Degradation of organic pollutants in near-neutral pH solution by Fe-C micro-electrolysis system

The degradation of organic pollutants in the simulated and realistic wastewaters was investigated by Fe-C micro-electrolysis system. Effects of initial pH, Fe/C mass ratio, gas bubbling type (air or N2) and the type of anions on degradation and mineralization of Sunset Yellow (SY) were studied. The degradation and mineralization efficiencies of 500 mg·L−1 SY were approximately 99.0% and 77.5% after 90 min treatment, when the initial pH, Fe/C ratio and air bubbling flow rate were 6.0, 1:1 and 45 L·h−1, respectively. Besides, the type of anions had a significant influence on the Fe-C micro-electrolysis process. The results of kinetics study indicated that Fe-C micro-electrolysis process followed second-order-kinetics well. The degradation pathway and mechanism for SY were proposed based on FTIR and LC–MS analyses of treated wastewater. Additionally, the Fe-C micro-electrolysis process could dispose linear alkyl chain and benzene ring compounds efficiently under the optimal conditions, and the mineralization efficiencies were in the range of 94–96% and approximately 80%, respectively. The degradation feasibility of a realistic wastewater by the Fe-C micro-electrolysis system was investigated with landfill leachate. In conclusion, Fe-C micro-electrolysis system is an effective and promising technology for organic wastewater treatment in near-neutral pH condition.