Construction Of Bipolar Microbial Fuel Cell And Treatment Of Oil Production Wastewater

Microbial fuel cells(MFC)can recover electric energy from organic matter in wastewater by combining the metabolic process of anode microorganisms with the redox reaction(ORR)of the cathode.It is a bioelectric energy conversion device with environmental protection properties.For a long time,MFC with oxygen as electron acceptor has greatly limited its engineering amplification application in practical fields because of its inefficient cathode ORR performance in a neutral environment.Under alkaline conditions,the conductivity and electrocatalytic activity of transition metal nitrogen carbon catalysts can be comparable to that of platinum based catalysts.And its price is relatively low,suitable for large-scale applications.However,the best growth environment for microorganisms is a neutral environment.There is a contradiction between microbial growth conditions and alkaline cathode oxygen reduction,which is not conducive to the improvement of power production performance of MFC.The traditional two-chamber MFC uses a proton exchange membrane to isolate the anode and cathode chambers.Although it can achieve different p H ranges of the anode and cathode,there are problems in ion transfer efficiency and working stability.In this paper,cobalt based metal nitrogen carbon catalyst(Co NCNT-CFP)is used as cathode,and bipolar membrane(BP),cationic membrane(CEM)and anionic membrane(AEM)are used as separator to construct two-chamberr MFC with an alkaline cathode system.By investigating the power generation performance of MFC and the population information of anode microorganisms,a bipolar MFC with excellent performance is explored and applied to the treatment of oil production wastewater.The experimental results show that the bipolar MFC(BP-MFC)constructed by BP achieves the maximum power generation performance,and the maximum output power reaches 460.07 MW/m~2,which is twice the maximum output power(221.78 MW/m~2)of the traditional neutral double chamber MFC(Nafion MFC).In addition,bp-mfc has the highest coulomb efficiency of 25.76±0.85%,followed by AEM and CEM.CEM makes the p H of anode solution decrease rapidly,inhibits the metabolic activities of microorganisms,and leads to the worst power generation capacity.Through 16SRNA sequencing,the microorganism at BP-MFC anode has the highest biological activity,species selectivity and dominant population abundance of electricity producing bacteria.It shows that it has a positive effect on the acclimation of anode microorganisms and is conducive to improving the power production capacity of MFC.Based on the successful construction of bi-polar microbial fuel cells,we carried out the treatment of oilfield wastewater.The experimental results show that bi-polar MFC has significant advantages over traditional neutral two compartment MFC.BP-MFC obtained the highest crude oil degradation rate(90%),which was significantly higher than that of Nafion MFC(74.2%).The hydraulic retention rate of oil field wastewater is up to85.5 days,and the degradation efficiency of oilfield wastewater is greatly improved.