Study On Treatment Of P-Nitrophenol Containing Wastewater By Microbial Fuel Cells

Microbial fuel cell (MFC) is a technology which combines microbiology and electrichemistry, which can generate electricity while treating wastewater. In this paper, two bioelectrochemical systems (BESs), an abiotic cathode MFC and a biocathode MFC, were setup and startup after the successful cultivation and acclimation of exoelectrogens and p-nitrophenol (PNP) degrading bacteria. The degration performance of PNP within these two BESs were studied, and the mechanism of PNP removed by abiotic cathode MFC was also included.Various operating parameters, such as current density, coulombic efficiency, removal rate and some other parameters on PNP removal in abiotic cathode MFC were evaluated under different cathode potential, PNP concentration and hydraulic retention time (HRT). The results indicated that they had a significant influence on PNP removal in abiotic cathode MFC. PNP removal performance was optimal under the conditions of cathode potential-700mV, PNP concentration 500 mg·L-1 and HRT 8.5h, with PNP removal efficiency up to 90%.The cathode influent and cathode effluent in abiotic cathode MFC were analyzed by UV-vis, HPLC and IR.p-Aminophenol was identified as the dominant reductive product of PNP, and the degration mechanism of PNP removal in abiotic cathode MFC could be described.The degration rate of PNP, MNP, ONP with abiotic cathode MFC was measured, and the degradation capacity of different nitrophenols in MFC was analyzed and explained by density distribution of electron in nitryl nitrogen atom. It was found that PNP was the most difficult to degrade and ONP was the easiest one. These results gave basic information for the systematic study on removal of nitrophenol pollutants.Performance of conventional anaerobic process, abiotic cathode MFC and biocathode MFC on PNP removal were compared. It was found that electron donor usage in the BESs was much less than those in conventional anaerobic system, while maximum PNP removal rates in the BESs were much higher. The removal performance of biocathode MFC was better than abiotic cathode MFC as a whole, demonstrating bacterial in cathode played an important role in PNP removal.