Arshyn Zhengis, Mirat Karibayev, Asset Aliyev, Yenglik Amrenova, Arailym Yergesheva, Ramazan Asmatulu, Munziya Abutalip, Nurxat Nuraje
The development of nanofiltration (NF) membranes is critical for achieving sustainable water purification and resource recovery. However, conventional polyamide NF membranes often encounter trade-offs between ion selectivity and water permeability. Herein, we introduce a dual-zwitterionic strategy by assembling zwitterionized polyethyleneimine (Z-PEI) and polyanionic phytic acid (PA) onto a polyamide substrate. This architecture enhances surface hydration and charge density, enabling synergistic ion exclusion through Donnan repulsion, steric hindrance, and metal-chelation mechanisms. The resulting M1-ZPEI-PA membrane achieved high removal efficiencies of more than 98% for heavy metal ions, including Zn 2+ , Cu 2+ , Pb 2+ , Cd 2+ , and Fe 2+ , as well as 58.93% removal of NaCl, while maintaining high water permeability. Classical all-atom Molecular Dynamics simulations performed to study the molecular structural properties and intermolecular interactions of M1-ZPEI-PA membrane with contaminants. This study offers a promising pathway toward high-performance NF membranes for sustainable water treatment and environmental remediation.