A new technique to fabricate high-performance biologically inspired membranes for water treatment

Aquaporin, a highly selective water channel protein, has received worldwide attention because of its potential to form biomimetic membranes with high flux and rejection for water reuse and desalination. In this study, purified aquaporins were incorporated into the active layer of the polybenzimidazole (PBI) nanofiltration membrane. Aquaporins were dispersed in gum arabic and embedded in amphiphilic polyvinyl alcohol with alkyl side chains (PVA-alkyl). PVA-alkyl embedded with treated aquaporins was then attached to flat sheet PBI membranes using carbodiimide chemistry. PVA-alkyl acted as support for aquaporins to prevent their chemical alteration and also gave the membranes mechanical strength. It was found that membranes modified with PVA-alkyl-AqpZ displayed lower flux declines and higher flux recoveries as compared to unmodified PBI membranes. Higher protein and salt rejections were also observed using PVA-alkyl-AqpZ modified membranes as compared to unmodified PBI membranes.