UF membrane of PVA modified with TDI

Poly (vinyl alcohol) (PVA) is an excellent membrane material for preparation of hydrophilic ultrafiltration (UF) and nanofiltration membranes. But its chemical constitution and water solubility infer the disadvantage of easier degradation and elimination after use. This study focuses on the modification of interfacial polymerization PVA composite UF membrane with toluene diisocyanate (TDI). The effects of the reaction time and PVA, TDI, sodium dodecyl sulfate and sodium hydroxide with different concentrations were investigated on the performances of composite membranes. Anti-fouling to protein and oil was obtained when it was compared with no modified membrane. Also, the recovery ratio of pure water flux of PVA modified UF membrane is higher than that of support membrane.

The modified PVA composite UF membrane with good water flux and anti-fouling performance was prepared by interfacial polymerization in the best condition PVA 0.5–2% (wt.), TDI 0.08–0.5% (vol.), sodium hydroxide 0.2–0.4% (wt.), SDS 0.8–1% (wt.) and at 30–60 s. The modified PVA composite UF membrane with thin hydrophilic PVA layer had better anti-fouling performance than PES support membrane. When PES UF membrane was used as the support, the oil removal and water flux could get to 92% and 40 L/(m2 h), respectively, for the composite membrane, which were only 80% and 20 L/(m2 h) for the support membrane. And PVA could exist in composite membrane through chemical modify, which reserve PVA’s hydrophilicity.