粘土矿物微结构和界面特性对硫酸根离子吸附的影响和机理

Sulphur is one of the most abundant and widely distributed elements in the crust. The element sulphur plays an important role in the physiological activities of living beings and soil acidification. As the active minerals in soils and sediments, clay minerals are crucial to the ion sorption, acidification buffering, transformation from organic to inorganic phase, and redox of sulphur. In this proposed project, we will take natural montmorillonite and kaolinite, and synthetic saponite as the research objects. The natural and synthetic samples with gradient change in their microstructural (the crystallinity and the order degree of layer stacking) and interface characteristics (isomorphism) by experimental methods will be obtained and used to the sorption of sulphate in solution. We propose to explore the effects and mechanisms of microstructural and interface characteristics of clay minerals on the sulphate sorption. Based on the sorption results, we aim to derive a reasonable sorption model that can consistently bridge the gap between microscopic interaction mechanisms and macroscopic experimental observations. It is anticipated that the research on the interface interaction process between clay minerals and sulphate, the role of microstructural and interface characteristics of clay minerals in the sulphate sorption and adsorptive mechanism have important implications for the sulphate sorption in soils and rhizosphere. Our research would also be beneficial to the profound understanding of the migration and enrichment processes of sulphur in geological environments, and can be the experimental basis of understanding and managing the destruction of soils and ecosystems by the acid deposition in watersheds.

硫是地壳中含量最丰富、分布最广泛的元素之一，对生物的生理活动调节和土壤酸化发挥重要影响。粘土矿物作为土壤和沉积物中较为活跃的矿物组分，在硫的离子吸附、缓冲酸化、有机向无机转化、变价硫的氧化还原等方面至关重要。本项目拟以天然蒙脱石、高岭石和合成皂石为研究对象，以实验方法实现矿物微结构特性（矿物结晶程度、层堆垛有序度）和界面特性（类质同象置换）的梯度变化，并将所得样品用于硫酸根的吸附。本研究旨在探究粘土矿物微结构与界面特性对硫酸根吸附的影响和微观机制，进而推导基于微观机制的能够合理解释宏观规律的吸附模型。粘土矿物与硫酸根间的界面作用过程、微结构和界面特性对吸附的影响和吸附模型对于硫酸盐在土壤和根际吸附的研究方面具有重要意义。有助于深刻理解硫元素在地质介质中的迁移、富集过程，同时也可为认识和治理流域酸沉降对土壤和生态系统的破坏提供实验依据。