Preparation and characterization of PVDF–PVP–TiO₂ composite hollow fiber membranes for oily wastewater treatment using submerged membrane system

Abstract

A series of polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration membranes made of different titanium dioxide (TiO₂) concentrations with the presence of polyvinylpyrrolidone as additive was prepared. The membrane performances were characterized in terms of pure water flux, permeate flux, and oil rejection, while the membrane morphologies were analyzed using scanning electron microscope and atomic force microscope. The experimental results showed that when 2 wt.% TiO₂ was incorporated into PVDF membranes, optimized permeate flux and oil rejection of 70.48 L/m²h (±1.41) and 99.7% (±0.3), respectively, could be obtained when tested using 250 ppm synthesized oily solution under vacuum condition. Compared to the PVDF membrane without TiO₂ addition, all the composite membranes showed relatively higher permeate flux and oil rejection. Based on the results obtained, it is reported that the composite PVDF membrane incorporated with 2 wt.% TiO₂ exhibited the best separation performance in which complete removal of oil was able to achieve regardless of the feed oil concentration. However, decrease in permeate flux was observed when the feed oil concentration increased from 250 to 1,000 ppm. The results concluded that the composite PVDF membrane showed better performance in treating oily solution compared to that of without TiO₂.

Keywords:

• Polyvinylidene fluoride
• Ultrafiltration
• Oily solution
• Titanium dioxide
• Hydrophilicity