Abstract
Membranes for water treatment face a major problem of fouling. One of the solutions to reduce fouling propensity in membranes is the addition of hydrophilic additives during membrane preparation. In this study, a significant enhancement of hydrophilicity, flux and rejection of Na2SO4 by a modified polysulfone membrane was observed. The membrane was prepared using graphene oxide (GO) as a hydrophilic additive followed by surface modification through imprinting on Graphene oxide-polysulfone (GO-Psf) mixed composite membranes. GO was synthesized through oxidation and exfoliation of graphite. The GO-Psf composite membrane was prepared through a phase inversion process of a mixture of GO and polysulfone (Psf) in N-methylpyrrolidone (NMP). Imprinting on the surface of composite membrane was achieved through a free radical polymerization.
Characterization of the GO and the prepared membranes was achieved using Fourier-transform spectroscopy (FT-IR), Raman spectroscopy, thermogravimetric analysis (TGA), contact angle, scanning electron microscope (SEM) and transmission electron microscope (TEM). FT-IR of the composite imprinted membranes (CIMs) showed new peaks at 935 cm-1 and 1638 cm-1 indicating the success of surface imprinting. Raman spectroscopy was used to confirm the presence of GO in the modified membrane. The CIMs showed improvement in flux from 8.56 LM-2h-1 of neat polysulfone membrane, to 15.3 LM-2h-1 in the CIM. Similarly, rejection of Na2SO4 salt rejection also increased from 57.2±4.2 % of polysulfone membrane to 76±4.5 % in CIMs. The surface modified membranes also showed improvement of surface hydrophilicity; the contact angle measurements for the neat polysulfone membrane was measured to be 72±2.7 % compared to...
Ph.D. (Chemistry)