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Y K Agrawal - One of the best experts on this subject based on the ideXlab platform.

  • solvent extraction speciation separation and recovery of uranium vi from nuclear fuel phosphate rocks and Monazite Sand with n phenylbenzo 18 crown 6 hydroxamic acid
    Journal of Radioanalytical and Nuclear Chemistry, 2006
    Co-Authors: Y K Agrawal, G Shah, S B Vora
    Abstract:

    A method for solvent extraction, separation and recovery of uranium was developed using a new reagent, N-phenylbenzo-18-crown-6-hydroxamic (PBCHA) in the presence of cerium, thorium and lanthanides. Uranium was extracted with a dichloromethane solution of PBCHA producing an orange coloured complex at lmax = 400 nm with a molar absorptivity of 5.0 . 104 l . mol-1 . cm-1 and which obeyed Beer's Law in the range of 0.48-5.76 ppm. For ICP-AES the extract was directly introduced into the plasma to enhance the sensitivity several folds with a detection limit of 0.5 ppb. The extraction constants of uranium crown hydroxamic acid complexes were also determined. The selectivity factors Kuranyl(b2K/K or b2K'e/K) for uranium crown hydroxamate were evaluated by comparing the Kuranyl with the stability constants of competing metal cations (K) and anions (K) and were found remarkably large. Uranium was recovered in 99.95% purity from Monazite Sand and phosphate rocks. It could be also preconcentrated and determined in environmental samples.

  • solvent extraction separation and recovery of lanthanum iii and cerium iv from Monazite Sand by n phenylbenzo 18 crown 6 hydroxamic acid
    Indian journal of chemistry. Sect. A: Inorganic physical theoretical & analytical, 2005
    Co-Authors: Y K Agrawal, S B Vora, G Shah
    Abstract:

    A new N-phenylbenzo-18-crown-6-hydroxamic acid is reported for the separation of lanthanum(lll) and cerium(IV) from Monazite. Lanthanum(lll) and cerium(IV) ha ve been ex tracted and separated in presence of th ori um, uranium and other associated cations at pH 8.8 and 9.5, respectively, in dichloromethane. Lanthanum(III) gives a colourless complex with the reagent which is extracted into dichloromethane and has molar absorptivity of 9.0 x I 0 3 L mo1" 1 cnf 1 at 385 nm. Cerium(IV) forms a red colour complex with th e reagent extracted in dichloromethane with Amax 450 nm and molar absorp­ ti vity 6.5 x 10 3 L mol" 1 em·'. For tr ace determination, the ex tracts are in se rt ed directly into th e plasma for ICP-AES meas­ urement s of La(lll) and Ce(!V) in the range of 4-80 ng mL·' and 8- 120 ng mL· ' , res pecti ve ly with the detection limit of 0.5 ng mL·'. The complexes of lanthanum(lll ) and cerium(IV) are very stable, (log f:hk 20.20 and 20.50, respecti ve ly) as com­ pared to those of th ori um ( 1.60) , uranium ( 1. 80), and ot her re la ted cations. The proposed method of preconcentration and analysis of La(lll) and Ce(IV) is not adversely affected by hi ghl y ionic med ia , rendering the method suitable for their trac e determination in sea water. IPC Code: Int. Cl. 7 GOlN; C07C 59/00; C22B 59/00 The analysis of cerium(IV), lanthanum(III) elements is important in several industries, e.g., nuclear power production and waste water analysis. Cerium occurs as a major element in the Monazite Sand and is associated with lanthanides, thorium and traces of uranium. It is used as a catalyst in automobile and nuclear chemistry. Monazite Sand is mainly associated with Ce, La, Th, Y, Fe etc. Usually, it is treated with alkali followed by acid digestion and then extracted with tetrabutylphos­ phate for separation of lanthanides. The process is time consuming and also requires further purification. A large number of reagents have been described for the separation of cerium(IV) and lanthanum(III), However, several closely related ions interfere in the separation and determination of cerium and lantha­ num1 ·5. Macrocyclic compounds have also been re­ ported for the complexation of lanthanides . However, . . h b d "b dG-IO

  • polymer supported calix 4 arene semicarbazone derivative for separation and preconcentration of la iii ce iii th iv and u vi
    Reactive & Functional Polymers, 2002
    Co-Authors: Vinod K Jain, Avtar K Handa, Pranav S Shrivastav, Rujul A Pandya, Y K Agrawal
    Abstract:

    Abstract The new “upper-rim” functionalized 11,23-disemicarbazono-26,28- n -dipropoxy-25,27-dihydroxy calix[4]arene has been synthesized by condensing 11,23-diformyl-26,28- n -dipropoxy-25,27-dihydroxy calix[4]arene with semicarbazide hydrochloride. This calix[4]arene-semicarbazone derivative was then covalently linked with commercially available Merrifield’s peptide resin at the “lower-rim” to obtain polymeric chelating resin and its analytical properties were investigated. The resin was then used successfully for the separation and preconcentration of lanthanum(III), cerium(III), thorium(IV) and uranium(VI) prior to their determination by spectrophotometry and inductively coupled plasma atomic emission spectroscopy. The resin exhibits good separating ability with maximum sorption between pH 2.5–4.5 for Th(IV) and between pH 5.5–7.0 for U(VI) whereas La(III) and Ce(III) were found to have maximum sorption between pH 6.5–8.5. The elution studies were carried out with 0.01 M HCl for La(III) and Ce(III), 2.0 M HCl for Th(IV) and 0.25 M HCl for U(VI). The preconcentration factors for La(III), Ce(III), Th(IV) and U(VI) were 125, 130, 102 and 108, respectively. The resin shows good stability along with faster rate of equilibrium for all the metal ions. The influence of several ions (cations and anions) on the resin performance is also discussed. The relative standard deviation was between 96 and 98% with good analytical reliability. The proposed method was applied for the determination of metal ions in Monazite Sand and some standard geological materials.

  • Polymer supported calix[4]arene-semicarbazone derivative for separation and preconcentration of La(III), Ce(III), Th(IV) and U(VI)
    'Elsevier BV', 2002
    Co-Authors: Vk Jain, Handa A, Pandya R, Shrivastav P, Y K Agrawal
    Abstract:

    The new "upper-rim" functionalized 11,23-disemicarbazono-26,28-n-dipropoxy-25,27-dihydroxy calix[4]arene has been synthesized by condensing 11,23-diformyl-26,28-n-dipropoxy-25,27-dihydroxy calix[4]arene with semicarbazide hydrochloride. This calix[4]arene-semicarbazone derivative was then covalently linked with commercially available Merrifield's peptide resin at the "lower-rim" to obtain polymeric chelating resin and its analytical properties were investigated. The resin was then used successfully for the separation and preconcentration of lanthanum(III), cerium(III), thorium(IV) and uranium(VI) prior to their determination by spectrophotometry and inductively coupled plasma atomic emission spectroscopy. The resin exhibits good separating ability with maximum sorption between pH 2.5-4.5 for Th(IV) and between pH 5.5-7.0 for U(VI) whereas La(III) and Ce(III) were found to have maximum sorption between pH 6.5-8.5. The elution studies were carried out with 0.01 M HCl for La(III) and Ce(III), 2.0 M HCl for Th(IV) and 0.25 M HCl for U(VI). The preconcentration factors for La(III), Ce(III), Th(IV) and U(VI) were 125, 130, 102 and 108, respectively. The resin shows good stability along with faster rate of equilibrium for all the metal ions. The influence of several ions (cations and anions) on the resin performance is also discussed. The relative standard deviation was between 96 and 98% with good analytical reliability. The proposed method was applied for the determination of metal ions in Monazite Sand and some standard geological materials. © 2002 Elsevier Science B.V. All rights reserved

  • pre concentration separation and trace determination of lanthanum iii cerium iii thorium iv and uranium vi on polymer supported o vanillinsemicarbazone
    Analytica Chimica Acta, 2001
    Co-Authors: Vinod K Jain, Avtar K Handa, S S Sait, Pranav S Shrivastav, Y K Agrawal
    Abstract:

    Abstract A nonionic polymeric adsorbent styrene divinylbenzene, Amberlite XAD-4 was functionalized with o-vanillinsemicarbazone and its analytical properties have been studied. The synthesized resin was utilized for selective column separation, pre-concentration and trace determination of lanthanum(III) (La(III)), cerium(III) (Ce(III)), thorium(IV) (Th(III)) and uranium(VI) (U(VI)). The resin exhibits good chemical stability, reusability and faster rate of equilibrium for their determination by spectrophotometry and their simultaneous confirmation of the results by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and graphite furnace-atomic absorption spectrometry (GF-AAS). Both, the uptake and stripping of these metal ions were fairly rapid, indicating a better accessibility of the chelating sites. The proposed method has been applied to sequential chromatographic separation of their binary and ternary mixtures. Uranium(VI) has been determined from simulated river water sample with good analytical reliability. The detection limit of these metal ions on the resin is 100 ng cm−3 with recovery upto 96–98%. The method is also applied for their determination in Monazite Sand and some standard geological materials.

Vinod K Jain - One of the best experts on this subject based on the ideXlab platform.

  • polymer supported calix 4 arene semicarbazone derivative for separation and preconcentration of la iii ce iii th iv and u vi
    Reactive & Functional Polymers, 2002
    Co-Authors: Vinod K Jain, Avtar K Handa, Pranav S Shrivastav, Rujul A Pandya, Y K Agrawal
    Abstract:

    Abstract The new “upper-rim” functionalized 11,23-disemicarbazono-26,28- n -dipropoxy-25,27-dihydroxy calix[4]arene has been synthesized by condensing 11,23-diformyl-26,28- n -dipropoxy-25,27-dihydroxy calix[4]arene with semicarbazide hydrochloride. This calix[4]arene-semicarbazone derivative was then covalently linked with commercially available Merrifield’s peptide resin at the “lower-rim” to obtain polymeric chelating resin and its analytical properties were investigated. The resin was then used successfully for the separation and preconcentration of lanthanum(III), cerium(III), thorium(IV) and uranium(VI) prior to their determination by spectrophotometry and inductively coupled plasma atomic emission spectroscopy. The resin exhibits good separating ability with maximum sorption between pH 2.5–4.5 for Th(IV) and between pH 5.5–7.0 for U(VI) whereas La(III) and Ce(III) were found to have maximum sorption between pH 6.5–8.5. The elution studies were carried out with 0.01 M HCl for La(III) and Ce(III), 2.0 M HCl for Th(IV) and 0.25 M HCl for U(VI). The preconcentration factors for La(III), Ce(III), Th(IV) and U(VI) were 125, 130, 102 and 108, respectively. The resin shows good stability along with faster rate of equilibrium for all the metal ions. The influence of several ions (cations and anions) on the resin performance is also discussed. The relative standard deviation was between 96 and 98% with good analytical reliability. The proposed method was applied for the determination of metal ions in Monazite Sand and some standard geological materials.

  • pre concentration separation and trace determination of lanthanum iii cerium iii thorium iv and uranium vi on polymer supported o vanillinsemicarbazone
    Analytica Chimica Acta, 2001
    Co-Authors: Vinod K Jain, Avtar K Handa, S S Sait, Pranav S Shrivastav, Y K Agrawal
    Abstract:

    Abstract A nonionic polymeric adsorbent styrene divinylbenzene, Amberlite XAD-4 was functionalized with o-vanillinsemicarbazone and its analytical properties have been studied. The synthesized resin was utilized for selective column separation, pre-concentration and trace determination of lanthanum(III) (La(III)), cerium(III) (Ce(III)), thorium(IV) (Th(III)) and uranium(VI) (U(VI)). The resin exhibits good chemical stability, reusability and faster rate of equilibrium for their determination by spectrophotometry and their simultaneous confirmation of the results by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and graphite furnace-atomic absorption spectrometry (GF-AAS). Both, the uptake and stripping of these metal ions were fairly rapid, indicating a better accessibility of the chelating sites. The proposed method has been applied to sequential chromatographic separation of their binary and ternary mixtures. Uranium(VI) has been determined from simulated river water sample with good analytical reliability. The detection limit of these metal ions on the resin is 100 ng cm−3 with recovery upto 96–98%. The method is also applied for their determination in Monazite Sand and some standard geological materials.

Avtar K Handa - One of the best experts on this subject based on the ideXlab platform.

  • polymer supported calix 4 arene semicarbazone derivative for separation and preconcentration of la iii ce iii th iv and u vi
    Reactive & Functional Polymers, 2002
    Co-Authors: Vinod K Jain, Avtar K Handa, Pranav S Shrivastav, Rujul A Pandya, Y K Agrawal
    Abstract:

    Abstract The new “upper-rim” functionalized 11,23-disemicarbazono-26,28- n -dipropoxy-25,27-dihydroxy calix[4]arene has been synthesized by condensing 11,23-diformyl-26,28- n -dipropoxy-25,27-dihydroxy calix[4]arene with semicarbazide hydrochloride. This calix[4]arene-semicarbazone derivative was then covalently linked with commercially available Merrifield’s peptide resin at the “lower-rim” to obtain polymeric chelating resin and its analytical properties were investigated. The resin was then used successfully for the separation and preconcentration of lanthanum(III), cerium(III), thorium(IV) and uranium(VI) prior to their determination by spectrophotometry and inductively coupled plasma atomic emission spectroscopy. The resin exhibits good separating ability with maximum sorption between pH 2.5–4.5 for Th(IV) and between pH 5.5–7.0 for U(VI) whereas La(III) and Ce(III) were found to have maximum sorption between pH 6.5–8.5. The elution studies were carried out with 0.01 M HCl for La(III) and Ce(III), 2.0 M HCl for Th(IV) and 0.25 M HCl for U(VI). The preconcentration factors for La(III), Ce(III), Th(IV) and U(VI) were 125, 130, 102 and 108, respectively. The resin shows good stability along with faster rate of equilibrium for all the metal ions. The influence of several ions (cations and anions) on the resin performance is also discussed. The relative standard deviation was between 96 and 98% with good analytical reliability. The proposed method was applied for the determination of metal ions in Monazite Sand and some standard geological materials.

  • pre concentration separation and trace determination of lanthanum iii cerium iii thorium iv and uranium vi on polymer supported o vanillinsemicarbazone
    Analytica Chimica Acta, 2001
    Co-Authors: Vinod K Jain, Avtar K Handa, S S Sait, Pranav S Shrivastav, Y K Agrawal
    Abstract:

    Abstract A nonionic polymeric adsorbent styrene divinylbenzene, Amberlite XAD-4 was functionalized with o-vanillinsemicarbazone and its analytical properties have been studied. The synthesized resin was utilized for selective column separation, pre-concentration and trace determination of lanthanum(III) (La(III)), cerium(III) (Ce(III)), thorium(IV) (Th(III)) and uranium(VI) (U(VI)). The resin exhibits good chemical stability, reusability and faster rate of equilibrium for their determination by spectrophotometry and their simultaneous confirmation of the results by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and graphite furnace-atomic absorption spectrometry (GF-AAS). Both, the uptake and stripping of these metal ions were fairly rapid, indicating a better accessibility of the chelating sites. The proposed method has been applied to sequential chromatographic separation of their binary and ternary mixtures. Uranium(VI) has been determined from simulated river water sample with good analytical reliability. The detection limit of these metal ions on the resin is 100 ng cm−3 with recovery upto 96–98%. The method is also applied for their determination in Monazite Sand and some standard geological materials.

Pranav S Shrivastav - One of the best experts on this subject based on the ideXlab platform.

  • polymer supported calix 4 arene semicarbazone derivative for separation and preconcentration of la iii ce iii th iv and u vi
    Reactive & Functional Polymers, 2002
    Co-Authors: Vinod K Jain, Avtar K Handa, Pranav S Shrivastav, Rujul A Pandya, Y K Agrawal
    Abstract:

    Abstract The new “upper-rim” functionalized 11,23-disemicarbazono-26,28- n -dipropoxy-25,27-dihydroxy calix[4]arene has been synthesized by condensing 11,23-diformyl-26,28- n -dipropoxy-25,27-dihydroxy calix[4]arene with semicarbazide hydrochloride. This calix[4]arene-semicarbazone derivative was then covalently linked with commercially available Merrifield’s peptide resin at the “lower-rim” to obtain polymeric chelating resin and its analytical properties were investigated. The resin was then used successfully for the separation and preconcentration of lanthanum(III), cerium(III), thorium(IV) and uranium(VI) prior to their determination by spectrophotometry and inductively coupled plasma atomic emission spectroscopy. The resin exhibits good separating ability with maximum sorption between pH 2.5–4.5 for Th(IV) and between pH 5.5–7.0 for U(VI) whereas La(III) and Ce(III) were found to have maximum sorption between pH 6.5–8.5. The elution studies were carried out with 0.01 M HCl for La(III) and Ce(III), 2.0 M HCl for Th(IV) and 0.25 M HCl for U(VI). The preconcentration factors for La(III), Ce(III), Th(IV) and U(VI) were 125, 130, 102 and 108, respectively. The resin shows good stability along with faster rate of equilibrium for all the metal ions. The influence of several ions (cations and anions) on the resin performance is also discussed. The relative standard deviation was between 96 and 98% with good analytical reliability. The proposed method was applied for the determination of metal ions in Monazite Sand and some standard geological materials.

  • pre concentration separation and trace determination of lanthanum iii cerium iii thorium iv and uranium vi on polymer supported o vanillinsemicarbazone
    Analytica Chimica Acta, 2001
    Co-Authors: Vinod K Jain, Avtar K Handa, S S Sait, Pranav S Shrivastav, Y K Agrawal
    Abstract:

    Abstract A nonionic polymeric adsorbent styrene divinylbenzene, Amberlite XAD-4 was functionalized with o-vanillinsemicarbazone and its analytical properties have been studied. The synthesized resin was utilized for selective column separation, pre-concentration and trace determination of lanthanum(III) (La(III)), cerium(III) (Ce(III)), thorium(IV) (Th(III)) and uranium(VI) (U(VI)). The resin exhibits good chemical stability, reusability and faster rate of equilibrium for their determination by spectrophotometry and their simultaneous confirmation of the results by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and graphite furnace-atomic absorption spectrometry (GF-AAS). Both, the uptake and stripping of these metal ions were fairly rapid, indicating a better accessibility of the chelating sites. The proposed method has been applied to sequential chromatographic separation of their binary and ternary mixtures. Uranium(VI) has been determined from simulated river water sample with good analytical reliability. The detection limit of these metal ions on the resin is 100 ng cm−3 with recovery upto 96–98%. The method is also applied for their determination in Monazite Sand and some standard geological materials.

M Vasundhara - One of the best experts on this subject based on the ideXlab platform.

  • mixed rare earth oxides derived from Monazite Sand as an inexpensive precursor material for room temperature magnetic refrigeration applications
    Materials Research Bulletin, 2017
    Co-Authors: B Arun, V R Akshay, Geeta Rani Mutta, Ch Venkatesh, M Vasundhara
    Abstract:

    Abstract An inexpensive perovskite type (REMIX)0.67Sr0.33MnO3 compound is synthesized via solid state method using mixed rare earth oxide precursor derived from Monazite Sand. Rietveld refinement of X-ray powder diffraction patterns confirms the compound is a mixture of rare earth manganites which is the major phase and CeO2 as the secondary phase. The compound shows a second order ferromagnetic to paramagnetic transition near room temperature and exhibits a magnetic entropy change (-ΔSM) of 3.28 J kg−1 K−1 with a relative cooling power (RCP) of 120 J kg−1 and an adiabatic temperature change (ΔTad) of 2.11 K at 310 K under 50 kOe magnetic field. The Debye temperature of the compound is found to be 543 K and room temperature thermal conductivity is 4.26 W m−1 K−1. The temperature variation of electrical resistivity shows a metal to insulator transition around 180 K, which gets shifted towards higher temperature upon the application of magnetic field. The compound shows a large value of −ΔSM and this work makes an endeavor to develop low–cost materials for the magnetic refrigeration applications near the room temperature.