Fabrication of high-flux asymmetric polyethersulfone (PES) ultrafiltration membranes via Nonsolvent-Induced phase separation: impact of coagulation bath temperature

The isothermal non-solvent induced phase separation (NIPS) process was utilized to produce asymmetric polyethersulfone (PES) membranes in order to assess the effects of coagulation bath temperature (CBT) on their morphology and performance. The experimental process involved the use of quaternary dopes that were composed of glycerol, poly(vinylpyrrolidone) (PVP), γ-butyrolactone (GBL), and PES. Membranes were cast and precipitated in coagulation baths at temperatures of 22 °C, 30 °C, 40 °C, and 50 °C. Higher CBT has a significant effect on the membrane structure, leading to an increase in pore sizes from 18.51 nm to 40.36 nm, while maintaining approximately 80% porosity and the formation of interconnected microporous channels at temperatures from 30 °C to 50 °C. These structural enhancements played a crucial role in enabling the membranes to achieve remarkably high water flux rates, which range from 2000 to 4000 L m⁻² h⁻¹ bar ⁻¹. This achievement demonstrates the membranes exceptional performance and their advanced capability for use in ultrafiltration applications.