Polyethersulfone membranes prepared with Rhodiasolv®Polarclean as water soluble green solvent

Polyethersulfone (PESU) porous membranes with high pure water permeability were successfully produced by coupling non-solvent induced phase separation (NIPS) with vapor induced phase separation (VIPS) techniques by employing Rhodiasolv®Polarclean (Polarclean®) for the first time, as eco-friendly sustainable solvent. Membrane morphology and performance were tailored by varying the casting solution composition and the exposure time to controlled humidity and temperature. Polyvinylpyrrolidone (PVP) and poly(ethylene glycol) (PEG) were used as hydrophilic pore former agent and small-molecule liquid, respectively. The resulting membranes were characterized in terms of morphology, thickness, porosity, contact angle, mechanical features, pore size and pure water permeability. The obtained data indicated that the exposure time to humid air as well as the polymer and the PEG concentration in the casting solution represent the most relevant parameters to obtain hydrophilic membranes with different structure and properties. Both ultrafiltration (UF) and microfiltration (MF) membranes, with a pore size ranging from ~0.04 to ~0.4 ?m, were efficiently prepared by using the investigated novel solvent, offering the possibility to replace commonly used toxic diluents in polysulfones' membrane fabrication.