A gas–liquid chemical reaction treatment and phase inversion technique for formation of high permeability PAN UF membranes

Polyacrylonitrile (PAN) ultrafiltration (UF) membranes were prepared by the pretreatment (gas–liquid interfacial chemical reaction) and the phase inversion process from a casting solution containing dimethylacetamide (DMAC) as a solvent and CaCl2/NH3·H2O/H2O as a composite additive. Deionized (DI) water was used as a coagulant. The membranes were characterized in terms of the pure water fluxes, protein retention and direct field emission scanning electron microscopy (FESEM) observations. The effects of gas–liquid interfacial chemical reaction on the membrane performance were investigated by changing the pretreatment time, CO2 contacting method (static or flowing) and Partial pressure of CO2. The gas–liquid interfacial chemical reaction had great influence on reducing pore size and increasing porosity of PAN membrane.