Document Type : Research Paper
Authors
1 Department of Gas and Petroleum, Yasouj University, Gachsaran 75918-74831, Iran.
2 Department of Applied Chemistry, Faculty of Gas and Petroleum, Yasouj University, Gachsaran 75918-74831, Iran
Abstract
This study presents a direct comparative and synergistic investigation of polyvinylpyrrolidone (PVP) and trimesic Acid (TMA) as additives for polyethersulfone (PES) ultrafiltration (UF) 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.
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