The interplay role of vanillin, water, and coagulation bath temperature on formation of antifouling polyethersulfone (PES) membranes: Application in wood extract treatment

Abstract In this study vanillin was tested as the hydrophilicity promoter in a PES membranes to improve the feasibility of the membranes in the treatment of a biorefinery stream, namely a pressurized hot water extract (PHWE). The commercial PES membranes are typically prepared by phase inversion technique and thus, phase inversion is also used in this study. The ultimate structure of the phase inversion prepared membranes is asymmetric and it can be affected by various key parameters such as the temperature and the concentration of the PES solution, the solvent and additives which are used in PES solution, the coagulation bath temperature as well as the thickness of the cast PES film. In the present study, the effect of vanillin (0–6 wt.%) as a hydrophilic promoter agent, water as strong non-solvent additive in dope solution (0–2 wt.%) and coagulation bath temperature (CBT) on the formation of PES membranes was investigated in order to improve the understanding on the manufacturing of PES/vanillin membranes. The mentioned fabrication parameters were optimized and their effects on the membrane morphology, hydrophilicity, thickness, PHWE permeability, fouling and rejection properties were sequentially analyzed. It can be concluded that a small quantity of vanillin and water together in dope solution can preferably change the membrane morphology and increase the surface hydrophilicity and thus lead to formation of membrane with better wood extract permeability and antifouling characteristics.