Solvent extraction of la III using some commercial extractants

Abstract

newlineTitle of the thesis: SOLVENT EXTRACTION OF La (III) USING SOME newlineCOMMERCIAL EXTRACTANTS . newlineThe present investigation deals with the extraction studies of La (III) using the commercial newlineextractants like DEHPA, PC88A, Cyanex 921 and Aliquat 336 using petrofin and kerosene newlineas diluents. In case of DEHPA and PC88A being acidic extractants, the aqueous pH has newlinebeen carefully chosen while extracting with these extractants whereas for the other two newlineextractants the extraction studies have been carried out from the acidic nitrate medium. A newlinenumber of operating variables affecting the extraction of La (III) such as equilibration time, newlineaqueous pH, nitrate ion concentration, extractant concentration, nitric acid concentration, newlinetemperature, phase volume ratio, nature of diluents has been examined. Analysis of metal newlinecontent before and after extraction has been done using ICP-OES spectrophotometer. The newlinecomposition of the extracted complex has been determined using slope analysis method. newlineSeparation studies of La (III) from the lighter lanthanides Ce, Pr, Nd and Sm has been newlinecarried out the separation factor(and#946;) has been determined.The thermodynamic parameters newlinelike standard enthalpy change (and#916;Ho) and standard entropy change (and#916;So) have been newlinedetermined using Van t Hoff equation. Stripping of La (III) has been carried out using newlinevarious mineral acids to obtain effective stripping. Solvent regeneration studies have been newlinecarried out in order to reduce environmental pollution. Modeling of extraction data has newlinebeen performed with the help of linear and non linear techniques in order to optimize the newlineextraction conditions.