Low-cost crosslinked PVA membranes as alternative proton exchange membrane in hemodialysis wastewater fed bioelectrochemical fuel cells

Abstract

Hemodialysis (HD) is a highly water and electricity-consuming process. Untreated hemodialysis wastewater (HDWW) has high chemical oxygen demand when discharged at a temperature of 20–25 °C. It causes significant wastage of thermal energy posing a challenge in achieving zero liquid discharge (ZLD). Microbial Fuel Cells (MFCs) offers a ground-breaking solution for reusing HDWW, thereby reducing the carbon footprint of HD. However, MFCs are practically limited by cost of Nafion 117. In this study, Polyvinyl Alcohol (PVA) previously used in HD for the effective removal of creatinine and larger molecular weight pollutants, is utilized as Nafion-alternative proton exchange membrane by crosslinking PVA with 5 % glutaraldehyde to harvest bioelectricity from HDWW fed MFCs. The crosslinked PVA membrane achieved a remarkable power density of 320 mW/m² due to its low ohmic resistance of 68.97 Ω, as confirmed by EIS analysis. Additionally, the membrane cost is reduced by eight-fold compared to Nafion-117, making it economically feasible. Moreover, PVA's manufacturing process, which uses water as a solvent, requires no catalyst, and involves zero activation steps, is eco-friendly. Reutilizing HDWW with crosslinked PVA membrane in MFCs advances ZLD in HD by harnessing low-grade heat and generating bioelectricity, thus significantly reducing dialysis waste and its ecological impact.