As(V) removal from aqueous media using an environmentally friendly zwitterion L-cysteine functionalized silica adsorbent

[Display omitted] •Novel L-cysteine hybrid adsorbent prepared by sol–gel route used in As(V) removal.•High As(V) uptakes by adsorbent and fast adsorption kinetics obtained.•Low loss of As(V) removal capacity demonstrated after reuse cycles.•A bidentate complex of AsO2(OH)2- and L-cysteine helped explain As(V) uptake data.•As(V) adsorption results suggest potential industrial use. An L-cysteine functionalized environmentally friendly adsorbent was synthesized via sol–gel processing and applied in the removal of As(V) from aqueous media. The adsorbent demonstrated enhanced As(V) uptake capacities with maximum uptake of 147.5 mg g−1 at pH 3. Equilibrium was reached at 120 min. Kinetic data were explained by a pseudo-second order model; isotherm data were fitted by a Freundlich model. Reuse of adsorbent after 5 adsorption/desorption cycles indicated ∼23% removal capacity loss. Elemental analysis results indicated high ligand densities of SG-3PS-Cys. The L-cysteine moieties were thermally stable up to ∼170 °C. Solid state NMR and XPS techniques confirmed the presence of cysteine on the surface of SG-3PS-Cys. Efficient adsorption of As(V) was ensured by the formation of a bidentate complex between the AsO2(OH)2- anion, the NH3+ and carboxyl groups of L-cysteine. The results of this work demonstrated that SG-3PS-Cys possesses potential in the removal of As(V) from industrial wastewater discharges.