Authors:V. Ramachandhran, S. Samanta, and B. Misra
Complexation aided ultrafiltration (CAUF) is an attractive separation process for the removal of trace toxic elements from
effluents at low pressures. Freshly prepared polysulfone, polyamide, polyamide hydrazide and polyvinyl butyral blended cellulose
acetate membranes are studied with respect to the separation behavior for radioactive cerium tracer in the presence of polyethyleneimine.
The effect of polymer loading and pH of the feed system are investigated.
Authors:Suman Singh, S. Misra, S. Pandit, K. Parikh, and S. Tripathi
This paper presents a simple, rapid and sensitive radiometric method for the determination of uranium in Thorex Process stream
containing large amount of thorium. This method involves the extraction of uranium into 0.05M tri-n-octyl phosphine oxide
(TOPO) in xylene at 2M HNO3. The extraction of thorium is prevented by masking them with suitable quantity of fluoride ions. The optimum experimental
parameters for extraction of 233U were evaluated and using the most suitable experimental conditions the extracted uranium is radiometrically determined by
α-counting in proportional counter with a prior knowledge of specific activity of uranium. Simultaneously in the same sample
uranium was determined by spectrophotometric method using 2-(5bromo-2 pyridylazo)-5-diethylaminophenol (Bromo-PADAP) as chromogenic
reagents. Simulated as well as actual samples of dissolver, conditioner and raffinate tank of Thorex stream have been analyzed
by both these methods. The method was tested for as low as 0.15 μg of uranium and the results of these analyses were found
to be satisfactory within the experimental limits.
Authors:S. Gangadharan, S. Yegnasubramanian, S. Misra, and U. Gupta
14-MeV neutron activation has been used for the determination of F, Al, Si, P, K, Mn, Mo and W in minerals and steel. Most
of these elements have been estimated simultaneously through gamma-ray spectrometry. The evaluation of the effects of interferences
is discussed and the sensitivities are given. The main features of the neutron generator fabricated in this Centre and used
in this work are briefly described.
Authors:K. Gupta, S. Misra, S. Tripathi, and Manmohan Kumar
2-Ethylhexyl-2-ethylhexyl phosphonic acid (PC-88A) and Tributylphosphate (TBP) extractants have been attached to polypropylene
(PP) in granular, film and non-woven fabric forms, by a simultaneous γ-ray irradiation method. The extraction of plutonium
from the acidic radioactive liquid waste by modified polymers was studied by varying the γ-ray dose. The uptake of plutonium
was also studied by polyethylene (PE) in film form. This modified polymer also showed extraction capability for plutonium
from nitric acid medium. The uptake of plutonium depends upon the γ-ray dose as well as the nature and source of the polymer.
Liquid–solid extraction studies showed that the equivalent amount of uptake of plutonium on TBP–polyethylene film requires
twice the γ-ray dose as compare to TBP–polypropylene film. It was observed that at given γ-ray dose polypropylene fabric is
not sturdy, compare to the granules and films, and material leach out in aqueous phase. The presence of other solvents like
di-methyl formamide (DMF) and cyclohexane during γ-ray irradiation were able to enhance the extraction capabilities. The optimum
conditions established during this study was successfully applied for the separation of plutonium, uranium and thorium from
the fission products in acidic waste solution.
Authors:P. Naik, P. Dhami, S. Misra, U. Jambunathan, and J. Mathur
Silica-gel has been used as an inert support for the extraction chromatographic separation of actinides and lanthanides from HNO3 and synthetic high level waste (HLW) solutions. Silica-gel was impregnated with tri-butyl phosphate (TBP), to yield STBP; 2-ethylhexyl phosphonic acid, mono 2-ethylhexyl ester (KSM-17, equivalent to PC-88A), SKSM; octyl(phenyl)-N,N-diisobutyl carbamoylmethylphosphine oxide (CMPO), SCMPO; and trialkylphosphine oxide (Cyanex-923), SCYN and sorption of Pu(IV), Am(III) and Eu(III) from HNO3 solutions was studied batchwise. Several parameters, like time of equilibration, HNO3 and Pu(IV) concentrations were varied. The uptake of Pu(IV) from 3.0M HNO3 followed the order SCMPO>SCYN>SKSM>STBP. With increasing HNO3 concentration, DPu increased up to 3.0M of HNO3 for STBP, SKSM and SCMPO and then decreased. In the case of Am and Eu with SCMPO, the D values initially increased between 0.5 to 1.0M of HNO3, remained constant up to 5.0M and then slightly decreased at 7.5M. Also, the effects of NaNO3, Nd(III) and U(VI) concentrations on the uptake of Am(III) from HNO3 solutions were evaluated. With increasing NaNO3 concentration up to 3.0M, DAm remained almost constant while it was observed that it decreases drastically by adding Nd(III) or U(VI). The uptake of Pu and Am from synthetic pressurized heavy water reactor high level waste (PHWR-HLW) in presence of high concentrations of uranium and after depleting the uranium content, and finally extraction chromatographic column separation of Pu and Am from U-depleted synthetic PHWR-HLW have been carried out. Using SCMPO, high sorption of Pu, Am and U was obtained from the U-depleted HLW solution. These metal ions were subsequently eluted using various reagents. The sorption results of the metal ions on silica-gel impregnated with several phosphorus based extractants have been compared. The uptake of Am, Pu and rare earths by SCMPO has been compared with those where CMPO was sorbed on Chromosorb-102, Amberchrom CG-71 and styrene divinylbenzene copolymer immobilized in porous silica particles.
Authors:Ankita Misra, Amit Srivastava, Sharad Srivastava, and A.K.S. Rawat
Commelina benghalensis (Commelinaceae) is widely used as traditional and folklore medicine in India. In the present study, a reverse-phase high-performance liquid chromatography—photodiode array detection (RP-HPLC—PDA) method was developed for the separation, identification, and quantification of bioactive phenolics. Antioxidant potential was also accessed to validate the presence of identified markers. Method was developed on C18 column with 1% formic acid (in water) and acetonitrile as solvent system, and data acquisitions were achieved at wavelength of 285 nm. The developed method was also validated for accuracy, precision, robustness, limit of detection and quantification (LOD and LOQ), repeatability, and recovery according to International Conference on Harmonization (ICH) guidelines. In this method, five phenolics, viz., protocatechuic acid (0.033%), vanillic acid (0.262%), ferulic acid (0.365%), apigenin (0.126%), and kaempferol (0.544%), were quantified in linearity range of 0.2–1.0 μg with correlation coefficient of more than 0.9949. Relative standard deviation (RSD) (%), LOD, LOQ, and recovery (%) are within the acceptable limit. Besides that, methanolic extract shows the inhibition (%) range from 24.45 to 68.75% at 0.02–0.12 mg mL−1. IC50 of extract was observed at 46.75 μg mL−1, suggesting the promising activity in methanol extract. Hence, the proposed method for simultaneous quantification of five bioactive phenolics in the tuber of C. benghalensis using HPLC–PDA detection under the specified conditions is specific and accurate, and validation proves its selectivity and reproducibility.