摘要
用量子化学的理论和计算方法,研究高岭石表面的化学状态、表面化学活性位置及其成键特征。结果表明,高岭石分子簇的最高占据轨道基本上是由上、下表面的一些氧原子组成的,且具有较高的能态,说明这些位置具有较高的化学活性,易于与获得电子能力较强的物质形成化学键。而其最低空轨道则主要由硅、铝和少量的侧面O原子组成,相对而言,能级较低,易于与提供电子的体系作用,其化学反应活性较大。因此,当高岭石与带负电荷的离子或离子基团作用时,可能在侧面的位置形成表面化合物。Al和Si都是组成LUMO分子轨道的主要成分,但Al原子的化学活性要大于Si原子,因此,当高岭石表面与提供电子的体系发生化学作用时,最可能的位置应该是八面体的Al原子。
The chemistry, reactivity sites and bond-formation characteristics of kaolinite surfaces were investigated by using quantum chemistry methods. The result shows that the highest occupied molecular orbits (HOMO) of the kaolinite cluster mainly consist of some of the oxygen atoms on both the upper surface and lower surface, with relative high energy level. It is indicative of higher reactivity of these sites; therefore it may readily form chemical bond with those of electron acceptor. On the other hand, the lowest unoccupied molecular orbits (LUMO) of the kaolinite cluster is dominantly composed of silicon, aluminum and few edge oxygen atoms, with relative lower energy level, which suggests that these atoms may tend to form chemical bond with those of electron donor. Hence, it can be inferred that surface complex will be formed on the edge planes of kaolinite while interaction with negative-charged ion or ion group. Both the silicon and aluminum are the main components of LUMO, however, the reactivity of aluminum is much stronger than silicon and the reactivity sites are the octahedral aluminum when interaction electron donor system.
出处
《武汉理工大学学报》
EI
CAS
CSCD
北大核心
2005年第1期25-29,共5页
Journal of Wuhan University of Technology
基金
国家自然科学基金(40172017).
