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<p>Thiocyanate spectrophotometry method is routinely employed for determination of wide concentration range of U in aqueous streams of PUREX process. Uranium thiocyanate waste gets generated in radioactive laboratories with significant quantities of U in analytical waste. It is important to recover U from such waste because of its strategic significance. In this context a novel ligand/extractant, diamylamyl phosphonate(DAAP) was employed for the recovery of U from thiocyanate medium. Distribution ratios for U were measured as a function of various parameters such as pH, concentration of thiocyanate and extractant. The back-extraction or stripping studies for the recovery of U from DAAP phase was examined with different concentrations of sodium carbonate. DAAP was also employed for the extractive spectrophotometric determination of U by ammonium thiocyanate as chromogenic agent. Thiocyanate spectrophotometry method suffers drawbacks due to interferences from Mo, Fe. An extractive spectrophotometry was developed for the determination of U using thiocyanate as chromogenic agent. In this method U was extracted with DAAP from nitric acid medium and U in the organic phase was estimated by thiocyanate method. Fe and Mo was not extracted into the organic phase and hence interference from these elements were avoided. All the experiments were also performed with TBP under identical conditions for comparison. DFT computations were performed to understand the complexation behavior of U with DAAP in presence of thiocyanate and nitrate medium. The lowest energy structures of DAAP and TBP and its complexes with U were optimized at DFT level. The gas phase complexation energies of DAAP and TBP with uranyl in the nitric acid and thiocyanate medium were calculated at the RI-BP86-D3BJ/def2-TZVP-ZORA level. This study provides a comprehensive understanding on the recovery, and extractive spectrophotometry of uranium complexes.</p>

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Extractive spectrophotometric determination and recovery of uranium from thiocyanate medium using diamylamyl phosphonate: experimental and theoretical study

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年6月4日

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  • B. Shiva Rama Krishna,
  • Diganta Raychaudhuri,
  • B. Sreenivasulu,
  • Gopinadhanpillai Gopakumar,
  • C. V. S. Brahmananda Rao,
  • V. K. Madhavan Kutty,
  • G. Srinivasa Rao

摘要

Thiocyanate spectrophotometry method is routinely employed for determination of wide concentration range of U in aqueous streams of PUREX process. Uranium thiocyanate waste gets generated in radioactive laboratories with significant quantities of U in analytical waste. It is important to recover U from such waste because of its strategic significance. In this context a novel ligand/extractant, diamylamyl phosphonate(DAAP) was employed for the recovery of U from thiocyanate medium. Distribution ratios for U were measured as a function of various parameters such as pH, concentration of thiocyanate and extractant. The back-extraction or stripping studies for the recovery of U from DAAP phase was examined with different concentrations of sodium carbonate. DAAP was also employed for the extractive spectrophotometric determination of U by ammonium thiocyanate as chromogenic agent. Thiocyanate spectrophotometry method suffers drawbacks due to interferences from Mo, Fe. An extractive spectrophotometry was developed for the determination of U using thiocyanate as chromogenic agent. In this method U was extracted with DAAP from nitric acid medium and U in the organic phase was estimated by thiocyanate method. Fe and Mo was not extracted into the organic phase and hence interference from these elements were avoided. All the experiments were also performed with TBP under identical conditions for comparison. DFT computations were performed to understand the complexation behavior of U with DAAP in presence of thiocyanate and nitrate medium. The lowest energy structures of DAAP and TBP and its complexes with U were optimized at DFT level. The gas phase complexation energies of DAAP and TBP with uranyl in the nitric acid and thiocyanate medium were calculated at the RI-BP86-D3BJ/def2-TZVP-ZORA level. This study provides a comprehensive understanding on the recovery, and extractive spectrophotometry of uranium complexes.