Relating Solute–Membrane Electrostatic Interactions to Solute Permeability in Reverse Osmosis Membranes

• DOI: 10.1021/acs.est.4c13212
• Publication Date: 2025-03-12T08:17:04Z
• Authors: Tianchi Cao; Li Wang; Kevin E. Pataroque; Ruoyu Wang; Menachem Elimelech
• Keywords: Osmosis

Despite the widespread use of reverse osmosis (RO) membranes in water desalination, role solute-membrane interactions solute transport remains complex and relatively not well understood. This study elucidates relationship between electrostatic permeability RO membranes. The salt neutral molecules through charged polyamide (PA) uncharged cellulose triacetate (CTA) was examined. Results show that rejection PA membrane are highly dependent on solution pH due to variations charge density Donnan potential at membrane-solution interface. Specifically, a higher (and hence lower permeability) is observed under alkaline conditions compared acidic conditions. observation attributed enhanced pH, which hinders co-ion partitioning into membrane. In contrast, for CTA both membranes, independent concentration negligible effect. Overall, our results demonstrate important interactions, combined with steric exclusion, regulating