Publications by authors named "Ch Siva Kesava Raju"

A new class of polymeric resin has been synthesized by grafting Merrifield chloromethylated resin with (dimethyl amino-phosphono-methyl)-phosphonic acid (MCM-DAPPA), for the preconcentration of U(VI), Th(IV) and La(III) from both acidic wastes and environmental samples. The various chemical modification steps involved during grafting process are characterized by FT-IR spectroscopy, (31)P and (13)C-CPMAS (cross-polarized magic angle spin) NMR spectroscopy and CHNS/O elemental analysis. The water regain capacity data for the grafted polymer are obtained from thermo-gravimetric (TG) analysis.

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The retention behaviour of uranium and thorium was investigated on modified reverse phase supports using 3-oxo-pentanedioicacid bis-[bis-(2-ethyl-hexyl)-amide (OPAEHA), 3-oxo-pentanedioicacid bis diisobutyl amide (OPAIBA) and bis-2-ethylhexyl succinamic acid (BEHSA). alpha-Hydroxy isobutyric acid (alpha-HIBA) was employed as the complexing reagent for elution. Elution profiles of uranium and thorium were studied as a function of the modifier concentration, mobile phase composition and its pH.

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A novel grafted polymer for selective extraction and sequential separation of lanthanides, thorium and uranium from high acidic wastes has been developed by grafting Merrifield chloromethylated (MCM) resin with octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) (MCM-CMPO). The grafting process is well characterized using FT-IR spectroscopy, (31)P and (13)C CPMAS (cross-polarized magic angle spin) NMR spectroscopy and CHNPS elemental analysis. The influence of various physico-chemical parameters during metal ion extraction by the resin phase are studied and optimized by both static and dynamic methods.

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