Srivastava Bhavya, Barman Milan K, Chatterjee Mousumi, Roy Dipika, Mandal Bhabatosh
Analytical Laboratory, Department of Chemistry, Visva-Bharati Santiniketan, 731235, India.
Analytical Laboratory, Department of Chemistry, Visva-Bharati Santiniketan, 731235, India.
J Chromatogr A. 2016 Jun 17;1451:1-14. doi: 10.1016/j.chroma.2016.04.079. Epub 2016 May 7.
The present work reports the systematic studies on extraction, separation and preconcentration of Th(IV), U(VI), Zr(IV), Ce(IV) and Cr(III) amid several other foreign ions using EBT anchored {SiO2}n3-D microarray. The effect of various sorption parameters, such as pH, concentration, temperature, sample volume, flow-rate and co-existing foreign ions were investigated. Quantitative sorption was ensured at solution pH: 6.0-6.5 for Th(IV), Ce(IV), Cr(III) and pH: 2.75-3.0 for Zr(IV), U(VI) couple. Analysis on extracted species and extraction sites reveals that Th4(μ(2)-OH)8(H2O)4, Ce6(μ(2)-OH)12(H2O)5, Cr3(μ(2)-OH)4(H2O), (UO2)3(μ(2)-OH)5(H2O)3 and Zr4(μ(2)-OH)8(H2O)0.5 for the respective metal ions gets extracted at HOMO of the extractor. HOMO-{metal ion species} was found to be 1:1 complexation. Sorption was endothermic, entropy-gaining, instantaneous and spontaneous in nature. A density functional theory (DFT) calculation has been performed to analyze the 3-D structure and electronic distribution of the synthesized extractor.
本工作报道了使用EBT锚定的{SiO2}n 3-D微阵列对钍（IV）、铀（VI）、锆（IV）、铈（IV）和铬（III）以及其他几种外来离子进行萃取、分离和预富集的系统研究。研究了各种吸附参数的影响，如pH值、浓度、温度、样品体积、流速和共存的外来离子。在溶液pH值为6.0 - 6.5时，钍（IV）、铈（IV）、铬（III）实现定量吸附；在pH值为2.75 - 3.0时，锆（IV）、铀（VI）实现定量吸附。对萃取物种和萃取位点的分析表明，相应金属离子的Th4(μ(2)-OH)8(H2O)4、Ce6(μ(2)-OH)12(H2O)5、Cr3(μ(2)-OH)4(H2O)、(UO2)3(μ(2)-OH)5(H2O)3和Zr4(μ(2)-OH)8(H2O)0.5在萃取剂的最高占据分子轨道（HOMO）处被萃取。发现HOMO - {金属离子物种}为1:1络合。吸附是吸热的、熵增的、瞬时的且自发的。已进行密度泛函理论（DFT）计算以分析合成萃取剂的三维结构和电子分布。
