A study on the effects of the addition of graphene oxide and multi-walled carbon nanotubes for surface modification on polyvinylidene fluoride membranes

We report graphene oxide (GO) and multi-walled carbon nanotube (MWCNT)-based polyvinylidene fluoride (PVDF) to improve the nanopore properties of pure PVDF for water treatment. The surface properties such as morphology, size of pores, and hydrophilicity were characterized using an optical microscope, FE-SEM, Raman spectra, and a capillary flow porometer. The membrane performance was evaluated for free residual chlorine and water flux. GO and MWCNTs were uniformly synthesized in the PVDF, and the hydrophobic properties of pure PVDF became hydrophilic because of the oxygen functional group of GO and the hydrophilic functional group of MWCNTs. The membrane with GO dramatically increased the number of pores from 145 to 1,197, with greater pore depth than that of pure PVDF. Additionally, the free residual chlorine removal performance of the GO and MWCNTs added PVDF was about 270 % and 415% improved compared to the pure PVDF and commercially used ultra-filter, respectively. These results reveal that the number and size of pores on the PVDF can be controlled and performance of the water treatment can be increased by the addition of carbon nanomaterials.