Adsorptive removal of nickel from waste water using synthesized sodium alginate encapsulated magnetic graphene oxide nanoadsorbent from Strychnous Potatorum seeds

Abstract

The present study investigated the synthesis of sodium alginate encapsulated magnetic graphene oxide (SAMGO) beads from Strychnous Potatorum seeds. The synthesized SAMGO beads were investigated for adsorptive removal of nickel from aqueous solution. The synthesized SAMGO beads were characterized for surface morphology, functional groups, magnetic property and phase identification using SEM, FT-IR, VSM and XRD analysis. The optimization process involving the SAMGO beads for adsorptive removal of nickel resulted in maximum removal rate under the conditions of contact time – 15 min, SAMGO bead dose – 10 mg/50 mL of solution, nickel ion concentration – 50 mg/L, pH-9 and temperature of 30 °C. Adsorption of nickel onto SAMGO beads was well studied by pseudo-second-order kinetic studies. Also, the adsorption equilibrium study was well fitted towards Freundlich isotherm (R²= 0.99). The findings from the regeneration studies demonstrated that the selected desorbing agents, 0.5 M HCl and 0.5 M EDTA were well-suited for desorption. After five experimental cycles, the desorption efficiency decreased by only 10.93% and 7.76% using 0.5 M HCl and 0.5 M EDTA, respectively indicating that the SAMGO beads for reusability. The synthesized SAMGO beads have shown potential to reuse, nontoxic green adsorbent with maximum removal rate.