Speaker
Description
The research is focused on comparing the effectiveness of various extraction agents for separation/extraction of europium from different aqueous phases into ionic liquids.This comparison was carried out in order to describe the influence of several key parameters on the extraction efficiency (pH, extractant concentration, possible synergism between extractants) which could help to clarify the mechanism of europium extraction.
Several extractants or their combination were used and subsequently compared: TBP, TOPO, TPPO, CMPO, TODGA, and 8-HQ. Extractants were added to a conventional solvent represented by chloroform, and a perspective solvent - ionic liquid - in order to compare their extraction efficiencies in different organic media.
Ionic liquids are investigated since they are generally less volatile, toxic, and have better radiation and thermal stability compared to conventional solvents. In extraction, imidazolium based ionic liquids are one of the most studied as solvents; in this work, 1-butyl-3 methylimidazolium bis(trifluoromethylsulfonyl)imide [C4mim][NTf2] was chosen. The butyl group present in the structure is hydrophobic, which is advantageous for extraction from aqueous media, and the relatively low viscosity of [C4mim][NTf2] enables its potential use on larger, industrial, scale.
Experimental work revealed a synergistic effect between TBP and TOPO/TODGA, i.e., their extraction efficiencies improved with the addition of TBP. An obvious positive influence on extraction efficiency with the usage of the ionic liquid was confirmed for TPPO, 8-HQ, and CMPO. From all the studied organophosphorus compounds (TBP, TOPO, TPPO, CMPO) the most perspective candidate in combination with [C4mim][NTf2] appears to be CMPO, which, compared to the others, is able to efficiently extract trivalent europium to the ionic liquid across the entire studied pH range (1-10) from all the aqueous phases used.