Capture of iodine gas by Bi0 modified silica with different morphologies: Influence of pore characteristic on the stable and unstable forms of adsorption
Capture of iodine gas by Bi0 modified silica with different morphologies: Influence of pore characteristic on the stable and unstable forms of adsorption
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DOI：
10.1016/j.cej.2022.138887
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发表时间：
2022-08-31
影响因子：
15.1
通讯作者：
Duan, Tao
中科院分区：
文献类型：
--
作者：
Ding, Yi;Fan, Weijie;Duan, Tao
开发高效的碘气体吸附剂是放射性废物处理领域一个有意义且具有挑战性的课题。本文以SnCl2为还原剂，采用改进的浸渍法制备了不同形貌（片状、棒状和球状）的Bi-0改性SiO2。系统地考察了所得材料对碘气体的吸附行为。研究了孔隙特性、温度和时间对总吸附量、化学吸附量（稳定形态）和物理吸附量（不稳定形态）的影响。孔隙特征和温度不仅影响总吸附，而且影响稳定和不稳定的吸附形式。结果表明，具有有序、短、直孔特征的片状Bi-0修饰SiO2 （Bi-0@SiO2-P）具有最高的总吸附容量（可达960 mg/g），而具有无序孔特征的球状Bi-0修饰SiO2 （Bi-0@SiO2-S）具有最高的稳定吸附率（94.8%）。随着温度的升高，总形态和不稳定形态的吸附量略有减少，而稳定形态的吸附量有所增加。拟二级动力学方程较好地拟合了吸附过程。结果表明，Bi-0改性SiO2材料对I-2的吸附主要是化学吸附（Bi + I-2 = BiI3）。
Exploring efficient iodine gas adsorbent is a meaningful and challenging topic in the field of radioactive waste treatment. Herein, Bi-0 modified SiO2 with different morphologies (platelet-like, rod-like, and sphere-like) were fabricated by an improved impregnation method using SnCl2 as reductant. The iodine gas adsorption behaviors of the obtained materials were systematically investigated. The effects of pore characteristic, temperature and time on the adsorption capacity including total, chemical (stable form) and physical (unstable form) were studied. Pore characteristic and temperature affected not only the total adsorption, but also the stable and unstable forms of adsorption. The results demonstrated that the platelet-like Bi-0 modified SiO2 (Bi-0@SiO2-P) with ordered, short and straight pore characteristics had the highest total adsorption capacity (up to 960 mg/g), while sphere-like (Bi-0@SiO2-S) with disordered pore showed the highest ratio of stable form of adsorption (94.8 %). Furthermore, with increasing temperature, the total and unstable form adsorption decreased slightly, but stable form increased. The adsorption processes were better fitted by the pseudo-second-order kinetic equation. The results demonstrated that I-2 adsorption for Bi-0 modified SiO2 materials was mainly chemical (Bi + I-2 = BiI3).