Anti-biofouling carrier-free tannic acid chelating resin for selective uranyl ion capture in low-level radioactive wastewater.

There is an urgent need for effective treatment methods of low-level radioactive wastewater. This study developed an eco-friendly and effective adsorbent material (carrier-free tannic acid chelating resin, CTACR) through the electrophilic substitution reactions of tannic acid for the capture of uranyl ions (UO) in water environments. The as-prepared CTACR showed excellent stability in water under different temperature, pH, and ionic strength conditions, which allowed separation of the adsorbent after UO adsorption. Moreover, antibacterial experiments suggested that CTACR had good bactericidal properties and could persist in the water environment for a long time without decomposing. More importantly, CTACR could provide a phenolic hydroxyl-functionalized surface, resulting in effective removal ability and high selectivity for UO ions over 120 min, with an adsorption capacity of 365.7 mg g. The adsorption rate reached ∼88 % in a simulated multicomponent ionic solution. The adsorption process involved chemical adsorption, in which the chelation effect between the phenolic hydroxyl group of CTACR and UO species caused the immobilization of the latter, followed by in situ reduction, ultimately facilitating the separation and adsorption of UO. Therefore, this study highlights the significant potential of CTACR as a versatile and environmentally friendly adsorbent for the efficient removal of UO from aqueous environments.