Preparation of UiO-66/chitosan and its adsorption mechanism of U(VI)

Uranium mining and smelting processes produce a large amount of low-concentration uranium wastewater, which endangers the ecological environment and human health. It is urgent to remove uranium(VI) from uranium-containing wastewater. In this work, UiO-66 and chitosan (CS) were used as raw materials to prepare UiO-66/CS new composite materials by cross-linking method. Through static adsorption experiments, different pH values, adsorbent dosage, adsorption time and initial uranium concentration were investigated of the influence of external factors on U(VI) removal rate. The UiO-66/CS material was characterized and analyzed by SEM, FTIR, XPS, etc., revealing the mechanism of adsorbent removal of U(VI). The results show that when the initial uranium concentration is 5 mg/L, the temperature is 298 K, the pH is 5, the dosage is 0.15 g/L, and the adsorption time is 120 min, the removal rate of U(VI) by UiO-66/CS can reach 90.24%. The adsorption process conforms to the quasi-second-order kinetic model and Freundlich isotherm adsorption model. The adsorption and removal mechanism of U(VI) is mainly the complexation of -NH, -COOH, Zr-O,-OH and other functional groups with U(VI). © 2022, Editorial Office of Acta Materiae Compositae Sinica. All right reserved.