Uptake of Pb(II) onto nanochitosan/sodium alginate hybrid beads: Mechanism and kinetics study.

Nanochitosan/sodium alginate (NCS/SA) beads were prepared using nanochitosan and alginate as a high-performance absorbent for Pb(II) removal from aqueous solution. The morphology, structure, thermal stability, surface area, and elements present in the NCS/SA beads before and after adsorption were characterized using instrumental techniques like SEM, FTIR, TGA, BET, and EDX analysis, respectively. Various adsorption parameters were studied. The results indicated that the equilibrium adsorption data were fitted to Langmuir isotherms and the maximum Langmuir monolayer capacity of Pb(II) was 178.57 mg/g at 45°C. The adsorption process was in good agreement with pseudo-first-order kinetic model. Mechanism studies showed that electrostatic interaction and ion exchange were the major mechanisms for lead (II) removal by the NCS/SA beads. The results of this study indicate that NCS/SA beads could be used as an effective adsorbent for the elimination of lead (II) present in aqueous solution. PRACTITIONER POINTS: Nanochitosan/sodium alginate beads were synthesized using Ca2+ as a crosslinking agent. NCS/SA beads were used to remove Pb(II) for the first time and working parameters were optimized. Adsorption monolayer capacity of NCS/SA adsorbent towards Pb (II) was found to be 178.57 mg/g.