Hydrophobic CHA-ZIFs with a junctional trap between cha and d6r cages for adsorption of 2,3-butanediol in aqueous solution  

作　　者：Lifang Ge Meizhen Gao Xiaosheng Zhang Jiang Wang Qi Shi Jinxiang Dong 

机构地区：[1]College of Chemical Engineering and Technology,Shanxi Key Laboratory of Chemical Product Engineering,Taiyuan University of Technology,Taiyuan 030024,China

出　　处：《Chinese Journal of Chemical Engineering》2024年第9期90-100,共11页中国化学工程学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(22278289 and 21822808);the Science Foundation for Distinguished Young Scholar of Shanxi Province(202303021223002);the Special Fund for Science and Technology Innovation Teams of Shanxi Province(202204051001009).

摘　　要：The adsorption and separation of diols from dilute aqueous solution using hydrophobic materials is very challenging due to the strong diol-water hydrogen-bonding interactions. Herein, we screened hydrophobic zeolitic imidazolate frameworks(ZIFs) with chabazite(CHA) topology for separation of 2,3-butanediol(2,3-BDO) and 1,3-propanediol(1,3-PDO), which had junctional and hydrophobic traps matching the two end methyl groups of the 2,3-BDO molecule. Based on CHA-ZIFs with the same small-sized ligand 2-methylimidazole(mIm) and different large-sized ligand benzimidazole derivatives(RbIm),CHA-ZIFs with larger surface areas were obtained by the addition of excess small-sized ligand mIm in the synthesis process. We showed that all of the hydrophobic CHA-ZIFs preferentially adsorbed 2,3-BDO over 1,3-PDO by static batch adsorption and dynamic column adsorption experiments. But ZIF-301 and ZIF-300 with halogen groups exhibited better adsorptive separation performance for 2,3-BDO/1,3-PDO than ZIF-302 with methyl groups. For a typical ZIF-301, its adsorption capacity for 2,3-BDO was 116.4 mg·g^(-1)and selectivity for 2,3-BDO/1,3-PDO was 3.8 in dynamic column adsorption of the binary-component system(2,3-BDO/1,3-PDO: 50 g·L^(-1)/50 g·L^(-1)). Computational simulations revealed that 2,3-BDO preferentially adsorbed in a trap at the junction between the cha and d6r cages of CHA-ZIFs,meaning the strong host-guest interactions. Therefore, the hydrophobic CHA-ZIFs with a junctional trap were promising candidate materials for adsorbing 2,3-BDO, which also provided a new perspective for separating diols in dilute aqueous solutions.

关 键 词：Adsorption Separation Aqueous solution Zeolitic imidazolate frameworks Junctional and hydrophobic trap DIOLS 

分 类 号：TQ424[化学工程] TQ028