Effect of reduced graphene oxide/TiO2 nanocomposite with different molar ratios on the performance of PVDF ultrafiltration membranes

Abstract

A partially reduced graphene oxide (rGO)/TiO2 nanocomposite with five different molar ratios (rGO/TiO2: 3/97, 30/70, 50/50, 70/30 and 90/10) were synthesized and characterized using X-ray diffraction and scanning electron microscopy (SEM) techniques. The polyvinylidene fluoride (PVDF) mixed matrix membranes containing 0.05wt.% of the nanocomposites were prepared by phase inversion method. The effect of rGO/TiO2 additive on the morphology and performance of prepared blended membranes was studied by atomic force microscopy (AFM), SEM, energy dispersive X-ray (EDX), FTIR, water contact angle, porosity and permeation measurements, rejection tests and antifouling parameters. The SEM images revealed finger-like structure of the membranes and EDX analysis confirmed well distribution of rGO/TiO2 nanocomposite in the polymer matrix. The rGO/TiO2/PVDF membranes showed enhanced hydrophilicity, higher pure water flux and flux recovery ratio compared to the bare PVDF. A comparison of pure water flux of TiO2 and rGO/TiO2 containing membranes showed that dispersion of inorganic TiO2 nanoparticles on the GO surface decreased the aggregation of the nanoparticles and improved the characteristics of the resulted mixed matrix membrane. The blended membrane containing 0.05wt.% rGO/TiO2 nanocomposite with GO to TiO2 ratio of 70/30 showed improved permeability and antifouling performance.