Alleviation of membrane fouling and enhancement of trace organic compounds removal in an electric field assisted microfiltration system

Abstract

Continuous experiments were conducted in the Electric Field assisted Microfiltration (EFMF) reactors under different applied voltages to investigate the effects of electric fields on membrane fouling and trace organic compounds (TrOCs) removal during microfiltration processes. The Bovine serum albumin (BSA) was used as the model foulant in the EFMF system and its property change in electric field was found to be the key reason of membrane fouling alleviation. The oxidants, especially hypochlorite, generated on anodes led to protein unfolding and solubility reduction. Through the combined effects of electrochemical oxidation and electrophoretic migration, the denatured protein aggregated into flocs with larger size than the pore diameter of membrane, which obviously reduced the hydraulic irreversible resistance of microfiltration by 64.8% and 70.5% at 2 V and 3 V, respectively. Compared with microfiltration, the elimination of TrOCs could be significantly improved from 6.3%∼13.8% to 34.4%∼91.6% at the 3 V applied voltage. Electrochemical oxidation was the main contributor to the TrOCs removal in the EFMF system and the electrophoretic migration made the TrOCs tend to remain in the electric field and have more contact time with oxidants and thus enhanced their removal efficiencies.