Chitosan-based beads as sustainable adsorbents for wastewater remediation: a review

Water contamination is increasing worldwide, yet actual methods of water and wastewater treatment are limited, in particular by actual fossil-fuel derived nano-adsorbents that are difficult to regenerate. This calls for advanced methods that use sustainable materials such as chitosan. Chitosan is a biopolymer extracted from the outer skeleton of shellfish, including crab, lobster, and shrimp. Chitosan is non-toxic, abundant, and chemical and physical stable. Moreover, chitosan can be shaped into beads, sheets, membranes, and composites. Here, we review chitosan-based beads for wastewater treatment with focus on adsorption mechanisms, removal of pollutants, functionalization, metal organic frameworks, magnetic beads, imprinted and co-polymeric beads, and regeneration. We found that chitosan/Fe-hydroxyapatite beads exhibit an adsorption capacity of 1385 mg/g for the removal of lead. Imprinted magnetic chitosan beads display a reusability of 15 cycles for nickel removal.

Automated summary

Water contamination is a growing global issue, and current methods for water and wastewater treatment are limited, especially in terms of difficult regeneration of fossil-fuel derived nano-adsorbents. Advanced methods using sustainable materials like chitosan are needed. Chitosan, a biopolymer extracted from shellfish, is non-toxic, abundant, and chemically stable. It can be shaped into various forms for wastewater treatment. In this review, we focus on chitosan-based beads and their applications in wastewater treatment, including adsorption mechanisms, pollutant removal, functionalization, and regeneration. Notably, chitosan/Fe-hydroxyapatite beads have high adsorption capacity for lead removal, while imprinted magnetic chitosan beads show good reusability for nickel removal.