High electricity generation and wastewater treatment enhancement using a microbial fuel cell equipped with conductive and anti-biofouling CuGNSs/SPES proton exchange membrane

•The biosynthesized Cu/Graphene nanosheets used as modifier agents in PEM.•The CuGNSs2.0/SPES exhibited outstanding performance in MFC compared to Nafion 117.•The highest current and power density were 320 mA/m2 and 84.1 mW/m2, respectively.•The CuGNSs2.0/SPES removed 97.41% of COD and had a coulombic efficiency of 43.29%.•All the modified PEMs showed antibacterial activity against S. aureus and E. coli. This research is the first to examine the use of biosynthesized Cu-Graphene nanosheets (CuGNSs) in a sulfonated polyethersulfone (SPES) matrix to fabricate an anti-biofouling proton exchange membrane (PEM) applied in a microbial fuel cell (MFC) for high power generation and treatment of ostrich skin tanning wastewater. The study involved fabricating CuGNSs/SPES membranes using a phase inversion method with different CuGNSs loadings (0.25, 0.5, 1.0, and 2.0 wt%), and characterizing them using several techniques, including FTIR, XRD, SEM, EDS, XPS, water uptake, cation exchange capacity, zeta potential, oxygen penetration, and antibacterial activity. The results showed that the presence of Cu, graphene, and biofunctionalities in the membrane's structure increased their hydrophilicity, proton selectivity, and anti-biofouling resistance, thereby improving the MFC's performance. The MFC using CuGNSs2.0/SPES generated a maximum power and current density of 84.1 mW/m2 and 320 mA/m2, respectively, which was twice higher than the MFC using Nafion117. The result was also confirmed by the proton conductivity and cation exchange capacity analysis, as the CuGNSs2.0/SPES showed a value of 1.84 mS/cm and 0.98 meq/g respectively, which was higher than Nafion117 (1.28 mS/cm and 0.83 meq/g). The modified membranes also exhibited a higher COD removal of ostrich tanning effluent (maximum 97.72%) and coulombic efficiency (maximum 43.29%), as well as maximum antibacterial activity against gram-negative and gram-positive bacteria (>95%). The study suggests that the new CuGNSs/SPES membranes can be effectively used in dual-chamber MFCs.