Economical amidoxime-functionalized non-porous β-cyclodextrin polymer for selective detection and extraction of uranium

Abstract

Herein, a dual-functional adsorbent (amidoxime-functionalized non-porous β-cyclodextrin polymer (AO-NPCDP)) with simultaneous detection and adsorption of U(VI) is developed. Fascinatingly, the luminescence intensity of AO-NPCDP could be selectively and efficiently quenched by U(VI) with a quenching rate of 80.5 % in 30 s. The adsorption of U(VI) on AO-NPCDP results in fluorescence quenching with an ultra-low detection limit (10.3 nM) in deionized water, which is much lower than the maximum contamination standard in drinking water of the World Health Organization contamination limit for U(VI) in drinking water (63 nM). More importantly, AO-NPCDP exhibits high sensitivity in detecting U(VI) ions in natural water systems such as lake water, seawater and tap water with the calculated detection limits of 63.5 nM, 22.2 nM and 17.6 nM, respectively. Moreover, the AO-NPCDP can be easily regenerated using a gentle washing procedure and maintains a high reusability of 95.8 % after 7 adsorption–desorption cycles. Density functional theory (DFT) calculation shows that the fluorescence mechanism between AO-NPCDP and U(VI) is photo-induced electron transfer. The sensitivity and selectivity as well as the economy and high reusability reveal the promise of AO-NPCDP for on-site, real-time monitoring and adsorption of U(VI).