Construction of Composite Membranes for Desalination and Adsorption of Heavy Metals

Abstract

Freshwater scarcity and heavy metal toxicity is a pressing global issue which has provoked the scientific community to look for energy and cost-efficient seawater treatment techniques. In this research study, TFC membranes of rGO/NiMoV LDH are synthesized with varying wt% of rGO i.e., 3%, 7% and 10%. The physiochemical properties of fabricated membranes are analyzed with characterization techniques i.e., scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The TFC membranes were tested for desalination and adsorption of heavy metal through forward osmosis individually and simultaneously both. The results showed that by increasing the wt. % of rGO in TFC membranes, the desalination performance and adsorption efficiency increased. The highest desalination performance is shown by 10% rGO/NiMoV LDH with 100% Pb (II) adsorption. When analyzed for simultaneous operation, there was a slight decrease in desalination and adsorption both due to increased competing effect of Pb (II), Na+, and Cl- ions. Additionally, effect of pH, composite dose and pollutant concentration is also investigated for adsorption. This study serves as a milestone to achieve simultaneous desalination and heavy metal adsorption by forward osmosis which can be a basis for further research and development in seawater treatment.