The influence of dissolved Si on Ni precipitate formation at the kaolinite water interface: Kinetics, DRS and EXAFS analysis
The influence of dissolved Si on Ni precipitate formation at the kaolinite water interface: Kinetics, DRS and EXAFS analysis
复制标题
溶解的 Si 对高岭石水界面 Ni 沉淀形成的影响：动力学、DRS 和 EXAFS 分析
DOI：
10.1016/j.chemosphere.2017.01.061
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发表时间：
2017
期刊：
影响因子：
8.8
通讯作者：
Chen Changlun
中科院分区：
文献类型：
--
作者：
Tan Xiaoli;Liu Ge;Mei Huiyang;Fang Ming;Ren Xuemei;Chen Changlun
在分子尺度上揭示镍沉淀的形成过程对于理解镍物种在真实的环境中的命运和迁移性具有重要意义。溶解的Si普遍存在于自然环境中，其可以改变Ni吸附以及并入新形成的沉淀物中。批实验表明，溶解的Si导致Ni吸附速率的快速增加，并干扰Ni沉淀的形成。漫反射光谱（DRS）和扩展X射线吸收精细结构（EXAFS）光谱分析结果表明，层状硅酸盐（Ni，Al）相的成核过程涉及高岭石状的局部结构。然后，Si的大量存在影响Ni沉淀物成核的初始形成和所得到的晶体生长。二八面体高岭石可以作为一个成核表面的三八面体（镍，铝）层状硅酸盐在环境相关的条件下的非均相形成。该研究为镍沉淀在高岭石上的成核和外延生长过程提供了实验证据，并为深入了解基质和沉淀之间的关系提供了依据，这对于理解镍在矿物表面的物理化学行为至关重要。
Unraveling the formation process of Ni precipitates at molecular scale is important for understanding the fate and mobility of Ni species in the real environment. Dissolved Si presents in the natural environment ubiquitously, which can alter Ni sorption as well as incorporation into neoformed precipitates. Batch experiments show that the dissolved Si leads to a rapid increase in the Ni sorption rate and interferes with the formation of Ni precipitates. The results of diffuse reflectance spectroscopy (DRS) and extended X-ray absorption fine structure (EXAFS) spectroscopy analyses suggest that the nucleation of a (Ni,Al) phyllosilicate phase involves a kaolinite-like local structure. Then, the substantial presence of Si affects the initial formation of Ni precipitate nucleation and the resulting crystal growth. Dioctahedral kaolinite may act as a nucleating surface for the heterogeneous formation of trioctahedral (Ni,Al) phyllosilicates under environmentally relevant conditions. This study provides experimental evidence on nucleation and epitaxial growth processes of Ni precipitate on kaolinite and provides insight on the relationship between substrates and precipitation, which is crucial for understanding the physicochemical behavior of Ni on mineral surfaces.