Ethyl-bis-triazinylpyridine (Et-BTP) for the separation of americium(III) from trivalent lanthanides using solvent extraction and supported liquid membrane methods

摘要

The present paper deals with the solvent extraction and supported liquid membrane studies on Ln(III)/An (111) separation using ethyl-bis-triazinylpyridine (Et-BTP) as the extractant. The solvent extraction studies involved evaluation of a) diluents, b) phase modifiers, c) stripping agents and d) role of feed acidity. Though reasonably high separation factor values were obtained when Et-BTP was used along with alpha-bromo carboxylic acids, the mixtures could not be used for liquid membrane studies due to unsatisfactory stripping. On the other hand, a combination of Et-BTP with chlorinated cobalt dicarbollide (CCD) in nitrobenzene resulted in significant Am(III) mass transfer when used in the solvent extraction as well as SLM studies. Improved transport, membrane stability, and decontamination from lanthanides were observed when the organic phase diluent composition was 60 percent nitrobenzene + 40 percent n-dodecane. Using 0.02 M Et-BTP along with 0.005 M CCD in 60 percent nitrobenzene + 40 percent n-dodecane, the SLM studies on a mixture of ~(241)Am, ~(152)Eu and ~(147)Nd in a feed containing 0.1 M HNO_3, indicated quantitative Am~(3+) transport in 3.5 h with co-transport of about 8 percent Nd~(3+) and 22 percent Eu~(3+).