吴琼,张洋,孟昭福.十二烷基二甲基甜菜碱(BS-12)在合成针铁矿表面的吸附特征[J].环境科学学报,2019,39(9):3045-3052
十二烷基二甲基甜菜碱(BS-12)在合成针铁矿表面的吸附特征
- Characteristics of the adsorption of dodecyl bataine (BS-12) on synthetic goethite
- 基金项目：国家自然科学基金（No.41271244）
- 吴琼
- 西北农林科技大学资源环境学院, 杨凌 712100
- 孟昭福
- 1. 西北农林科技大学资源环境学院, 杨凌 712100;2. 农业部西北植物营养与农业环境重点实验室, 杨凌 712100
- 摘要：为了探究十二烷基二甲基甜菜碱（BS-12）在水合针铁矿（α-FeOOH）表面的吸附过程和机理，在不同pH值、离子强度以及温度下采用批处理法研究了针铁矿对BS-12的吸附特征；并对BS-12在针铁矿表面的吸附机制进行了探讨.研究结果表明：针铁矿对BS-12的吸附平衡时间约为8 h，吸附过程符合伪二级动力学模型，吸附速率受化学吸附机理控制.Freundlich等温吸附模型能较好地描述针铁矿对BS-12的吸附，pH值对针铁矿吸附BS-12影响显著，主要取决于针铁矿的电荷零点和BS-12的等电点；离子强度的增加对BS-12的吸附有促进作用；温度的升高促进BS-12的吸附.热力学参数结果表明，针铁矿对BS-12的吸附是一个具有熵增和焓增特征的自发性吸热过程.BS-12在针铁矿表面的吸附是一个较慢发生的吸热的化学吸附的过程，主要吸附机制为化学键作用和疏水结合模式.
- Abstract：To explore the process and the mechanism of dodecyl bataine (BS-12) adsorption on the goethite, batch experiments were carried out under different contact time, pH, ionic strengths and temperatures. The adsorption kinetics and thermodynamics were studied. The results show that the adsorption equilibrium time of BS-12 on goethite was about 8 hours. The adsorption process can be described by the Pseudo-second-order kinetic model and Freundlich equation with good correlation coefficients. The adsorption was significantly influenced by pH, depending on the pHZPC of the goethite and the isoelectric point of BS-12. The adsorption ability could be enhanced with the increase of ionic strength and the temperature. The thermodynamic parameters analysis results show that the adsorption of BS-12 on goethite was a spontaneous process characterized by entropy and enthalpy. The adsorption of BS-12 on goethite was a slow endothermic process which was regulated by chemical bonding and hydrophobic binding mode.
