蒙脱石与滑石矿物对菲吸附-解吸行为的对比研究

COMPARISON OF SORPTION-DESORPTION BEHAVIORS OF BOTH MONTMORILLONITE AND TALC MINERALS FOR PHENANTHRENE

采用批量处理平衡实验,考察蒙脱石与滑石矿物对菲的吸附解吸行为。采用Henry和Freundlich方程对其吸附等温线进行分析比较,并着重考察软阳离子K+对上述两种矿物吸附菲的影响机制。研究结果表明:蒙脱石对菲的吸附等温线表现出明显的非线性,吸附/解吸有滞后现象,Freundlich方程最符合其吸附/解吸曲线;滑石吸附菲的能力较之蒙脱石的强,且吸附呈线性,其吸附曲线与Henry方程吻合程度最好。此外,随着溶液中K+离子浓度增加,蒙脱石吸附菲的能力增强,而滑石吸附菲的能力减弱,说明软阳离子K+对蒙脱石吸附菲有明显的强化作用,而对滑石吸附菲却有抑制作用。说明黏土矿物内部结构与表面理化性质控制着污染物的吸附-解吸环境行为,从而影响着PAHs等污染物的迁移转化。

Batch methodological experiments were conducted to study the sorption and desorption behaviors of both montmorillonite and talc for phenanthrene. The study was focused on the effect of soft cation K＋ in solution on the sorption abilities of minerals,which were analyzed and compared with Henry and Freundlich equation. The research experimental results showed that sorption-desorption isotherms of montmorillonite for phenanthrene behaved distinct nonlinearity and presented sorption-desorption hysteresis, and it can be fitted well by Freundlich equation compared to Henry equation. As for talc, the phenanthrene sorption ability on talc is stronger than on montmorillonite,and Henry equation was the most appropriate to fit the sorption-desorption isotherms of talc for phenanthrene. Furthermore,with the increase of K＋ concentration in solution, the phenanthrene sorption capacity of montmorillonite increased, on the contrary, the sorption capacity of talc decreased. It was suggested that the structural character and surface physicochemical properties of clay minerals controlled the environmental behaviors of sorption-desorption, and thus impact the transport and transformation of pollutants such as PAHs on and/or near the mineral surfaces.