不同粘土矿物对赖氨酸的吸附行为对比研究

以皂石、高岭石、绿泥石和伊利石为原材料，分别与赖氨酸进行反应，研究赖氨酸在上述粘土矿物上的吸附行为， 并运用粉末X-射线衍射技术（XRD）、傅里叶变换红外吸收光谱术（FTIR）和热重（TG）等分析方法，表征反应前后粘土 矿物的变化。实验结果表明，不同粘土矿物对赖氨酸的吸附等温线均符合Freundlich等温方程，且不同粘土矿物对赖氨酸的 饱和吸附量大小顺序为：皂石>蒙脱石>绿泥石>高岭石>伊利石；XRD结果表明皂石对赖氨酸的吸附发生在矿物层间，而绿 泥石、高岭石和伊利石对赖氨酸的吸附主要在矿物表面进行；FTIR和TG结果表明赖氨酸主要取代粘土矿物层间吸附水，以 氢键的形式与Si-O-Si(IVAl)键合。实验结果将有助于进一步探明环境中粘土矿物对有机质的吸附机理。

Comparative Study of the Adsorption of L-lysine on the Different Clay Minerals

Adsorption of organic matters on clay minerals is a ubiquitous phenomenon. In order to better understand such a reaction, adsorption behavior of lysine onto clay minerals including saponite, montmorillonite, kaolinite, chlorite and illite was investigated and characterized by powder X-ray (XRD), Fourier-transform Infrared Spectroscopy (FTIR) and Thermal Gravimetric Analysis (TGA). The results showed that the adsorption isotherms of lysine on clays were well fitted using the Freundlich equation (R2=0.98-0.83) and the adsorption capacity followed the order: saponite>montmorillonite>chlorite>kaolinite>illite. XRD results indicated that the adsorption of lysine on saponite and montmorillonite ocurred mainly in the interlayer regions, while lysine was mainly present on the surface of chlorite, kaolinite and illite. Furthermore, FTIR and TG results showed adsorption of lysine in the interlay region might take place via replacement of interlayer water and subsequent formation of hydrogen bond with O-Si-Si(IVAl). This work will contribute to understanding of adsorption behavior and mechanisms of organic matters on clay minerals.