The performance of Pd-rGO electro-deposited PVDF/carbon fiber cloth composite membrane in MBR/MFC coupled system

Abstract

A new PVDF composite cathode membrane (PCCM) with electro-deposited Pd-rGO on PVDF/carbon fiber cloth, abbreviated as Pd-rGO PCCM, was developed. The as-prepared Pd-rGO PCCM was characterized by SEM, TEM and XRD. And it was further used in membrane bioreactor (MBR)/microbial fuel cell (MFC) coupled wastewater treatment system. The results indicated after electro-deposition, the Pd-rGO was uniformly distributed on the surface of PCCM. Under 15 cycled Pd electro-deposition on carbon fiber cloth, the Pd15-rGO PCCM exhibited the highest catalytic activity compared to other cycles, and the optimized deposition density of rGO and Pd were 0.124 mg cm−2 and 2.31 mg cm−2 respectively. Under an electric field of −0.4 V cm−1, the Pd15-rGO PCCM showed approximately 1.9 times improvement of stable membrane flux (128–130 L m−2 h−1) compared to the condition without electric field (66 L m−2 h−1). In MBR/MFC wastewater treatment system, using Pd15-rGO PCCM as cathode membrane, the maximum power density was 1210 mW m−3, approximately 3.8 times higher than using initial PCCM (312 mW m−3). Moreover, The Pd15-rGO PCCM in MBR/MFC coupled system showed excellent contaminants removal rates towards both traditional organic contaminants (COD at 90% and NH4+-N at 81%) in sewage and trace persistent contaminants (i.e. PAHs and phenols) in the effluent of coking wastewater.