TamiSolve® NxG as novel solvent for polymeric membrane preparation

Abstract Poly(vinylidene fluoride-hexafluoropropylene) P(VDF-HFP) porous membranes with a pore size ranging in the ultra- and micro-filtration range were successfully prepared for the first time by employing a Tamisolve® NxG as novel, non-reprotoxic solvent via non-solvent induced phase inversion. Membrane morphology and performance were tailored by acting on the casting solution composition, more specifically on the presence and the concentration of polyvinylpyrrolidone (PVP) and/or poly(ethylene glycol) (PEG) as pore former agents and by changing the polymer content in the dope solution. The resulting membranes were characterized in terms of morphology, thickness, porosity, contact angle, mechanical features, pore size, liquid entry pressure and pure water permeability (PWP). Direct Contact Membrane Distillation (DCMD) experiments were performed in order to evaluate the applicability of the novel membrane in water treatment by desalination operations. The obtained data indicated as both the additive and the polymer concentration in the casting solution played a crucial role for the final membrane structure and properties. Preliminary DCMD tests showed as the prepared P(VDF-HFP) membrane with a pore size comparable to that of a commercial polypropylene (PP), exhibited promising results in terms of permeate flux and salt rejection, opening new perspectives in the sustainable membrane technology.