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以凹凸棒石与Zn2+为例研究粘土矿物与重金属离子长期作用过程,并运用高分辨透射电镜和X射线衍射分析粘土矿物与重金属离子长期作用的次生物相。结果表明:Zn2+与凹凸棒石的长期作用是一个二阶段的过程,初始阶段为快速吸附作用,其后表现为慢速沉淀反应。高分辨透射电镜和X射线衍射分析表明,凹凸棒石与Zn2+的长期作用过程中,具有纳米矿物特性的凹凸棒石表面快速水化,提高了悬浮液的pH值,诱导Zn2+水解沉淀。而后,凹凸棒石缓慢溶解释放Al3+和SiO44-与Zn(OH)2沉淀反应,形成Zn-A1双氢氧化物和异极矿。这一结果对认识土壤环境中重金属与粘土矿物的作用及重金属的归宿具有重要意义。
Taking attapulgite and Zn2 + as an example, the long-term action process of clay minerals and heavy metal ions was studied. The secondary phases of clay minerals and heavy metal ions were analyzed by high resolution transmission electron microscopy and X-ray diffraction. The results show that the long-term action of Zn2 + and attapulgite is a two-stage process. The initial stage is rapid adsorption and then the slow precipitation reaction. High-resolution transmission electron microscopy and X-ray diffraction analysis showed that during the long-term action of attapulgite and Zn2 +, the surface of attapulgite with nanometer mineral properties was rapidly hydrated, the pH value of the suspension was increased, and the Zn2 + hydrolytic precipitation was induced. Then, the attapulgite slowly dissolves and releases Al3 + and SiO44- with Zn (OH) 2 to form a Zn-Al double hydroxide and hemimorphite. This result is of great significance for understanding the role of heavy metals and clay minerals in the soil environment and the fate of heavy metals.