Preparation of an adsorptive membrane of polyvinylidene fluoride incorporated functionalized boron nitride nanosheets for arsenic removal

Abstract

Incorporating nanomaterials into membranes will enhance wastewater treatment efficiency with their unique characteristics, such as higher permeability, thermal stability, surface roughness, hydrophilicity, and fouling control. In this study, the surface modified boron nitride with phosphoric acid 2-hydroxyethyl methacrylate ester (PA/BN) was grafted with polyethylene glycol (PEG) via conventional grafting. The PEG grafted PA/BN (PEG-g-PA/BN) melt blended with polyvinylidene fluoride (PVDF) resin by using an internal mixer at different mass percentages (100% PVDF (PVDF), 3% PEG-g-PA/BN + 97% PVDF (97:3 BN), 5% PEG-g-PA/BN + 95% PVDF (95:5 BN), 7% PEG-g-PA/BN + 93% PVDF (93:7 BN), and 7% PEG-g-PA/BNNS + 93% PVDF (93:7 BNNS). Phase inversion technique was used to cast the blended mixture into a thin membrane. The prepared membranes were analyzed with different characterization techniques to determine chemical composition, crystallinity, morphology, and thermal properties. The prepared composite membrane was evaluated in terms of water permeability, anti-fouling resistance, and solute rejection efficiency with deionized water, bovine serum albumin, and arsenic solution as well. PVDF membranes show high water flux and porosity. The water flux and porosity of the blends decrease as the percentage of PEG-g-PA/BN increases. However, the highest removal capacity for arsenic was observed at 93:7 BN. The adsorption of arsenic ions takes place via complexation with PA/BN in the PVDF matrix. This was confirmed with field emission scanning electron microscopy–energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy analyses.