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 75918-74831, Iran.

² Department of Applied Chemistry, Faculty of Gas and Petroleum, Yasouj University, Gachsaran 75918-74831, Iran

Abstract

This study directly compares Polyvinylpyrrolidone (PVP) and Trimesic Acid (TMA) as modifiers for polyethersulfone (PES) ultrafiltration membranes. Membranes fabricated with 20% PES and varying concentrations of each additive, with their thickness adjusted to 150 µm, using the phase-inversion technique. Then their combinations were characterized for morphology, hydrophilicity, and performance. Scanning electron microscopy (SEM) showed PVP acts as a pore-forming agent, while TMA creates a finer and sponge-like structure. Contact angle measurements confirmed TMA imparts greater hydrophilicity. Pure water flux (PWF) data, monitored at 4 bar pressure, showed that membranes embedded with TMA as a single additive had significantly lower flux than the bare membrane, due to their sponge-like pore structure and the low solubility of TMA in water. A significant synergy was found in dual-additive membranes. The optimal membrane, containing 1 wt.% PVP and 1 wt.% TMA, achieved the highest hydrophilicity (37.5° contact angle) and the highest pure water flux (38.4 kg/m²·h). Antifouling tests against a milk powder solution (with concentration of 1000 mg/l over 90 min of operation in a dead-end set-up) revealed this membrane also had acceptable flux recovery ratio (FRR) of 79%. The results demonstrate 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

• Phase inversion
• Hydrophilicity
• Antifouling
• Pure water flux
• Synergistic effect