Synthesis of N-GQDs/CuS/Cv-CNNs hydrogels and their performance in hexavalent chromium wastewater treatment

Abstract

A hydrogel is a three-dimensional structural body with a polymer network that effectively absorbs and stabilizes a wide range of small molecules and ions, thereby reducing the precipitation of metal ions from the matrix. In this study, we successfully prepared a hydrogel named N-GQDs/CuS/Cv-CNNs-70-2 (abbreviated as NCCH-X) by employing the chemical cross-linking method of sodium alginate and calcium chloride and conducted an in-depth study on the morphological and optoelectronic properties of the hydrogel with different photocatalyst contents, as well as on its effectiveness at removing hexavalent chromium Cr(VI). The study's findings indicated that the composite photocatalyst exhibited high treatment efficiency for chromium-containing wastewater when the photocatalyst content was NCCH-10. The hydrogel achieved a high removal rate of 96.37% with a Cr(VI) concentration of 100 mg L⁻¹ under visible light irradiation for 60 min. Moreover, the unique hydrogel structure effectively avoids the precipitation of excessive Cu²⁺, which reduces the possibility of the lethal risk of copper to organisms in the environment.