ZIF-8/Chitosan Composite Hydrogel as a High-Performance Separator for Bioelectrochemical Systems

Chitosan biopolymer membranes reinforced with channel-selective ZIF-8 nanofillers were developed and thoroughly characterized as separators for bioelectrochemical systems. This study explores the synergistic effect of incorporating ZIF-8 into a chitosan matrix to enhance membrane performance. Key properties including water retention, chemical and thermal stability, surface resistance, antifouling capacity, and ionic conductivity were evaluated and benchmarked against commercial Nafion-117 and nanofiltration (NF) membranes. The ZIF-8/chitosan composite membranes (ZIF-8/CS) demonstrated excellent water retention and structural stability under harsh conditions, along with significantly reduced surface resistance and effective rejection of organic contaminants and salts (NaCl, Na₂SO₄). Notably, the composite ZIF-8/CS membranes achieved an ionic conductivity of 0.099 S/cm, approaching the value of Nafion-117 (0.13 S/cm) and substantially surpassing that of the NF membrane (0.013 S/cm). These results indicate that ZIF-8-reinforced chitosan membranes present a promising, sustainable, and cost-effective alternative to traditional separators in bioelectrochemical applications.