Mechanisms of surface charge development of serpentine mineral

蛇纹石表面电荷的形成机理(英文)

The electrokinetic behavior and surface dissolution of serpentine mineral were studied through Zeta potential measurements, dissolution experiments and X-ray photoelectron spectroscopy. The results show that serpentine has an iso-electric point （IEP） of 11.9, which is higher than that of other phyllosilicate minerals. Dissolution experiments show that the hydroxyl is easy to dissolve with respect to the magnesium cations in the magnesium oxide octahedral sheet. As a result of hydroxyl dissolution, the magnesium ions are left on serpentine surface, which is responsible for serpentine surface charge. The removal of magnesium ions from serpentine surface by acid leaching results in a decrease of serpentine IEP. Therefore, it has been clearly established that the surface charge developed at the serpentine/aqueous electrical interface is a function of the serpentine surface incongruent dissolution.

通过zeta电位测试、溶解试验以及X射线光电子能谱测试研究了蛇纹石矿物的动电行为和表面溶解行为。结果表明,蛇纹石的等电点为11.9,比其它的镁硅酸盐矿物的高。溶解试验表明蛇纹石结构中的镁氧八面体层中的羟基比镁离子容易溶出,羟基的溶出使镁离子留在蛇纹石表面,这是蛇纹石等电点较高的原因。移除表面的镁离子可以降低蛇纹石的等电点。因此,可以推断蛇纹石等电点较高的原因在于蛇纹石表面羟基和镁离子的不等量溶解。