Amidoxime functionalized magnetic MXene/chitosan composites for efficient uranium extraction

Uranium extraction from unconventional uranium resources is among the major constraints to the development of the nuclear industry at present. In this dissertation, we here propose to effectively graft amidoxime groups on magnetic MXene and chitosan (CS) composites to extract uranium from low-enriched uranium solutions (MCFAO). The data of adsorption experiments displayed that MCF-AO possessed fast adsorption kinetics (within 120 min), outstanding selectivity and salient adsorption capacity (1305.7 mg/g at pH=4, T=298.15 K) for uranium and could be easily separated with a magnet. Adsorption studies revealed a behavior consistent with the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model, which is suitable for the spontaneous heat-absorption chemical monolayer adsorption process. Its sorption remains at more than 55 % of the original after 5 adsorption-desorption tests, and has great tolerance to interfering ions. Mechanistic research pointed out that the selective adsorption of uranium by MCF-AO was significantly enhanced by the presence of hydroxyl, amino and amidoxime groups. Meanwhile, MCF-AO exhibited superb resistance to two common bacteria (E. coli and B. subtilis) and achieved more than 95 % uranium extraction capacity in simulated seawater, even more 4.12 mg/g of uranium extraction in Salt Lake water. Consequently, MCF-AO has a broad application prospect in the recovery and treatment of complex uranium systems.