Exploring the potential of anti-bacterial and conductive ZnO–Al2O3/SPES proton exchange membrane applied in MFC for sustainable energy generation and sugar beet industry effluent treatment

Abstract

This research introduces a novel approach wherein a sulfonated polyethersulfone (SPES) membrane is modified using bio-synthesized ZnO–Al2O3 nanoparticles (ZANPs). This modified membrane serves as a proton exchange membrane (PEM) within a dual-chamber microbial fuel cell (MFC) for energy production and sugar beet industry effluent treatment. We fabricated ZANPs/SPES membranes through a phase inversion process, varying the ZANPs loadings from 0.5 to 4.0 wt%. The ZANPs underwent analysis using a range of methods, including FTIR, EDS, SEM, and XRD, and the PEMs were thoroughly studied through several analyses, such as FTIR, SEM, EDS, AFM, water contact angle, water uptake, zeta potential, oxygen permeability, ion exchange capacity, proton conductivity, COD removal, coulombic efficiency, and anti-bacterial efficiency. According to the findings, ZANPs exhibited significant benefits for modified PEMs, such as improved proton conductivity, ion exchange capacity, and anti-bacterial capability. The MFC utilizing PEM with 4.0 wt% of ZANPs (ZANPs4.0/SPES) demonstrated a peak power output of 142.75 mW/m2 and a maximum current of 413 mA/m2. The values observed were notably elevated compared to the MFC that used commercial Nafion 117. The ZANPs4.0/SPES also had a maximum ion exchange capacity of 2.75 meq/g and 3.91 mS/cm proton conductivity among the fabricated PEMs compared to Nafion117, which only had 1.07 mS/cm proton conductivity and ion exchange capacity of 0.89 meq/g. Modified membranes improved COD removal from sugar beet industry effluent by up to 98.22 % and had a higher coulombic efficiency of up to 39.26 %. The anti-bacterial efficiency of ZANPs4.0/SPES was over 97 % against two types of bacteria. As per the research findings, it is confirmed that the ZANPs/SPES membranes can function efficiently in dual-chamber MFCs.