
[0068] (3) Pretreatment of carbon cloth substrate
[0069] Same as step (3) in Example 1.
[0070] (4) Preparation of porous carbon electrode
[0071] Mix 18 mg of porous carbon, 300 μL of absolute ethanol, 150 μL of ethylene glycol, and 100 μL of 5% Nafion solution, and subject the mixture to ultrasonic treatment for 30 min to obtain a mixed ink. Then, evenly coat the mixed ink onto the carbon cloth substrate using a pipette gun and dry it in a forced-air drying oven at 60 °C for 24 h to obtain the coal-based porous carbon catalyst anode. The MFC cathode directly uses the pretreated carbon cloth substrate.
[0072] (5) Construction of the CPC-ZnO-MFC system
[0073] Same as step (5) in Example 1.
[0074] (6) Start-up of the dual-chamber MFC
[0075] Same as step (6) in Example 1.
[0076] (7) Operation of the microbial fuel cell using actual wastewater as the substrate
[0077] Same as step (7) in Example 1.
[0078] Example 4
[0079] A method for generating electricity by treating landfill leachate using a dual-chamber MFC with a porous carbon anode, the specific steps are as follows:
[0080] (1) Deashing treatment of the carbon source of the porous carbon material
[0081] Same as step (1) in Example 1.
[0082] (2) Preparation of the zinc hydroxycarbonate template porous carbon
[0083] Same as step (2) in Example 1.
[0084] (3) Pretreatment of the carbon cloth substrate
[0085] Same as step (3) in Example 1.
[0086] (4) Preparation of the carbon cloth electrode
[0087] Both the MFC anode and cathode directly use the pretreated carbon cloth substrate.
[0088] (5) Construction of the CPC-ZnO-MFC system
[0089] Same as step (5) in Example 1.
[0090] (6) Start-up of the dual-chamber MFC
[0091] Same as step (6) in Example 1.
[0092] (7) Operation of the microbial fuel cell using actual wastewater as the substrate
[0093] Same as step (7) in Example 1.
[0094] Experimental results
[0095] The CPC-ZHC electrode prepared in Example 1 has the best power generation performance and degradation performance for treating aged landfill leachate in the MFC anode.
[0096] The N2 adsorption-desorption curves of the prepared CPC-ZHC and the CPC-ZnO and CPC used as control samples are as Figure 1 shown. All samples show weak broad peaks around 2θ of about 22° and 43°. These two diffraction peaks correspond to the (002) and (100) crystal planes of graphite respectively, proving the successful preparation of the porous carbon material. The N2 adsorption-desorption curves of CPC-ZHC and the CPC-ZnO and CPC used as control samples are as Figure 2 shown. All the coal-based carbon materials show a combined adsorption-desorption isotherm of type I and type IV, specifically showing a rapid rise at low relative pressures, reaching a plateau and then quickly becoming stable, corresponding to the characteristics of type I isotherm, indicating the presence of a large number of micropores; as the relative pressure continues to increase, there is a bulge again in the latter part of the curve, corresponding to the characteristics of type IV isotherm. At this time, gas molecules begin to adsorb in larger pores, indicating that the coal-based carbon materials have a mesoporous structure. The specific surface areas of CPC-ZHC, CPC-ZnO and CPC are 1795.37 m 2 / g, 2068.63 m 2 / g and 2323.73 m 2 / g respectively; the pore volumes are 0.79 cm 3 / g, 0.95 cm 3 / g and 1.09 cm 3 / g respectively. Compared with the CPC material, the specific surface area of CPC-ZHC has increased by nearly 30%, which is beneficial to loading more microorganisms, thus improving the power generation and degradation performance of MFC.
[0097] The MFC system was started and operated under different anode catalyst conditions ( Figure 3 ), and the curve of its output voltage changing with time is as Figure 4 shown. Under the condition that the anode catalyst is CPC-ZHC, the maximum output voltage of the battery is 640.0 mV, which is 3.0 times, 3.4 times and 4.9 times that of Example 2, Example 3 and Example 4 respectively; the maximum power density reaches 1271.2 mW / m 2 ( Figure 5 ), much higher than that of Example 2, Example 3 and Example 4. The anode catalyst CPC-ZHC significantly improves the power generation performance of MFC.
[0098] Tests show that when the anode catalyst is CPC-ZHC, the COD removal amount of aged landfill leachate in the MFC system is 1739.3 mg / L, and the removal rate is 41.4%; the ammonia nitrogen removal amount is 2204.5 mg / L, and the removal rate is 54.7%; the wastewater chromaticity is reduced from 800 times to 80 times, which is better than that of Example 4 (the COD removal amount is 907.7 mg / L, the removal rate is 21.6%; the ammonia nitrogen removal amount is 941.4 mg / L, the removal rate is 23.3%; the wastewater chromaticity is reduced from 800 times to 300 times). This shows that the constructed modified anode dual-chamber microbial fuel cell improves the removal efficiency of COD and ammonia nitrogen and the decolorization effect in aged landfill leachate.
Claims
1. A new method for electricity generation by treating landfill leachate using a zinc hydroxycarbonate template porous carbon anode dual-chamber MFC, characterized in that, It includes the following steps: (1) Preparation of basic zinc carbonate template porous carbon electrode Place the anthracite coal sample in a mortar, grind it for 30 min and then screen it to obtain a -200 mesh coal sample; successively pickle the coal sample with 4 mol / L hydrochloric acid and 10 wt% hydrofluoric acid, wash away the excess acid with distilled water, and then place it in a blast drying oven to dry at 50 °C for 12 h to obtain deashed anthracite; Weigh 1 g of deashed anthracite, 3 g of KOH and 0.5 g of basic zinc carbonate and place them in a 100 mL beaker, add 50 mL of ethanol to form a suspension, ultrasonicate for 30 min, stir magnetically for 2 h, and dry to obtain a black mixture; place the mixture in a tubular furnace, under the condition of a heating rate of 5 °C / min, after introducing N2, first heat up to 300 °C and pyrolyze for 30 min, then continue to heat up to 800 °C and activate for 2 h, and after natural cooling to room temperature, wash it 3 times with 4 mol / L hydrochloric acid and deionized water respectively, and vacuum dry at 60 °C to obtain basic zinc carbonate template porous carbon CPC-ZHC; Use clean scissors to cut the carbon cloth into small pieces of 2×3 cm, ultrasonically clean it successively with absolute ethanol and a sulfuric acid-nitric acid mixed solution with a volume ratio of 3:1, then wash it with distilled water, put it into a blast drying oven to dry at 60 °C, and calcine it in a muffle furnace at 300 °C for 4 h to obtain the carbon cloth substrate CC; Mix 18 mg of basic zinc carbonate template porous carbon, 300 μL of absolute ethanol, 150 μL of ethylene glycol and 100 μL of 5% Nafion solution, ultrasonically treat for 30 min to obtain a mixed ink, evenly coat the mixed ink onto the carbon cloth substrate with a pipette, and dry it in a 60 °C blast drying oven for 24 h to obtain a basic zinc carbonate template porous carbon catalyst anode; (2) Construction of CPC-ZHC-MFC system Select a double-chamber MFC made of plexiglass, the effective volumes of the anode chamber and the cathode chamber are both 800 mL, the two chambers are connected by a flange, and the flange is separated by a DuPont Nafion N117 proton exchange membrane. The cathode and anode form a closed loop with an external resistor with a resistance value of 1 kΩ through titanium wires, and a data acquisition card is connected in parallel at both ends of the external resistor to record the voltage data during the operation of the MFC; (3) Start-up of CPC-ZHC-MFC system Add 500 mL of anode inoculum (250 mL of anaerobic sludge mixed with 250 mL of 0.1 mol / L phosphate buffer solution) to the anode chamber of the MFC, add 8.75 mL of nutrients, that is, 6.25 mL of trace metal solution mixed with 2.5 mL of vitamin solution to maintain the growth of microorganisms in the anode chamber, and add 500 mL of potassium ferricyanide phosphate buffer solution to the cathode chamber, that is, 250 mL of 0.05 mol / L potassium ferricyanide solution mixed with 250 mL of 0.05 mol / L phosphate buffer solution; when it is observed that the output voltage of the MFC rapidly drops below 50 mV, it is regarded as the completion of the start-up of the MFC; (4) Operation of a microbial fuel cell with landfill leachate as the substrate Replace the anaerobic sludge substrate in the anodic chamber with 500 mL of landfill leachate, and at the same time, replace the cathodic chamber with 500 mL of fresh potassium ferricyanide phosphate buffer solution; operate the MFC at room temperature and constant pressure, use a data acquisition instrument to record its output voltage, and measure the chemical oxygen demand, ammonia nitrogen, and chromaticity values of the wastewater before the start and after the end of the operation respectively.