Cross-flow deposited hydroxyethyl cellulose (HEC)/polypropylene (PP) thin-film composite membrane for aqueous and non-aqueous nanofiltration

In this study, hydroxyethyl cellulose (HEC) was cross-flow deposited on flat-sheet polypropylene (PP) porous support and insolubilized by cross-linking using glutaraldehyde (GA) to fabricate cost-effective thin-film composite membrane for aqueous and non-aqueous nanofiltration. Membrane physico-chemical property, permeation performance, as well as tolerance to acid, alkaline and organic solvents were systematically characterized. The obtained HEC/PP composite membrane was found to be effectively modulated in pore size via changing HEC and GA contents and possessed good fabrication reproducibility. The desired HEC/PP composite membrane with an average pore diameter of around 2.21   nm exhibited high fluxes of 41.0 and 8.2   L/m 2   h to pure water and ethanol, respectively, and removals of 99.9%, 99.9% and 96.7% to 50   mg/L dye aqueous solutions of methyl blue, Congo red and sunset yellow, respectively. Soaking tests revealed that the HEC/PP composite membrane possessed good tolerance to acid, alkali and organic solvents of tetrahydrofuran, ethyl acetate and ethanol. Continuous filtration of dye/ethanol solution demonstrated that the HEC/PP membrane possessed excellent long-term durability in ethanol solution, maintaining a stable flux higher than 4.6   L/m 2   h and removals of 95.4% and 84.2% to methyl blue and Congo red, respectively, during the whole filtration of 110   h.