System and method for microbial/photocoupled reduction of carbon dioxide to produce methane

Abstract

The invention discloses a system and a method for reducing CO2 to produce methane through microorganism / photoelectric-coupling. The system herein includes an anode chamber and a cathode chamber, which are respectively filled with an anode solution and a cathode solution; a cation exchange membrane is disposed between the anode chamber and the cathode chamber. The system is also characterized in that a photo-anode is disposed in the anode chamber, wherein an n-type semiconductor serves as a photocatalyst on the photo-anode. The conduction band potential of the n-type semiconductor, under any pH value, is lower than the redox equilibrium potential of CO2 / CH4; meanwhile, the valence band potential of the n-type semiconductor is higher than the redox equilibrium potential of H2O / O2; a bio-cathode is arranged in the cathode chamber, wherein electrochemical active methanogens are adhered to the surface of the bio-cathode. The microorganisms can directly acquire electrons from the electrode to reduce CO2 and produce the methane, so that CO2 and microorganism conversion is achieved by means of solar energy. The system and the method have great application prospect.

Description

technical field [0001] The invention relates to the field of systems and methods for methane production, and in particular to a system and method for producing methane by reducing carbon dioxide with microorganisms / photoelectric coupling. Background technique [0002] Climate change has an increasing impact on the natural environment and human life, and the problems brought about by global warming are particularly obvious. Carbon dioxide is the main emission gas that causes global warming. With the rapid growth of population, the rapid development of industry and the wide application of fossil fuels, the emission of carbon dioxide is continuously increasing. Among them, the pollutant emission from coal combustion in power plants has always been the main source of carbon dioxide emission. Controlling the emission of carbon dioxide is considered It is the key measure to solve the greenhouse effect. Carbon dioxide emission reduction has become a global focus topic and researc...

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Problems solved by technology

[0003] Carbon dioxide capture methods include absorption method, adsorption method, deep burial storage method and resource utilization of carbon dioxide. 2 In terms of research, the absorption method is mainly carried out, which has a large absorption capacity and good absorption effect, but the cost is high and the separation efficiency is not high; while the adsorption method has a simple process and low energy consumption, but the adsorbent capacity is limited and the amount used is large, and Adsorption and desorption are frequent, requiring a high degree of automation; CO 2 Although the deep burial storage method can have a certain positive effect on reducing the greenhouse effect, it cannot be recycled, and it cannot completely solve the problem of the greenhouse effect.

But the system is reducing CO 2 In the process, an external power source is required, that is, input electric energy to overcome CO 2 Revert to CH 4 energy barrier, but electric energy is a high-grade secondary energy

[0005] At present, in the artificial photosynthesis system, using solar energy, microorganisms are used as catalysts to directly convert CO 2 The study of electrochemical reduction to methane has not been reported

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