P. N. Pathak

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A novel solvent system containing a dipicolinamide in room temperature ionic liquids for actinide ion extraction

Ajay B. Patil, P. N. Pathak, V. S. Shinde, M. Yu. Alyapyshev, more

Journal of Radioanalytical and Nuclear Chemistry > 2015 > 305 > 2 > 521-528

Solvent extraction of Am(III), Pu(IV) and Eu(III) was done from nitric acid medium using a solvent system containing a substituted dipicolinamide extractant dissolved in room temperature ionic liquid. The solvent system was found to be more efficient as compared to the previously reported solvents in molecular diluents.

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Online recovery of radiocesium from soil, cellulose and plant samples by supercritical fluid extraction employing crown ethers and calix-crown derivatives as extractants

A. S. Kanekar, P. N. Pathak, P. K. Mohapatra

Journal of Radioanalytical and Nuclear Chemistry > 2014 > 300 > 3 > 1281-1289

Two crown ethers (CEs) viz. dibenzo18crown6, and dibenzo12crown7 and three calix-crown derivatives viz. (octyloxy)calix[4]arene-mono-crown-6 (CMC), calix[4]arene-bis(o-benzocrown-6) (CBC), and calix[4]arene-bis(naphthocrown-6) (CNC) were evaluated for the recovery of ¹³⁷Cs from synthetic soil, cellulose (tissue paper), and plant samples by supercritical fluid extraction (SFE) route. CEs showed poor...

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N,N-Dialkyl amides as extractants for spent fuel reprocessing: an overview

P. N. Pathak

Journal of Radioanalytical and Nuclear Chemistry > 2014 > 300 > 1 > 7-15

Reprocessing of spent nuclear fuel is vital for the long-term global nuclear power growth and is the major motivation for developing novel separation schemes. Conventionally, PUREX and THOREX processes have been proposed for the reprocessing of U and Th based spent fuels employing tri-n-butyl phosphate (TBP) as extractant. However, based on the experiences gained over last five–six decades on the...

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Biphasic kinetic investigations on the evaluation of non-salt forming reductants for Pu(IV) stripping from tributyl phosphate and N,N-dihexyl octanamide solutions in n-dodecane

D. R. Prabhu, Neelam Kumari, A. S. Kanekar, P. N. Pathak

Journal of Radioanalytical and Nuclear Chemistry > 2013 > 298 > 1 > 691-698

The relative stability of different oxidation states of actinide elements is influenced by the nature of complexes formed and redox equilibria in aqueous/non-aqueous solutions. The reduction/stripping studies on Pu(IV) ions from loaded organic phases of 1.1 M tributyl phosphate and of 1.1 M N,N-dihexyl octanamide in n-dodecane were studied using organic soluble tert-butyl hydroquinone (TBH) and aqueous...

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Hydrodynamic properties for N,N,N′,N′‐tetraalkyl diglycolamides dissolved in n‐dodecane system

A. S. Kanekar, S. A. Ansari, R. B. Gujar, D. R. Prabhu, more

The Canadian Journal of Chemical Engineering > 90 > 3 > 682 - 689

N,N,N′,N′‐tetraoctyl diglycolamide (TODGA) and N,N,N′,N′‐tetra(2‐ethylhexyl) diglycolamide (T2EHDGA) have been identified as promising extractants for actinide partitioning from high‐level nuclear waste. These extractants are proposed to be used along with suitable phase modifiers, viz. N,N‐dihexyl octanamide (DHOA), tri‐n‐butyl phosphate (TBP) and 2‐decanol dissolved in n‐dodecane. Hydrodynamic parameters,...

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Redox Behavior of Neptunium(V) in Tributyl Phosphate and N,N-Dihexyl Octanamide Extractants Dissolved in n-Dodecane

P. N. Pathak, Neelam Kumari, D. R. Prabhu, V. K. Manchanda

Journal of Solution Chemistry > 2012 > 41 > 3 > 410-421

Spectrophotometric investigations have been carried out on the disproportionation of Np(V) to form Np(IV) and Np(VI) in 1.1 mol⋅L⁻¹ solutions of tributyl phosphate (TBP) and in N,N-dihexyl octanamide (DHOA) in n-dodecane medium. The Np(V) was found to coordinate with Np(IV) in 1.1 mol⋅L⁻¹ TBP solution in n-dodecane to form a mixed valence “cation–cation” complex by bonding through an axial oxo group...

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Mathematical modeling of solvent extraction of uranium from sulphate media employing 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and its mixture with trioctylphosphine oxide (TOPO) as extractants

S. Biswas, P. N. Pathak, D. K. Singh, S. B. Roy, more

Journal of Radioanalytical and Nuclear Chemistry > 2011 > 289 > 2 > 557-564

The extraction of U(VI) from sulphate medium with 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A, H₂A₂ in dimeric form) in n-dodecane has been investigated under varying concentrations of sulphuric acid and uranium. Slope analysis of uranium (VI) distribution data as a function of PC88A concentration suggests the formation of monomeric species, viz. UO₂(HA₂)₂. This observation was further...

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Extraction studies of uranium into a third-phase of thorium nitrate employing tributyl phosphate and N,N-dihexyl octanamide as extractants in different diluents

Neelam Kumari, D. R. Prabhu, P. N. Pathak, A. S. Kanekar, more

Journal of Radioanalytical and Nuclear Chemistry > 2011 > 289 > 3 > 835-843

Extraction behavior of 1 × 10⁻²–0.1 M U(VI) from aqueous phases containing 0.86 M Th(IV) at 4 M HNO₃ in 1.1 M tributyl phosphate (TBP) and 1.1 M N,N-dihexyl octanamide (DHOA) solutions in different diluents viz. n-dodecane, 10% 1-octanol + n-dodecane, and decahydronaphthalene (decalin) was studied. Third-phase formation was observed in both the extractants using n-dodecane as diluent. There was a...

article

Studies on the radiolytic stability of N,N,N′,N′-tetra-2-ethylhexyl diglycolamide in n-dodecane solution containing different phase modifiers

R. B. Gujar, S. A. Ansari, A. Bhattacharyya, P. K. Mohapatra, more

Journal of Radioanalytical and Nuclear Chemistry > 2011 > 288 > 2 > 621-627

The radiolytic stability of a branched diglycolamide extractant, namely N,N,N′,N′-tetra-2-ethylhexyl diglycolamide (T2EHDGA) dissolved in n-dodecane containing several phase modifiers, viz. N,N-dihexyloctanamide (DHOA), tri-n-butyl phosphate (TBP), 1-decanol and iso-decanol has been investigated. The distribution ratio of Am(III) decreased with increased radiation dose studied up to 1000 kGy. Nevertheless,...

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Gross alpha-activity estimation in simulated high level waste after actinides partitioning by solid state nuclear track detection

Chhavi Agarwal, P. C. Kalsi, D. R. Prabhu, P. N. Pathak, more

Journal of Radioanalytical and Nuclear Chemistry > 2011 > 287 > 3 > 749-752

The estimation of low level alpha activity is difficult in waste samples containing large concentration of salts and beta–gamma activity. In the present study, the feasibility of gross alpha-activity measurement for simulated high level waste (SHLW) in solution medium by alpha-track registration technique has been attempted. The results showed that it is possible to use this technique for gross alpha-activity...

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Alpha radiolytic degradation of N,N-dihexyl octanamide

P. N. Pathak, D. R. Prabhu, M. Bindu, S. C. Tripathi, more

Journal of Radioanalytical and Nuclear Chemistry > 2011 > 288 > 1 > 137-142

The primary purpose of this study was to understand the alpha radiolytic degradation behavior of N,N-dihexyl octanamide (DHOA) vis a vis tributyl phosphate (TBP) solutions in n-dodecane under plutonium loading conditions. These studies were carried out as a function of dose on different Pu loaded samples (containing 0.002-10 g/L Pu) from 4 M HNO₃ medium. These Pu loaded solutions were evaluated for...

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Sorption of Am(III) on natural sediment: experiment and modeling

D. K. Das, Sumit Kumar, P. N. Pathak, B. S. Tomar, more

Journal of Radioanalytical and Nuclear Chemistry > 2011 > 289 > 1 > 137-143

Release of long-lived radioactivity to the aquatic bodies from various nuclear fuel cycle related operations is of great environmental concern in view of their possible migration into biosphere. This migration is significantly influenced by various factors such as pH, complexing ions present in aquatic environment and sorption of species involving radionuclides on the sediments around the water bodies...

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²³³Pa(2n_th, f ) cross-section determination using a fission track technique

H. Naik, P. M. Prajapati, S. V. Suryanarayana, P. N. Pathak, more

The European Physical Journal A > 2011 > 47 > 8 > 1-5

The ²³³Pa(2n_th, f) cross-section has been experimentally determined for the first time using a fission track technique. It was found to be 4834 ± 57 b, which is significantly high and thus is very important for ²³²Th-²³³U-based fuel in advanced heavy-water reactors (AHWR) and accelerator-driven sub-critical systems (ADSs). This is because the ²³³Pa is an important intermediary in the thorium-based...

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Reactions of N,N-dihexyloctanamide with nitrate and dodecane radicals: a pulse radiolysis study

Ravi Joshi, P. N. Pathak, V. K. Manchanda, S. K. Sarkar, more

Research on Chemical Intermediates > 2010 > 36 > 5 > 503-510

Recently, completely incinerable N,N-dihexyloctanamide (DHOA) has been identified as a promising alternative to tri-n-butyl phosphate for the reprocessing of spent nuclear fuels. The present work deals with the pulsed radiolytic investigation on the reactions of DHOA with the radicals produced in the radiolysis of nitric acid and dodecane medium. The rate constants of the reactions of DHOA with solvated...

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Comparative extraction efficiencies of tri-n-butyl phosphate and N,N-dihexyloctanamide for uranium recovery using supercritical CO₂

A. S. Kanekar, P. N. Pathak, P. K. Mohapatra, V. K. Manchanda

Journal of Radioanalytical and Nuclear Chemistry > 2010 > 283 > 3 > 789-796

Extraction of uranium from tissue paper, synthetic soil, and from its oxides (UO₂, UO₃ and U₃O₈) was carried out using supercritical carbon dioxide modified with methanol solutions of extractants such as tri-n-butyl phosphate (TBP) or N,N-dihexyl octanamide (DHOA). The effects of temperature, pressure, extractant/nitric acid (nitrate) concentration, and of hydrogen peroxide on uranium extraction were...

article

Neptunium estimation in the spent fuel dissolver solution by inductively coupled plasma-atomic emission spectroscopy

D. K. Pant, G. A. Chaugule, K. K. Gupta, P. G. Kulkarni, more

Journal of Radioanalytical and Nuclear Chemistry > 2010 > 283 > 2 > 513-518

This paper deals with the optimization of experimental conditions for the estimation of Np in spent fuel dissolver solution using 2-thenoyltrifluoroacetone (HTTA) as extractant. The quantitative extraction of Np from the dissolver solution employing 0.5 M HTTA/xylene was followed by its estimation by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) after stripping it from the organic...

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Synergistic extraction of uranium with mixtures of PC88A and neutral oxodonors

S. Biswas, P. N. Pathak, D. K. Singh, S. B. Roy, more

Journal of Radioanalytical and Nuclear Chemistry > 2010 > 284 > 1 > 13-19

The extraction of uranium(VI) from nitric acid medium is investigated using 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A in dimeric form, H₂A₂) as extractant either alone or in combination with neutral extractants such as tri-n-butyl phosphate (TBP), trioctyl phosphine oxide (TOPO), and dioctyl sulfoxide (DOSO). The effects of different experimental parameters such as aqueous phase...

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Sorption behavior of Am³⁺ on suspended pyrite

D. K. Das, P. N. Pathak, S. Kumar, V. K. Manchanda

Journal of Radioanalytical and Nuclear Chemistry > 2009 > 281 > 3 > 449-455

Sorption behavior of ²⁴¹Am (~10⁻⁹ M) on naturally occurring mineral pyrite (particle size: ≤70 μm) has been studied under varying conditions of pH (2–11), and ionic strength (0.01–1.0 M (NaClO₄)). The effects of humic acid (2 mg/L), other complexing anions (1 × 10⁻⁴ M CO₃ ²⁻, SO₄ ²⁻, C₂O₄ ²⁻ and PO₄ ³⁻), di- and trivalent metal ions (1 × 10⁻³ M Mg²⁺, Ca²⁺ and Nd³⁺) on sorption behavior of Am³⁺ at...

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Complexation of Eu(III), Am(III) and Cm(III) with Dicarboxylates: Thermodynamics and Structural Aspects of the Binary and Ternary Complexes

P. Thakur, P. N. Pathak, T. Gedris, G. R. Choppin

Journal of Solution Chemistry > 2009 > 38 > 3 > 265-287

The complexation of Eu(III), Am(III) and Cm(III) with dicarboxylate anions with O, N or S donor groups was measured in I=6.60 mol⋅kg⁻¹ (NaClO₄) at temperatures of 0–60 °C by potentiometry and solvent extraction. The complexation thermodynamics of these complexes show that their stability is due to highly favorable complexation entropies because the complexation enthalpies are endothermic. Luminescence...

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Sorption of Am³⁺ cations on suspended silicate: Effects of pH, ionic strength, complexing anions, humic acid and metal ions

P. N. Pathak, G. R. Choppin

Journal of Radioanalytical and Nuclear Chemistry > 2007 > 274 > 3 > 517-523

Sorption of tracer Am³⁺ to silicate particles was studied as a function of pcH (4 to 9) and of ionic strength [0.20M to 1.50M (NaClO₄)] at 298 K. The sorption increased with increased pcH from 4 to 6 above which saturation was observed. The insensitivity of Am³⁺ sorption to increased ionic strength indicates inner-sphere complexation with the surface silicate sites. The effects of different complexing...

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Search results for: P. N. Pathak

A novel solvent system containing a dipicolinamide in room temperature ionic liquids for actinide ion extraction

Online recovery of radiocesium from soil, cellulose and plant samples by supercritical fluid extraction employing crown ethers and calix-crown derivatives as extractants

N,N-Dialkyl amides as extractants for spent fuel reprocessing: an overview

Biphasic kinetic investigations on the evaluation of non-salt forming reductants for Pu(IV) stripping from tributyl phosphate and N,N-dihexyl octanamide solutions in n-dodecane

Hydrodynamic properties for N,N,N′,N′‐tetraalkyl diglycolamides dissolved in n‐dodecane system

Redox Behavior of Neptunium(V) in Tributyl Phosphate and N,N-Dihexyl Octanamide Extractants Dissolved in n-Dodecane

Mathematical modeling of solvent extraction of uranium from sulphate media employing 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and its mixture with trioctylphosphine oxide (TOPO) as extractants

Extraction studies of uranium into a third-phase of thorium nitrate employing tributyl phosphate and N,N-dihexyl octanamide as extractants in different diluents

Studies on the radiolytic stability of N,N,N′,N′-tetra-2-ethylhexyl diglycolamide in n-dodecane solution containing different phase modifiers

Gross alpha-activity estimation in simulated high level waste after actinides partitioning by solid state nuclear track detection

Alpha radiolytic degradation of N,N-dihexyl octanamide

Sorption of Am(III) on natural sediment: experiment and modeling

²³³Pa(2n_th, f ) cross-section determination using a fission track technique

Reactions of N,N-dihexyloctanamide with nitrate and dodecane radicals: a pulse radiolysis study

Comparative extraction efficiencies of tri-n-butyl phosphate and N,N-dihexyloctanamide for uranium recovery using supercritical CO₂

Neptunium estimation in the spent fuel dissolver solution by inductively coupled plasma-atomic emission spectroscopy

Synergistic extraction of uranium with mixtures of PC88A and neutral oxodonors

Sorption behavior of Am³⁺ on suspended pyrite

Complexation of Eu(III), Am(III) and Cm(III) with Dicarboxylates: Thermodynamics and Structural Aspects of the Binary and Ternary Complexes

Sorption of Am³⁺ cations on suspended silicate: Effects of pH, ionic strength, complexing anions, humic acid and metal ions

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