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  • Author or Editor: D. Bhattacharyya x
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Abstract  

A study of fixation of molybdenum on crystalline zirconia was carried out. Molybdenum ions was co-precipitated with zirconium hydroxide at pH-9 and a maximum of ≈39 wt% of molybdenum was found to be incorporated. The mixed material was calcined separately at 800 and 1000°C in a pelletized form and the leachabilities for molybdenum were determined by Soxhlet refluxing at 97°C for 7 days at regular interval, which were found to be negligibile, in the order of 10−3 g m−2 d−1. The analysis of the composite materials by X-ray powder diffraction patterns revealed that molybdenum was fixed in the crystalline lattice of baddeleyite type of mineral of zirconia forming new phases of monoclinic and hexagonal forms of Zr(MoO4)2 which co-existed with a small amount of MoO3 besides baddeleyite.

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Abstract  

The study of the Nicotiana rustica variety from North Bengal, revealed that the respective amounts of radioactive nuclei40K,90Sr,90Y and rare earth activity as well as210Pb were found to be 4.04, 2.42, 4.52, and 0.052 pCi/g of cured leaves. In another investigation with Nicotiana tabaccum variety from Rajahmundri, Andhra Pradesh, contents of40K,90Sr,90Y and rare earth activity, and210Pb were observed to be 4.06, 1.02, 3.44 and 0.20 pCi/g of cured leaves, respectively. Results indicate that the amount of polonium which is presumably in equilibrium with RaD in these two varieties of Indian tobacco leaves is very small. Detailed studies on different varieties of Indian tobacco are in progress.

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Abstract  

Titanium phosphate as ion exchanger for column operation has been prepared by mixing TiCl4 and H3PO4 in suitable proportion. The ratio of titanium: phosphate was obtained to be 1:2.02. The uptake of Na+, K+, Rb+, Cs+, Ag+, Ca2+, Sr2+, Ba2+, Pb2+, Sc3+, Co3+, Y3+, Tb3+, Zr4+ and Th4+ cations at very small concentrations has been studied on this exchanger. The data indicated that the different cations are adsorbed in the exchanger by different mechanisms. Radiochemical separations of carrier free95Nb from95Zr, UX1 from U and45Ca from46Sc have been achieved by adopting very simple chemical procedures through a column of titanium phosphate. The -spectrum of the separated95Nb, UX1 and46Sc showed that the products are of high radionuclidic purity. The individual separation procedures took less than 20 min and the yields are quantitative.

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Abstract  

Radiochemical separations of carrier-free210Bi and UX1 activities from210Pb and U, respectively, have been carried out using a silica gel column.210Pb was adsorbed in the column as molybdate and210Bi passed unadsorbed. Lead activity was next removed with 25 ml of 0.1 M HNO3. In the case of separation of UX1, the coloured carbonate complex of U was removed from the silica surface by washing with saturated sodium carbonate solution, keeping UX1 retained, and finally UX1 was washed out with 25 ml of conc. HNO3. Studies of the beta decay of210Bi and the γ-spectrum analysis of UX1 has shown that the separated products in both cases are of high radiochemical purity. The processes in each case took less than one hour and the yield was satisfactory.

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Abstract  

Separations of tracer cations in parent daughter systems such as carrier-free210Bi from210Pb,90Y from90Sr and UX1 from U have been carried out in a column of ceric phosphate as ion exchanger. The exchanger has been prepared by mixing ceric sulfate in hot 10M orthophosphoric acid at 80°C and keeping for overnight. A pale yellow coloured precipitate was formed which was washed, dried at 70°C for 48 hours when a hard, granular variety suitable for column use, with a cerium to phosphate ratio of 1∶2 was obtained. 0.1M H3PO4 was used as medium in each of the systems studied. The β-decay curves of the separated210Bi and90Y and the γ-spectrum of UX1 show that all these activities are radiochemically pure. The separation procedures adopted in each case were very clean and simple, gave quantitative yields and took less than half an hour.

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Abstract  

Zirconium phosphate as ion exchanger suitable for column operation has been prepared by mixing hot metaphosphoric acid solution with a solution of zirconium oxychloride when the white insoluble phosphate separated out which was dried and purified. The ratio of zirconium: phosphate was found to be 1:2. Separation of parent-daughter systems like115Cd-115mIn,144Ce-144Pr and210Pb-210Bi were carried out with this exchanger. γ-ray spectrum of the separated115mIn and the β-decay curve of144Pr and210Bi showed that all the daughter activities are radiochemically pure. The separation process in each case takes less than half an hour and the yield is quantitative.

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Abstract  

A new way of radiochemical separation of carrier-free115mIn from115Cd and132I from132Te over the column of zirconium oxide is described. Activities of Cd and In in equilibrium in dilute acetic acid solution were bufferred with dilute sodium acetate and fed into the column at a pH 7, when cadmium activity passed out unadsorbed and the115mIn was adsorbed in the column. A study of the γ-ray peak of the separated115mIn showed that the product is of high radionuclidic purity. Te-I pair was separated by passing the weakly acidic solution of132Te and132I in the presence of AgNO3 and Na2SO3, through the column where both activities were adsorbed. Iodine was washed outh with 5% sodium thiosulphate solution and the retained tellurium activity was later washed out with 6M HNO3. The β-decay study showed that the separated132I product is of high radiochemical purity. The processes took less than half an hour and the yields were quantitative.

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Abstract  

A co-precipitation method was adopted for the immobilization of yttrium radioactive waste over crystalline titania. A high uptake of91Y was observed over the preformed hydrous titania. Weighable quantity of Y was coprecipitated with Ti(IV) hydroxide and a maximum of 38 wt% was found to be adsorbed. Mixed masses were calcined separately at 800 and 1000°C for 20 hours, and soxhlet leach tests at 97°C, repeated 7 times at an interval of 24 hours, showed the release of yttrium in the order of 10–1 and 10–2 g·m–2·d–1, respectively. X-ray powder diffraction analysis revealed that the yttrium was immobilized in the titania crystal lattice which suffered some structural changes with the formation of new mineral phase Y2Ti2O7 which is accompanied by rutile and little quantity of anatase form of titania at 800°C, and only rutile form of titania at 1000°C.

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Abstract  

The uptake of a few polyvalent ions Ca2+ Cu2+, Zn2+, Cd2+, UO2+, Cr3+, Y3+, Ce3+, Nd3+, Sm3+, Tb3+, Tm3+, Yb3+, Lu3+, Zr4+, Hf4+, Sn4+, Nb5+, Se6+, Mo6+ and W6+ at very small concentrations has been studied over ceric tungstate exchanger. A good column variety of the material was prepared by mixing ceric sulphate in 2N H2SO4 and aqueous solution of sodium tungstate in suitable proportion. The ratio of cerium: tungstate was obtained to be 11. Separation of carrier-free95Nb from95Zr and113mIn from113Sn have been carried out by applying a very simple chemical procedure over the column of ceric tungstate. The -spectrum of separated95Nb and113mIn products were found to be of high radionuclidic purity. The separation procedure took less than 15 min and the yields were close to 100%.

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Abstract  

The uptake of Na+, K+, Rb+, Cs+, Ag+, Ca2+, Cu2+, Sr2+, Cd2+, Ba2+, Pb2+, Sc3+, Co3+, Y3+, Sb3+, Tb3+, Zr4+ and Th4+ cations at very small concentrations has been studied over a column of stannic phosphate. The exchanger was prepared by mixing H3PO4, NaCl and SnCl4 in suitable proportions and the ratio of PSn, in the product was obtained to be 1.96. Radiochemical separations of carrier free95Zr from234Th and115mIn, from115Cd have been carried out by adopting a simple chemical procedure over a column of stannic phosphate. The -spectrum analysis showed that the separated products are of high radionuclidic purity. The separation procedures took less than half an hour with quantitative yield.

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