Preparation of ceramic ultrafiltration membrane using green synthesized CuO nanoparticles for chromium (VI) removal and optimization by response surface methodology

Abstract Application of toxic materials for fabrication of membrane and its use for water treatment may create serious environmental threats. In this study, a new alternative approach was employed to synthesize copper oxide (CuO) nanoparticles (NPs) via green route using Catharanthus Roseus leaf extract and its efficacy as membrane material was also explored for chromium (VI) removal. Optimization by response surface methodology was adopted for uniform nanoparticle synthesis. The low cost clay-alumina ceramic support was coated with CuO slurry by dip coating method for the fabrication of membrane where the structural properties of CuO NPs in active layer were also studied. Adhesion of CuO NPs on membrane surface was established by FESEM analysis where the images demonstrated homogeneous and defect free coating over porous support. A detailed XPS analysis revealed the binding properties of the CuO NPs with clay-alumina membrane surface and the rejection mechanism of chromium (VI). BET analyses further confirmed the pore size reduction of the coated membrane towards ultrafiltration range (from 1-1.5 μm to 3.2 nm). The novel CuO clay-alumina ceramic membrane showed high clean water permeability, flux and toxic chromium (VI) ions rejection as 85.51 L m−2 h−1 bar−1, 253 L m−2 h−1 and 88.08%, respectively. This paper explores a new alleyway of environment friendly membrane preparation process that can be potentially elaborated for waste water treatment in large scale.