Recovery of plutonium from polymeric waste matrices using supercritical fluid extraction

Sujatha, K.; Pitchaiah, K.C.; Sivaraman, N.; Nagarajan, K.; Srinivasan, T. G.; Rao, P. R. Vasudeva

doi:10.1080/19443994.2013.808729

“…The SFE of actinides from various matrices has been reported in literature [5][6][7][8][9][10][11][12][13][14][15][16][17]. The Sc-CO 2 containing chelating agent was employed for the extraction of metal ions such as transition metal ions, lanthanides and actinides [5][6][7][8][9][10][11][12][13][14][15][16][17]. The extraction of uranium from its oxide matrices was carried out using TBP-HNO 3 complex [7,10].…”

Section: Introductionmentioning

confidence: 99%

“…The extraction of uranium from its oxide matrices was carried out using TBP-HNO 3 complex [7,10]. SFE based methods were also developed and demonstrated at our laboratory for the recovery of uranium, plutonium and americium from diverse waste matrices such as polymer, cellulose, teflon and glass matrices [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Supercritical fluid extraction of uranium and thorium from nitric acid medium using organophosphorous compounds

Pitchaiah¹,

Sujatha²,

Rao³

et al. 2014

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In recent years, Supercritical Fluid Extraction (SFE) technique has been widely used for the extraction of metal ions. In the present study, extraction of uranium from nitric acid medium was investigated using supercritical carbon dioxide (Sc-CO 2 ) containing various organophosphorous compounds such as trialkyl phosphates e.g. tri-iso-amyl phosphate (TiAP), tri-sec-butyl phosphate (TsBP) and tri--butyl phosphate (TBP), dialkylalkyl phosphonates, e.g. diamylamyl phosphonate (DAAP) and dibutyl butyl phosphonate (DBBP), dialkyl hydrogen phosphonates, e.g. dioctyl hydrogen phosphonate (DOHP), dioctylphosphineoxide (DOPO), trioctyl phosphine oxide (TOPO), n-octylphenyl N,N-diisobutyl carbamoylmethylphosphine oxide (CMPO) and di-2-ethylhexyl phosphoric acid (HDEHP). Some of these ligands have been investigated for the first time in the supercritical phase for the extraction of uranium. The extraction efficiency of uranium was studied with TiAP, DAAP and DBBP as a function of nitric acid concentration; the kinetics of the equilibration period (static extraction) and transportation of the metal complex (dynamic extraction) was investigated. The influence of pressure and temperature on the extraction behaviour of uranium with DAAP was studied from 4 N HNO 3 . The extraction efficiency of uranium from 4 N nitric acid medium was found to increase in the order of phosphates < phosphonates < HDEHP < TOPO < CMPO. In the case of phosphates and phosphonates, the maximum extraction of uranium was found to be from 4 N HNO 3 medium. The acidic extractants, HDEHP and DOHP showed relatively higher extraction at lower acidities. The relative extraction of uranium and thorium from their mixture was also examined using Sc-CO 2 containing phosphates, phosphonates and TOPO. The ligand, TsBP provided better fractionation between uranium and thorium compared to trialkyl phosphates, dialkyl alkyl phosphonates and TOPO.

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“…Addition of organic ligands results in the conversion of charged metal species into neutral metal complexes, which become quite soluble in Sc-CO 2 . Supercritical carbon dioxide (Sc-CO 2 ) containing chelating agents was employed for the extraction of metal ions such as transition metal ions, lanthanides and actinides [5]- [17]. Sc-CO 2 containing ligands such as diketones, fluorinated diketones and trin-butyl phosphate (TBP) was used for the recovery of actinides such as thorium, uranium, plutonium and americium.…”

Section: Introductionmentioning

confidence: 99%

“…Sc-CO 2 containing ligands such as diketones, fluorinated diketones and trin-butyl phosphate (TBP) was used for the recovery of actinides such as thorium, uranium, plutonium and americium. SFE technique was developed and demonstrated in our laboratory for the recovery of actinides from various matrices such as cellulose and polymer [12]- [17].…”

Section: Introductionmentioning

confidence: 99%

Organophosphorous Compounds

2016

Encyclopedia of Parasitology

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Supercritical Fluid Extraction (SFE) is emerging as a powerful technique in the extraction of metal ions.In the present study, the extraction of nitrates of uranium and thorium in their solid form was carried out using supercritical carbon dioxide (Sc-CO 2 ) modified with various organophosphorous compounds such as dialkylalkyl phosphonates, trialkyl phosphates and trialkyl phosphine oxides in the presence of co-solvents such as methanol, dichlormethane and n-hexane. The influence of ligand and co-solvent on the extraction of the metal nitrates was studied in detail. These studies have established that co-solvent plays an important role in the extraction as well as fractionation of uranium and thorium nitrates. Polar co-solvent, methanol provided faster extraction without fractionation whereas the non-polar solvent, e.g. n-hexane provided some fractionation of metal nitrates though the extraction kinetics was slower.

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“…Addition of organic ligands results in the conversion of charged metal species into neutral metal complexes, which become quite soluble in Sc-CO 2 . Supercritical carbon dioxide (Sc-CO 2 ) containing chelating agents was employed for the extraction of metal ions such as transition metal ions, lanthanides and actinides [5]- [17]. Sc-CO 2 containing ligands such as diketones, fluorinated diketones and trin-butyl phosphate (TBP) was used for the recovery of actinides such as thorium, uranium, plutonium and americium.…”

mentioning

confidence: 99%

Influence of Co-Solvent on the Extraction Behaviour of Uranium and Thorium Nitrates with Organophosphorous Compounds

Pitchaiah

¹

,

Sujatha²,

Rao³

et al. 2014

IJAMSC

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1

0

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Supercritical Fluid Extraction (SFE) is emerging as a powerful technique in the extraction of metalions. In the present study, the extraction of nitrates of uranium and thorium in their solid form was carried out using supercritical carbon dioxide (Sc-CO 2 ) modified with various organophosphorous compounds such as dialkylalkyl phosphonates, trialkyl phosphates and trialkyl phosphine oxides in the presence of co-solvents such as methanol, dichlormethane and n-hexane. The influence of ligand and co-solvent on the extraction of the metal nitrates was studied in detail. These studies have established that co-solvent plays an important role in the extraction as well as fractionation of uranium and thorium nitrates. Polar co-solvent, methanol provided faster extraction without fractionation whereas the non-polar solvent, e.g. n-hexane provided some fractionation of metal nitrates though the extraction kinetics was slower. Keywords Co-Solvent, Uranium and Thorium, Organophosphorous Compounds* Corresponding author. K. C. Pitchaiah et al. 34sults in interesting analytical separations and provides a medium for various organic reactions. CO 2 is the most widely used supercritical fluid due to its moderate critical temperature and critical pressure; moreover, it is non-flammable, non-toxic, inexpensive and environmental friendly [1]. The most distinctive properties of the supercritical fluids are their enhanced mass transfer and variable density. The density of supercritical fluid can be fine tuned by varying the pressure and temperature [1]; hence solvating power of carbon dioxide can be easily altered. Supercritical fluids offer faster, efficient and cleaner extraction as CO 2 escapes as gas after extraction leaving the solute in its pure form. SFE is attractive technique to the nuclear industry, where the replacement of organic solvents with Sc-CO 2 has the potential to minimize the generation of secondary liquid waste.Supercritical carbon dioxide is an excellent candidate for the extraction of non-polar and moderately polar compounds. The extraction of polar compounds is generally carried out with Sc-CO 2 containing small quantities of organic solvent e.g. methanol as the co-solvent. The extraction of metal ions is accomplished by the addition of suitable ligand into Sc-CO 2 medium [2]- [4]. Addition of organic ligands results in the conversion of charged metal species into neutral metal complexes, which become quite soluble in Sc-CO 2 . Supercritical carbon dioxide (Sc-CO 2 ) containing chelating agents was employed for the extraction of metal ions such as transition metal ions, lanthanides and actinides [5]- [17]. Sc-CO 2 containing ligands such as diketones, fluorinated diketones and trin-butyl phosphate (TBP) was used for the recovery of actinides such as thorium, uranium, plutonium and americium. SFE technique was developed and demonstrated in our laboratory for the recovery of actinides from various matrices such as cellulose and polymer [12]-[17].In the present study, we have examined for the first time the use o...

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Recovery of plutonium from polymeric waste matrices using supercritical fluid extraction

Cited by 19 publications

References 20 publications

Supercritical fluid extraction of uranium and thorium from nitric acid medium using organophosphorous compounds

Supercritical fluid extraction of uranium and thorium from nitric acid medium using organophosphorous compounds

Organophosphorous Compounds

Influence of Co-Solvent on the Extraction Behaviour of Uranium and Thorium Nitrates with Organophosphorous Compounds

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