Terylene membrane modification with Polyrotaxanes, TiO 2 and Polyvinyl alcohol for better antifouling and adsorption property

Abstract

For better antifouling membranes and removal of small organic toxic pollutants from water by membrane adsorption, Polyrotaxanes (PRs)–TiO 2–Polyvinyl alcohol (PVA) modified terylene membranes were prepared by dip-coating in an aqueous solution containing PR (0–3%), a derivatives of α-cyclodextrin (α-CD), TiO 2 sol and PVA (1–10%), drying and cross-linking treatment with glutaraldehyde (GA). The filtration performance and antifouling property of modified membranes in filtering water containing dissolved milk powder as simulate extracellular polymer substances (EPSs) were studied, also studied was the membrane adsorption capacity to toluene in water. The PR–TiO 2–PVA modified terylene membranes were characterized by FTIR (Fourier transform infrared spectroscopy) and scanning electron microscopy (SEM). It was found that the concentrations of PVA and PR, ratio of PR to TiO 2 in casting solution affected modification parameters such as immobilization degree ( ID), membrane water uptake ratio ( W r ) and filtration performance parameters such as total resistance ( R t ) and irreversible fouling resistance ( R f ). Modified membrane resistance ( R m ) and slope of V– t curves followed the same order, while slope of R t / V– t curve reflected overall membrane fouling tendency including pore blocking and cake layer formation. Furthermore, this kind of modified membrane possesses a good adsorption capacity towards toluene in water which can be regenerated to different degrees by photo-catalytic UV irradiation depending on membrane modification conditions and deposited coating layer composition. Modification at PVA 5%, PR 2% and TiO 2 produced the best membrane in antifouling, filtration performance and adsorptive removal of toluene and regeneration. Modification at PVA 10% and TiO 2 may produce a membrane with better filtration performance but poor adsorption capacity.