Efficient Separation of Uranium(VI) by CaCO<sub>3</sub>-Doped Chitosan with PO<sub>4</sub><sup>3–</sup> Modification: Adsorption Behaviors and Mechanism Study
Jun Liao, Congcong Ding, Junping Shi, Liang Jiang, Qiuyi Wang, Lielin Wang
Abstract
The application of chitosan-based materials for the separation of uranium from wastewater was limited due to the lack of active sites. In this work, a chitosan-based composite (CaCO 3 @aCS/PA) was effectively created by modifying chitosan with CaCO 3 and phytic acid to enhance the adsorption performance of chitosan materials. CaCO 3 @aCS/PA showed no significant changes and no Ca 2+ was detected in the solution after stirring for 10 h in a solution with pH > 3, indicating good stability of CaCO 3 @aCS/PA, which was beneficial for use in adsorption. Moreover, the adsorption capacity and adsorption percentage of CaCO 3 @aCS/PA for uranium reached 842.0 mg/g (298 K, pH = 4) and 95.4% ( C 0 = 10 mg/L, pH = 4) and the adsorption equilibrium time was significantly shortened, indicating that the modification with CaCO 3 and phytic acid enhanced the adsorption ability of chitosan for uranium, which was related to the synergistic effect of various active sites (CO 3 2–, PO 4 3–, −OH, and –NH 2 ) on CaCO 3 @aCS/PA for uranium adsorption.