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71.
S. Dutta P. K. Mohapatra V. K. Manchanda A. K. Das 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(2):245-250
The work describes a procedure of preconcentration and separation of trace amounts of Pd(II) by solid phase extraction of
the metal ion by dithiooxamide groups incorporated into a matrix of polystyrene-divinylbenzene whereas the determination of
palladium has been carried out by radiotracer technique using 109Pd (T
1/2 = 13.43 hr, E
γ = 311, 647 keV). The experiments were carried out using both batch method and column operation. Parameters such as the amount
of resin, effect of pH, equilibration rate, sorption and desorption of metal ions have been studied. The maximum sorption
capacity for palladium was found to be 0.10 mmol·g−1 at pH 6.0. The method is rapid, has a good accuracy and can be used routinely. 相似文献
72.
D.R. Raut P.K. Mohapatra S.A. Ansari V.K. Manchanda 《Journal of membrane science》2008,310(1-2):229-236
Facilitated transport of Cs(I) from aqueous nitrate feed solutions to a receiver solution containing distilled water through a supported liquid membrane (SLM) containing calix[4]-bis-2,3-naphtho-crown-6 (CNC) in 0.45 μm PTFE (polytetrafluoroethylene) membranes was investigated. The carrier solution usually consisted of CNC dissolved in a mixture of 80% 2-nitrophenyl octyl ether and 20% n-dodecane. The transport rates were found to be influenced by the mobile carrier concentration, cesium concentration as well as the feed acidity. The extracted species conformed to a stoichiometry of 1:1 metal to ligand ratio suggesting the extraction of an organophilic mono-Cs-crown complex. Fission products obtained from an irradiated natural uranium target were found to be poorly transported while Cs-137 got significantly transported suggesting the possible application of the separation method for the removal of bulk Cs-137 from radioactive waste solutions. Durability/chemical stability of the membrane was remarkably good when tested over 20 days of continuous operation. 相似文献
73.
Pammy Manchanda Aimen A. S. Mukheimer A. H. Siddiqi 《Numerical Functional Analysis & Optimization》2013,34(1-2):217-225
Invention of wavelets and fractals have revolutionized several areas of emerging technologies, especially image processing and scientific computing. The iterated function system [2-4,13,17,18,20,25,26,29], inverse problem of images [5,14-16] and wavelet-based numerical methods [6,7,10,19,22,23] are basic in-gredients of these exciting developments. The iterated function system and the collage theorem are among the basic mathematical tools which are consequences of the Banach contraction fixed point theorem. In one of the sections of this paper we have generalized these two theorems applying a generalization of the Banach contraction fixed point theorem due to Edelstein [11]. In the other section we have studied the inverse problem of images by the iterative function system with grey-level in the context of Besov space, extending a result of Forte and Vrscay [16]. 相似文献
74.
75.
A. Bhattacharyya P. K. Mohapatra P. N. Pathak V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):323-328
Summary Sorption
behavior of Th and U on cation-exchange resins was investigated from nitric
acid medium by both batch and column methods. The cation-exchange studies
involved the sorption of UO22+ and Th4+ and
their cationic complexes onto Dowex 50Wx8 and Dowex 50Wx4 resins (50-100 mesh).
The batch data yielded a separation factor (Kd,Th/Kd,U)
value of >100 for the cation-exchanger, Dowex 50Wx4 at 1-2M HNO3.
Separation of uranium from thorium was also carried out by column method in
nitric acid medium using cation-exchangers, Dowex 50Wx4 as well as Dowex 50Wx8.
While uranium elution was possible at 1M HNO3, Th could be eluted
only at higher concentration of nitric acid (>6M). The stripped solution
emanating from a mixer settler employing di-2-ethyl hexyl isobutyramide as
extractant and feed solution similar to THOREX process comprising 350 mg/l U
and 380 mg/l Th in 0.75M HNO3 was loaded on the column and the
decontamination factor value for U in the product was >1000.</p>
</p> 相似文献
76.
Antony J. Deeming Romila Vaish Alejandro J. Arce Ysaura de Sanctis 《Polyhedron》1994,13(24):3285-3294
The cluster [Os3(CO)10(MeCN)2] reacts with 2,2′-dipyridyl disulphide (1, pySSpy) to give a range of oxidative addition products which were separated by TLC on silica and crystallization : [Os3(pyS)2(CO)10] (2), [Os3(pyS)2(CO)9] (3), [Os2(pyS)2(CO)6] (4) and [Os(pyS)2(CO)2] (5), together with some of the hydride [Os3H(pyS)(CO)9] (6), which is not an expected oxidative addition product. The X-ray crystal structures of compounds 2, 3, 4 and 6 (compounds 2 and 6 occurring within a single crystal), together with the known structure of compound 5, reveal several modes of pyS bonding : chelating pyS, μ2-pyS (both sulphur-bonded and nitrogen, sulphur-bonded) and μ3-pyS. 相似文献
77.
M. V. Balarama Krishna J. Arunachalam M. S. Murali Surendra Kumar V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(3):551-557
The efficiency of immobilized moss as a bio-sorbent for the removal of 137Cs and 90Sr radionuclides from actual low-level radioactive waste (LLW) solutions was investigated. Preliminary batch experiments with
the moss (Funaria hygrometrica) for the sorption of Cs and Sr have shown a pH dependent binding trend from pH 1–13, with maximum binding between pH 5–10.
Time dependence of the batch studies showed that a contact time of 30 minutes was sufficient to reach equilibrium. Column
experiments for the sorption of Cs and Sr by moss after immobilizing in polymer silica matrix demonstrated that the sorbent
is capable of removing considerable amounts of Cs and Sr from actual LLW solutions under constant flow conditions. The adsorption
capacity was estimated to be 8.5 mg/g for Cs and 15 mg/g for Sr. These sorbed metal ions from the column could be leached
out using 0.20M nitric acid. The regenerated sorbent exhibited relatively the same initial binding capacity of both Cs and
Sr even after 3 cycles of reuse.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
78.
S. Kumar N. Rawat B. S. Tomar V. K. Manchanda S. Ramanathan 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(2):229-231
Sorption of technetium on hematite colloids, at varying pH (3–10), has been studied in absence and presence of humic acid
using 95mTc-96Tc radiotracers. Technetium was found to be weakly sorbed on hematite at lower pH (<5) values, while no sorption was observed
at higher pH values. Humic acid was found to have no effect on the sorption of technetium on hematite under aerobic conditions,
while at lower pH values small reduction was observed which was attributed to the reduced zeta potential of the hematite colloids
owing to the strong sorption of humic acid. 相似文献
79.
Bhattacharyya A Mohapatra PK Ghanty TK Manchanda VK 《Physical chemistry chemical physics : PCCP》2008,10(41):6274-6280
Transport of Am(III) was studied through the composite polymer membrane of Cyanex-301 [bis(2,4,4-trimethylpentyl)dithiophosphinic acid] and tri-n-butylphosphate (TBP). Depending on the pH of the strip solution containing alpha-hydroxyisobutyric acid (AHIBA), the transport behaviour of Am(III) was changed significantly. After approximately 70% of the Am(III) transported to the strip side, interestingly, back transport of Am(III) was observed at a pH of 3.5. The back transport phenomenon was not so significant at pH 1 and 5.7. The back transport of Am(III) was attributed to the transport of AHIBA from strip to the feed side due to its interaction with TBP in the membrane and the attainment of Donnan equilibrium because of the presence of Na(+) in the feed as the driving ion. The experimental observations were rationalized using the hydrogen bonding interaction energies obtained through ab initio molecular orbital and DFT calculations. 相似文献
80.
P. K. Mohapatra R. Veeraraghavan V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):31-38
The extraction behavior of Th(IV) from dilute nitric as well as perchloric acid medium using 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone
(PMBP) and its mixture with tri-n-octyl phosphine oxide (TOPO) was investigated. The species of the type Th(X)(PMBP)3·(HPMBP) and Th(X)(PMBP)3·(TOPO) were extracted for the binary and ternary extraction systems, respectively, where X=NO3− or ClO4−. The presence of 1.25·10−5M Th carrier in the aqueous phase resulted in the extracted species of the type of Th(PMBP)4 and Th(PMBP)4·(TOPO), respectively. The extraction constant (logk
ex
) for the binary species Th(PMBP)4 was found to be 6.89±0.01 while the overall extraction constant (logK) for the ternary species Th(PMBP)4·(TOPO) was calculated to be 13.17±0.06. 相似文献