蛭石的层电荷调控及机理研究

Study on Modification and Mechanism of Vermiculite Layer Charge

采用酸改性方法,对河北灵寿蛭石进行了层电荷调控实验,获得了层电荷不同的改性蛭石。分别通过X射线衍射、CEC测试、溶出离子ICP测试、红外光谱分析、差热分析、核磁共振谱分析等对改性蛭石进行了表征,探讨了蛭石层电荷调控的机理。结果表明,蛭石在酸化过程中四面体Si、Al均被溶出,而且Si相对于Al优先溶出,而四面体Al相对于八面体Al优先溶出,Si/Al的减小使蛭石的层电荷增加,但CEC呈先增大后减小的变化趋势。改性蛭石CEC的减小与其层电荷增大有关,层电荷增大使层间阳离子与结构层结合更牢固,因而不易被交换。

Vermiculite（ Lingshou, Hebei provence） was modified by different concentrations of hydrochloric acid to obtain vermiculites with different cation exchange capacity（ CEC）. The modified vermiculites were analyzed by X-ray diffraction,CEC test,ICP test,IR analysis,differential thermal analysis（ DTA） and nuclear magnetic resonance（ NMR）. The results show that Si was prior to Al to be leached out from the tetrahedron and Al in tetrahedron was easier to be dissolved into the solution than the one in octahedron. The layer charge of vermiculate was enhanced because of the decrease of the Si / Al resulted from the acid leaching. The CEC increased firstly and then decreased as the content of the acid increasing. The decrease of CEC was due to the layer charges increase,which resulted in stronger combination of the cations with structure layer,and more difficult to be exchanged.