Facile synthesis of novel graphene-based magnetized nanocomposite for the simultaneous elimination of lead (II) and chromium (VI) in aqueous medium: Insights of interfacial studies

Abstract

Green and sustainable approaches have received greater attention in synthesizing advanced materials for efficient wastewater treatment processes. The mesoporous magnetized nanomaterials were synthesized employing bioderived graphene oxide and bentonite. The advanced tools characterized the nanocomposite materials extensively. Further, the synthesized composite was utilized to efficiently eliminate lead (II) and chromium (VI), both individually and simultaneously, from aqueous medium. The theoretical modeling using the Sips expanded equation proved the material's effectiveness in eliminating such ions. Parametric studies reveal solid-solution interface interactions influenced by pH, concentration, and electrolyte levels. 32.84 and 5.17 mg/g are the sorption capacities of the nanocomposite solid for lead (II) and chromium (VI), respectively. In contrast, pH being 3.7, a binary system of lead (II) to chromium (VI) with a 1:1 ratio showed 27.5 and 25.1 mg/g for lead (II) and chromium (VI), respectively. Several studies involving interfering co-ions and real matrix samples further demonstrate the efficacy of nanocomposite materials in eliminating these pollutants. The 0.1 mol/L of HCl and H₂SO₄ solutions efficiently recover the pre-sorbed lead (II) and chromium (VI) from the solid surface for four successive sorption/desorption processes, and successive use of the nanocomposite solid entails the potential of the nanocomposite solid in the sustainable unit operations.