CN107142492B - A CO conversion and utilization method - Google Patents

Abstract

The invention provides a bioelectrochemical conversion method of CO, which comprises the following steps: first, place domesticated anaerobic activated sludge, a cathode electrode, and a microbial culture medium in the cathode area, and stir, and place the anode electrode and the electron donor Placed in the anode area; the cathode area and the anode area are separated by a diaphragm; then the gas containing CO is passed into the cathode area to form an anaerobic environment, and then the electrode potential is applied to the cathode electrode to obtain gas CH ₄ . The present invention develops a new method for carbon monoxide conversion, adopts microbial electrolysis, utilizes domesticated anaerobic activated sludge, effectively overcomes the severe toxicity of carbon monoxide, and reduces carbon monoxide under different potential conditions. Produce usable biofuel methane in the state. The conversion method provided by the invention has the advantages of simple process, mild conditions and low equipment requirements, and is suitable for wide application.

Description

A CO conversion and utilization method

technical field

The invention belongs to the technical field of resource utilization of carbon monoxide, and relates to a method for converting and utilizing CO, in particular to a bioelectrochemical method for resource utilization of CO.

Background technique

Carbon monoxide (CO) is a common and common gas in industry. The pure product is colorless, odorless and non-irritating gas. Low solubility in water, extremely difficult to dissolve in water. Carbon monoxide is a product of incomplete combustion of carbon-containing substances such as coal and petroleum. It is not easy to chemically react with other substances in the air, so it can stay in the atmosphere for 2 to 3 years. If the local pollution is serious, it will be harmful to the health of the crowd.

Due to the continuous development of transportation, industrial and mining enterprises in various countries in the world, the consumption of fuels such as coal and oil continues to increase, and the emission of carbon monoxide also increases thereupon. According to incomplete statistics in 1970, the total emissions of carbon monoxide in the world reached 371 million tons. Among them, the emission of automobile exhaust gas accounts for 237 million tons, accounting for about 64%, which has become an increasingly serious source of urban air pollution. The use of heating and samovar stoves not only pollutes the indoor air, but also increases the urban air pollution. Some natural disasters, such as volcanic eruptions, forest fires, mine explosions and earthquakes, will also cause an increase in the concentration of carbon monoxide in local areas. Smoking also poses a carbon monoxide pollution hazard.

In addition to its ability to burn, carbon monoxide is the most well-known toxicity. Carbon monoxide is easily combined with hemoglobin to form carboxyhemoglobin, which makes hemoglobin lose its ability and function to carry oxygen, causing tissue suffocation and death in severe cases. Carbon monoxide has a toxic effect on tissue cells throughout the body, especially the cerebral cortex.

With the continuous development of the global economy and industry, the content of carbon monoxide, whether in by-products or exhaust gas, is increasing, especially in recent years, in metallurgy, chemistry, graphite electrode manufacturing, household gas or coal stoves, and automobile exhaust. Carbon monoxide emissions are increasing. Although carbon monoxide can be burned and reused, its toxicity is huge, and it has great potential safety hazards whether it is used in civil or industrial use. Therefore, most of these carbon monoxides are not fully utilized except that most of the furnace gas is used for combustion and heating.

Therefore, how to make full use of carbon monoxide, transform it, turn waste into wealth, and reduce its environmental pollution and harm to the population has gradually become one of the focuses of many researchers in the field.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is to provide a method for the conversion and utilization of CO, especially a bioelectrochemical method for resource utilization of CO. , to convert carbon monoxide into usable biofuel methane.

The invention provides a bioelectrochemical conversion method of CO, comprising the following steps:

1) placing the acclimated anaerobic activated sludge, the cathode electrode and the microbial culture medium in the cathode area, and stirring, and placing the anode electrode and the electron donor in the anode area; the cathode area and the anode area are separated by a diaphragm;

2) Pass CO-containing gas into the cathode area to form an anaerobic environment, and then apply electrode potential to the cathode electrode to obtain gas CH ₄ .

Preferably, in the cathode area, the mass volume ratio of the acclimatized anaerobic activated sludge to the microbial culture medium is (5-20) g: 500 mL;

The dominant bacterial species in the domesticated anaerobic activated sludge include one or more of Thermoautotrophicum, Methanobrevibacter, Methanosaeta, Methanomassiliiccus and Acetogenicbecteria.

Preferably, the CO-containing gas includes CO and diluent gas;

The electrode potential is -0.65--1.0V.

Preferably, the volume content of CO in the CO-containing gas is 10% to 60%;

The diluent gas includes nitrogen or an inert gas.

Preferably, the electron donor includes one of potassium ferrocyanide solution, water and electrogenic bacteria;

The membrane includes one or more of proton exchange membrane, anion exchange membrane and cation exchange membrane.

Preferably, the cathode electrode includes one or more of carbon felt, carbon paper, carbon cloth, carbon brush and gas diffusion electrode;

The anode electrode includes one or more of carbon felt electrodes, carbon paper, carbon cloth, carbon brushes and gas diffusion electrodes.

Preferably, the specific steps of said domestication are:

a) After mixing the anaerobic activated sludge raw material, microbial culture medium, trace element solution and vitamin solution, a mixture is obtained;

b) Under an anaerobic environment containing CO and H ₂ gases, the mixture obtained in the above steps is subjected to domestication to obtain the domesticated anaerobic activated sludge.

Preferably, in step a), the mass volume ratio of the anaerobic activated sludge raw material to the microbial culture medium is (5-20) g: 100 mL;

In the step a), the volume ratio of the trace element solution to the microbial culture medium is (1～10):500;

In the step a), the volume ratio of the vitamin solution to the microorganism culture medium is (1-10):500.

Preferably, the CO and H ₂ containing gas includes CO, H ₂ and diluent gas;

The diluent gas comprises nitrogen or an inert gas;

The volume content of H ₂ in the gas containing CO and H ₂ is 10% to 40%;

The volume content of CO in the gas containing CO and H ₂ is 10%-40%.

Preferably, the microorganism culture medium includes NH ₄ Cl, NaCl, MgSO ₄ , CaCl ₂ and buffer solution;

The buffer solution includes a phosphate buffer solution;

The trace element solution includes FeCl ₃ , H ₃ BO ₃ , CuSO ₄ , KI, MnCl ₂ , Na ₂ MoO ₄ , ZnSO ₄ , CoCl ₂ , EDTA and NiCl ₂ ;

The vitamin solution includes biotin, folic acid, vitamin B6, riboflavin, vitamin B1, niacin, pantothenic acid, vitamin B12, p-aminobenzoic acid and lipoic acid.

The invention provides a bioelectrochemical conversion method of CO, which comprises the following steps: first, place domesticated anaerobic activated sludge, a cathode electrode, and a microbial culture medium in the cathode area, and stir, and place the anode electrode and the electron donor Placed in the anode area; the cathode area and the anode area are separated by a diaphragm; then the gas containing CO is passed into the cathode area to form an anaerobic environment, and then the electrode potential is applied to the cathode electrode to obtain gas CH ₄ . Compared with the prior art, the present invention develops a new method for carbon monoxide conversion, adopts microbial electrolysis, adds microorganisms to the cathode chamber of the double-chamber microbial electrolytic cell, and reduces carbon monoxide under different potential conditions to produce usable biofuel methane . The present invention adopts the microbial electrolysis cell, which is a new type of environmental biotechnology that can carry out both pollutant treatment and energy recovery at the same time. The domesticated anaerobic activated sludge is used to effectively overcome the severe toxicity of carbon monoxide itself. At a certain potential, microorganisms can convert carbon monoxide into methane by bioelectrochemical method under normal temperature and pressure. The conversion method provided by the invention has the advantages of simple process, mild conditions and low equipment requirements, and is suitable for wide application.

Experimental results show that the bioelectrochemical conversion method provided by the invention can convert carbon monoxide into methane, and the amount of methane produced under different potential conditions is different, and the more negative the potential, the higher the methane amount.

Description of drawings

Fig. 1 is the model schematic diagram of the used microbial electrolysis cell reactor of the embodiment of the present invention 1;

Fig. 2 is the current figure under different applied potentials in the embodiment of the present invention 1;

Fig. 3 is the content diagram of producing methane under different applied potentials in Example 1 of the present invention;

Fig. 4 is a gas variation curve of the anaerobic activated sludge for carbon dioxide and the anaerobic activated sludge provided by the present invention in Comparative Example 1 of the present invention.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent requirements of the present invention.

All raw materials in the present invention have no particular limitation on their sources, they can be purchased from the market or prepared according to conventional methods well known to those skilled in the art.

The purity of all raw materials in the present invention is not particularly limited, and the present invention preferably adopts analytical purity or conventional purity requirements in the field of bioelectrochemistry.

All the raw materials of the present invention, their sources and abbreviations belong to conventional sources and abbreviations in the field, and are clear and definite in the field of their related uses. Those skilled in the art can buy them from the market or obtain them according to the abbreviations and corresponding uses. Prepared by conventional methods.

The invention provides a bioelectrochemical conversion method of CO, comprising the following steps:

1) placing the acclimated anaerobic activated sludge, the cathode electrode and the microbial culture medium in the cathode area, and stirring, and placing the anode electrode and the electron donor in the anode area; the cathode area and the anode area are separated by a diaphragm;

2) Pass CO-containing gas into the cathode area to form an anaerobic environment, and then apply electrode potential to the cathode electrode to obtain gas CH ₄ .

In the present invention, the domesticated anaerobic activated sludge, the cathode electrode and the microbial culture medium are first placed in the cathode area, and stirred, and the anode electrode and the electron donor are placed in the anode area; the cathode area and the anode area are separated by a diaphragm .

The present invention has no special restrictions on the anaerobic activated sludge, and the anaerobic activated sludge well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The present invention The anaerobic activated sludge refers to the anaerobic activated sludge usually used for sewage treatment.

The present invention has no special limitation on the source of the anaerobic activated sludge, the source of the anaerobic activated sludge well known to those skilled in the art can be used, and those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control , the anaerobic activated sludge of the present invention is preferably obtained from a sewage treatment tank.

The present invention has no special restrictions on the mixing method and conditions, and the mixing methods and conditions well known to those skilled in the art can be selected and adjusted according to actual production conditions, electrolysis requirements and product control. The mixing described in the invention preferably includes stirring and mixing, specifically magnetic stirring. In the present invention, the purpose of the mixing is to make the anaerobic activated sludge adhere to the cathode electrode material. In other embodiments, other methods can also be used, and the preferred solution is that the anaerobic activated sludge can better adhere to the cathode electrode material.

The present invention has no special limitation on the cathode electrode, and the cathode material for microbial electrolysis well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. Described cathode electrode preferably comprises one or more in carbon felt, carbon paper, carbon cloth, carbon brush and gas diffusion electrode, is more preferably carbon felt, carbon paper, carbon cloth, carbon brush or gas diffusion electrode, most preferably is carbon felt.

In order to enable the anaerobic activated sludge to resist the toxicity of carbon monoxide, convert the carbon monoxide, and provide conversion capacity, the invention particularly adopts domesticated anaerobic activated sludge. The present invention has no particular limitation on the specific method of domestication. Those skilled in the art can select and adjust according to actual production conditions, electrolysis requirements and product control. The specific steps of domestication in the present invention are preferably:

a) After mixing the anaerobic activated sludge raw material, microbial culture medium, trace element solution and vitamin solution, a mixture is obtained;

b) Under an anaerobic environment containing CO and H ₂ gases, the mixture obtained in the above steps is subjected to domestication to obtain the domesticated anaerobic activated sludge.

The invention firstly mixes anaerobic activated sludge raw material, microorganism culture medium, trace element solution and vitamin solution to obtain the mixture.

The present invention is not particularly limited to the source of the anaerobic activated sludge raw material, the source of the anaerobic activated sludge well known to those skilled in the art can be used, and those skilled in the art can select and select according to actual conditions, electrolysis requirements and product control. Adjustment, the present invention is to further ensure conversion ability, remove the impurity in the sludge, especially large particle impurity, described anaerobic activated sludge raw material is preferably through grinding and sieving, and described anaerobic activated sludge raw material is preferably through grinding And screened anaerobic activated sludge raw material. The present invention has no special limitation on the particle size of the grinding and sieving, the conventional particle size well known to those skilled in the art can be used, and those skilled in the art can select and adjust according to the actual situation, electrolysis requirements and product control.

The present invention has no particular limitation on the specific components of the microbial culture medium, the culture medium of anaerobic activated sludge well known to those skilled in the art can be used, and those skilled in the art can select and select according to actual conditions, electrolysis requirements and product control. For adjustment, in order to further improve transformation ability in the present invention, the microorganism culture medium preferably includes NH ₄ Cl, NaCl, MgSO ₄ , CaCl ₂ and buffer solution.

The present invention has no particular limitation on the specific components of the buffer solution, and the buffer solution for microorganism culture medium well-known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. In order to further improve the conversion ability, the buffer solution preferably includes a phosphate buffer solution, more specifically preferably includes two or more of Na ₂ HPO ₄ , KH ₂ PO ₄ , K ₂ HPO ₄ and NaH ₂ PO ₄ , and more preferably It is preferably two of Na ₂ HPO ₄ , KH ₂ PO ₄ , K ₂ HPO ₄ and NaH ₂ PO ₄ , that is, it is more preferably a buffer solution of pH=7 composed of any group of conjugated acids and bases.

In order to further improve the microbial culture medium in the present invention, it is also preferred to add 25% hydrochloric acid or 25% sodium hydroxide solution to adjust the pH value to 7.0.

The present invention has no particular limitation on the specific proportions of the components in the microbial culture medium, and the specific proportions of such microbial culture mediums well known to those skilled in the art can be used. Those skilled in the art can select according to the actual situation, electrolysis requirements and product control. For selection and adjustment, the specific components of the medium of the present invention can be NH ₄ Cl, NaCl, MgSO ₄ , CaCl ₂ , Na ₂ HPO ₄ and KH ₂ PO ₄ , and the specific ratio can be (g/L):Na ₂ HPO ₄ ·12H ₂ O 11.7; KH ₂ PO ₄ 2.34; NH ₄ Cl 0.5; NaCl 0.5; MgSO ₄ 0.049 _;

The present invention has no special limitation on the amount of the microbial culture medium, the amount of microbial culture medium known to those skilled in the art can be used as an example, and those skilled in the art can select and adjust according to the actual situation, electrolysis requirements and product control , in step a) of the present invention, the mass volume ratio of the anaerobic activated sludge raw material to the microbial culture medium is preferably (5-20) g: 100 mL, more preferably (7-18) g: 100 mL , more preferably (9-16) g: 100 mL, most preferably (11-14) g: 100 mL.

The present invention has no special restrictions on the specific components of the trace element solution, and the trace element solution well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The present invention is To further improve the conversion ability, the trace element solution preferably includes FeCl ₃ , H ₃ BO ₃ , CuSO ₄ , KI, MnCl ₂ , Na ₂ MoO ₄ , ZnSO ₄ , CoCl ₂ , EDTA and NiCl ₂ , more preferably It is FeCl ₃ , H ₃ BO ₃ , CuSO ₄ , KI, MnCl ₂ , Na ₂ MoO ₄ , ZnSO ₄ , CoCl ₂ , EDTA and NiCl ₂ .

The present invention has no particular limitation on the specific proportions of the components in the trace element solution, and the specific proportions of such trace element solutions well known to those skilled in the art will suffice, and those skilled in the art can select according to the actual situation, electrolysis requirements and product control. For selection and adjustment, the specific components of the trace element solution in the present invention can be FeCl ₃ , H ₃ BO ₃ , CuSO ₄ , KI, MnCl ₂ , Na ₂ MoO ₄ , ZnSO ₄ , CoCl ₂ , EDTA and NiCl ₂ , specifically The ratio can be (g/L): FeCl ₃ 6H ₂ O 1.5; H ₃ BO ₃ 0.15; CuSO ₄ 5H ₂ O 0.03; KI 0.18; MnCl ₂ 4H ₂ O 0.12; Na ₂ MoO ₄ 2H ₂ O0 .06; ZnSO ₄ .7H ₂ O 0.12; CoCl ₂ .6H ₂ O 0.15; EDTA 10; NiCl ₂ .6H ₂ O 0.023.

The present invention has no special limitation on the amount of the trace element solution, and the amount of such trace element solution known to those skilled in the art can be used as an example, and those skilled in the art can select and adjust according to the actual situation, electrolysis requirements and product control , in the step a) of the present invention, the volume ratio of the trace element solution to the microbial culture medium is preferably (1-10):500, more preferably (2-9):500, more preferably (3 ~8):500, most preferably (4~7):500.

The present invention has no special restrictions on the specific components of the vitamin solution, and the vitamin solution well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The present invention is to further improve conversion ability, the vitamin solution preferably includes biotin, folic acid, vitamin B6, riboflavin, vitamin B1, niacin, pantothenic acid, vitamin B12, p-aminobenzoic acid and lipoic acid, more preferably biotin , folic acid, vitamin B6, riboflavin, vitamin B1, niacin, pantothenic acid, vitamin B12, p-aminobenzoic acid and lipoic acid.

The present invention has no particular limitation on the specific proportions of the components in the vitamin solution. The specific proportions of such vitamin solutions known to those skilled in the art can be used. Those skilled in the art can choose according to the actual situation, electrolysis requirements and product control. And adjust, the specific composition of vitamin solution of the present invention can be biotin, folic acid, vitamin B6, riboflavin, vitamin B1, nicotinic acid, pantothenic acid, vitamin B12, p-aminobenzoic acid and lipoic acid, concrete ratio can be ( g/L): biotin 0.002; folic acid 0.002; vitamin B6 0.01; riboflavin 0.05; vitamin B1 0.05; niacin 0.05; pantothenic acid 0.05; vitamin B12 0.001;

The present invention has no special limitation on the amount of the trace element solution, and the amount of such trace element solution known to those skilled in the art can be used as an example, and those skilled in the art can select and adjust according to the actual situation, electrolysis requirements and product control , in step a) of the present invention, the volume ratio of the vitamin solution to the microbial culture medium is preferably (1-10):500, more preferably (2-9):500, more preferably (3-9): 8):500, most preferably (4～7):500.

The present invention has no special limitation on the mixing method and parameters, and the mixing methods and parameters well-known to those skilled in the art can be used, and those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control.

In the present invention, under the anaerobic environment containing CO and _H2 gas, that is to fill with CO and _H2 gas to exhaust oxygen to obtain an anaerobic environment, and domesticate the mixture obtained in the above steps to obtain domesticated anaerobic activated sludge .

The present invention is not particularly limited to the definition of the anaerobic environment, the definition of the anaerobic environment when the anaerobic activated sludge well known to those skilled in the art can be used, those skilled in the art can according to the actual situation, electrolysis requirements and product control to make selections and adjustments.

The present invention has no special limitation on the CO and _H2 -containing gas, and such gases known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The gas containing CO and _H2 preferably refers to CO, _H2 and diluent gas.

_In the present invention, the ratio of H in the _CO and H containing gas is not particularly limited, and the conventional content well known to those skilled in the art can be used, and those skilled in the art can select and select according to actual conditions, electrolysis requirements and product control. Adjustment, in order to further improve the conversion effect in the present invention, the volume content of H ₂ in the gas containing CO and H ₂ is preferably 10%-40%, more preferably 15%-35%, and most preferably 20%-30%.

The present invention has no special limitation on the ratio of CO in the CO and _H2 -containing gas, and the conventional content well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control, In order to further improve the conversion effect in the present invention, the volume content of CO in the gas containing CO and H ₂ is preferably 10%-40%, more preferably 15%-35%, and most preferably 20%-30%.

The present invention has no special restrictions on the selection of the diluent gas in the CO and _H2 -containing gas, and conventional protective gases well known to those skilled in the art can be used, and those skilled in the art can conduct the process according to actual conditions, electrolysis requirements and product control. For selection and adjustment, the diluent gas in the gas containing CO and H ₂ in the present invention preferably includes nitrogen or inert gas, more preferably nitrogen or argon.

The present invention has no particular limitation on the method of adding CO and H ₂ -containing gas, and those skilled in the art can select and adjust it according to the actual situation, electrolysis requirements and product control. The method of adding in the present invention is preferably aeration.

The present invention has no special limitation on the time of the aeration, and the conventional feeding time of this type of reaction known to those skilled in the art can be used, and those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control, The aeration time of the present invention is preferably 15-30 minutes, more preferably 18-28 minutes, most preferably 20-25 minutes.

The present invention has no particular limitation on the specific method of acclimation, and the conventional domestication method of anaerobic activated sludge well known to those skilled in the art can be selected and adjusted by those skilled in the art according to actual conditions, electrolysis requirements and product control In the present invention, the acclimatization is preferably carried out in a shaker, and more specifically, the medium is preferably changed every 2-4 days.

The specific steps of the above-mentioned domestication of the present invention can be specifically preferably:

The present invention first grinds and sieves the sludge particles to remove the large particle impurities in the sludge, then inoculates 10g of sludge into the serum bottle for acclimation, and adds 100ml of medium in the serum bottle, and the composition of the medium is (g/ L): Na ₂ HPO ₄ ·12H ₂ O 11.7; KH ₂ PO ₄ 2.34; NH ₄ Cl 0.5; NaCl 0.5; MgSO ₄ 0.049; CaCl ₂ 0.011; Trace element composition (g/L): FeCl ₃ 6H ₂ O 1.5; H ₃ BO ₃ 0.15; CuSO ₄ 5H ₂ O 0.03; KI0.18; MnCl ₂ 4H ₂ O 0.12; Na ₂ MoO ₄ 2H ₂ O 0.06; ZnSO ₄ 7H ₂ O 0.12; CoCl ₂ 6H ₂ O 0.15; EDTA10; NiCl ₂ 6H ₂ O 0.023; vitamin composition (g/L): biotin 0.002; folic acid 0.002; vitamin B6 0.01; Riboflavin 0.05; vitamin B1 0.05; niacin 0.05; pantothenic acid 0.05; vitamin B12 0.001; p-aminobenzoic acid 0.05; lipoic acid 0.05.

The pH of the medium was adjusted to 7.0 with 25% hydrochloric acid and 25% sodium hydroxide solution.

Aerate the serum bottle with CO gas (CO:N ₂ =2:8) for 20 minutes to remove the oxygen in the bottle to maintain an anaerobic environment in the bottle, and finally inject into the closed serum bottle bottle with a 30ml syringe H ₂ , put in a shaker to acclimatize the sludge, and change the medium every three days. The domestication is complete when the microorganisms can produce methane stably.

The present invention has no special restrictions on the domesticated anaerobic activated sludge. Those skilled in the art can get the domesticated anaerobic activated sludge obtained by the above-mentioned domesticated method of the present invention. Those skilled in the art can, according to the actual situation, electrolyze Requirements and product control are selected and adjusted, and the dominant bacterial species in the anaerobic activated sludge after the domestication of the present invention preferably includes one or more of Thermoautotrophicum, Methanobrevibacter, Methanosaeta, Methanomassiliiccus and Acetogenicbecteria, more preferably Thermoautotrophicum, A plurality of Methanosaeta, Methanomassiliiccus, and Acetogenic bacteria, most preferably Thermoautotrophicum, Methanosaeta, and Acetogenic bacteria.

The present invention has no special limitation on the definition of the dominant strains, and the definition of conventional dominant strains well known to those skilled in the art can be used. Those skilled in the art can determine the specific strains according to the actual situation, electrolysis requirements and product control. Scale selection and adjustment.

In the present invention, the anode electrode is not particularly limited, and the anode electrode material for microbial electrolysis well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The present invention The anode electrode preferably comprises one or more of carbon felt, carbon paper, carbon cloth, carbon brush and gas diffusion electrode, more preferably carbon felt, carbon paper, carbon cloth, carbon brush or gas diffusion electrode, most preferably For carbon felt.

The present invention has no special limitation on the diaphragm, and the diaphragm used for microbial electrolysis well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The diaphragm of the present invention It preferably includes one or more of proton exchange membrane, anion exchange membrane and cation exchange membrane, more preferably proton exchange membrane, anion exchange membrane or cation exchange membrane, most preferably cation exchange membrane.

The present invention is not particularly limited to the cathode area and the anode area, the cathode area and the anode area of the microbial electrolysis cell well known to those skilled in the art can be selected and selected according to the actual situation, electrolysis requirements and product control by those skilled in the art. Adjustment, the bioelectrochemical conversion device of the present invention is preferably a microbial electrolytic cell, more preferably a double-chamber microbial electrolytic cell. The double-chamber microbial electrolytic cell of the present invention preferably includes a cathode chamber and an anode chamber, ie, a cathode area and an anode area, and the cathode and anode chambers are separated by a cation exchange membrane. The microbial electrolytic cell of the present invention also includes a shell of the microbial electrolytic cell made of plexiglass.

In the present invention, for the convenience of use and detection, the bioelectrochemical conversion process, that is, the bioelectrochemical conversion device preferably further includes a reference electrode. The present invention is not particularly limited to the specific selection of the reference electrode, and the reference electrode commonly used in microbial electrolytic cells well known to those skilled in the art can be used. Those skilled in the art can select and select according to actual conditions, electrolysis requirements and product control. Adjustment, the reference electrode of the present invention preferably includes one or more of Ag/AgCl reference electrode, saturated calomel electrode and hydrogen electrode, more preferably (E=0.198v vs NHE) Ag/AgCl electrode.

The present invention has no particular limitation on the specific components of the microbial culture medium, the culture medium of anaerobic activated sludge well known to those skilled in the art can be used, and those skilled in the art can select and select according to actual conditions, electrolysis requirements and product control. For adjustment, in order to further improve transformation ability in the present invention, the microorganism culture medium preferably includes NH ₄ Cl, NaCl, MgSO ₄ , CaCl ₂ and buffer solution.

The present invention has no particular limitation on the specific components of the buffer solution, and the buffer solution for microorganism culture medium well-known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. In order to further improve the transformation ability, the buffer solution preferably includes a phosphate buffer solution, more specifically preferably includes two or more of Na ₂ HPO ₄ , KH ₂ PO ₄ , K ₂ HPO ₄ and NaH ₂ PO ₄ , and more preferably It is preferably two of Na ₂ HPO ₄ , KH ₂ PO ₄ , K ₂ HPO ₄ and NaH ₂ PO ₄ , that is, it is more preferably a buffer solution of pH=7 composed of any group of conjugated acids and bases.

In the present invention, in order to further control the pH value of the medium so as to provide a more suitable environment for microbial growth, it is also preferred to add 25% hydrochloric acid or 25% sodium hydroxide solution to adjust the pH value to 7.0.

The present invention has no particular limitation on the specific proportions of the components in the microbial culture medium, and the specific proportions of such microbial culture mediums well known to those skilled in the art can be used. Those skilled in the art can select according to the actual situation, electrolysis requirements and product control. For selection and adjustment, the specific components of the medium of the present invention can be NH ₄ Cl, NaCl, MgSO ₄ , CaCl ₂ , Na ₂ HPO ₄ and KH ₂ PO ₄ , and the specific ratio can be (g/L):Na ₂ HPO ₄ ·12H ₂ O 11.7; KH ₂ PO ₄ 2.34; NH ₄ Cl 0.5; NaCl 0.5; MgSO ₄ 0.049 _;

The present invention has no special limitation on the amount of the microbial culture medium, the amount of microbial culture medium known to those skilled in the art can be used as an example, and those skilled in the art can select and adjust according to the actual situation, electrolysis requirements and product control , in the cathode area of the present invention, the mass volume ratio of the acclimatized anaerobic activated sludge to the microbial culture medium is (5-20) g: 500 mL, more preferably (7-18) g: 500 mL , more preferably (9-16) g: 500 mL, most preferably (11-14) g: 500 mL.

The present invention has no particular limitation on the specific selection of the electron donor, the electron donor of the microbial electrolysis process well known to those skilled in the art can be used, and those skilled in the art can select and adjust according to the actual situation, electrolysis requirements and product control , the electron donor in the present invention preferably includes one of potassium ferrocyanide solution, water and electrogenic bacteria, more preferably potassium ferrocyanide solution.

The present invention has no special restrictions on the specific components of the potassium ferrocyanide solution, and the potassium ferrocyanide solution well known to those skilled in the art can be used, and those skilled in the art can choose according to the actual situation, electrolysis requirements and product control And adjustment, in order to further improve the conversion ability in the present invention, the potassium ferrocyanide solution preferably includes K ₄ Fe(CN) ₆ , KCl and a buffer solution.

The present invention has no particular limitation on the specific components of the buffer solution, and the common buffer solution well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The present invention is a further To improve conversion ability, the buffer solution preferably includes a phosphate buffer solution, more specifically preferably includes two or more of Na ₂ HPO ₄ , KH ₂ PO ₄ , K ₂ HPO ₄ and NaH ₂ PO ₄ , more preferably Na Two of ₂ HPO ₄ , KH ₂ PO ₄ , K ₂ HPO ₄ and NaH ₂ PO ₄ , that is, more preferably a buffer solution of pH=7 composed of any set of conjugate acids and bases.

The present invention has no particular limitation on the specific proportions of the components in the potassium ferrocyanide solution, the specific proportions of such potassium ferrocyanide solutions well known to those skilled in the art can be used, and those skilled in the art can , electrolysis requirements and product control are selected and adjusted. The specific components of the potassium ferrocyanide solution in the present invention can be K ₄ Fe(CN) ₆ , KCl, Na ₂ HPO ₄ and KH ₂ PO ₄ , wherein the The concentration of K ₄ Fe(CN) ₆ ·3H ₂ O is preferably 21.125-42.23g/L, more preferably 25-40g/L, more preferably 30-35g/L, and the specific ratio can be (g/L): K ₄ Fe(CN) ₆ ·3H ₂ O 42.23g/L; KCl 7.445g/L; Na ₂ HPO ₄ ·12H ₂ O 23.4g/L; KH ₂ PO ₄ 4.68g/L.

In the present invention, the amount of the electron donor in the anode region is not particularly limited, and the conventional amount well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements, and product control.

In the present invention, the gas containing CO is fed into the cathode area at last to form an anaerobic environment, and then the electrode potential is applied to the cathode electrode to obtain gas CH ₄ .

The present invention is not particularly limited to the definition of the anaerobic environment, the definition of the anaerobic environment when the anaerobic activated sludge well known to those skilled in the art can be used, those skilled in the art can according to the actual situation, electrolysis requirements and product control to make selections and adjustments.

The present invention has no special limitation on the CO-containing gas, as long as it is known to those skilled in the art, those skilled in the art can select and adjust it according to the actual situation, electrolysis requirements and product control. The CO-containing gas described in the present invention The CO gas preferably means CO and diluent gas.

In the present invention, the proportion of CO in the CO-containing gas is not particularly limited, and the conventional content well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The present invention is To further improve the conversion effect, the volume content of CO in the gas containing CO and H ₂ is preferably 10%-60%, more preferably 20%-50%, and most preferably 30%-40%.

The present invention has no special restrictions on the selection of the diluent gas in the CO-containing gas, and the conventional protective gas well known to those skilled in the art can be used. Those skilled in the art can select and select according to actual conditions, electrolysis requirements and product control. Adjustment, the diluent gas in the CO-containing gas in the present invention preferably includes nitrogen or inert gas, more preferably nitrogen or argon.

The present invention has no special limitation on the way of introducing, just use the conventional way of introducing this type of reaction well known to those skilled in the art, and those skilled in the art can select and adjust according to the actual situation, electrolysis requirements and product control, The way of introducing in the present invention is preferably aeration.

The present invention has no special limitation on the time of the introduction, and the conventional introduction time of this type of reaction well known to those skilled in the art can be selected and adjusted by those skilled in the art according to the actual situation, electrolysis requirements and product control, The feeding time of the present invention is preferably 15-30 minutes, more preferably 17-27 minutes, most preferably 15-25 minutes.

The present invention has no special limitation on the size of the electrode potential, and the conventional protective gas well known to those skilled in the art can be used. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The electrode potential is preferably -0.65 to -1.0V, more specifically -0.85v, -0.90v, -0.95v or -1.0v.

In order to improve the contact between carbon monoxide and anaerobic activated sludge and further improve the transformation ability and rate, the present invention preferably stirs respectively in the process of introducing and applying electrode potential to enhance mass transfer. The present invention has no particular limitation on the specific parameters of the stirring, which can be selected and adjusted by those skilled in the art according to actual conditions, electrolysis requirements and product control.

The present invention has special restrictions on the equipment for generating the electrode potential, which is known to those skilled in the art. Those skilled in the art can select and adjust according to actual conditions, electrolysis requirements and product control. The device for generating electrode potential is preferably an electrochemical workstation, and the cathode, anode and reference electrode are more preferably connected to the electrochemical workstation through a titanium wire. The electrochemical workstation provides different potentials to the cathode of the microbial electrolysis cell.

The invention provides a CO bioelectrochemical conversion method and a corresponding microbial electrolysis cell. The present invention develops a new method of carbon monoxide conversion, creatively adopts the microbial electrolysis method, adds microbial anaerobic activated sludge into the cathode chamber of the double-chamber microbial electrolytic cell, and reduces carbon monoxide under different potential conditions to produce usable biofuels methane. Compared with the conversion of traditional non-toxic raw materials, the anaerobic activated sludge cannot function normally due to the high toxicity of carbon monoxide. , to effectively overcome the severe toxicity of carbon monoxide itself, apply a certain potential on the cathode, and further combine with a microbial culture medium of a specific composition, using bioelectrochemical methods, under normal temperature and pressure, microorganisms can convert carbon monoxide into methane. Moreover, the domesticated anaerobic activated sludge provided by the present invention can not only reduce carbon monoxide, but also reduce carbon dioxide, or a mixture of the two, and has a wider range of applications. The conversion method provided by the invention has the advantages of simple process, mild conditions and low equipment requirements, and is suitable for wide application.

Experimental results show that the bioelectrochemical conversion method provided by the invention can convert carbon monoxide into methane, and the amount of methane produced under different potential conditions is different, and the more negative the potential, the higher the methane amount.

In order to further illustrate the present invention, a CO conversion and utilization method provided by the present invention will be described in detail below in conjunction with examples, but it should be understood that these examples are implemented on the premise of the technical solution of the present invention, and detailed The embodiment and the specific operation process are only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following examples.

Example 1

Anaerobic activated sludge domestication:

In the present invention, the cathode microorganisms use anaerobic activated sludge. Before use, the sludge particles are ground and sieved to remove large particles of impurities in the sludge, and then 10g of sludge is inoculated into the serum bottle for acclimation, and then injected into the serum bottle Add 100ml medium, the medium composition is (g/L): Na ₂ HPO ₄ 12H ₂ O 11.7; KH ₂ PO ₄ 2.34; NH ₄ Cl 0.5; NaCl 0.5; MgSO ₄ 0.049; CaCl ₂ 0.011; 1ml trace elements , 1ml vitamins. Trace element composition (g/L): FeCl ₃ ·6H ₂ O1.5; H ₃ BO ₃ 0.15; CuSO ₄ ·5H ₂ O 0.03; KI 0.18; MnCl ₂ ·4H ₂ O 0.12; Na ₂ MoO ₄ ·2H ₂ O 0.06; ZnSO ₄ 7H ₂ O 0.12; CoCl ₂ 6H ₂ O 0.15; EDTA 10; NiCl ₂ 6H ₂ O 0.023; vitamin composition (g/L): biotin 0.002; folic acid 0.002; vitamin B6 0.01 ; riboflavin 0.05; vitamin B1 0.05; niacin 0.05; pantothenic acid 0.05; vitamin B12 0.001; p-aminobenzoic acid 0.05; 7.0. Use CO gas (CO:N ₂ =2:8) to aerate the serum bottle for 20 minutes to remove the oxygen in the bottle and maintain the anaerobic environment in the bottle, and finally inject into the closed serum bottle bottle with a 30ml syringe H ₂ , put in a shaker to acclimatize the sludge, and change the medium every three days. The domestication is complete when the microorganisms can produce methane stably.

Add 500ml of potassium ferrocyanide solution to the anode, add domesticated microorganisms to the cathode, and replenish the microbial culture medium to the anode to 500ml, then aerate with syngas (CO:N ₂ =2:8) for 20min, and finally plug it with a stopper Keep the anaerobic state in the cathode of the reactor tightly, and control the cathode potential at -0.85v, -0.9v, -0.95v, -1.0v with the electrochemical workstation. The gas composition in the cathode headspace volume was monitored at intervals during reactor operation. When the carbon monoxide gas in the cathode headspace gas is completely consumed, suspend the electrochemical workstation, extract the cathode solution and centrifuge, the centrifugal speed is preferably 5000rpm, pour off the upper liquid after centrifugation, and return to the reactor after washing with new medium After aeration for 20 minutes, the electrochemical workstation was adjusted to another potential for the experiment.

Referring to Fig. 1, Fig. 1 is a schematic diagram of the model of the microbial electrolysis cell reactor used in Example 1 of the present invention.

The above-mentioned experimental process of the present invention is monitored and measured.

Referring to FIG. 2 , FIG. 2 is a diagram of currents under different applied potentials in Example 1 of the present invention.

It can be seen from Figure 2 that the current is different under different applied potentials, and the more negative the potential, the greater the current, which means that the faster the electron transfer rate, the faster the cathode reduction rate of carbon monoxide.

Referring to FIG. 3, FIG. 3 is a graph showing the content of methane produced under different applied potentials in Example 1 of the present invention.

It can be seen from Figure 3 that the amount of methane produced is different under different applied potentials, and the more negative the potential, the higher the amount of methane produced and the faster the rate of methane production.

Example 2

The cathode solution after the reaction in Example 1 is taken out and centrifuged, and the centrifugal speed is preferably 5000rpm. After centrifugation, the upper layer liquid is poured off, and it is returned to the reactor after being washed with a new medium, and then the carbon monoxide gas with a higher concentration is used. (CO:N ₂ =4:6) aerate for 20min, replace the anode with a new 500ml potassium ferrocyanide solution, and finally use a stopper to keep the anaerobic state in the cathode of the reactor, and use an electrochemical workstation to control the cathode potential to - 0.85v, -0.9v, -0.95v, -1.0v. The gas composition in the cathode headspace volume was monitored at intervals during reactor operation. When the carbon monoxide gas in the cathode headspace gas is completely consumed, suspend the electrochemical workstation, extract the cathode solution and centrifuge, the centrifugal speed is preferably 5000rpm, pour off the upper liquid after centrifugation, and return to the reactor after washing with new medium After aeration for 20 minutes, the electrochemical workstation was adjusted to another potential for the experiment.

When aerated with a higher concentration of CO gas, more methane gas was produced than at a lower concentration but the rate of methane production did not change significantly.

Comparative example 1

Using ordinary anaerobic activated sludge for carbon dioxide conversion for comparison

Take 3g of each of the two kinds of sludge, add it to a serum bottle with a volume of 265ml, add 100ml of the medium of the above-mentioned embodiment to the serum bottle, and aerate the carbon monoxide mixture CO:N ₂ =2:8 in the serum bottle for 15min Afterwards, stopper the bottle tightly, inject 60ml of hydrogen gas into each of the two serum bottles with a glass syringe, put them on a shaker at 25°C for reaction, and measure the gas changes in the serum bottles during the reaction.

Referring to Fig. 4, Fig. 4 is a gas change curve of the anaerobic activated sludge for carbon dioxide in Comparative Example 1 of the present invention and the anaerobic activated sludge provided by the present invention.

As can be seen from Fig. 4, black and red lines are respectively the carbon monoxide change situation in the serum bottle of the sludge in the carbon monoxide microbial electrolytic cell and the carbon monoxide microbial electrolytic cell among Fig. 4, as can be seen from the figure carbon monoxide in the carbon monoxide microbial electrolytic cell It is consumed quickly and is easily converted, while anaerobic activated sludge for carbon dioxide is affected by the toxicity of carbon monoxide, and the amount of carbon monoxide hardly changes, which lacks practical significance in practical applications.

The bioelectrochemical method for resource utilization of CO provided by the present invention has been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The description of the above examples is only for helping Understanding the methods of the invention and its core concepts, including the best mode, also enables any person skilled in the art to practice the invention, including making and using any devices or systems, and performing any incorporated methods. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims (10)

1. a bioelectrochemical conversion method of CO, is characterized in that, comprises the following steps: 1) placing the acclimated anaerobic activated sludge, the cathode electrode and the microbial culture medium in the cathode area, and stirring, and placing the anode electrode and the electron donor in the anode area; the cathode area and the anode area are separated by a diaphragm; The dominant bacterial species in the domesticated anaerobic activated sludge includes one or more of Thermoautotrophicum, Methanobrevibacter, Methanosaeta and Methanomassiliicoccus, or a combination of one or more of Thermoautotrophicum, Methanobrevibacter, Methanosaeta and Methanomassiliicoccus with Acetogenicbecteria ; 2) Pass CO-containing gas into the cathode area to form an anaerobic environment, and then apply an electrode potential to the cathode electrode to obtain gas CH ₄ ; The CO-containing gas includes CO and diluent gas. 2. bioelectrochemical transformation method according to claim 1, is characterized in that, in described cathode area, the mass volume ratio of the anaerobic activated sludge after described domestication and described microorganism culture medium is (5～20 )g: 500mL. 3. The bioelectrochemical conversion method according to claim 1, characterized in that the electrode potential is -0.65--1.0V. 4. The bioelectrochemical conversion method according to claim 1, wherein the volume content of CO in the CO-containing gas is 10% to 60%; The diluent gas includes nitrogen or an inert gas. 5. The bioelectrochemical conversion method according to claim 1, wherein the electron donor comprises one of potassium ferrocyanide solution, water and electrogenic bacteria; The membrane includes a proton exchange membrane or a cation exchange membrane. 6. bioelectrochemical transformation method according to claim 1, is characterized in that, described cathode electrode comprises one or more in carbon felt, carbon paper, carbon cloth, carbon brush and gas diffusion electrode; The anode electrode includes one or more of carbon felt electrodes, carbon paper, carbon cloth, carbon brushes and gas diffusion electrodes. 7. The bioelectrochemical conversion method according to any one of claims 1 to 6, characterized in that, the specific steps of domestication are: a) After mixing the anaerobic activated sludge raw material, microbial culture medium, trace element solution and vitamin solution, a mixture is obtained; b) Under an anaerobic environment containing CO and H ₂ gases, the mixture obtained in the above steps is subjected to domestication to obtain the domesticated anaerobic activated sludge. 8. The bioelectrochemical conversion method according to claim 7, characterized in that, in the step a), the mass volume ratio of the anaerobic activated sludge raw material to the microbial culture medium is (5-20) g: 100mL; In the step a), the volume ratio of the trace element solution to the microbial culture medium is (1～10):500; In the step a), the volume ratio of the vitamin solution to the microorganism culture medium is (1-10):500. 9. The bioelectrochemical conversion method according to claim 7, wherein the _CO and H gas comprises _CO , H and diluent gas; The diluent gas comprises nitrogen or an inert gas; The volume content of H ₂ in the gas containing CO and H ₂ is 10% to 40%; The volume content of CO in the gas containing CO and H ₂ is 10%-40%. 10. The bioelectrochemical conversion method according to claim 7, characterized in that, the microbial culture medium comprises NH ₄ Cl, NaCl, MgSO ₄ , CaCl ₂ and buffer solution; The trace element solution includes FeCl ₃ , H ₃ BO ₃ , CuSO ₄ , KI, MnCl ₂ , Na ₂ MoO ₄ , ZnSO ₄ , CoCl ₂ , EDTA and NiCl ₂ ; The vitamin solution includes biotin, folic acid, vitamin B6, riboflavin, vitamin B1, niacin, pantothenic acid, vitamin B12, p-aminobenzoic acid and lipoic acid.