Microbial Electrochemical Treatment Process And Performance Of Several Typical Pollutant Components In Wastewater

The rapid development of China's economy is accompanied by the gradual deterioration of the environment.The discharge of some pollutants leads to extensive organic pollution,toxic pollution and serious ecological damage.The impact of water pollution on human health has become a matter of close concern.A new class of micro-refractory pollutants is emerging in the aquatic environment.These substances are composed of a large number of man-made or natural substances,including drugs,personal care products and industrial chemicals.They usually exist in water at a low concentration because there are no or very few preventive and monitoring measures to ensure the maximum permissible concentration of these compounds in the water environment.Water pollution is becoming more and more serious.Each of these compounds has its own form and mechanism of action.Detection and analysis in drinking water and wastewater treatment plants are very complex.It is more difficult to remove them.In recent years,microbial fuel cell(MFCs)technology has developed rapidly.It uses electroactive microorganisms as catalysts to convert the chemical energy of organic substances in wastewater into electric energy,and realizes the "win-win" technology of wastewater treatment and power generation.Its application in wastewater treatment has good prospects and is one of the hotspots of current research.According to the two operational advantages of microbial fuel cells in treating wastewater and generating electricity at the same time,using nitrobenzene(NB),carbamazepine(CBZ)and p-Fluoronitrobenzene(p-FNB)as simulated wastewater substrates,starting from the two aspects of battery output voltage and wastewater treatment effect,the possibility of MFCs treating wastewater for generating electricity and the three kinds of nitrobenzene,carbamazepine and p-Fluoronitrobenzene were studied.Removal efficiency of contaminated components.In this study,a single-chamber activated carbon air cathode MFCs was constructed.The organic substrate was sodium acetate.Different concentrations of nitrobenzene,carbamazepine and p-Fluoronitrobenzene were added to the medium under neutral conditions.The anodization of nitrobenzene,carbamazepine and p-Fluoronitrobenzene on MFCs carbon felt was studied by recording the changes of output voltage and electrode potential during discharge of MFCs and measuring polarization curves.The properties of membrane and MFCs were studied.(1)Single chamber MFCs assembled with carbon felt anode and activated carbon air cathode enriched with electricity-producing microorganisms can produce higher voltage and remove higher concentration of nitrobenzene.When the concentration of NB was 1.0 mmol·L-1,the maximum output voltage of single chamber MFCs was kept at about 0.38 V,and the power density was 16±1.5 W·m-3.When the medium without NB was replaced,the maximum output voltage of the battery gradually restored to about 0.4 V,indicating that the inhibition of nitrobenzene on the anodic microorganisms was reversible.The mechanism of NB degradation by MFCs was studied by assembling two-chamber microbial fuel cells and electrolytic cells.The results showed that MFCs adsorbed NB by cathodic activated carbon,anaerobic degradation of NB by anodic microorganisms in single-chamber MFCs and removal of nitrobenzene by cathodic electrocatalytic reduction of NB.(2)Single chamber MFCs can produce high voltage while removing 10.0 mg/L CBZ.When the concentration of CBZ is 10.0 mg/L,the maximum output voltage of single-chamber MFCs is kept at about 0.45 V,and the power density of single-chamber MFCs is 15±1.5 W·m-3.When the concentration of CBZ is 1.0 mg/L,the power density of single-chamber MFCs is 45±1.5 W·m-3.The removal rate of carbamazepine by MFCs was more than 80%for 10.0 mg/L CBZ by cathodic activated carbon adsorption and anodic electrocatalytic oxidation in single-chamber MFCs.(3)Single-cell MFCs can remove 0.5 mM p-FNB at the same time of high voltage output.The maximum power density produced by the battery is 40 W·m-3.The removal rate of p-FNB by single-cell MFCs is more than 85%on the basis of maintaining the output voltage of 0.45 V.In addition,the reduction products of p-FNB(p-FA,AN)can also be removed.The microbial electrochemical treatment processes of nitrobenzene,carbamazepine and p-fluoronitrobenzene,which are typical pollutants in wastewater,are preliminarily understood.The theoretical basis for the treatment of wastewater containing pollutants is provided,and the application of MFCs in wastewater treatment is further expanded.