Vermiculite nanosheet augmented novel proton exchange membrane for microbial fuel cell

Abstract

Microbial fuel cell (MFC) is promoted as an eco-friendly technology for wastewater treatment. However, the use of synthetic polymeric membrane separators raises concerns about the sustainability of MFC, mandating efforts to develop sustainable polymeric membrane with high protonic transfer for MFC assembly. Low-cost and eco-friendly polymer matrix of agar-polyvinyl alcohol (AP) augmented with exfoliated vermiculite nanosheets (Vm NSs) are used to prepare membrane separators for MFC. A simple and facile method for synthesis of AP membrane without and with Vm NSs concentration of 0.25 mg/mL (0.25 Vm), 0.5 mg/mL (0.5 Vm) and 1 mg/mL (1.0 Vm) is adopted in aqueous phase. The proton mass transfer coefficients of prepared membranes (AP, 0.25 Vm, 0.5 Vm and 1.0 Vm) are respectively 94.4, 134.46, 216.26 and 197.69 % higher than commercially available Nafion membrane. These membranes are tested in three different configurations of MFC: aerated cathode, air cathode and anaerobic dye cathode MFC. Highest current densities of 1515 and 949 mA/m3 are obtained with 1.0 Vm membrane in aerated and air cathode-MFC respectively while Nafion membrane could produce 623 and 405 mA/m3. In anaerobic dye cathode MFC, 0.5 Vm membrane is able to achieve the highest current density of 935 mA/m3 along with 71 % methyl red decolorization while Nafion membrane produced highest current density of 104 mA/m3 with 59 % decolorization. Vm NSs augmentation enhances the properties of base AP membrane which can be conveniently used as an alternative to expensive Nafion membrane in the desired configuration of MFC. © 2023