Efficient and selective removal cesium from strong acidic medium by novel butenyl-calix [4]-crown 6 functionalized millimeter-sized mesoporous carbon spheres sorbent: Experimental and theoretical study

Abstract

Eliminating the radioactive Cesium from high level waste (HLW) is crucial to avoid the radioactive pollution. Herein, a novel carbon-based recognizable material, butenyl-calix [4]-crown 6 functionalized millimeter-sized mesoporous carbon spheres (ButC[4]C6/MMCs), was prepared via “interpenetrating functionalization” strategy to remove Cs(I) from strongly acidic solution. ButC[4]C6 supramolecular was incorporated into the channels of MMCs and polymerized to form cross-linked IPN structure. The morphology and microstructure of the final product were characterized by SEM, NMR, FT-IR, TG-DSG and N2 adsorption–desorption isotherms. The adsorption behaviors of Cs(I) onto ButC[4]C6/MMCs were systematically investigated. ButC[4]C6/MMCs displayed an astonishing adsorption capacity (55.22 mg g−1), high selectivity and reusability at a low dose (2.0 g L-1) under 3.0 M HNO3 medium. Pseudo-second-order kinetic model, Brouers-Sotolongo model and thermodynamic study revealed that the adsorption process is a spontaneous endothermic chemical and heterogeneous adsorption process. Theoretical study revealed that the Cs(I) was tightly fixed in the calixarene cavity via cation-π interaction. This work proposes an effective approach to selectively remove Cs(I) from HLW by skillfully coupling supramolecular recognizer with millimeter-sized porous material to address radioactive pollution issue.