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Heavy metal toxicity has demonstrated to be a crucial issue for environment and human health. There has been an increasing ecological and global public health concern related with environmental contamination by these metals. For these reasons, a considerable attention has been paid to design efficient materials for heavy metal removal. This article offers a solution to develop a green adsorbent based on Chitosan Microspheres/Sodium Alginate hybrid beads (CSM/ SA) for metal ion elimination from aqueous solutions. The efficiency of this eco-friendly material was divulged using kinetic study for Cr(VI) and Pb(II) removal. Properties of the obtained hybrid beads were improved by correlation between original chitosan microspheres and sodium alginate. Moreover, at different metal concentration, pH solution and contact time, the beads were evaluated in discharged batch operations from Pb(II) and Cr(VI). The maximum adsorption capacity was 180 mg g − 1 for Pb(II) and 16 mg g − 1 for Cr(VI). The adsorption kinetics were evaluated using pseudo-first and pseudo-second rate models. Adsorption isotherms were simulated by Langmuir and Freundlich models. This study indicates that the CSM/SA hybrid beads could be developed into a very sustainable technology for highly effective elimination of metal ions from wastewater.

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 Ca 2+ 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.

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