Magnetically separable and recyclable Fe3O4@PDA covalent grafted by l-cysteine core-shell nanoparticles toward efficient removal of Pb2+.

Magnetic composites had attracted considerable attention owing to their outstanding properties in separation techniques. In this work, Fe 3 O 4 @polydopamine-g- l -cysteine (Fe 3 O 4 @PDA-g-L-Cys) core-shell composites were successfully fabricated via dopamine self-polymerization and zwitterionic cysteine covalent graft, aiming for removing Pb2+ from an aqueous solution. The structure and morphology of Fe 3 O 4 @PDA-g-L-Cys were verified by FT-IR, XRD, TEM and SEM. The factors (pH, adsorbent dosage, temperature, initial concentration, etc.) affecting the adsorption properties were systematically evaluated. Adsorption data were expressed by the Langmuir isotherm. The kinetic date of Fe 3 O 4 @PDA-g-L-Cysadsorbent for Pb2+adsorptionfitted the pseudo-second order kinetic model well. The obtained thermodynamics constantsΔ G 0, Δ H 0, and Δ S 0 indicated that process of Pb2+ removal by Fe 3 O 4 @PDA-g-L-Cys were endothermic and spontaneous. • A controllable strategy to prepare Fe 3 O 4 @PDA@L-Cys was presented for the first time. • The factors affecting the adsorption properties were systematically evaluated. • Fe 3 O 4 @PDA@L-Cys exhibited high adsorption capacity to Pb2⁺ and excellent recyclability. • The thermodynamic properties of adsorption behavior of Fe 3 O 4 @PDA@L-Cys were studied. [ABSTRACT FROM AUTHOR]