Solvent Extraction of Chromium(VI) with Tri-n-butyl Phosphate from Aqueous Acidic Solutions

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• 作者：Weidong Zhang ; Junteng Liu ; Zhongqi Ren ; Changshun Du ; Jingnan Ma
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2007
• 出版时间：November 2007
• 年：2007
• 卷：52
• 期：6
• 页码：2220 - 2223
• 全文大小：53K
• 年卷期：v.52,no.6(November 2007)
• ISSN：1520-5134

文摘

The solvent extraction of Cr(VI) from aqueous acidic solutions by tri-n-butyl phosphate (TBP) in kerosene wasinvestigated. HCl, H₂SO₄, and H₃PO₄ were used for the pH adjustment of the aqueous phase. The results showthat the distribution coefficient exhibited a maximum when HCl was used. The distribution coefficient increasedwith increasing TBP concentration (from (0.2 to 3.0) mol·L^-1) and decreasing pH (from 2.0 to 0). The resultsalso show that one molecule of Cr(VI) was approximately coordinated to three TBPs in the complex. The enthalpychange of -17.4 kJ·mol^-1 was determined using the van't Hoff equation, suggesting that the extraction of Cr(VI)from a HCl medium is an exothermic process. The presence of NaCl in the feed phase improved the extractionefficiency, whereas the presence of Na₂SO₄ or KH₂PO₄ has no benefit. The stripping of loaded organic and thereuse of the extractant are also discussed in this paper.