Efficient removal of Cr(VI) by triethylenetetramine modified sodium alginate/carbonized chitosan composite via adsorption and photocatalytic reduction

Conventional photocatalysts for the removal of hexavalent chromium (Cr(VI)) suffers from low metal uptake capacity, expensive cost, and slow desorption of chromium species from photocatalysts' surface. In this study, a polysaccharide-derived composite was prepared by embedding carbonized chitosan into triethylenetetramine modified sodium alginate (CTS/CS-50). The chemical modification of sodium algi-nate and the doping of carbonized chitosan significantly enhanced the adsorption and photocatalysis pro-cess of Cr(VI) in aqueous solutions. The synthesized composite has exhibited a maximum adsorption capacity of 144.49 mg/g for Cr(VI), while the removal rate for Cr(VI) could reach 98 % within 80 min under UV light irradiation. Moreover, experimental results suggested that the composite material remained effective with the co-existence of conventional interfering ions. Characterization results indicated that N and O functional groups governed the electrostatic interaction with Cr(VI) and the photo-induced electron-hole pairs for the photo-reduction process. Therefore, CTS/CS-50 can be used as an efficient pho-tocatalyst for the treatment of Cr(VI) containing wastewaters, providing a new pathway for the applica-tion of polysaccharide-derived photocatalysts. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

A polysaccharide-derived composite was prepared by embedding carbonized chitosan into triethylenetetramine modified sodium alginate for the removal of hexavalent chromium. The composite exhibited high adsorption capacity and photocatalytic activity, effectively removing hexavalent chromium under UV light irradiation.