文章基本信息

标题：Exploring the Sorption Mechanism of Ni(II) on Illite: Batch Sorption, Modelling, EXAFS and Extraction Investigations
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作者：Xiaolan Zhao ; Shirong Qiang ; Hanyu Wu 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2017
卷号：7
期号：1
DOI：10.1038/s41598-017-09188-z
语种：English
出版社：Springer Nature
摘要：The sorption mechanism of nickel (Ni) at the illite/water interface was investigated using batch, sorption modelling, extended X-ray absorption fine structure (EXAFS), and extraction approaches. The results showed that Ni(II) sorption on illite was strongly dependent on pH, contact time, temperature, and initial Ni(II) concentration. At a low initial Ni(II) concentration, the ion exchange species of ≡X2Ni° and the inner-sphere complexes including ≡S(s)ONi(+), ≡S(w)ONi(+) and ≡S(w)ONiOH° species are observed on the sorption edges of Ni(II) on illite. As the initial Ni(II) concentration increased to 1.7 × 10(-3) mol/L, precipitates including surface-induced precipitation of s-Ni(OH)2 and amorphous Ni(OH)2 became more significant, especially under neutral to alkaline conditions. EXAFS analysis confirmed that Ni-Al layered double hydroxide (LDH) can gradually form with an increase in the contact time. At pH 7.0, α-Ni(OH)2 was produced in the initial stage and then transformed to the more stable form of Ni-Al LDH with increasing contact time because of the increased Al(3+) dissolution. With an increase in temperatures, α-Ni(OH)2 phase on illite transformed to Ni-Al LDH phase, indicating a lower thermodynamic stability compared to Ni-Al LDH phase. These results are important to understand the geochemical behaviors to effectively remediate soil contaminated with Ni(II).