Authors:K. Roy, S. Basu, D. Pal, S. Lahiri, and A. Ramaswami
95Tc has been produced through -particle activation of a natural niobium target. The carrier-free 95Tc radionuclide has been separated from the bulk target using tri-n-octylamine (TOA) diluted by cyclohexane as extracting agent and HCl, HNO3 as aqueous phase. Solid-liquid extraction has also been carried out with TOA impregnated Kieselguhr mineral acid system. Technetium-95 was recovered from the organic phase by stripping with 0.1M EDTA above pH 9.
Authors:D. Chowdhury, S. Saha, Sujit Pal, and P.K. Mathur
The rare earth elements (REE), Pr, Sm, Eu, Gd, Ho, Er and Tm have been determined by charged particle activation analysis using 40 MeV a-particles through radiochemical approach. The radiochemical separation of REE as a group has been carried out from the bulk matrix. It has been shown from the theoretical computation that the products obtained from (a,xn) reactions (x = 1, 2, 3) are more suitable compared to those from (a,pyn) reactions (y = 0, 1, 2) due to the former having higher cross section (of the order of thousand millibarns).
Authors:D. Chowdhury, J. Arunachalam, Rakesh Verma, Sujit Pal, and S. Gangadharan
40 MeV -particles have been used to determine oxygen impurity at ppm levels in silicon, copper, and stainless steel, through the radiochemical separation of18F from the matrix. The separation of18F has been carried out by two techniques, viz.(1) distillation of H2SiF6 and (2) precipitation of KBF4 and some modification has been applied in the separation, depending on the nature of interferences from the matrix. Instrumental approach was also carried out to determine the oxygen impurity at 100 ppm in Si matrix because this approach is not possible in Cu and stainless steel samples due to matrix activity.
Authors:Sachin Pathak, I. Pius, S. Mukerjee, Sangeeta Pal, and P. Tewari
Polyacrylhydroxamic acid resin synthesized by functionalization of polyacrylamide with hydroxylamine has been investigated
for the sorption of plutonium(IV) from carbonate medium, aiming at its application for the removal of plutonium from alkali
wash effluent generated during purification of TBP in PUREX process. Batch experiments have been carried out to determine
distribution coefficient of plutonium(IV) between this exchanger and various compositions of carbonate medium. Effect of the
concentration of sodium carbonate, sodium bicarbonate and pH of the solution on the distribution coefficient have been studied
to optimize the conditions for the uptake of Pu(IV) by this exchanger. Column experiments were carried out to determine the
practical capacity of the exchanger for plutonium. Elution studies were also carried out to recover the loaded plutonium from
the ion exchange column The exchanger displayed good exchange capacity for Pu(IV) from feed solution simulating the conditions
of carbonate wash effluent generated in PUREX process. The exchanger also exhibited fast elution of Pu, suggesting the feasibility
of using it for the recovery of Pu from carbonate based wash effluent.
Authors:N. Chakraborty, R. Pal, A. Ramaswami, D. Nayak, and S. Lahiri
The bioaccumulation of gold in trace concentration by Nitzschia obtusa and Navicula minima, two members of bacillariophyceae, has been studied. It has been observed that Nitzschia obtusa showed better accumulation of gold in acidic pH in comparison to neutral and basic pH. Maximum accumulation was observed
with 1 mg . kg-1 or less gold concentration. However, the accumulation by the living cells was reduced when the matrix concentration was higher. Navicula minima, on the other hand, found to be a better accumulator of gold in wide ranges of pH and substrate concentration of the media.
It was also inferred that the gold accumulation by diatom was mainly due to adsorption by biosilica (siliceous frustules of
dead diatom cells). Accumulated gold was recovered with conc. HNO3.
Authors:D. Nayak, S. Lahiri, A. Mukhopadhyay, and R. Pal
The bio-sorption of heavy and toxic radionuclides by three genera of algae from different taxonomic groups was studied employing the recently developed 'Tracer Packet' technique. The tracer packet of heavy and toxic metals' contained 197Hg, 198,199,200,201Tl, 199,200,201Pb, 204Bi and 204,205Po radionuclides in carrier-free state and was produced by irradiating a gold metal foil with medium energy 7Li and 12C beams successively in a 12 MV Pelletron. Three genera, Spirulina from Cyanophyceae, Oedogonium from Chlorophyceae and Catenella from Rhodophyceae were cultured in laboratory condition and were used in the experiment. The radionuclide accumulation varied according to different genera at different pH levels. At basic pH Spirulina showed a maximum radionuclide accumulation in comparison to other genera.
Authors:D. Nayak, M. Nag, S. Banerjee, R. Pal, S. Laskar, and S. Lahiri
bioaccumulation of 198Au radionuclide, by Rhizocloniumriparium
a member of Chlorophyceae has been studied. It has been observed that
accumulation of gold on Rhizoclonium is almost pH independent and
slightly higher at basic pH. Accumulation of gold was studied with 198Au
radiotracer, 0.1, 1 and 5 ppm concentrations of gold. It has been concluded
from the biochemical analysis that the gold accumulation is due to adsorption
in the cellulose and not in protein, fat and carbohydrate. Accumulated gold was
recovered when washed with conc. HNO3.
Authors:V. Nazarov, V. Chinaeva, M. Frontasyeva, S. Parry, B. Bennet, Chen Pal, and Li Zu
The present paper based on experimental results contains discussions and suggestions on the possible use of fine-powder Al2O3 and SiO2 with their original content of microimpurities of up to 40 elements, as multielement standards for neutron activation analysis. For example, activation analysis of As, Au, Ba, Cr, Cs, Fe, Ga, K, Ni, Sb, Sc, Se, Sr, Ta, Th, Ti, U, W, Zn, Zr and the REE La, Ce, Nd, Sm, Eu, Tb, Tm, Yb contained in SiO2 powder off MERCK reagents showed their concentrations to be 0.1 to 5% of those in IAEA standard SL-1. In Al2O3 this level is even lower, approximately 10 times and more for the majority of the above-mentioned elements. As Al2O3 and SiO2 are good sorbents for the majority of elements, additional introduction of some elements may allow more methods of analysis. The homogeneity of Al2O3 and SiO2 samples both in the original state and after introduction of some elements was determined by neutron activation analysis, and the SD did not exceed 1% for an Al2O3 sample weight of 0.1 g, and 2% for SiO2.
Authors:Sangita Pal, Suchismita Mishra, S. Satpati, G. Pandit, P. Tewari, and V. Puranik
“In-House” resin Polyacrylhydroxamic acid (PHOA) has been synthesized and utilized targeting ground water remediation; recovery
of uranium from low concentration aqueous solution e.g., mining activities related water, flooding of excavated or deplumed
areas, nuclear plant washed effluent and process generated effluents in nuclear plant during front-end as well as back-end
treatment. In the present study, treatment of field effluent containing heavy metals and radio-nuclides from contaminated
mining sites reflected preference for uranium with respect to manganese. The specific complexation between the extractant
and metal ion especially uranium provides high distribution co-efficient (Kd) for uranium (Kd,U = 1,450 mL/g from inlet of Effluent Treatment Plant (ETP) and Kd,U = 74,950 mL/g for synthetic solution) compared to high level impurity (1,000 times higher concentration) of manganese (Kd,Mn = 111 mL/g from inlet of ETP and Kd,Mn = 10,588 mL/g for synthetic solution). The “In-House” resin showed significant extractability (70–95% elution efficiency)
and indicates a possibility of selective removal/recovery of the valuable metal ions even from secondary sources. As a specialty,
resin can be regenerated and reused.
Authors:Gurdip Singh, A. K. Shrimal, Inder Pal Singh Kapoor, Chandra Prakash Singh, Dinesh Kumar, and Manan S. Mudi
Three transition metal perchlorate complexes of general formula [M(dah)2)](ClO4)2 (where M = Zn, Cu, and Ni; dah = 1,6-diaminohexane) have been prepared, and characterized by elemental analysis, infrared spectroscopy (IR), and gravimetric method. The thermal decomposition has been studied by thermogravimetry (TG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). Kinetics parameters of their thermolysis were evaluated by model-fitting and isoconversional methods using isothermal TG data. Model-fitting method has given the single value of activation energy (E) whereas; isoconversional method yields a series of E values which vary with the extent of conversion. Further ignition delay of these complexes was measured to see the response toward rapid heating with varying amounts. The thermal stability of the complexes decreases in the order as: [Zn(dah)2)](ClO4)2 > [Cu(dah)2)](ClO4)2 > [Ni(dah)2)](ClO4)2