A method has been described for the isolation of radiochemically pure140La from140Ba. The tracer140Ba−140La is mixed with 6M LiNO3 solution to make an anionic complex. The solution is then fed into a column (1 cm×0.4 cm) of Kieselguhr impregnated with
Aliquat-336.140La is adsorbed in the column while140Ba is eluted with 6M LiNO3. After complete removal of140Ba,140La is eluted with 0.002M HNO3 solution. The purity of140La is established by both its half-life and γ-spectrum.
A simple solvent extraction procedure for an effective separation of traces of tantalum from rock phosphate samples has been
developed and used in its determination through neutron activation analysis. The tantalum contents in the samples were found
to be about 3.10−7%.
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.
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.
Studies on the distribution of various oxidation states of recoil sulphur formed by35Cl(n, p)35S reaction in the alkali halides, namely, NaCl, KCl and RbCl have been made. A suitable anion exchange method using Amberlite
IRA-410 in the chloride form has been described for rapid separation of the various radiosulphur species. The elution was
carried out by means of nitrate solutions. The observed results on the effect of cation environment in affecting the distribution
of radioactive sulphur amongst its various oxidation states were discussed on the basis of electron affinity and ionic size
of the metal ion in question.
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.
A solvent extraction procedure for the separation of niobium and tantalum has been developed. The method consists of extracting tantalum from its aqueous mixture with niobium, with the help of di(2-ethylhexyl)phosphoric acid (HDEHP) in n-heptane. The aqueous feed consists of niobium and tantalum in an aqueous medium containing hydrochloric and oxalic acids. The concentrations of niobium and tantalum were raised to 1 mg/ml in the aqueous solution. The extraction efficiency of tantalum under these conditions was found to be 85%. Effects of chloride and oxalate ions as well as those of the concentration of HDEHP on the extraction efficiency were studied and discussed in detail.
A new stable chelating resin was synthesized by incorporating 2-aminothiophenol into Merrifield polymer through C-N covalent
bond and characterized by elemental analysis, IR and thermal study. The sorption capacity of the newly formed resin for Hg2+ as a function of pH has been studied using 203Hg radioisotope. The resin exhibits no affinity to alkali or alkaline earth metal ions and common anions. The separation of
mercury(II) in presence of different alkali and alkaline earth metal ions (Na+, K+, Mg2+, Ca2+, Sr2+, Ba2+), common anions (ClO4−, SO42−) and other diverse ions (Ag+, Cu2+, Pb2+, Fe3+, Ni2+ and Zn2+) has been checked. In column operation it has been observed that Hg2+ content of the waste water can be removed at usual pH of natural water. Mercury was determined by isotope dilution method
and the concentration of Hg2+ in the waste water spiked with 203Hg was found to be 0.05 to 0.09 μg/ml.
A radiochemical procedure for separation of carrier-free22Na from bulk of Mg is described. The method involves the initial removal of bulk of Mg as Mg(OH)2 by means of ammonia followed by separation of the last traces of Mg by means of extraction with a cationic liquid exchanger,
di-(2-ethylhexyl) phosphoric acid (HDEHP) in cyclohexane.
Reactions of carbonate radical (CO3–), generated by photolysis or by radiolysis of a carbonate solution with nickel(II)-iminodiacetate (Ni(II)IDA) were studied at pH 10.5 and ionic strength (I)==0.2 mol·dm–3. The stable product arising from the ligand degradation in the complex is mainly glyxalic acid. Time-resolved spectroscopy and transient kinetics were studied using flash photolysis. From the kinetic data it was suggested that the carbonate radical initially reacts with Ni(III)IDA with a rate constant (2.4±0.4)·106 dm3·mol–1·s–1 to form a Ni(II)IDA species which, however, undergoes a first-order transformation (k=2.7·102·s–1) to give a radical intermediate of the type Ni(II)RNHCHCO
) which rapidly forms an adduct containing a Ni–C bond. This adduct decays very slowly to give rise to glyoxalic acid. From a consideration of equilibrium between Ni(II)IDA and Ni(III)IDA, the one electron reduction potential for the Ni(III)IDA/Ni(II)IDA couple was determined to be 1.467 V.