Efficient and selective adsorption of TcO₄^- /ReO₄^- by n-alkyl-imidazolium ionic liquids functionalized cellulose microspheres and their application in simulated Beishan groundwater

Removal of technetium from radioactive waste has become attractive due to its huge environmental hazard. Herein, a series of n-alkyl-imidazolium ionic liquids functionalized cellulose microspheres (MCC-[C(n)VIm]Br, n = 2, 4, 6, 8, 10) were synthesized by radiation method, and their grafting regularity were investigated. In order to explore the effect of alkyl chain length on adsorption performance, the adsorption behaviors of MCC-[C(n)VIm]Br for TcO4-/ReO4- were researched in detail via batch and column experiments. MCC-[C(n)VIm]Br exhibited high ReO4- adsorption efficiency over a wide pH range from 4 to 9, and the maximum adsorption capacity was 230.41 mg/g. The adsorption efficiency of MCC-[C(n)VIm]Br barely changed after 5 times reused. Remarkably, the selectivity of ReO4- enhanced with the increase of alkyl chain length, while the adsorption capacity and rate were hardly affected by it. The column experiment showed that MCC-[C(10)VIm]Br can selectively capture ReO4- from simulated Beishan groundwater. The adsorption performance suggested that MCC-[C(10)VIm]Br is promising for high-efficiency uptake of ReO4- from Beishan groundwater and other radioactive wastes.