Antifouling Graphene Oxide Polymeric Nanocomposites Membranes for Water Desalination

Abstract

The graphene-oxide (GO) based nanoparticles blended in polymer mixed matrix membranes have a lot of applications in wastewater and water treatment due to more than one functionalities of these membranes. In this work, we synthesize a unique polyethersulfone (PES) matrix membrane that contains GO nanoparticles via phase inversion method. We investigate the impact of newly added GO nanoparticles on the morphology and performance of membranes using water contact angle, pure water flux & fouling parameters, and optical profilometry. We characterize these novel membranes by using a scanning electron microscope (SEM), water contact angle, and porosity measurements. GO nanoparticles analysis via FT-IR ATR spectra indicates that hydroxyl and carboxylic acid groups emerge on the surface GO incorporated membranes. Due to the considerably larger value of hydrophilicity of these newly developed membranes, the water flux from these membranes enhances after incorporating GO to the casting solution. The water contact angle experiment also indicates that the hydrophilicity of these upgraded membranes increases. According to SEM results, the morphology of membranes with GO nanoparticles is different from the morphology of unfilled PES membranes. Membranes with GO nanoparticles have finger-like pores that are significantly wider than the finger-like pores of unfilled PES membranes. The novel membranes with 0.4wt% GO nanoparticles have the largest pore size and water flux. These novel membranes also indicate that they are worthy in terms of reusability. Due to the increased hydrophilicity of the GO incorporated membrane, the permeability of the membrane increases to a very high level. However, when the concentration of the casting solution is very high, the permeability decreases. This unusual behavior is maybe because the casting solution of high concentration makes a layer of higher density on the surface of the membrane, which reduces the permeability of the membrane. We have studied the effect of GO nanoparticles on the mechanical properties of the PES membrane. The GO-PES with 1wt% shows a very significant antibacterial activity against Staphylococcus and E-coli.