A single functionalized graphene nanocomposite in cross flow module for removal of multiple toxic anionic...

Polyether sulfone (PES)-based thin-film nanofiltration (TFN) membranes embedded with ferric hydroxide (Fe^III(OH)_x) functionalized graphene oxide (GO) nanoparticles were fabricated through interfacial polymerization for a generalized application in removal of a plethora of anionic and toxic water contaminants. Following the most relevant characterization, the newly synthesized membranes were fitted in a novel flat sheet cross-flow module, for experimental investigation on purification of live contaminated groundwater collected from different affected areas. The separation performances of the membranes in the flat sheet cross-flow module demonstrated that GOF membranes had higher selectivity for monovalent and divalent salt rejections than pristine GO membranes. Furthermore, both membranes were tested for simultaneously removing widely occurring hazardous ions of heavy metals and metalloids in groundwater, such as arsenic, selenium, chromium, and fluoride. Compared to the pristine GO and the reported membranes in the literature, the GOF membrane exhibited remarkable performance in terms of rejection efficiency (Cr (VI): 97.2%, Se (IV): 96.6%, As(V): 96.3%, F^- 88.4%) and sustained flux of 184 LMH (Lm^-2 h^-1) at an optimum transmembrane pressure of 16 bar. The investigated membrane module equipped with the GOF membrane proved to be a low-cost system with higher anionic rejection and sustained high flux at a comprehensive pH range, as evident over long hours of study vis-à-vis reported systems.