Document Type : Research Paper

Authors

• Azar Asadi ¹
• Soheila Hamidi ²
• Samin Sedaghatfard ²
• Hadi Naderi ²

¹ Department of Gas and Petroleum, Yasouj University, Gachsaran, Iran.

² Department of Applied Chemistry, Faculty of Gas and Petroleum, Yasouj University, Gachsaran, Iran

Abstract

This study presents a direct comparative and synergistic investigation of polyvinylpyrrolidone (PVP) and trimesic Acid (TMA) as additives for polyethersulfone (PES) membranes. Scanning electron microscopy (SEM) analysis revealed that PVP primarily acts as a pore-forming agent, while TMA induces a finer, sponge-like morphology. Water contact angle (WCA) measurements confirmed that TMA imparts higher surface hydrophilicity (37.5°) compared to PVP, attributed to its lower aqueous solubility and greater retention of hydrophilic carboxylic acid groups within the polymer matrix. Pure water flux (PWF) data, monitored at 4 bar pressure, showed that membranes embedded with TMA as a single additive had lower flux than the bare membrane, due to their sponge-like pore structure. A powerful synergistic effect was discovered in dual-additive formulations. The optimal membrane (M7), containing 1 wt.% each of PVP and TMA, achieved an exceptional PWF of 103 kg/m²·h. This synergy is driven by accelerated co-leaching during phase inversion, which optimizes pore structure. From the antifouling test, single TMA-based membranes demonstrated the highest FRR values (approximate 100%). Meanwhile, the membranes containing both PVP and TMA showed compromised FRR. Nevertheless, M7 membrane maintained an acceptable FRR of 75%. The results indicate that combining PVP and TMA creates a synergistic effect, producing membranes with a superior balance of high permeability and antifouling resistance compared to those with a single additive.

Keywords

• Antifouling
• Pure water flux
• Synergistic effect
• Trimesic acid