Unraveling the influence of palygorskite electronegativity on the interfacial polymerization process of reverse osmosis membranes

Acid-activated palygorskite with tunable electronegativity regulates IP kinetics. • MD simulations reveal synergistic steric hindrance and electrostatic MPD inhibition. • Stopped-flow analysis uncovers “initial inhibition, subsequent promotion” mechanism. • The TFN-ACP 8,0.02 membrane achieves 75.27 L/m 2 ·h water flux with 99.39% rejection. • Simple acid treatment of Pal offers a scalable route to high-performance TFN-RO. Nanoparticle-mediated interfacial polymerization (IP) offers a promising route to high-performance reverse osmosis membranes, and optimizing the intrinsic properties of nanomaterials to better regulate the IP layer structure has become a critical research direction. In the present study, palygorskite (Pal) was modified via acid activation to tailor its particle size and surface charge, systematically decoupling the roles of steric hindrance, electrostatic interaction, and adsorption capacity during the IP process. By tuning the acid treatment duration (4–10 h), the particle size, specific surface area, and zeta potential of Pal were effectively modulated across wide ranges (219–311 nm, 130–200 m 2 /g, −17.6 to −26.0 mV). Combining molecular dynamics simulations, UV–vis diffusion monitoring, and stopped-flow kinetic analysis, a quantitative structure-property relationship between nanofiller electronegativity and MPD diffusion inhibition was established. The optimized acid activation (8 h) endowed the TFN membrane with a 2.52-fold enhancement in water flux (75.27 L/m 2 ·h) while maintaining a high NaCl rejection of 99.39%. This work provides mechanistic insights and a practical material strategy for designing next-generation TFN membranes through simple surface regulation of naturally abundant clay minerals.