Aminotriazole isomers modified cellulose microspheres for selective adsorption of U(VI): Performance and mechanism investigation.

Aminotriazole isomers with high nitrogen content show potential affinity for U(VI). Combining the advantages of both aminotriazole and cellulose, two n-aminotriazole isomers modified cellulose microspheres (n-ATARs, n = 3, 4) were newly prepared as adsorbents via radiation technology. Batch adsorption experiments showed that n-ATARs possessed good adsorption capacity of U(VI) in the order of 3-ATAR > 4-ATAR, and the adsorption process followed the Langmuir-Freundlich isotherm model and the pseudo-second-order kinetic model. Both n-ATARs exhibited good selectivity and reusability. Besides, 3-ATAR and 4-ATAR were more suitable for the extraction of trace amount of U(VI) from the contaminated groundwater and the simulated seawater, respectively. The effect of amino position on triazole ring on adsorption behavior of n-ATAR was studied and explained by DFT calculation. Finally, the adsorption mechanism of U(VI) onto n-ATARs was revealed to be inner-sphere complexation via different 1:1 or 1:2 coordination models by FTIR, MS, XPS analysis and DFT calculation.