Adsorption mechanism of silica/polymer-based 2,6-bis(5,6-diisohexyl-1,2,4-triazin-3-yl)pyridine adsorbent towards Ln(III) from nitric acid solution

作者：Ning, Shunyan; Zou, Qing; Wang, Xinpeng; Liu, Ruiqin; Wei, Yuezhou^*

来源：Journal of Nuclear Science and Technology, 2016, 53(9): 1417-1425.

DOI：10.1080/00223131.2015.1123122

• isoHexyl-BTP
• HLLW
• lanthanide
• adsorption
• chromatography
• EXAFS

2,6-Bis(5,6-diisohexyl-1,2,4-triazin-3-yl)pyridine (isoHexyl-BTP) is a nitrogen-donor chelating ligand which shows high extraction selectivity for minor actinides (MA) over lanthanides (Ln). We synthesized a macroporous sillica/polymer-based isoHexyl-BTP adsorbent (isoHexyl-BTP/SiO2-P) for the separation of MA(III) from Ln(III) in high-level liquid waste. The work focused on the isoHexyl-BTP/SiO2-P adsorption mechanism towards Ln(III) in nitric acid solution and the coordination chemistry between Ln(III) and isoHexyl-BTP/SiO2-P through batch adsorption experiments, extended X-ray absorption fine spectroscopy, acid-base titration and ion chromatography. It was found that both H+ and NO3- directly participated in the adsorption reaction. For the middle and heavy Ln(III), Ln(isoHexyl-BTP/SiO2-P)(3)(NO3)(3)3HNO(3) was supposed as the main product of the adsorption. The Ln(III)-N (Ln(isoHexyl-BTP/SiO2-P)(3)(3+)) bond length of the first coordination layer decreased as the atomic number of Ln(III) increased, which explains the increased adsorption affinity of isoHexyl-BTP/SiO2-P towards middle and heavy Ln(III) in relatively high concentration nitric acid as the Ln(III) atomic number increased.

• 出版日期2016
• 单位上海交通大学