Fe_2O_3改性蒙脱土对邻苯二酚的高效去除机理

Efficient removal mechanism of catechol by Fe_2O_3 modified montmorillonite

蒙脱土及其改性后的吸附材料在环境领域广泛应用。本文研究了蒙脱土(MT-Na)及其Fe_2O_3改性后(MT-Fe_2O_3)用于去除不同p H条件溶液中的邻苯二酚。与MT-Na相比,MT-Fe_2O_3对邻苯二酚表现出更快速和高效的去除效果。随着p H升高,MT-Na从溶液中除去邻苯二酚增加,而MT-Fe_2O_3表现出相反的现象。双室一级去除动力学模型拟合结果表明,MT-Na的快室去除邻苯二酚来自于吸附,慢室去除主要是来自于降解;MT-Fe_2O_3快室主要是吸附和最初的降解,随着降解中间产物在表面的生成,阻碍了邻苯二酚在颗粒上的吸附,减缓了降解速率,表现为慢室去除。Fe_2O_3诱导生成的·OH是MT-Fe_2O_3高效去除邻苯二酚的主要因素。区分黏土颗粒去除邻苯二酚过程中的吸附和降解的贡献,将有助于更加准确地评估黏土颗粒的环境功效和描述邻苯二酚的环境行为。

Montmorillonite and its derivatives are widely used adsorbent in environmental field. In this study, montmorillonite (MT-Na) and Fe2O3 modified montmorillonite (MT-Fe2O3) were used to remove catechol at various pH. Higher efficacy and faster removal of catechol was detected for MT-Fe2O3 than MT-Na. Catechol removal from solution was higher with MT-Na with increasing pH, while MT-Fe2O3 showed a reverse trend. Removal kinetics results showed fast and slow compartment of catechol removal involving adsorption and subsequent degradation of the latter. For MT-Fe2O3, fast compartment was attributed to adsorption and initial degradation. The retardation of catechol degradation rate manifested in the slow compartment was attributed to the hindrance of the active reaction sites by intermediate degradation products, Fe2O3 mediated generation of ·OH is central regarding removal of catechol using MT-Fe2O3. Efficient degradation of organic contaminants by montmorillonite underscores the importance of clay particles as capable adsorbent. This study will provide more precise assessment of the distinct contribution of clay particles in adsorption and degradation of catechol in environmental media.