A method for treating pollutants by a special microorganism-enhanced microbial fuel cell

Abstract

The present invention discloses a method for treating pollutants by a special microorganism-enhanced microbial fuel cell, belonging to the field of wastewater treatment. The present invention provides a single-chamber microbial fuel cell, which includes an anode electrode material, a cathode electrode material and an inoculation solution; the inoculation solution is prepared by mixing Stenotrophomonas acidaminiphila bacterial solution, nutrient solution, phosphate buffer solution and activated sludge in a volume ratio of 1-5:1-5:1-3:2-4 to form an inoculation solution; connecting the anode and cathode electrode materials with a metal wire and immersing them in the inoculation solution, adding edible oil or machine oil, and standing still, using the bacterial solution to degrade the activated sludge and oil and generate electrons and protons, and the electrons flow from the anode material through the external circuit to the cathode electrode material to form a current loop with protons to generate electricity. The method for treating oil pollutants by the Stenotrophomonas acidaminiphila microbial fuel cell of the present invention is beneficial to the sustainable development of the ecological environment.

Description

Technical Field

[0001] The present invention relates to a method for treating pollutants by strengthening a microbial fuel cell with special microorganisms, and belongs to the field of wastewater treatment. Background Art

[0002] With the rapid development of the world industry, petroleum resources have been widely utilized. The frequent occurrence of events such as the exploitation and transportation of offshore petroleum resources and oil spill accidents has seriously polluted the marine environment and damaged the ecological balance of the marine system. In the marine chapter of the "China Ecological Environment Bulletin 2018", it is mentioned that petroleum substances are one of the important pollutants in seawater. At present, the commonly used degradation treatment methods for marine petroleum hydrocarbon pollutants can be divided into three categories: physical methods, chemical methods, and biological methods. The biological method mainly refers to bioremediation, which uses microorganisms naturally present in the ocean or soil that have the ability to oxidize and decompose petroleum, and can use petroleum hydrocarbon compounds as a carbon source and an energy source, and finally generate H2O and CO2. The biological method is an important way to completely remove oil pollution. Compared with physical and chemical methods, the biological method has little impact on humans and the environment, and the cost of repair treatment is only 30% and 50% of traditional physical and chemical treatment and repair. The biological method is regarded as the most promising environmental governance means due to its advantages of small investment, no secondary pollution, and fixed-point repair.

[0003] With the continuous acceleration of the urbanization process, the amount of kitchen waste generated by residents in China is increasing and the degree of centralization is getting higher. According to investigations, kitchen waste accounts for 30-40% of urban domestic waste. For a long time, kitchen waste in China has been collected, transported, landfilled, and piled up together with other domestic waste, and the harmless treatment rate is about 20%. The untreated kitchen waste is directly discharged into the environment, causing environmental pollution and seriously affecting people's production and life. The currently commonly used biological treatment method for kitchen waste is composting, but the oil and salt in kitchen waste have an inhibitory effect on the growth of microorganisms and affect the composting effect. Therefore, it is necessary to remove the oil in the kitchen waste before subsequent treatment and disposal.

[0004] A microbial fuel cell (MFC) is a device that directly converts the chemical energy in organic matter into electrical energy by using microorganisms, and is a new energy and environmental governance technology. There are many configurations of MFC. Compared with the typical double-chamber MFC, the use of separation materials such as PEM leads to increased costs and increased internal resistance, affecting its power generation efficiency and other deficiencies. The structure of the single-chamber MFC is simpler, the cost is reduced, and electrical energy is generated while degrading and removing pollutants, and it has broad development prospects.

[0005] Stenotrophomonas acidaminiphila has strong environmental adaptability, can use oil substances for its own growth and reproduction, and can degrade oil pollutants and generate electric energy. Summary of the Invention

[0006] The present invention provides a method for treating pollutants by a special microorganism enhanced microbial fuel cell. Applying Stenotrophomonas acidaminiphila in a microbial fuel cell based on the treatment of oil pollutants can effectively improve the degradation of oil pollutants and generate electric energy.

[0007] The technical solution of the present invention is as follows:

[0008] The present invention provides a single-chamber microbial fuel cell, which includes an anode electrode material, a cathode electrode material and an inoculation solution;

[0009] The inoculation solution is prepared by mixing the bacterial solution of Stenotrophomonas acidaminiphila CGMCC No. 22273, nutrient solution, phosphate buffer solution and activated sludge according to a volume ratio of (1-5):(1-5):(1-3):(2-4);

[0010] The anode and cathode electrode materials connected by metal wires are immersed in the inoculation solution, and edible oil or machine oil is added, and then left standing. The bacterial solution is used to degrade the activated sludge and oil and generate electrons and protons. The electrons flow from the anode material through the external circuit to the cathode electrode material, and form a current loop with protons to generate electricity.

[0011] The Stenotrophomonas acidaminiphila CGMCC No. 22273 is recorded in the Chinese invention patent text with the publication number CN113430134B.

[0012] In an embodiment of the present invention, the nutrient solution is prepared by adding cellobiose C 12 H 22 O 11 : 0.1-2 g, KH2PO4: 0.1-2 g, K2HPO4·3H2O: 0.1-2 g, (NH4)3C6H5O7: 0.1-2 g, NaCl: 0.01-0.1 g, NH4Cl: 0.1-1 g, MgCl2: 0.1-1 g, CaCl2: 0.1-0.5 g, CH3COONa: 1-5 g into 1 L of deionized water and mixing evenly;

[0013] The phosphate buffer solution is prepared by adding Na2HPO4·7H2O: 2-3 g, NaH2PO4: 4-5 g, NaCl: 2-3 g into 1 L of deionized water and mixing evenly.

[0014] In an embodiment of the present invention, the nutrient solution is prepared by adding C 12 H 22O 11 : 0.38 g of KH₂PO₄, 0.21 g of K₂HPO₄·3H₂O, 0.12 g of (NH₄)₃C₆H₅O₇, 0.07 g of NaCl, 0.40 g of NH₄Cl, 0.40 g of MgCl₂, 0.12 g of CaCl₂, 1 g of CH₃COONa were added to 1 L of deionized water and mixed evenly;

[0015] The phosphate buffer solution is: 2.75 g of Na₂HPO₄·7H₂O, 4.22 g of NaH₂PO₄, 2.93 g of NaCl were added to 1 L of deionized water and mixed evenly.

[0016] In one embodiment of the present invention, when the output voltage drops suddenly or is lower than 28 mV, the inoculation liquid is updated, and 10 - 20% of the original inoculation liquid is retained.

[0017] In one embodiment of the present invention, the addition amount of the edible oil is at least: 0.1 - 5 g.

[0018] In one embodiment of the present invention, at least 2% (w / v) of engine oil is added to the reaction system.

[0019] In one embodiment of the present invention, the preparation method of the Stenotrophomonas acidaminiphila CGMCC No.22273 bacterial liquid is: activating the Stenotrophomonas acidaminiphila and inoculating it into the LB liquid medium, and culturing it in a shaking incubator at a constant temperature. The culture temperature is 25 - 35 °C, and the culture time is: 40 h.

[0020] In one embodiment of the present invention, the anode electrode material of the microbial fuel cell is carbon cloth, and the cathode electrode material is carbon cloth loaded with 0.2 - 0.6 g / cm 2 of Pt / C catalyst.

[0021] The present invention also provides a method for treating oil pollutants by a Stenotrophomonas acidaminiphila - enhanced microbial fuel cell. The method is to immerse the cathode and anode electrode materials connected by metal wires in the inoculation liquid, add edible oil or engine oil, and let it stand. Use the bacterial liquid to degrade activated sludge and oil and generate electrons and protons. The electrons flow from the anode material through the external circuit to the cathode electrode material, and form a current loop with protons to generate electricity;

[0022] The inoculation liquid is: the Stenotrophomonas acidaminiphila CGMCC No.22273 bacterial liquid, nutrient solution, phosphate buffer solution, and activated sludge are mixed in a volume ratio of (1 - 5):(1 - 5):(1 - 3):(2 - 4) to make the inoculation liquid.

[0023] In one embodiment of the present invention, the method includes the following steps:

[0024] ① Strain preparation and activation: Activate Stenotrophomonas acidaminiphila and inoculate it into LB liquid medium, then place it in a shaking incubator for constant-temperature cultivation. The cultivation temperature is 25 - 35°C, and the cultivation time is 40h.

[0025] ② Inoculation of the chamber bacterial liquid in the single-chamber microbial fuel cell: Mix the cultivated bacterial liquid with nutrient solution, buffer solution, and activated sludge according to the volume ratio of (1 - 5):(1 - 5):(1 - 3):(2 - 4) to prepare an inoculation solution, and then inoculate it into the single-chamber microbial fuel cell device, submerging the anode electrode material in the inoculation solution. Let it stand still to utilize the bacterial liquid to degrade activated sludge and edible oil and generate electrons and protons. The electrons reach the cathode through the external circuit and form a current loop with protons to generate electricity.

[0026] ③ Renewal of the inoculation solution: Renew the inoculation solution once when the output voltage drops suddenly or is lower than 30mV, and retain 10 - 20% of the original mixture, which includes bacterial liquid, nutrient solution, buffer solution, sludge, and oil pollutants.

[0027] In one embodiment of the present invention, the LB liquid medium in step ① includes 10g of tryptone, 5g of yeast extract powder, 10g of sodium chloride, and 1L of water.

[0028] In one embodiment of the present invention, the nutrient solution in step ② is an organic matter or a mixture of nitrogen source, inorganic salts, and trace elements or a mixture of organic matter, nitrogen source, inorganic salts, and trace elements.

[0029] In one embodiment of the present invention, the Stenotrophomonas acidaminiphila includes, but is not limited to, Stenotrophomonas acidaminiphila, Stenotrophomonas acidaminiphila fermentation broth, and Stenotrophomonas acidaminiphila metabolites.

[0030] In one embodiment of the present invention, the buffer solution selected in step ② is a PBS buffer solution with a molar concentration of 0.2 - 1.0mmol / L.

[0031] In one embodiment of the present invention, the microbial fuel cell is a single-chamber microbial fuel cell, the anode is carbon cloth, and the cathode is carbon cloth loaded with Pt / C catalyst of 0.2 - 0.6g / cm 2 of.

[0032] In one embodiment of the present invention, the nutrient solution is, by mixing gentiobiose C 12 H 22 O 11: 0.1 - 2 g, KH2PO4: 0.1 - 2 g, K2HPO4·3H2O: 0.1 - 2 g, (NH4)3C6H5O7: 0.1 - 2 g, NaCl: 0.01 - 0.1 g, NH4Cl: 0.1 - 1 g, MgCl2: 0.1 - 1 g, CaCl2: 0.1 - 0.5 g, CH3COONa: 1 - 5 g, are added to 1 L of deionized water and mixed evenly;

[0033] The phosphate buffer solution is: Na2HPO4·7H2O: 2 - 3 g, NaH2PO4: 4 - 5 g, NaCl: 2 - 3 g, which are added to 1 L of deionized water and mixed evenly.

[0034] In one embodiment of the present invention, the nutrient solution is prepared by adding C 12 H 22 O 11 : 0.38 g, KH2PO4: 0.21 g, K2HPO4·3H2O: 0.21 g, (NH4)3C6H5O7: 0.12 g, NaCl: 0.07 g, NH4Cl: 0.40 g, MgCl2: 0.40 g, CaCl2: 0.12 g, CH3COONa: 1 g, to 1 L of deionized water and mixing evenly;

[0035] The phosphate buffer solution is: Na2HPO4·7H2O: 2.75 g, NaH2PO4: 4.22 g, NaCl: 2.93 g, which are added to 1 L of deionized water and mixed evenly.

[0036] In one embodiment of the present invention, the addition amount of the edible oil is at least: 0.1 - 5 g.

[0037] In one embodiment of the present invention, at least 2% (w / v) of engine oil is added to the reaction system.

[0038] The present invention also provides the application of the above single - chamber microbial fuel cell in treating oil pollutants in the environmental field.

[0039] In one embodiment of the present invention, the oil pollutants include but are not limited to petroleum hydrocarbon wastewater, kitchen waste oil pollutants, engine oil - polluted wastewater, etc.

[0040] Beneficial effects

[0041] (1) In the present invention, microorganisms with electro - catalytic activity are used to replace traditional expensive materials (such as noble metals like platinum) as catalysts for electrochemical reactions, and the operation process is relatively mild; it can achieve the direct conversion of chemical energy into electrical energy; and no secondary pollution is generated during the treatment process.

[0042] (2) The microbial fuel cell of the present invention has the dual functions of treating sewage and generating electricity, meeting the requirements of sustainable development and promoting its application in the field of wastewater treatment, which has become the main trend of the future development of MFC technology.

[0043] (3) The present invention provides a method for treating oil pollutants by using Stenotrophomonas acidaminiphila to enhance a microbial fuel cell. Applying Stenotrophomonas acidaminiphila to a microbial fuel cell based on the treatment of oil pollutants can utilize microorganisms to degrade pollutants without generating secondary pollution while generating electricity, effectively enhancing the biodegradation of pollutants.

[0044] Therefore, the method for treating oil pollutants by using the microbial fuel cell of Stenotrophomonas acidaminiphila in the present invention is conducive to the sustainable development of the ecological environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 : Preliminary inference of the degradation pathway of diphenylamine (substances not detected by GC-MS are in parentheses). DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] The activated sludge involved in the following embodiments was taken from: Jiangbian Sewage Treatment Plant in Changzhou, with a moisture content of: 99.8%, and a sludge concentration of 3 - 4 g / L.

[0047] The culture media involved in the following embodiments are as follows:

[0048] LB liquid culture medium: Tryptone, 10 g / L; NaCl, 10 g / L; Yeast extract powder, 5 g / L, deionized water 1 L.

[0049] The detection methods involved in the following embodiments are as follows:

[0050] COD determination method: In accordance with GB11914 - 89 "Determination of Chemical Oxygen Demand".

[0051] Determination method for oil content in wastewater: In accordance with SY / T5329 - 94 "Recommended Indexes and Analytical Methods for Injection Water Quality in Clastic Rock Reservoirs".

[0052] Technical terms:

[0053] Microbial fuel cell technology: Through the metabolic action of microorganisms, the catalytic conversion of organic substances in water is achieved to generate bioelectricity. This water treatment technology has obvious advantages compared with traditional water treatment technologies, realizing the secondary utilization of organic pollutants in water. It has changed the traditional concept of water treatment technology, regarding organic pollutants in water as a renewable energy source to alleviate the energy crisis.

[0054] Working principle of the microbial fuel cell:

[0055] The MFC uses functional microorganisms enriched on the anode surface as catalysts to decompose organic matter, achieving the conversion of chemical energy into electrical energy. The treatment process is not only green and efficient but also reuses the organic matter in wastewater. It is a new type of energy conversion device and is regarded as an ideal alternative to traditional fossil fuels.

[0056] A typical microbial fuel cell consists of the following four parts: an anode chamber, a cathode chamber, a proton exchange membrane, and an external circuit.

[0057] The anode and cathode chambers are separated by a proton exchange membrane. Its working principle is as follows: In the anode chamber, organic matter is oxidized by microorganisms under anaerobic conditions. The released electrons are transferred from the organisms to the anode in various forms and then transmitted to the cathode through the external circuit. At the same time, the generated protons diffuse through the proton exchange membrane into the cathode chamber and undergo reduction with the electron acceptor and electrons. In addition to oxygen widely used as an electron acceptor, there are also ferricyanide, potassium permanganate, and various components in wastewater, such as nitrates. The anode substrate is continuously oxidized by microorganisms to generate an electron flow, continuously outputting electrical energy to the external circuit to maintain stable power supply. Among them, the anode, as the "core" of the MFC, plays an extremely important role, mainly reflected in three aspects: (1) The place for microbial enrichment and reproduction; (2) The center for electrons to be transmitted to the external circuit; (3) Catalytic conversion of refractory organic matter in water.

[0058] Oil pollutants: Oil pollutants include "petroleum" pollutants and "animal and vegetable oil" pollutants. The development of oil in coastal areas and estuaries, oil tanker transportation, the discharge of wastewater from the oil refining industry, inland water transportation, and the large discharge of domestic wastewater, etc., will all cause oil pollution in water bodies. Oil pollutants can form an oil film on the water surface, affecting the entry of oxygen into the water body and destroying the dissolved oxygen conditions of the water body.

[0059] Example 1: Preparation of a microbial fuel cell (adding edible oil)

[0060] The specific steps are as follows:

[0061] (1) Inoculate Stenotrophomonas acidaminiphila CGMCC No.22273 into 100 mL of LB liquid medium at an inoculation amount of 2% by volume, and activate it at 30 °C and 140 rpm. After activation, inoculate the Stenotrophomonas acidaminiphila into fresh LB liquid medium at an inoculation amount of 0.2% by volume, and place it in a shaking incubator for constant temperature culture. The culture temperature is 25 - 35 °C, and the culture time is 40 h to obtain a bacterial solution with a bacterial concentration of 8×10 8 cells / mL.

[0062] (2) Preparation of the nutrient solution for the anode chamber of the microbial fuel cell:

[0063] Take C 12 H22 O 11 : 0.38 g of KH₂PO₄, 0.21 g of K₂HPO₄·3H₂O, 0.12 g of (NH₄)₃C₆H₅O₇, 0.07 g of NaCl, 0.40 g of NH₄Cl, 0.40 g of MgCl₂, 0.12 g of CaCl₂, 1 g of CH₃COONa were added to 1 L of deionized water and mixed evenly.

[0064] (3) Preparation of the buffer solution for the anode chamber of the microbial fuel cell:

[0065] 2.75 g of Na₂HPO₄·7H₂O, 4.22 g of NaH₂PO₄, 2.93 g of NaCl were added to 1 L of deionized water and mixed evenly.

[0066] (4) Preparation of the electrode solution for the microbial fuel cell:

[0067] The bacterial solution prepared in step (1), the nutrient solution prepared in step (2), the buffer solution obtained in step (3), and the activated sludge were mixed evenly according to a volume ratio of 1.5:3:1:2 to prepare the electrode solution.

[0068] (5) Preparation of the electrodes for the microbial fuel cell:

[0069] Carbon paper with dimensions of 40×50×2 mm was selected as the anode and cathode electrodes of the single-chamber MFC. Before use, the anode was boiled in deionized boiling water for 2 h, then naturally dried and connected to a titanium wire with a diameter of 1 mm for standby.

[0070] The cathode electrode consists of a catalytic layer and a waterproof layer. The preparation process of the cathode is as follows:

[0071] 1) The carbon paper was boiled in deionized boiling water for 2 h and then taken out and naturally dried;

[0072] 2) The dried carbon paper was immersed in a 30% PTFE solution for 30 min and then taken out and naturally dried;

[0073] 3) The dried carbon paper was placed in a muffle furnace and burned at 370 °C for 20 min and then taken out;

[0074] 4) A layer of carbon base layer (composed of 5 g of conductive carbon black + 50 mL of 40% PTFE) was evenly coated on one side of the waterproof layer of the carbon paper and then naturally dried;

[0075] 5) The dried carbon paper was placed in a muffle furnace and burned at 370 °C for 20 min and then taken out;

[0076] 6) A layer of 60% PTFE solution was evenly coated on the carbon base layer and dried, and then burned in a muffle furnace at 370 °C for 20 min (this step was repeated four times);

[0077] 7) Apply a layer of conductive silver paste evenly on one side of the carbon paper catalytic layer. Weigh 0.18 g of powdered activated carbon and use a brush to evenly attach the activated carbon to the conductive silver paste, then let it dry naturally.

[0078] (6) Operation of the microbial fuel cell:

[0079] Place the electrode solution in the microbial fuel cell and mix it evenly, then add 1 g of edible oil. The electrode distance between the cathode and the anode is 2 cm, and the cathode and anode are connected by titanium wire. Use a data collector to record the output voltage.

[0080] When the output voltage drops suddenly or is lower than 30 mV, take out 80% of the mixed solution in the anode chamber, then inoculate the fresh electrode solution into the microbial fuel cell and add 1 g of edible oil.

[0081] When the output voltage remains stable for 4 consecutive cycles, it indicates that the microbial fuel cell operates successfully.

[0082] (7) Experimental results: During the operation cycle, the output voltage of the microbial fuel cell can reach up to about 550 mV at most, the COD removal rate reaches 65%, and the degradation rate of oil reaches 74.11%. The edible oil before and after the reaction is detected by GC-MS, and the results are shown in Table 1 and Table 2.

[0083] Table 1: GC-MS analysis of edible oil before reaction

[0084]

[0085] Table 2: GC-MS analysis after reaction

[0086]

[0087] The results show that ethyl acetate is degraded to acetic acid, and bis(2-ethylhexyl) phthalate and diethyl 2,2-bis(acetyloxy)propane-1,3-dicarboxylate are completely degraded.

[0088] Example 2: Preparation of a microbial fuel cell without adding Stenotrophomonas acidaminiphila CGMCC No. 22273 (adding edible oil)

[0089] The specific steps are as follows:

[0090] (1) Preparation of the nutrient solution in the anode chamber of the microbial fuel cell:

[0091] Place C 12 H 22 O 11: 0.38 g of KH₂PO₄, 0.21 g of K₂HPO₄·3H₂O, 0.12 g of (NH₄)₃C₆H₅O₇, 0.07 g of NaCl, 0.40 g of NH₄Cl, 0.40 g of MgCl₂, 0.12 g of CaCl₂, 1 g of CH₃COONa were added to 1 L of deionized water and mixed evenly.

[0092] (2) Preparation of the buffer solution for the anode chamber of the microbial fuel cell:

[0093] 2.75 g of Na₂HPO₄·7H₂O, 4.22 g of NaH₂PO₄, 2.93 g of NaCl were added to 1 L of deionized water and mixed evenly.

[0094] (3) Preparation of the electrode solution for the microbial fuel cell:

[0095] The nutrient solution prepared in step (1), the buffer solution prepared in step (2), and the activated sludge were mixed evenly at a volume ratio of 3:1:2.

[0096] (4) Preparation of the electrodes for the microbial fuel cell:

[0097] Carbon paper with dimensions of 40×50×2 mm was selected as the anode and cathode electrodes of the single-chamber MFC. Before use, the anode was boiled in deionized boiling water for 2 h, then air-dried and connected to a titanium wire with a diameter of 1 mm for standby.

[0098] The cathode electrode consists of a catalytic layer and a waterproof layer. The preparation process of the cathode is as follows:

[0099] 1) The carbon paper was boiled in deionized boiling water for 2 h and then taken out and air-dried;

[0100] 2) The air-dried carbon paper was soaked in a 30% PTFE solution for 30 min and then taken out and air-dried;

[0101] 3) The air-dried carbon paper was placed in a muffle furnace and burned at 370 °C for 20 min and then taken out;

[0102] 4) A layer of carbon substrate (composed of 5 g of conductive carbon black + 50 mL of 40% PTFE) was evenly coated on one side of the waterproof layer of the carbon paper and then air-dried;

[0103] 5) The air-dried carbon paper was placed in a muffle furnace and burned at 370 °C for 20 min and then taken out;

[0104] 6) A layer of 60% PTFE solution was evenly coated on the carbon substrate, air-dried and then burned in a muffle furnace at 370 °C for 20 min (this step was repeated four times);

[0105] (7) Apply a layer of conductive silver paste evenly on one side of the carbon paper catalyst layer. Weigh 0.18 g of powdered activated carbon and evenly attach the activated carbon to the conductive silver paste with a brush, and then let it dry naturally.

[0106] (5) Operation of the microbial fuel cell:

[0107] Place the electrode solution in the microbial fuel cell and mix it evenly. Then add 1 g of edible oil to it. The electrode distance between the cathode and the anode is 2 cm. The cathode and the anode are connected by titanium wires, and a data collector is used to record the output voltage.

[0108] When the output voltage drops suddenly or is lower than 30 mV, take out 80% of the mixed solution in the anode chamber, then inoculate the fresh electrode solution into the microbial fuel cell, and add 1 g of edible oil again.

[0109] When the output voltage remains stable for 4 consecutive cycles, it indicates that the microbial fuel cell operates successfully.

[0110] Experimental results: During the operation cycle, the maximum output voltage of the microbial fuel cell can reach about 290 mV, the COD removal rate reaches 36%, and the degradation rate of oils reaches 30%. The reacted edible oil was detected by GC-MS, and the results are shown in Table 3.

[0111] Table 3: GCMS analysis after reaction

[0112]

[0113] The results show that ethyl acetate can be degraded into acetic acid, but bis(2-ethylhexyl) phthalate and diethyl 2,2-diacetate-1,3-dioxolane cannot be degraded.

[0114] Example 3: Preparation of a microbial fuel cell with only Stenotrophomonas acidaminiphila CGMCC No. 22273 and no activated sludge (without adding activated sludge)

[0115] The specific steps are as follows:

[0116] (1) Inoculate Stenotrophomonas acidaminiphila CGMCC No. 22273 into 100 mL of LB liquid medium at an inoculation amount of 2% by volume, and activate it at 30 °C and 140 rpm. The activated Stenotrophomonas acidaminiphila is inoculated into fresh LB liquid medium at an inoculation amount of 0.2% by volume, and placed in a shaking incubator for constant temperature culture. The culture temperature is 25 - 35 °C, and the culture time is 40 h to obtain a bacterial solution, and the bacterial concentration in the bacterial solution is 8×10 8 cells / mL.

[0117] (2) Preparation of the nutrient solution for the anode chamber of the microbial fuel cell:

[0118] Add C 12 H 22 O 11 : 0.38 g, KH2PO4: 0.21 g, K2HPO4·3H2O: 0.21 g, (NH4)3C6H5O7: 0.12 g, NaCl: 0.07 g, NH4Cl: 0.40 g, MgCl2: 0.40 g, CaCl2: 0.12 g, CH3COONa: 1 g, and add them to 1 L of deionized water and mix evenly.

[0119] (3) Preparation of the buffer solution for the anode chamber of the microbial fuel cell:

[0120] Na2HPO4·7H2O: 2.75 g, NaH2PO4: 4.22 g, NaCl: 2.93 g, and add them to 1 L of deionized water and mix evenly.

[0121] (4) Preparation of the electrode solution for the microbial fuel cell:

[0122] Mix the bacterial solution prepared in step (1), the nutrient solution prepared in step (2), and the buffer solution obtained in step (3) evenly according to a volume ratio of 1.5:3:1 to prepare the electrode solution.

[0123] (5) Preparation of the electrodes of the microbial fuel cell:

[0124] Select carbon paper with dimensions of 40×50×2 mm as the anode and cathode electrodes of the single-chamber MFC. Before use, boil the anode in deionized boiling water for 2 h, then let it dry naturally and connect it to a titanium wire with a diameter of 1 mm for standby.

[0125] The cathode electrode consists of a catalytic layer and a waterproof layer. The preparation process of the cathode is as follows:

[0126] 1) Boil the carbon paper in deionized boiling water for 2 h, then take it out and let it dry naturally;

[0127] 2) Immerse the dried carbon paper in a 30% PTFE solution for 30 min, then take it out and let it dry naturally;

[0128] 3) Put the dried carbon paper into a muffle furnace and bake it at 370 °C for 20 min, then take it out;

[0129] 4) Evenly apply a layer of carbon base (composed of 5 g of conductive carbon black + 50 mL of 40% PTFE) on one side of the waterproof layer of the carbon paper, then let it dry naturally;

[0130] 5) Put the dried carbon paper into a muffle furnace and bake it at 370 °C for 20 min, then take it out;

[0131] (6) Apply a 60% PTFE solution evenly on the carbon base layer, dry it in air, and then bake it in a muffle furnace at 370 °C for 20 min (repeat this step four times).

[0132] (7) Apply a layer of conductive silver paste evenly on one side of the carbon paper catalytic layer. Weigh 0.18 g of powdered activated carbon, and evenly attach the activated carbon to the conductive silver paste with a brush, and then dry it in air.

[0133] (6) Operation of the microbial fuel cell:

[0134] Place the electrode solution in the microbial fuel cell and mix it evenly. Then add 1 g of edible oil. The electrode distance between the cathode and the anode is 2 cm. The cathode and the anode are connected by titanium wires, and a data collector is used to record the output voltage.

[0135] When the output voltage drops suddenly or is lower than 30 mV, take out 80% of the mixed liquid in the anode chamber, then inoculate the fresh electrode solution into the microbial fuel cell, and add 1 g of edible oil.

[0136] When the output voltage remains stable for 4 consecutive cycles, it indicates that the operation of the microbial fuel cell is successful.

[0137] Experimental results: During the operation cycle, the output voltage of the microbial fuel cell can reach up to about 380 mV at most, the COD removal rate reaches 50%, and the degradation rate of oils reaches 55%. The reacted edible oil was detected by GC-MS, and the results are shown in Table 4.

[0138] Table 4: GCMS analysis after reaction

[0139]

[0140] The results show that ethyl acetate can be degraded into acetic acid, but bis(2-ethylhexyl) phthalate and diethyl 2,2-diacetoxy-1,3-dioxolane cannot be degraded.

[0141] Example 4: Preparation of microbial fuel cell (adding engine oil)

[0142] The specific steps are as follows:

[0143] (1) Inoculate Stenotrophomonas acidaminiphila CGMCC No. 22273 into 100 mL of LB liquid medium at an inoculation amount of 2% by volume, activate it at 30 °C and 140 rpm, and then inoculate the activated Stenotrophomonas acidaminiphila into fresh LB liquid medium at an inoculation amount of 0.2% by volume, and place it in a shaking incubator for constant temperature culture. The culture temperature is 25 - 35 °C, and the culture time is 40 h to obtain a bacterial solution with a bacterial concentration of \(8\times10\) 8 cells / mL.

[0144] (2) Preparation of the nutrient solution for the anode chamber of the microbial fuel cell:

[0145] Dissolve C 12 H 22 O 11 : 0.38 g, KH2PO4: 0.21 g, K2HPO4·3H2O: 0.21 g, (NH4)3C6H5O7: 0.12 g, NaCl: 0.07 g, NH4Cl: 0.40 g, MgCl2: 0.40 g, CaCl2: 0.12 g, CH3COONa: 1 g into 1 L of deionized water and mix evenly.

[0146] (3) Preparation of the buffer solution for the anode chamber of the microbial fuel cell:

[0147] Dissolve Na2HPO4·7H2O: 2.75 g, NaH2PO4: 4.22 g, NaCl: 2.93 g into 1 L of deionized water and mix evenly.

[0148] (4) Preparation of the electrode solution for the microbial fuel cell:

[0149] Mix the bacterial solution prepared in step (1), the nutrient solution prepared in step (2), the buffer solution obtained in step (3), and the activated sludge evenly according to a volume ratio of 1.5:3:1:2 to prepare the electrode solution.

[0150] (5) Preparation of the electrodes for the microbial fuel cell:

[0151] Select a carbon paper with dimensions of 40×50×2 mm as the anode and cathode electrodes of the single-chamber MFC. Before use, boil the anode in deionized boiling water for 2 h, then let it dry naturally and connect it to a titanium wire with a diameter of 1 mm for standby.

[0152] The cathode electrode consists of a catalytic layer and a waterproof layer. The preparation process of the cathode is as follows:

[0153] 1) Boil the carbon paper in deionized boiling water for 2 h, then take it out and let it dry naturally;

[0154] 2) Immerse the dried carbon paper in a 30% PTFE solution for 30 min, then take it out and let it dry naturally;

[0155] 3) Put the dried carbon paper into a muffle furnace and bake it at 370 °C for 20 min, then take it out;

[0156] 4) Evenly apply a layer of carbon base (composed of 5 g of conductive carbon black + 50 mL of 40% PTFE) on one side of the waterproof layer of the carbon paper, then let it dry naturally;

[0157] 5) Put the dried carbon paper into a muffle furnace and bake it at 370 °C for 20 min, then take it out;

[0158] (6) A 60% PTFE solution was evenly coated on the carbon substrate, and after air drying, it was calcined in a muffle furnace at 370 °C for 20 min (this step was repeated four times).

[0159] (7) A layer of conductive silver paste was evenly coated on one side of the carbon paper catalyst layer. 0.18 g of powdered activated carbon was weighed, and the activated carbon was evenly attached to the conductive silver paste with a brush and then air dried naturally.

[0160] (6) Operation of the microbial fuel cell:

[0161] The electrode solution was placed in the microbial fuel cell and mixed evenly, and then 2% (w / v) of engine oil was added thereto. The electrode distance between the cathode and the anode was 2 cm, and the cathode and the anode were connected by a titanium wire. A data collector was used to record the output voltage.

[0162] When the output voltage dropped suddenly or was lower than 30 mV, 80% of the mixed liquid in the anode chamber was taken out, and then fresh electrode solution was inoculated into the microbial fuel cell, and 2% (w / v) of engine oil was added again.

[0163] When the output voltage remained stable for 4 consecutive cycles, it indicated that the operation of the microbial fuel cell was successful.

[0164] Experimental results: During the operation cycle, the output voltage of the microbial fuel cell could reach up to about 380 mV at most, the COD removal rate reached 66%, and the degradation rate of oils reached 78%. The engine oil before and after the reaction was detected by GC-MS, and the results are shown in Table 5 and Table 6.

[0165] Table 5: GC-MS analysis of engine oil before the reaction

[0166]

[0167] Table 6: GC-MS analysis of metabolites during the degradation of engine oil

[0168]

[0169] The results showed that diphenylamine existed in the engine oil before degradation, but diphenylamine was not detected in the wastewater after degradation (the preliminary inference of the diphenylamine degradation pathway is as Figure 1 shown), but four intermediate products, tetradecane, n-pentadecane, 2,4-di-tert-butylphenol, 1-hexadecanol, and hexacosane, were obtained.

[0170] Example 5: Preparation of a microbial fuel cell without adding Stenotrophomonas acidaminiphila CGMCC No. 22273 (adding engine oil)

[0171] The specific steps are as follows:

[0172] (1) Preparation of the nutrient solution in the anode chamber of the microbial fuel cell:

[0173] Add C 12 H 22 O 11 : 0.38 g, KH2PO4: 0.21 g, K2HPO4·3H2O: 0.21 g, (NH4)3C6H5O7: 0.12 g, NaCl: 0.07 g, NH4Cl: 0.40 g, MgCl2: 0.40 g, CaCl2: 0.12 g, CH3COONa: 1 g into 1 L of deionized water and mix evenly.

[0174] (2) Preparation of the buffer solution in the anode chamber of the microbial fuel cell:

[0175] Add Na2HPO4·7H2O: 2.75 g, NaH2PO4: 4.22 g, NaCl: 2.93 g into 1 L of deionized water and mix evenly.

[0176] (3) Preparation of the electrode solution of the microbial fuel cell:

[0177] Mix the nutrient solution, buffer solution and activated sludge evenly according to the volume ratio of 3:1:2.

[0178] (4) Preparation of the electrodes of the microbial fuel cell:

[0179] Select carbon paper with a size of 40×50×2 mm as the anode and cathode electrodes of the single-chamber MFC. Before use, boil the anode in deionized boiling water for 2 h, then let it dry naturally and connect it to a titanium wire with a diameter of 1 mm for standby.

[0180] The cathode electrode consists of a catalytic layer and a waterproof layer. The preparation process of the cathode is as follows:

[0181] 1) Boil the carbon paper in deionized boiling water for 2 h, then take it out and let it dry naturally;

[0182] 2) Immerse the dried carbon paper in 30% PTFE solution for 30 min, then take it out and let it dry naturally;

[0183] 3) Put the dried carbon paper into a muffle furnace and bake it at 370 °C for 20 min, then take it out;

[0184] 4) Evenly apply a layer of carbon base (composed of 5 g of conductive carbon black + 50 mL of 40% PTFE) on one side of the waterproof layer of the carbon paper, then let it dry naturally;

[0185] 5) Put the dried carbon paper into a muffle furnace and bake it at 370 °C for 20 min, then take it out;

[0186] (6) Apply a 60% PTFE solution evenly on the carbon substrate layer. After air drying, bake it in a muffle furnace at 370 °C for 20 min (repeat this step four times).

[0187] (7) Apply a layer of conductive silver paste evenly on one side of the carbon paper catalytic layer. Weigh 0.18 g of powdered activated carbon and use a brush to evenly attach the activated carbon to the conductive silver paste, then let it air dry naturally.

[0188] (5) Operation of the microbial fuel cell:

[0189] Place the electrode solution in the microbial fuel cell and mix it evenly. Then add 2% (w / v) of engine oil. The electrode distance between the cathode and the anode is 2 cm. Connect the cathode and the anode with titanium wires, and use a data acquisition device to record the output voltage.

[0190] When the output voltage drops suddenly or is lower than 30 mV, take out 80% of the mixed solution in the anode chamber, then inoculate fresh electrode solution into the microbial fuel cell and add 2% (w / v) of engine oil.

[0191] When the output voltage remains stable for 4 consecutive cycles, it indicates that the operation of the microbial fuel cell is successful.

[0192] Experimental results: During the operation cycle, the maximum output voltage of the microbial fuel cell can reach about 180 mV, the COD removal rate reaches 30%, and the degradation rate of oil reaches 28%. Use GC-MS to detect the engine oil after the reaction, and diphenylamine can be detected.

[0193] Example 6: Preparation of a microbial fuel cell (adding engine oil) with only Stenotrophomonas acidaminiphila CGMCC No. 22273 and no activated sludge

[0194] The specific steps are as follows:

[0195] (1) Inoculate Stenotrophomonas acidaminiphila CGMCC No. 22273 into 100 mL of LB liquid medium at an inoculation amount of 2% by volume, and activate it at 30 °C and 140 rpm. After activation, inoculate the activated Stenotrophomonas acidaminiphila into fresh LB liquid medium at an inoculation amount of 0.2% by volume, and place it in a shaking incubator for constant temperature culture. The culture temperature is 25 - 35 °C, and the culture time is 40 h to obtain a bacterial solution with a bacterial concentration of 8×10 8 cells / mL.

[0196] (2) Preparation of the nutrient solution for the anode chamber of the microbial fuel cell:

[0197] Place C 12 H 22 O 11: 0.38 g, KH2PO4: 0.21 g, K2HPO4·3H2O: 0.21 g, (NH4)3C6H5O7: 0.12 g, NaCl: 0.07 g, NH4Cl: 0.40 g, MgCl2: 0.40 g, CaCl2: 0.12 g, CH3COONa: 1 g, are added to 1 L of deionized water and mixed evenly.

[0198] (3) Preparation of the buffer solution for the anode chamber of the microbial fuel cell:

[0199] Na2HPO4·7H2O: 2.75 g, NaH2PO4: 4.22 g, NaCl: 2.93 g, are added to 1 L of deionized water and mixed evenly.

[0200] (4) Preparation of the electrode solution for the microbial fuel cell:

[0201] The bacterial solution prepared in step (1), the nutrient solution prepared in step (2), and the buffer solution obtained in step (3) are mixed evenly according to a volume ratio of 1.5:3:1 to prepare the electrode solution.

[0202] (5) Preparation of the electrodes for the microbial fuel cell:

[0203] Carbon paper with dimensions of 40×50×2 mm is selected as the anode and cathode electrodes of the single-chamber MFC. Before use, the anode is boiled in deionized boiling water for 2 h, then naturally dried and connected to a titanium wire with a diameter of 1 mm for standby.

[0204] The cathode electrode consists of a catalytic layer and a waterproof layer. The preparation process of the cathode is as follows:

[0205] 1) The carbon paper is boiled in deionized boiling water for 2 h and then taken out and naturally dried;

[0206] 2) The dried carbon paper is immersed in a 30% PTFE solution for 30 min and then taken out and naturally dried;

[0207] 3) The dried carbon paper is placed in a muffle furnace and burned at 370 °C for 20 min and then taken out;

[0208] 4) A layer of carbon base layer (composed of 5 g of conductive carbon black + 50 mL of 40% PTFE) is evenly coated on one side of the waterproof layer of the carbon paper and then naturally dried;

[0209] 5) The dried carbon paper is placed in a muffle furnace and burned at 370 °C for 20 min and then taken out;

[0210] 6) A layer of 60% PTFE solution is evenly coated on the carbon base layer, dried and then burned in a muffle furnace at 370 °C for 20 min (this step is repeated four times);

[0211] (7) Apply a layer of conductive silver paste evenly on one side of the carbon paper catalytic layer. Weigh 0.18 g of powdered activated carbon and evenly attach the activated carbon to the conductive silver paste with a brush, then let it dry naturally.

[0212] (6) Operation of the microbial fuel cell:

[0213] Place the electrode solution in the microbial fuel cell and mix it evenly, then add 2% (w / v) of engine oil. The electrode distance between the cathode and the anode is 2 cm, and the cathode and anode are connected by titanium wires. Use a data collector to record the output voltage.

[0214] When the output voltage drops suddenly or is lower than 30 mV, take out 80% of the mixed solution in the anode chamber, then inoculate fresh electrode solution into the microbial fuel cell and add 2% (w / v) of engine oil.

[0215] When the output voltage remains stable for 4 consecutive cycles, it indicates that the operation of the microbial fuel cell is successful.

[0216] Experimental results: During the operation cycle, the maximum output voltage of the microbial fuel cell can reach about 260 mV, the COD removal rate reaches 40%, and the degradation rate of oil reaches 45%. The reacted engine oil is detected by GC-MS, and diphenylamine can be detected.

[0217] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with this technology can make various modifications and decorations without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. A method for treating oil pollutants by using a single-chamber microbial fuel cell enhanced by oligotrophic monocytogenes microacidophilus, characterized in that: The method comprises immersing cathode and anode electrode materials connected by metal wires in an electrode solution, adding 0.1 to 5 g of edible oil, and allowing the solution to stand. The bacterial solution is used to degrade activated sludge and oil to generate electrons and protons. The electrons travel from the anode electrode material through an external circuit to the cathode electrode material, forming a current loop with the protons to generate electricity. The edible oil contains di(2-ethylhexyl) phthalate and diethyl 1,3-dioxolane-2,2-diacetate. The electrode liquid is prepared by mixing a microacidophilic oligotrophic monocytogenes CGMCC No. 22273 bacterial solution, a nutrient solution, a phosphate buffer solution, and activated sludge in a volume ratio of 1.5:3:1:

2. The nutrient solution is gentiobiose C 12 H 22 O 11 :0.1~2 g, KH2PO4: 0.1~2 g, K2HPO4·3H2O: 0.1~2 g, (NH4)3C6H5O7: 0.1~2 g, NaCl: 0.01~0.1 g, NH4Cl: 0.1~1 g, MgCl2: 0.1~1 g, CaCl2: 0.1~0.5g, CH3COONa: 1~5 g, add to 1 L of deionized water and mix well; The phosphate buffer solution is composed of 2-3 g of Na2HPO4·7H2O, 4-5 g of NaH2PO4, and 2-3 g of NaCl, which are added to 1 L of deionized water and mixed evenly. Among them, di(2-ethylhexyl) phthalate and diethyl 1,3-dioxolane-2,2-diacetate were completely degraded.

2. The method according to claim 1, characterized in that When the output voltage drops sharply or is lower than 30 mV, the electrode solution should be renewed and 10~20% of the original electrode solution should be retained.

3. The method according to claim 1, characterized in that The preparation method of the microacidophilic oligotrophic mononas CGMCC No. 22273 bacterial liquid is as follows: after activating the microacidophilic oligotrophic mononas, inoculating it into LB liquid culture medium, and placing it in a shaking incubator for constant temperature culture at a temperature of 25-35°C.

4. The method according to any one of claims 1 to 3, characterized in that The anode electrode material of the microbial fuel cell is carbon cloth, and the cathode electrode material is a 0.2-0.6 g / cm 2 Carbon cloth with Pt / C catalyst.

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