Construction of hollow CMPs microspheres based on the kinetic quantum sieving effect for highly efficient adsorption of Iodide/Cesium ions

Abstract

Considering the dangers of radioactive elements to the human body and the environment, the efficient and rapid removal of radioactive ions in water is an urgent matter. In this paper, an efficient adsorption material based on kinetic quantum sieving (KQS) effect through skillfully molecular design with specific space structure conjugated microporous polymer hollow spheres (CMPs-1) for disposal of radioactive iodide/cesium ions is reported. The adsorption properties of iodide/cesium ions at different concentrations at 10℃ were investigated. Moreover, the test results show that the iodide ions adsorption capacity of the CMPs-1 will increase with the increase of iodine ions concentration when the temperature, volume, and other conditions are fixed. The CMPs-1 exhibited up to the highest 16.93 mg g−1 iodide adsorption capacity for the solution containing 0.10 mmol L-1 iodide ions within 6 h under static adsorption experiments at a low temperature of 10℃, and the adsorption rate fitted by the pseudo-second-order kinetic model was 0.11 g mg-1 h−1. Besides, the CMPs-1 maintained an effective adsorption capacity of 16.93, 7.51 and 5.92 mg g-1 at pH = 7, 10 and 13, respectively. Furthermore, unexpectedly, the constructed CMPs-1 showed superior heat resistance with higher adsorption capacity (26.32 mg g-1, 1.6 times) at 30℃ compared to 10℃. The improvement reason is that the expansion of pores (significantly increased at 4–20 nm), and the developed porosity can provide enough space to accelerate the diffusion rate of reactants and intermediates, exposing more active sites. And the π-conjugated system and hollow structure of CMPs materials can effectively solve the problem of low diffusion rate caused by low temperature and microporous structure in the transfer of iodide/cesium ions. Therefore, this work demonstrates the customizable potential of materials in the field of molecular adsorption applications and also provides a new idea for the design of unique hollow structure adsorption materials.