Adsorption characteristics of U(VI) in aqueous solution by chloroacetic acid-modified MXene-CS gel microspheres

Abstract

To solve the problems of the poor stability and low adsorption efficiency of MXene used as an adsorbent for heavy metal removal. In this study, the microwave-assisted novel composite of chloroacetic acid-modified MXene-chitosan gel microspheres (C-TC-CS) was prepared. The experimental results demonstrated that C-TC-CS exhibited good stability and U(VI) adsorption performance, the maximum adsorption capacity of U(VI) by C-TC-CS was up to 141.96 mg/g. Pseudo-second-order and Langmuir isotherm adsorption models fit the adsorption process well, and the thermodynamic parameters showed that the adsorption process was spontaneous and endothermic. Importantly, C-TC-CS could be easily separated and regenerated. After five cycles of regeneration, the adsorption efficiency of C-TC-CS for U(VI) remained above 74%. Spectroscopic analyses indicated that the main adsorption mechanism involved electrostatic interactions, ion exchange, and complexation. This study proved that C-TC-CS could be an effective and promising adsorbent for removing U(VI) from aqueous solution.