制备锆基柱撑蒙脱石矿物材料的影响因素探讨

同种柱化剂及粘土矿物，其柱化过程受pH值、基质粘土的粒度、柱化剂用量、粘土悬浮溶液质量浓度及分散性、搅拌速度、反应时间、温度、老化时间、滴定速度等众多因素的影响，通过对锆基柱撑蒙脱石矿物材料的研究发现，蒙脱石悬浮溶液的pH值和柱化剂用量是其主要影响因素。     

New evidence for microstructural evolution model of acid-activated montmorillonite

Ca-montmorillonite samples from Choushan treated at various acid concentrations were studied using chemical analysis, XRD, ²⁹Si and ²⁷Al MAS NMR, to investigate the microstructure of the activated montmorillonites. With the increase of acid concentration and dissolution of cations of montmorillonite, the intensity of d(001) decreased obviously and significant changes of the microstructure of Si and Al occurred. There were two new types of structural units of Si atoms formed: (SiO)₃SiOH units and Q⁴(0Al) units. For Al atoms, in the course of activation, the removal of one of a pair of octahedral aluminium atoms from montmorillonite removed two hydroxyl groups and left the other aluminum of the pair in the four-fold coordination. The ²⁷Al signal at δ 54.0 corresponding to Al^Ⅳ arose from the four- coordinated Al in the octahedral sheet. This study first con-firmed, by ²⁹Si and ²⁷Al MAS NMR spectra, that the model of microstructural evolution for activated montmorillonite postulated by Thomas et al. (1950) is correct.