Fuel Reprocessing Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
J Hazard Mater. 2011 Apr 15;188(1-3):281-7. doi: 10.1016/j.jhazmat.2011.01.109. Epub 2011 Feb 2.
Facilitated transport of uranyl ion from nitric acid feed solutions was investigated across PTFE supported liquid membranes using N,N,N',N'-tetra-2-ethylhexyl-3-pentane-diamide (T2EHDGA) in n-dodecane as the carrier extractant containing 30% iso-decanol as the phase modifier. Solvent extraction studies indicated extraction of species of the type, UO(2)(NO(3))(2)·T2EHDGA. The distribution coefficients increased in the presence of NaNO(3) as compared to equivalent concentration of HNO(3) which was exactly the opposite of what was reported for Am(III)-TODGA extraction system. Supported liquid membrane studies indicated about 11h were required for quantitative transport of U(VI) from a feed of 3M HNO(3) using 0.2M T2EHDGA in n-dodecane containing 30% iso-decanol as the carrier extractant. Effect of various parameters such as feed acidity, T2EHDGA concentration, and nature of the strippant on the transport rate was investigated. The transport was found to be diffusion controlled in the membrane phase and the permeability coefficient was calculated to be (3.20 ± 0.13)× 10(-4)cm/s for the feed composition of 3M HNO(3), receiver phase composition of 0.01 M HNO(3) and membrane carrier phase of 0.2M T2EHDGA in n-dodecane containing 30% iso-decanol. The present results may be useful for the separation of U from lean solutions or radioactive wastes considered hazardous due to the presence of alpha-particle emitting radionuclides.
采用聚四氟乙烯（PTFE）支撑液膜，以正十二烷为膜相，N，N，N'，N'-四（2-乙基己基）-3-戊二酰胺（T2EHDGA）为载体萃取剂，其中含有 30%异癸醇作为相调节剂，研究了硝酸进料溶液中铀酰离子的促进传递。溶剂萃取研究表明，萃取物种为 UO 2 (NO 3 ) 2 ·T2EHDGA。与相当浓度的 HNO 3 相比，在存在 NaNO 3 的情况下，分配系数增加，这与 Am(III)-TODGA 萃取体系的情况完全相反。支撑液膜研究表明，使用 0.2M T2EHDGA 正十二烷中的载体萃取剂，从 3M HNO 3 的进料中定量传输 U(VI)，需要约 11h。研究了进料酸度、T2EHDGA 浓度和反萃剂性质等各种参数对传输速率的影响。发现传输在膜相中受扩散控制，渗透率系数计算为 3.20±0.13×10 -4 cm/s，进料组成 3M HNO 3 ，接收相组成 0.01M HNO 3 ，膜相载体相为 0.2M T2EHDGA 正十二烷中的 30%异癸醇。这些结果可能有助于从贫溶液中分离铀，或者从由于存在发射 α 粒子的放射性核素而被认为危险的放射性废物中分离铀。
