A salt-tolerant biochar-based electrochemical material, its preparation method and application
A biocarbon-MOF composite catalyst, prepared from fruit biomass and metal salts, addresses catalyst corrosion in BES systems, enhancing pollutant removal in high-salt wastewater by stabilizing the catalyst and improving electrochemical performance.
Patent Information
- Application Number
- CN202310357690.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-04-04
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2043-04-04
AI Technical Summary
Existing bioelectrochemical technology in high-salt environments is prone to corrosion, poor stability and low catalytic performance, affecting the treatment efficiency of high-salt organic wastewater.
Salt-resistant biochar-based electrochemical material is prepared, and the biomass is mixed with metal ion solution and freeze-dried to form a MOF structure, and then roasted at high temperature under anaerobic conditions to form an M-NC composite material with biochar as a skeleton, enhancing catalytic performance.
It improves the stability and catalytic performance of the catalyst in a high-salt environment, and improves the degradation efficiency of new pollutants in high-salt organic wastewater.
Smart Images
Figure CN116550389B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of high-salt organic wastewater treatment, and particularly relates to a salt-tolerant biochar-based electrochemical material, a preparation method thereof, and an application thereof. Background Art
[0002] High-salt organic wastewater mainly comes from heavily polluting activities such as coal chemical industry, pharmaceutical industry, petrochemical industry, and printing and dyeing. The disposal of high-salt wastewater is a worldwide problem. In China, more than 300 million cubic meters of such wastewater are generated every year, and the by-produced high-salt hazardous waste exceeds 10 million tons, bringing great pressure to the ecological environment. At present, the main process for treating such wastewater is to desalt first and then degrade, but the process energy consumption is extremely high, the economy is poor, and the by-products generated during the treatment contain a large amount of toxic and harmful organic substances and other impurities, which are difficult to recycle and pose a great threat to the environment and have been listed in the national hazardous waste list (waste salt).
[0003] In recent years, the bioelectrochemical technology (BES) that can use microorganisms as catalysts to realize the resource utilization of pollutants in sewage has been favored by researchers. When BES treats high-salt wastewater, the internal resistance of BES decreases, which is more conducive to electricity generation. This is because the ion migration speed in the wastewater is accelerated by the influence of high-concentration anions and cations, the conductivity of the wastewater and the proton transfer ability are improved, so that the wastewater has good conductivity. On the other hand, high-concentration salts will inhibit the metabolism and enzyme activity of electricity-generating microorganisms, which is not conducive to electricity generation by BES and affects the removal efficiency of pollutants in the wastewater. However, there have been many studies on the enhancement of microorganisms at present, and high-concentration salts are likely to cause the corrosion and inactivation of the cathode catalyst, directly affecting the overall performance of BES. Therefore, designing and developing a cathode catalyst with strong corrosion resistance and strong stability in a high-salt environment plays an important role in improving the pollutant degradation rate of BES and promoting the practical application of BES. Summary of the Invention
[0004] Technical problems to be solved: Based on the actual problems of easy corrosion, poor stability, and low catalytic performance of the cathode in the application of electrochemical or bioelectrochemical technology in a high-salt environment, the present invention provides a salt-tolerant biochar-based electrochemical material, a preparation method thereof, and an application thereof.
[0005] Technical solution: A preparation method of a salt-tolerant biochar-based electrochemical material, the steps are as follows: (1) Crush and filter the biomass to separate the biomass juice and biomass residue; (2) Add any one of iron nitrate / cerium nitrate, cobalt nitrate / cerium nitrate, or iron nitrate / cobalt nitrate / cerium nitrate to the biomass juice to form solution A, where the mass ratio of the biomass juice to the metal ions is (1-2):(2-1); (3) Freeze-dry the biomass residue and add it to solution A to form mixture B, and the mass ratio of solution A to the biomass residue is 5:1; (4) Add 2-methylimidazole to deionized water and stir to form solution C, and the concentration of solution C is 0.25-0.3 g / mL; (5) Drop solution C into mixture B, and the mass ratio of mixture B to solution C is 1:(4-8), and continuously stir, and centrifuge the reacted solution to obtain a precipitate; (6) Remove the surface impurities of the precipitate by pickling and washing with deionized water, and then dry it in a vacuum drying oven; (7) Calcinate the dried precipitate at 800-1000 °C for 1-2 h under anaerobic conditions to obtain the salt-tolerant biochar-based electrochemical material M-NC / C MOF.
[0006] The above-mentioned biomass is fruit biomass.
[0007] Preferably, the above-mentioned fruit biomass is wax gourd or lettuce.
[0008] The molar ratio of the above-mentioned iron nitrate / cerium nitrate is (1-5):1, the molar ratio of cobalt nitrate / cerium nitrate is (1-5):1, and the molar ratio of iron nitrate / cobalt nitrate / cerium nitrate is (1-5):(1-5):1.
[0009] Preferably, the concentration of 2-methylimidazole in the above-mentioned solution B is 0.275 g / mL.
[0010] Preferably, in step (6), the drying temperature is 80 °C and the drying time is 2-3 h.
[0011] Preferably, in step (7), the calcination temperature is 900 °C and the calcination time is 1.5 h.
[0012] The salt-tolerant biochar-based electrochemical material M-NC / C MOF prepared by the above method.
[0013] The application of the above-mentioned salt-tolerant biochar-based electrochemical material in the preparation of a cathode catalyst for a bioelectrochemical system.
[0014] The above-mentioned catalyst is used to achieve the degradation of new pollutants in high-salt organic wastewater, and the salt content of the high-salt organic wastewater is 1%-4%, and the new pollutants are antibiotics or polycyclic aromatic hydrocarbons.
[0015] Beneficial effects: The M-NC prepared by the present invention is a MOF-NC material synthesized in-situ in biochar, having the following beneficial effects: 1) The biomass is crushed, and the C and N elements in the biomass juice are more likely to form complex structures with metal elements in the form of small molecules, strengthening the catalytic performance of the catalyst; 2) After in-situ synthesizing the MOF structure on the bio-residue and then performing high-temperature calcination, an M-NC composite material with biochar as the skeleton is formed, and the porous structure of biochar promotes the dispersion of the MOF material; 3) The nanostructure of the MOF material is stable, alleviating the corrosion of the catalytic material by salt; 4) The confinement effect of the mesoporous structure of biochar and the MOF nanocage structure alleviates the dissociation of metal elements after partial corrosion; 5) The catalytic material prepared by the present invention contains Ce element, and cerium oxide resists chlorine corrosion; 6) The metal elements combined with N and C have stronger corrosion resistance. Description of the Drawings
[0016] Figure 1 Flow chart of catalyst preparation;
[0017] Figure 2 Degradation rate of the new pollutant sulfamethoxazole in high-salt organic wastewater under different cathode catalysts;
[0018] Figure 3 Degradation rate of the new pollutant sulfamethoxazole in high-salt organic wastewater under different cathode catalysts;
[0019] Figure 4 Degradation rate of sulfamethoxazole in Control Experiment 1 to Control Experiment 6;
[0020] Figure 5 Degradation rate of phenanthrene in Control Experiment 1 to Control Experiment 6. Detailed Description of the Invention
[0021] Example 1
[0022] The preparation steps of the cathode catalyst are as follows:
[0023] (1) Crush the wax gourd and filter to separate it into biomass juice and bio-residue;
[0024] (2) Add iron nitrate / cerium nitrate to the biomass juice to form Solution A, and the molar ratio of iron nitrate to cerium nitrate is 1:1, and the mass ratio of the biomass mixture to metal ions is 1:2;
[0025] (3) After freeze-drying the bio-residue, add it to Solution A to form Mixture B, and the mass ratio of Solution A to the bio-residue is 5:1;
[0026] (4) Add 5.5 g of 2-methylimidazole to 20 mL of deionized water and stir to form Solution C;
[0027] (5) Add the C solution dropwise to the B mixture according to a volume ratio of B mixture: C solution of 1:4, and continuously stir. Centrifuge the reacted solution to obtain a precipitate;
[0028] (6) Remove the surface impurities of the precipitate by pickling and washing with deionized water, and then dry it in a vacuum drying oven at 80 °C for 2 h;
[0029] (7) Calcinate the dried precipitate at 800 °C for 2 h under anaerobic conditions to obtain the catalyst FeCe-NC / CMOF.
[0030] The prepared FeCe-NC / C MOF cathode catalyst was applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 1% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0031] Example 2
[0032] The preparation steps of the cathode catalyst are as follows:
[0033] (1) Crush the wax gourd and filter and separate it into biomass juice and biomass residue;
[0034] (2) Add iron nitrate / cerium nitrate to the biomass juice to form solution A, with a molar ratio of iron nitrate: cerium nitrate of 3:1 and a mass ratio of biomass mixture to metal ions of 1:1;
[0035] (3) Freeze-dry the biomass residue and add it to solution A to form mixture B, with a mass ratio of solution A to biomass residue of 5:1;
[0036] (4) Add 5.5 g of 2-methylimidazole to 20 mL of deionized water and stir to form solution C;
[0037] (5) Slowly add solution C dropwise to mixture B according to a volume ratio of B mixture: C solution of 1:6, and continuously stir. Centrifuge the reacted solution to obtain a precipitate;
[0038] (6) Remove the surface impurities of the precipitate by pickling and washing with deionized water, and then dry it in a vacuum drying oven at 80 °C for 2.5 h;
[0039] (7) Calcinate the dried precipitate at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst FeCe-NC / CMOF.
[0040] The prepared FeCe-NC / C MOF cathode catalyst was applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 2% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0041] Example 3
[0042] The preparation steps of the cathode catalyst are as follows:
[0043] (1) After breaking and filtering wax gourd to separate it into biomass juice and biomass residue;
[0044] (2) Adding iron nitrate / cerium nitrate to the biomass juice to form solution A, with the molar ratio of iron nitrate to cerium nitrate being 5:1 and the mass ratio of the biomass mixture to metal ions being 2:1;
[0045] (3) Freeze-drying the biomass residue and then adding it to solution A to form mixture B, with the mass ratio of solution A to the biomass residue being 5:1;
[0046] (4) Adding 5.5 g of 2-methylimidazole to 20 mL of deionized water and stirring to form solution C;
[0047] (5) Slowly dropping solution C into mixture B according to the volume ratio of mixture B to solution C being 1:8, and continuously stirring, then centrifuging the reacted solution to obtain a precipitate;
[0048] (6) Removing the surface impurities of the precipitate by pickling and washing with deionized water, and then drying it in a vacuum drying oven at 80 °C for 3 h;
[0049] (7) High-temperature calcining the dried precipitate at 1000 °C for 1 h under anaerobic conditions to obtain the catalyst FeCe-NC / CMOF.
[0050] The prepared FeCe-NC / C MOF cathode catalyst is applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 4% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0051] Example 4
[0052] The preparation steps of the cathode catalyst are as follows:
[0053] (1) Breaking and filtering lettuce to separate it into biomass juice and biomass residue;
[0054] (2) Adding cobalt nitrate / cerium nitrate to the biomass juice to form solution A, with the molar ratio of cobalt nitrate to cerium nitrate being 1:1 and the mass ratio of the biomass mixture to metal ions being 1:2;
[0055] (3) Freeze-drying the biomass residue and then adding it to solution A to form mixture B, with the mass ratio of solution A to the biomass residue being 5:1;
[0056] (4) Adding 5.5 g of 2-methylimidazole to 20 mL of deionized water and stirring to form solution C;
[0057] (5) Slowly add solution C to mixture B according to a volume ratio of B mixture:C solution of 1:4, and continuously stir. Centrifuge the reacted solution to obtain a precipitate;
[0058] (6) Remove the surface impurities of the precipitate by pickling and washing with deionized water, and then dry it in a vacuum drying oven at 80 °C for 2 h;
[0059] (7) Calcinate the dried precipitate at 800 °C for 2 h under anaerobic conditions to obtain the catalyst CoCe-NC / CMOF.
[0060] The prepared CoCe-NC / C MOF cathode catalyst is applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 1% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0061] Example 5
[0062] The preparation steps of the cathode catalyst are as follows:
[0063] (1) Crush lettuce and filter it to separate into biomass juice and biomass residue;
[0064] (2) Add cobalt nitrate / cerium nitrate to the biomass juice to form solution A, with a molar ratio of cobalt nitrate:cerium nitrate of 3:1 and a mass ratio of biomass mixture to metal ions of 1:1;
[0065] (3) Freeze-dry the biomass residue and then add it to solution A to form mixture B, with a mass ratio of solution A to biomass residue of 5:1;
[0066] (4) Add 5.5 g of 2-methylimidazole to 20 mL of deionized water and stir to form solution C;
[0067] (5) Slowly add solution C to mixture B according to a volume ratio of B mixture:C solution of 1:6, and continuously stir. Centrifuge the reacted solution to obtain a precipitate;
[0068] (6) Remove the surface impurities of the precipitate by pickling and washing with deionized water, and then dry it in a vacuum drying oven at 80 °C for 2.5 h;
[0069] (7) Calcinate the dried precipitate at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst CoCe-NC / CMOF.
[0070] The prepared CoCe-NC / C MOF cathode catalyst is applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 2% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0071] Example 6
[0072] The preparation steps of the cathode catalyst are as follows:
[0073] (1) Crush lettuce and filter it to separate into biomass juice and biomass residue;
[0074] (2) Add cobalt nitrate / cerium nitrate to the biomass juice to form solution A, the molar ratio of cobalt nitrate to cerium nitrate is 5:1, and the mass ratio of the biomass mixture to metal ions is 2:1;
[0075] (3) Freeze-dry the biomass residue and add it to solution A to form mixture B, the mass ratio of solution A to the biomass residue is 5:1;
[0076] (4) Add 5.5 g of 2-methylimidazole to 20 mL of deionized water and stir to form solution C;
[0077] (5) Slowly add solution C to mixture B according to the volume ratio of mixture B to solution C of 1:8, and continuously stir. Centrifuge the reacted solution to obtain a precipitate;
[0078] (6) Remove the surface impurities of the precipitate by pickling and washing with deionized water, and then dry it in a vacuum drying oven at 80 °C for 3 h;
[0079] (7) Calcinate the dried precipitate at 1000 °C for 1 h under anaerobic conditions to obtain the catalyst CoCe-NC / CMOF.
[0080] The prepared CoCe-NC / C MOF cathode catalyst is applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 4% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0081] Example 7
[0082] The preparation steps of the cathode catalyst are as follows:
[0083] (1) Crush wax gourd and filter it to separate into biomass juice and biomass residue;
[0084] (2) Add iron nitrate / cobalt nitrate / cerium nitrate to the biomass juice to form solution A, the molar ratio of iron nitrate to cobalt nitrate to cerium nitrate is 1:1:1, and the mass ratio of the biomass mixture to metal ions is 1:2;
[0085] (3) Freeze-dry the biomass residue and add it to solution A to form mixture B, the mass ratio of solution A to the biomass residue is 5:1;
[0086] (4) Add 5.5 g of 2-methylimidazole to 20 mL of deionized water and stir to form solution C;
[0087] (5) Slowly add solution C to mixture B at a volume ratio of B mixture:C solution of 1:4, and continuously stir. Centrifuge the reacted solution to obtain a precipitate.
[0088] (6) Remove the impurities on the surface of the precipitate by pickling and washing with deionized water, and then dry it in a vacuum drying oven at 80 °C for 2 h.
[0089] (7) Calcinate the dried precipitate at 800 °C for 2 h under anaerobic conditions to obtain the catalyst FeCoCe-NC / CMOF.
[0090] The prepared FeCoCe-NC / C MOF cathode catalyst is applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 1% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0091] Example 8
[0092] The preparation steps of the cathode catalyst are as follows:
[0093] (1) Crush the wax gourd and filter it to separate it into biomass juice and biomass residue.
[0094] (2) Add iron nitrate / cobalt nitrate / cerium nitrate to the biomass juice to form solution A, with a molar ratio of iron nitrate:cobalt nitrate:cerium nitrate of 3:3:1 and a mass ratio of biomass mixture to metal ions of 1:1.
[0095] (3) Freeze-dry the biomass residue and add it to solution A to form mixture B, with a mass ratio of solution A to biomass residue of 5:1.
[0096] (4) Add 5.5 g of 2-methylimidazole to 20 mL of deionized water and stir to form solution C.
[0097] (5) Slowly add solution C to mixture B at a volume ratio of B mixture:C solution of 1:6, and continuously stir. Centrifuge the reacted solution to obtain a precipitate.
[0098] (6) Remove the impurities on the surface of the precipitate by pickling and washing with deionized water, and then dry it in a vacuum drying oven at 80 °C for 2.5 h.
[0099] (7) Calcinate the dried precipitate at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst FeCoCe-NC / CMOF.
[0100] The prepared FeCoCe-NC / C MOF cathode catalyst is applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 2% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0101] Example 9
[0102] The preparation steps of the cathode catalyst are as follows:
[0103] (1) Crush wax gourd and filter to separate it into biomass juice and biomass residue;
[0104] (2) Add iron nitrate / cobalt nitrate / cerium nitrate to the biomass juice to form solution A. The molar ratio of iron nitrate:cobalt nitrate:cerium nitrate is 5:5:1, and the mass ratio of the biomass mixture to metal ions is 2:1;
[0105] (3) Freeze-dry the biomass residue and add it to solution A to form mixture B. The mass ratio of solution A to the biomass residue is 5:1;
[0106] (4) Add 5.5 g of 2-methylimidazole to 20 mL of deionized water and stir to form solution C;
[0107] (5) Slowly add solution C to mixture B dropwise according to the volume ratio of mixture B:solution C of 1:8, and continuously stir. Centrifuge the reacted solution to obtain a precipitate;
[0108] (6) Remove the surface impurities of the precipitate by pickling and washing with deionized water, and then dry it in a vacuum drying oven at 80 °C for 3 h;
[0109] (7) Calcinate the dried precipitate at 1000 °C for 1 h under anaerobic conditions to obtain the catalyst FeCoCe-NC / CMOF.
[0110] The prepared FeCoCe-NC / C MOF cathode catalyst is applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 4% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0111] Control experiment 1
[0112] The preparation steps of the cathode catalyst are as follows:
[0113] (1) Add iron nitrate to deionized water, stir evenly and let it stand for 2 h. The mass ratio of deionized water to metal ions is 1:1;
[0114] (2) Dry it in a vacuum drying oven at 80 °C;
[0115] (3) Calcinate the dried precipitate at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst FeOx.
[0116] The prepared FeOx cathode catalyst was applied to a bioelectrochemical system for treating high-salt organic wastewater with a salinity of 2%, and the new pollutants were 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0117] Control experiment 2
[0118] The preparation steps of the cathode catalyst were as follows:
[0119] (1) Cobalt nitrate was added to deionized water, stirred evenly, and then left standing for 2 h. The mass ratio of deionized water to metal ions was 1:1.
[0120] (2) It was dried in a vacuum drying oven at 80 °C.
[0121] (3) The dried precipitate was calcined at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst CoOx.
[0122] The prepared CoOx cathode catalyst was applied to a bioelectrochemical system for treating high-salt organic wastewater with a salinity of 2%, and the new pollutants were 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0123] Control experiment 3
[0124] The preparation steps of the cathode catalyst were as follows:
[0125] (1) Cerium nitrate was added to deionized water, stirred evenly, and then left standing for 2 h. The mass ratio of deionized water to metal ions was 1:1.
[0126] (2) It was dried in a vacuum drying oven at 80 °C.
[0127] (3) The dried precipitate was calcined at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst CeOx.
[0128] The prepared CeOx cathode catalyst was applied to a bioelectrochemical system for treating high-salt organic wastewater with a salinity of 2%, and the new pollutants were 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0129] Control experiment 4
[0130] The preparation steps of the cathode catalyst were as follows:
[0131] (1) Iron nitrate / cerium nitrate was added to deionized water, stirred evenly, and then left standing for 2 h. The molar ratio of iron nitrate to cerium nitrate was 3:1, and the mass ratio of deionized water to metal ions was 1:1.
[0132] (2) It was dried in a vacuum drying oven at 80 °C.
[0133] (3) The dried precipitate was calcined at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst FeCeOx.
[0134] The prepared FeCeOx cathode catalyst was applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 2% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0135] Control experiment 5
[0136] The preparation steps of the cathode catalyst are as follows:
[0137] (1) Cobalt nitrate / cerium nitrate was added to deionized water, stirred evenly, and then left standing for 2 h. The molar ratio of cobalt nitrate to cerium nitrate was 3:1, and the mass ratio of deionized water to metal ions was 1:1.
[0138] (2) Dried in a vacuum drying oven at 80 °C.
[0139] (3) The dried precipitate was calcined at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst CoCeOx.
[0140] The prepared CoCeOx cathode catalyst was applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 2% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0141] Control experiment 6
[0142] The preparation steps of the cathode catalyst are as follows:
[0143] (1) Iron nitrate / cobalt nitrate / cerium nitrate was added to deionized water, stirred evenly, and then left standing for 2 h. The molar ratio of iron nitrate:cobalt nitrate:cerium nitrate was 3:3:1, and the mass ratio of deionized water to metal ions was 1:1.
[0144] (2) Dried in a vacuum drying oven at 80 °C.
[0145] (3) The dried precipitate was calcined at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst FeCoCeOx.
[0146] The prepared FeCoCeOx cathode catalyst was applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 2% and new pollutants of 5 mg / L of the antibiotic sulfamethoxazole and 0.5 mg / L of the polycyclic aromatic hydrocarbon phenanthrene.
[0147] Control experiment 7
[0148] The preparation steps of the cathode catalyst are as follows:
[0149] (1) Crush and filter wax gourd to separate it into biomass juice and biomass residue;
[0150] (2) Add iron nitrate / cerium nitrate to the biomass juice, stir evenly, and let it stand for 2 h. The molar ratio of iron nitrate to cerium nitrate is 3:1, and the mass ratio of the biomass mixture to metal ions is 1:1;
[0151] (3) Freeze-dry the biomass residue and add it to solution A to form mixture B. The mass ratio of solution A to the biomass residue is 5:1;
[0152] (4) Dry mixture B in a vacuum drying oven at 80 °C;
[0153] (5) Calcinate the dried precipitate at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst FeCe-NC / C.
[0154] The prepared FeCe-NC / C cathode catalyst is applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 2% and new pollutants of 5 mg / L antibiotic sulfamethoxazole and 0.5 mg / L polycyclic aromatic hydrocarbon phenanthrene.
[0155] Control experiment 8
[0156] The preparation steps of the cathode catalyst are as follows:
[0157] (1) Crush and filter lettuce to separate it into biomass juice and biomass residue;
[0158] (2) Add cobalt nitrate / cerium nitrate to the biomass juice, stir evenly, and let it stand for 2 h. The molar ratio of cobalt nitrate to cerium nitrate is 3:1, and the mass ratio of the biomass mixture to metal ions is 1:1;
[0159] (3) Freeze-dry the biomass residue and add it to solution A to form mixture B. The mass ratio of solution A to the biomass residue is 5:1;
[0160] (4) Dry mixture B in a vacuum drying oven at 80 °C;
[0161] (5) Calcinate the dried precipitate at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst CoCe-NC / C.
[0162] The prepared CoCe-NC / C cathode catalyst is applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 2% and new pollutants of 5 mg / L antibiotic sulfamethoxazole and 0.5 mg / L polycyclic aromatic hydrocarbon phenanthrene.
[0163] Control experiment 9
[0164] The preparation steps of the cathode catalyst are as follows:
[0165] (1) crushing the wax gourd and filtering and separating it into biomass juice and biomass residue;
[0166] (2) adding ferric nitrate / cobalt nitrate / cerium nitrate to the biomass juice, stirring evenly and then standing for 2 hours, the molar ratio of ferric nitrate:cobalt nitrate:cerium nitrate is 3:3:1, and the mass ratio of the biomass mixture to the metal ions is 1:1;
[0167] (3) freeze-drying the biomass residue and adding it to solution A to form a mixture B, wherein the mass ratio of solution A to biomass residue is 5:1;
[0168] (4) drying the mixture B in a vacuum drying oven at 80°C;
[0169] (5) The dried precipitate was calcined at 900 °C for 1.5 h under anaerobic conditions to obtain the catalyst FeCoCe-NC / C.
[0170] The prepared FeCoCe-NC / C cathode catalyst was applied to a bioelectrochemical system to treat high-salt organic wastewater with a salinity of 2% and new pollutants of 5 mg / L antibiotic sulfamethoxazole and 0.5 mg / L polycyclic aromatic hydrocarbon phenanthrene.
[0171] Degradation rate of sulfamethoxazole, a new pollutant in high-salinity organic wastewater, under different cathode catalysts Figure 2 The degradation rate of sulfamethoxazole, a new pollutant in high-salinity organic wastewater, under different cathode catalysts is shown in Figure 3 shown. Figure 2 The data in the figure are the degradation rates of sulfamethoxazole in Examples 1 to 9. Figure 3 The data in the figure are the degradation rates of phenanthrene in Examples 1 to 9. Figure 4 The data in the figure are the degradation rates of sulfamethoxazole in control experiments 1 to 6. Figure 5 The data in the figure are the degradation rates of phenanthrene in control experiments 1 to 6. Among the 9 groups of examples, the removal rates of sulfamethoxazole and phenanthrene under the action of the FeCoCe-NC / C MOF cathode catalyst prepared in Example 8 were the highest, which were 93.4% and 86.8%, respectively; among the 9 groups of control experiments, the removal rates of sulfamethoxazole and phenanthrene under the action of the FeCoCe-NC / C cathode catalyst prepared in control experiment 9 were the highest, which were 55.6% and 52.2%, respectively. Overall, the combination of multi-metal elements and N and C under the MOF structure can better promote the removal of new pollutants and improve the stability of the catalyst under high salt conditions.
[0172] The embodiments of the present invention have been described in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments. For those of ordinary skill in the art of this technology, after learning the content recorded in the present invention, without departing from the principle of the present invention, several equivalent transformations and substitutions can still be made, and these equivalent transformations and substitutions should also be regarded as falling within the protection scope of the present invention.
Claims
1. A preparation method of a salt-tolerant biochar-based electrochemical material, characterized in that, The steps are as follows: (1) Crush and filter the biomass to separate biomass juice and biomass residue; (2) Add any one of iron nitrate / cerium nitrate, cobalt nitrate / cerium nitrate, or iron nitrate / cobalt nitrate / cerium nitrate to the biomass juice to form solution A, where the mass ratio of the biomass juice to the metal ions is (1-2):(2-1); (3) Freeze-dry the biomass residue and add it to solution A to form mixture B, where the mass ratio of solution A to the biomass residue is 5:1; (4) Add 2-methylimidazole to deionized water and stir to form solution C, and the concentration of solution C is 0.25-0.3 g / mL; (5) Drop solution C into mixture B, where the mass ratio of mixture B to solution C is 1:(4-8), and continuously stir, and centrifuge the reacted solution to obtain a precipitate; (6) Remove the surface impurities of the precipitate by pickling and washing with deionized water and then dry it in a vacuum drying oven; (7) Calcinate the dried precipitate at 800-1000 °C for 1-2 h under anaerobic conditions to obtain the salt-tolerant biochar-based electrochemical material M-NC / C MOF.
2. The preparation method of the salt-tolerant biochar-based electrochemical material according to claim 1, wherein, The biomass is fruit biomass.
3. The preparation method of the salt-tolerant biochar-based electrochemical material according to claim 2, characterized in that, The fruit biomass is wax gourd or lettuce.
4. The preparation method of the salt-tolerant biochar-based electrochemical material according to claim 1, characterized in that, The molar ratio of iron nitrate / cerium nitrate is (1-5):1, the molar ratio of cobalt nitrate / cerium nitrate is (1-5):1, and the molar ratio of iron nitrate / cobalt nitrate / cerium nitrate is (1-5):(1-5):
1.
5. The preparation method of the salt-tolerant biochar-based electrochemical material according to claim 1, characterized in that, The concentration of 2-methylimidazole in solution C is 0.275 g / mL.
6. The preparation method of the salt-tolerant biochar-based electrochemical material according to claim 1, characterized in that: In step (6), the drying temperature is 80 °C and the drying time is 2-3 h.
7. The preparation method of the salt-tolerant biochar-based electrochemical material according to claim 1, wherein: In step (7), the calcination temperature is 900 °C and the calcination time is 1.5 h.
8. The salt-tolerant biochar-based electrochemical material M-NC / C MOF prepared by the method according to any one of claims 1-7.
9. Use of the salt-tolerant biochar-based electrochemical material according to claim 8 in the preparation of a cathode catalyst for a bioelectrochemical system.
10. The application according to claim 9, characterized in that, The catalyst is used to achieve the degradation of new pollutants in high-salt organic wastewater, the salinity of the high-salt organic wastewater is 1%-4%, and the new pollutants are antibiotics or polycyclic aromatic hydrocarbons.