Chemically modified smectites
Chemically modified smectites
复制标题
DOI：
10.1180/0009855033810083
复制
发表时间：
2003-03-01
期刊：
影响因子：
1.5
通讯作者：
Komadel, P
中科院分区：
文献类型：
--
作者：
Komadel, P
本文综述了近年来蒙脱石化学改性的研究成果。其中包括用质子取代可交换阳离子，这是一个与蒙脱石自转化有关的过程——质子在层上的攻击和从八面体和四面体薄片上的中心原子的解放，导致粒子上酸位的修饰。更严重的变化发生在溶解在无机酸中，当层溶解和三维无定形二氧化硅形成。在高温处理下，蒙脱石层上的负电荷可以通过结构Fe（III）还原为Fe（II）而增加，也可以通过小交换阳离子（如Li+）的固定而减少。在100到300度之间的不同温度下加热，可以从同一种母矿物中制备出一系列化学性质相似但电荷不同的材料。该系列适用于研究层电荷对蒙脱石某些特性的影响。铁（II）可以在加热时通过Li固定在还原性蒙脱石中部分稳定。
This paper summarizes recent results obtained on chemical modifications of smectites. These include replacement of exchangeable cations with protons, a process connected with smectite autotransformation - attack of protons on the layers and liberation of central atoms from the octahedral and tetrahedral sheets, causing modification of the acid sites on the particles. More severe modifications occur during dissolution in inorganic acids, when the layers are dissolved and three-dimensional amorphous silica is formed. The negative charge on the smectite layers can be increased via reduction of structural Fe(III) to Fe(II) or decreased via fixation of small exchangeable cations, such as Li+, upon treatment at elevated temperatures. Heating for 24 It at different temperatures between 100 and 300degreesC leads to a series of chemically similar materials of different charge, prepared from the same parent mineral. Such series are suitable for investigation of the effect of the layer charge on selected properties of smectites. Fe(II) can be partly stabilized in reduced smectites by Li fixation upon heating.