title: The influence of dissolved Si on Ni precipitate formation at the kaolinite water interface: Kinetics, DRS and EXAFS analysis.
abstract: 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.
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, 230031, PR China. Electronic address: tanxl@ipp.ac.cn.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Tan
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, 230031, PR China; University of Science and Technology of China, Hefei, 230026, PR China.
authors.forename: Ge
authors.initials: G
authors.lastname: Liu
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, 230031, PR China; University of Science and Technology of China, Hefei, 230026, PR China.
authors.forename: Huiyang
authors.initials: H
authors.lastname: Mei
authors.affiliation: Institute of Solid States Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei, 230031, Anhui, PR China.
authors.forename: Ming
authors.initials: M
authors.lastname: Fang
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, 230031, PR China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Ren
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, 230031, PR China; NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
authors.forename: Changlun
authors.initials: C
authors.lastname: Chen
mesh_terms: D000327:Adsorption; D000930:Antidiarrheals / Q000737:chemistry; D011232:Chemical Precipitation; D003460:Crystallization; D007616:Kaolin / Q000737:chemistry*; D007700:Kinetics; D009532:Nickel / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D014867:Water / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy / Q000379:methods*
chemical_list: D000930:Antidiarrheals; D014867:Water; D007616:Kaolin; D009532:Nickel; D012825:Silicon
keywords: DRS; EXAFS; Kaolinite; Ni precipitate; Si