Polydopamine coating effects on ultrafiltration membrane to enhance power density and mitigate biofouling of ultrafiltration microbial fuel cells (UF-MFCs)

Abstract

Membrane resistance is due to the low accessibility of liquid electrolytes onto the membrane surface; resultant membrane biofouling lowers the power generation capacity of microbial fuel cells (MFCs). In this study, in order to reduce membrane resistance caused by migrative ion transport resistance and membrane biofouling, a polydopamine (PD) coating was adopted for the modification of ultrafiltration (UF) membrane surfaces in UF membrane integrated MFCs (UF-MFCs). After a PD coating was applied to a UF membrane, the contact angle measured on the support layer of a UF membrane decreased and the membrane surface charge became negative. The maximum power density of UF-MFC increased after the PD coating on a UF membrane and a remarkable reduction of charge transfer resistance was observed using electrochemical impedance spectroscopy (EIS) analysis. Lower extracellular polymeric substance (EPS) concentrations and total cell numbers were observed on the PD coated UF membrane surface after 72 h operation, although 17% of a permeate flux of UF-MFC decreased after PD coating.

Keywords: Hydrophilicity; Membrane surface charge; Polydopamine coating; Ultrafiltration microbial fuel cell (UF-MFC).