摘要
由于重金属镉离子的吸附性能较差、毒性大,因此,寻找镉离子的高效吸附材料具有重要现实意义。本文开展巯基硅烷对高岭石的嫁接改性研究,经红外光谱测试证实,成功将巯基引入到高岭石表面。同时,硅烷改性对高岭石晶体结构没有产生影响。通过批量实验考察了高岭石和巯基硅烷改性高岭石(K-SH)对Cd(Ⅱ)的吸附特征,主要探讨了p H值、时间对吸附效率的影响。矿物对Cd2+的吸附动力学符合准二级动力学模型,吸附等温方程更符合Langmuir模型,并估算的K-SH的最大吸附量是4.375 mg/g,比高岭石的大近20倍。改性高岭石表面嫁接了巯基后,可为高岭石吸附Cd(Ⅱ)提供大量的新吸附位点,通过配位复合作用显著提高对镉离子的吸附固定能力。因此,巯基硅烷改性高岭石是一种有应用前景的土壤修复材料。
Due to the poor adsorption performance and extreme toxicity of the heavy metal cadmium ion, it is of great practical significance to explore an efficient adsorption material for cadmium immobilization. In this paper, the modification by grafting sulfhydryl silane onto kaolinite was investigated and confirmed by infrared spectroscopy which proved that sulfhydryl groups were successfully introduced onto the surfaces of kaolinite. At the same time, silane modification did not cause the change of kaolinite in the crystal structure. Batch experiments were conducted to investigate the adsorption characteristics of kaolinite and modified kaolinite (K-SH) for Cd2+ under different conditions, mainly including pH and adsorption time. The adsorption kinetics of cadmium ions by the two materials is in agreement with the pseudo-second-order kinetic model. Nevertheless, the relevant adsorption isotherm equation showed a good fitness with the Langmuir model. The calculated maximum adsorption capacity of K-SH is 4.375 mg/g, which is 20 times higher than that of original kaolinite. The modified kaolinite grafted with sulfhydryl groups provided a large number of new adsorption sites on its surface, thus significantly improving the capacity of adsorption and immobilization for cadmium ions by coordination and complexation. It is therefore held that sulfydryl organic silicane-grafted kaolinite is a promising soil remediation material.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2017年第6期865-872,共8页
Acta Petrologica et Mineralogica
基金
国家自然科学基金资助项目(41372050)~~
关键词
硅烷改性
高岭石
CA(Ⅱ)
吸附
镉离子
silane modification
kaolinite
CA( Ⅱ)
adsorption
cadmium ions