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To avoid spectral interference it is required to separate Th preferentially during the determination of trace metallic constituents from Th matrix using ICP-OES.

Dried coconut leaf, Exhausted tea leaf and coffee powder were used to demonstrate the cost effective sorption of UO22+ ion from aqueous solution. The Kd followed the order: coconut leaf > tea leaf > coffee powder. The sorption mechanism was evaluated by linearly fitting the experimental data into different isotherm models: Langmuir, Dubinin-Radushkevich, Freundlich and Tempkin isotherm. Similarly, the sorption kinetics were also modelled. The extraction followed Langmuir isotherm, chemisorption and pseudo second order rate kinetics. The sorption was spontaneous, energetically favourable, endothermic and entropically driven in nature. Sodiumcarbonate was more efficient for stripping of uranyl. The biosorbent showed good radiolytic stability.

Wastewater remediation technologies are rapidly evolving to meet the increasing water demand. The need to develop efficient, low-cost, and simplistic strategies has motivated researchers to explore...

The development of a direct non-destructive synchrotron-radiation-based total reflection X-ray fluorescence (TXRF) analytical methodology for elemental determinations in zirconium alloy samples is reported for the first time. Discs, of diameter 30 mm and about 1.6 mm thickness, of the zirconium alloys Zr-2.5%Nb and Zircalloy-4 were cut from plates of these alloys and mirror polished. These specimens were presented for TXRF measurements directly after polishing and cleaning. The TXRF measurements were made at the XRF beamline at Elettra synchrotron light source, Trieste, Italy, at two different excitation energies, 1.9 keV and 14 keV, for the determinations of low- and high-Z elements, respectively. The developed analytical methodology involves two complementary quantification schemes, i.e. using either the fundamental parameter method or relative sensitivity based method, allowing quantification of fifteen minor and trace elements with respect to Zr with very good precision and accuracy. In order to countercheck the TXRF analytical results, some samples were analyzed using the DC arc carrier distillation atomic emission spectrometry technique also, which shows an excellent agreement with the results of the TXRF-based methodology developed in this work. The present work resulted in a non-destructive TXRF elemental characterization methodology of metal and alloy samples avoiding the cumbersome dissolution and matrix separation which are normally required in other techniques and traditional methods of TXRF determination. In addition, the production of analytical waste could also be avoided to a large extent. Although the work was carried out for specific applications in the nuclear industry, it is equally suitable for other such samples in different industrial applications.

A facile method to prepare 141Ce based fiducial marker sources was developed to put forward an alternate to 99mTc markers routinely used during nuclear imaging procedures. Cerium oxide microspheres were prepared as source substrate by ‘internal gelation process’. ‘State-of- the art’ analyzing tools were used for characterizing the substrate. Neutron irradiation of microspheres in ‘Dhruva’ reactor was optimized. Post irradiation and quality evaluation, the sources were enclosed in an in-house developed portable device. 141Ce sources containing 37–59 MBq (1.0–1.6 mCi) of 141Ce were supplied to three nuclear imaging centres. Newly developed 141Ce fiducial markers could successfully supplement real time SPECT imaging procedures.

An analytical method was developed based on the D.C. arc carrier distillation atomic emission spectrometric (D.C. Arc AES) technique for determination of trace metallic impurities (Al, Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Na, Ni, Si, Sn, Ti, V and Zn) in uranium silicide samples. Chemical quality control was also carried out for the precursor materials in order to track the source of impurities in the final fuel materials. The method was validated using synthetic samples. To minimize the spectral interference, a suitable carrier (5% AgCl) was used to sweep away the trace constituents into the arc preferentially, leaving the major matrix as a refractory material. The use of a charge coupled device (CCD) detector was found to improve the overall analytical performance in terms of detection limits, precision, linear dynamic range and most importantly providing an opportunity to choose additional analytical lines, which is highly desirable, especially for trace level determination of analytes in an emission-rich matrix. The energy dispersive X-ray fluorescence (EDXRF) spectroscopic technique was employed each time for comparative evaluation of the precursors and the product.

Plutonium in the form of oxide is stored in plastic vials and bottles during its analysis for trace metal assay. Due to radiation damage and moisture, small amount of oxide samples were found to be adhering to surface of vials/bottles. This required methods for safe disposal. Methods involving wet chemical and dry cleaning procedures were evaluated for effective removal of sticking α active plutonium oxide powder from these vials for their safe disposal. Dry cleaning method for removal of plutonium activity was found to be effective method for disposal of storage vial, while wet chemical method was found to be more suitable for removal of plutonium from damaged PVC bottles. The recovered Pu was checked for chemical purity for 24 analytes using glove box adopted high resolution inductively coupled plasma atomic emission spectrometry.

A simple, simultaneously multi-elemental, ICP-AES based method was optimized to characterize nuclear high level waste solutions from different origin: research reactors, pressurized heavy water reactor, thoria containing waste and 137Cs rich solutions. It involves identification of interference free analytical lines with the evaluation of their analytical performance including sensitivity, detection limit etc. To compare the results of ICP-AES system, ED-XRF technique has been employed and the results compared well indicating the efficacy of the optimized procedure. For analytes like Fe, Cr, Na, Mn and Ca the detection limits are in the range of 0.001–0.009 mg/L while for other analytes (except U and Th) the detection limits are almost on the order of magnitude poorer. For all the analytes the linear dynamic range exists from the detection limit up to 500 mg/L.

A simple two step synthetic methodology was developed for the fabrication of poly (ionic liquid) (PIL) membranes. Appropriate substituent on imidazolium ring was found to bring tunability in the properties and performance of the resulting membranes. FTIR was employed to identify the functional groups on the membranes, while microscopic imaging techniques (AFM and SEM) were used to investigate the surface morphology. Different substituents on the imidazolium ring were found to form membranes having different pore size. 1H and 13C NMR were extensively utilized to characterize PIL membranes. The surface charge of the PIL membranes can be tuned by the pH of the feed solution. These PIL membranes exhibited antimicrobial activity against gram positive bacteria (staphylococcus aureus and pseudomonas aeruginosa). The antibacterial activity was also found to depend on the nature of substituents of imidazolium ring. Stable water flux (correspond to ultrafiltration and microfiltration membranes) was obtained after pre-compaction of the membranes. Longer UV irradiation was found to form nanofiltration membranes. The performance of these PIL membranes were systematically evaluated by protein (dextran and bovine serum albumin) rejection.

Zwitterion augmented forward osmosis (FO) membranes were fabricated having polyamide active layer on the polysulfone support to improve the overall performance and antifouling characteristics. FTIR and XPS were employed in evidencing the incorporation of zwitterion in terms of functional groups and relative compositions of hetero atoms. AFM, SEM, water contact angle and zeta potential measurement are used to characterize the zwitterion augmented surface in terms of surface morphology, surface charge and hydrophilicity/hydrophobicity. Augmentation of zwitterion was found to enhance the hydrophilicity and surface roughness resulting the enhancement in the water permeability. The anionic moiety of the zwitterion was exposed outside, while the cationic moieties of the zwitterion mostly retained towards the core as suggested by negative zeta potential and protein absorption. Incorporation of zwitterion was found to enhance the antifouling property of the membrane as evident from static and dynamic test. The relative composition of zwitterion on active membrane surface was optimized by investigating the tradeoff between water permeability and reverse salt flux.

Nature inspired ‘green’ method has been reported for the fabrication of nanoparticles from the plant derived polyphenol tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES). In present investigation, TA-APTES nanoparticles decorated MXene nanosheets were acted as active layers and TA-APTES@MXene composite membrane were constructed by vacuum self-assembly on cellulose acetate support in order to improve membrane performance. The modified membrane showed an excellent hydrophilicity with a water flux of 5990.11 L·m-2·h-1 at 0.1 MPa, which is 15 times higher than pure MXene membrane. Moreover, the removal ratios of three different types of oil/water emulsions (petroleum ether, lubricating oil and vegetable oil) were found to be more than 98%. More importantly, the highly oleophobic membrane surface maintained a relatively high separation performances after four consecutive cycles of performances. This investigation achieves a leap of MXene-based membrane materials from nano- to micro-scale, which provides valuable insights in the field of oil/water separation.

The discharges from industries particularly petroleum industry at any stage from exploration/drilling to transportation are of major environmental concerns in the present scenario. In this work, mesoporous silica (SBA-15) was modified using a bio-inspired coating and was used as filler in the fabrication of efficient, robust polyetherimide composite ultrafiltration membranes. The membranes prepared by this facile two-step approach were seen to be highly hydrophilic with improved porosity and pore-interconnectivity with a thinner skin layer. The rougher top surfaces of these membranes imparted an oleophobic character under water. The composite membranes exhibited improved emulsion/water flux while maintaining >99.8% rejection of oil from a synthetic motor oil/water/surfactant emulsion. The composite membranes were investigated for its long-term efficiency in the removal of oil from produced water. The flux declination was only

Magnetically responsive nanofiltration membranes have been developed by attaching a superparamagnetic nanoparticle to the end of polymer chains grafted from the surface of commercially available nanofiltration membranes. In an oscillating magnetic field, movement of these magnetically responsive polymer chains leads to break up of the concentration polarization at boundary layer. Experiments using feed streams consisting of an organic salt, an inorganic salt, as well as a synthetic oily wastewater have been conducted for periods of up to 6 h in order to determine the effect on long term membrane fouling. The results indicate suppression of long term fouling in the presence of an oscillating magnetic field.

Extraction of actinide ions from nitric acid feeds was investigated using solutions of three CMPO (carbamoyl methyl phosphine oxide) functionalized pillar[5]arenes with varying spacer lengths in a room temperature ionic liquid, [C8mim][NTf2]. The extraction of Am3+ was found to decrease with increasing nitric acid concentration suggesting a mechanism analogous to a cation-exchange mechanism. The nature of the extracted species was determined by the conventional slope analysis method to be ML type which was subsequently confirmed by luminescence spectroscopy. Studies carried out to determine the thermodynamic parameters suggested highly exothermic reactions with negative entropy values. The reusability and recycling studies involved stripping and radiolytic stability of the solvent systems which suggested reasonably encouraging results. While a DTPA solution in guanidine carbonate was found to back extract the extracted metal ion from the ionic liquid phase, the radiolytic stability of the CMPO-pillararenes were reasonably good.

Dipicolinamide functionalized titania particles have been synthesized for efficient decontamination of uranyl and thorium ions from aqueous acidic waste solution. Langmuir isotherm was found to be predominating with maximum sorption capacity of 125 mg/g for Th and 111 mg/g for U, respectively. The sorption was found to follow pseudo 2nd order kinetics predominately, with rate constant 8.6E−04 mg g−1 min−1 for Th and 6.1E−04 mg g−1 min−1 for U, respectively. Up to 200 kGy of gamma irradiation, not much deterioration in extraction performance of sorbent material was observed. Three contacts of 0.1 M aqueous solutions of oxalic acid and sodium carbonate were found to be effective in quantitative elution of Th4+ and UO22+ from the loaded sorbent, respectively. The sorption of U and Th on dipicolinamide functionalized titania was evidenced by SEM images, elemental mapping and the EDX. Theoretical investigation revealed that, the solution phase free energy of sorption (ΔGsol) was higher for Th4+ (−114.1 kcal mol−1) compared to UO22+ (−80.41 kcal mol−1).

Selective chemical separation of U without any compromise of analyte concentration even at trace level; is a prerequisite to avoid the spectral interference in Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). “Green” approach based on application of ionic liquid; has been followed to bring down the U concentration below the tolerance limit, prior to the analyses of common metallic constituents (Al, Ca, Cu, Cr, Fe, Mn, Mg, Na, Ni, Pb, and Zn) and critical elements (B, Cd, Ag, Eu, Sm, Gd, and Dy). 'Anion exchange' mechanism was found to be predominantly operative for TBP/C3PyNTf2 based separation system during extraction of U, involving 1:2 anionic metal–ligand complex; while, in TBP/n-dodecane, conventional 'solvation' mechanism was operative involving 1:2 neutral metal–ligand complex. The methodologies were optimized (identification of interference free analytical lines, establishing calibration curves, estimation of detection limits, linear dynamic range, precision) using synthetic samples. Statistical t-test was performed to understand reliability of the data. Significant reductions in organic waste volume and sample processing time have been demonstrated by application of ionic liquids. For analysis of common analytes, three contacts of 1.1 M TBP/C3PyNTf2/6M HNO3 were found to be efficient in bringing down the U below tolerance level without much compromise on the concentrations of analytes at trace level. The associated error was within the limits of allowed statistical fluctuation. However, for critical elements, the methodology was not reliable. For them, the sample feed solution should be adjusted to 3 M HNO3 prior the U removal.

The k 0 -NAA method has been standardized by characterizing the G4 irradiation position of the upgraded Apsara (Apsara-U) reactor. The sub-cadmium to epithermal neutron flux ratio (f) and epithermal neutron flux shape factor ( α ) were determined taking dual (197Au and 94Zr), triple (197Au, 94Zr and 96Zr) and multi (197Au, 59Co, 64Zn, 68Zn, 96Zr and 94Zr) flux monitors using Cadmium ratio method. The value of f was found to be 19.94 ± 1.02 with average value of α as −0.027 ± 0.004. The method was validated by analysing SMELS-II (synthetic multielemental standards) and geological certified reference material (Andesite, AGV-1), wherein results are in good agreement with certified or recommended values. The k 0 -based NAA method was applied for chemical characterization of pure Iron metal and coal samples. The results obtained were further compared with ICP-OES analysis and the values are found to be in good agreement ( t t critical ) for all the elements determined. F-test was also performed in order to show the reliability of the results in terms of standard deviations.

An EDXRF based methodology was developed for the characterization of major and minor elemental constituents in Garnet samples. The method was optimized using multi-point calibration in high purity graphitic materials for the analytes: Ca, Mg, Si, Al, V, Zr, Fe, Mn and Cr. The method optimization was done based on evaluation of analytical performance including, detection limits, sensitivity, and precession. The actual garnet samples were analysed and based on the concentration of the major constituents, four different types of Garnet were identified: Pyrope (Mg 33 %, Si 41 % and Al 24%), Almandine (Si 19 %, Al 14 %, and Fe 53 %), Spessartine (Si 21%, Al 17 % and Mn 48 %) and Grossular (Ca 54%, Si 22% and Al 15 %). The analytical results were compared with AES. The results were found to be in good agreement with each other. Student t-test and F-test were performed with 95 % confidence level and ten degrees of freedom. The estimated t-values and F-values were found to be lower than t c = 2.228 and F c = 2.98. This analyses revealed that the data are reliable and the within statistical fluctuation, even the associated precision values are also accepted

Herein, sorption of pentavalent neptunium from aqueous acidic solution was carried out onto 1st and 2nd generation of poly(amidoamine) dendrimer functionalized MWCNTs. The Np(V) sorption kinetics followed pseudo second order kinetics with rate constants of 1.4 × 10−4 and 6.84 × 10−4 g mg−1 min−1 for MWCNT–PAMAMG1 and MWCNT–PAMAMG2, respectively. The sorption of Np(V) onto MWCNT–PAMAMGn proceeded via chemisorption and the data fitted well to Langmuir isotherm model. MWCNT–PAMAMGn was found radiolytically stable up to 500 kGy dose of gamma radiation. Sodium carbonate was found to strip Np effectively from sorbent.

Solid-phase extraction of neptunium in pentavalent and hexavalent oxidation states from the acidic aqueous medium was investigated. The extraction of neptunium, carried out using N,N-dihexylamide functionalized multiwalled carbon nanotubes (MWCNT-DHA) showed high K d values. The sorption was found to follow Freundlich isotherm via chemical interaction between the amide functionality and neptunium. The time-dependent sorption study showed that the kinetics followed pseudo second order rate constants. MWCNT-DHA was found radiolytically stable up to 1000 kGy. The selectivity of MWCNT-DHA for the sorption of Np ion was found to be satisfactory. Citric acid was evaluated as the best strippants.

New methods for estimation of concentration and distribution of plutonium in (Th,Pu)O2 MOX fuel samples have been attempted by spectroscopic analysis of SSNTD based alpha images using UV–Vis spectrophotometry and photoluminescence spectroscopy. (Th,Pu)O2 MOX fuel samples having a large range of PuO2 concentration, were subjected to this study and found beneficial when compared with the conventional analysis of alpha autoradiographs. UV–Vis absorbance and photoluminescence of the alpha autoradiograph showed linear decrease proportionally to PuO2% in the fuel sample. Optical band gap was found to proportionally increase with PuO2% in the fuel sample which was revealed in UV–Vis spectrophotometry.

Wild type Rhizopus arrhizus biomass was demonstrated as highly efficient bio-sorbent for trivalent f-elements. Both Am3+ and Eu3+ were found to follow the Fruendlich isotherm through chemi-sorption. The sorption for Am3+ was found be faster compared to Eu3+ while both proceeded via pseudo-second order reaction. EDTA was found to be effective strippant whereas up to 500 kGy, the bio-sorbent showed high radiolytic stability. Luminescence employed for probing the local environment of metal ion on sorption which revealed the presence of single adsorbed species with no inner sphere water molecules. The covalency of metal–ligand bond enhanced on complexation with the bio-sorbent.

A systematic photoluminescence based investigation was carried out to understand the complexation of Eu 3 + with different ligands (TBP: tri-n-butyl phosphate, DHOA: di-n-hexyl octanamide, Cyanex 923: tri-n-alkyl phosphine oxide and Cyanex 272: Bis (2,4,4 trimethyl) pentyl phosphinic acid) used for preferential separation of lanthanides and actinides in various stages of nuclear fuel cycle. In case of TBP and DHOA complexes, 3 ligand molecules coordinated in monodentate fashion and 3 nitrate ion in bidentate fashion to Eu 3 + to satisfy the 9 coordination of Eu. In case of Cyanex 923 and Cyanex 272 complexes, 3 ligand molecules, 3 nitrate ion and 3 water molecules coordinated to Eu 3 + in monodentate fashion. The Eu complexes of TBP and DHOA were found to have D 3h local symmetry while that for Cyanex 923 and Cyanex 272 were C 3h . Judd–Ofelt analysis of these systems revealed that the covalency of Eu O bond followed the trend DHOA > TBP > Cyanex 272 > Cyanex 923. Different photophysical properties like radiative and non-radiative life time, branching ratio for different transitions, magnetic and electric dipole moment transition probabilities and quantum efficiency were also evaluated and compared for these systems. The magnetic dipole transition probability was found to be almost independent of ligand field perturbation while electric dipole transition probability for 5 D 0 - 7 F 2 transition was found to be hypersensitive with ligand field with a trend DHOA > TBP > Cyanex 272 > Cyanex 923.

Sulphoxide ligands in piperidinium based ionic liquid were demonstrated as highly efficient, selective and environmentally benign systems for the extraction of plutonium from acidic aqueous solution. The extraction followed ‘cation-exchange mechanism’ via [Pu(NO3)·L]3+ and [PuO2(NO3)·L]+ species. The extraction efficiency followed the trend: APSO > BPSO > BMSO. The phenyl substituted sulphoxides showed higher affinity for plutonium due to a combination of steric as well as electronic factors. Extraction process was thermodynamically spontaneous for all three solvent systems. Oxalic acid and sodium carbonate were suitable for quantitative stripping of Pu4+ and PuO2 2+, respectively. APSO in ionic liquid showed good radiolytic stability.

An attempt was made to understand the sorption behaviour of Pu4+ and PuO2 2+ on Rhizopus arrhizus fungus. The sorption data were analyzed using Langmuir, Dubinin–Radushkevich, Freundlich isotherm and Tempkin isotherms, which revealed that the sorption proceeds via chemisorption through mono layer following Langmuir isotherm. the sorption kinetics were analyzed by different models revealing the predominance of pseudo 2nd order kinetics. Oxalic acid and sodium carbonate were used for effective stripping of Pu4+ and PuO2 2+, respectively. This biomass was found to be radiolytically stable and finally was applied for processing of SHLW from RR and FBR origins.

The extraction efficiency for thorium followed the trend: Cyanex-923 > Cyanex-272 > DHOA > TBP. In case of TBP and DHOA the extraction proceeded via ‘solvation mechanism’ through Th(NO3)4·2L, while for Cyanex-923 and Cyanex-272 it proceeded via ‘ion exchange’ mechanism through (Th(NO3)2·2L)2+. The extraction process followed slower kinetics while change in Gibb’s energy revealed the spontaneity of the process. These ionic liquid based systems were found to be radiolytically stable, highly efficient and selective for Th. Oxalic acid was found to be suitable for almost quantitative stripping of Th from extracted ionic liquid phase.

The extraction/complexation of uranyl ion by structurally modified sulphoxides in ionic liquid was investigated. These systems were found to be highly efficient, selective and radiolytically stable for hexavalent f-block elements. The extraction proceeds via ‘cation exchange’ mechanism through the species, [U(NO3)·2L]+. Processes were found to be kinetically slow, thermodynamically spontaneous and proceeded via single species. The extended resonance and steric crowding favoured the complexation of phenyl sulphoxides. Na2CO3 was found to be suitable for the quantitative back extraction of uranyl ion from the ionic liquid phase. Finally, these systems were employed for the processing radioactive waste.

Ionic liquid-based solvent systems containing diglycolamide-functionalized calix[4]arenes (C4DGAs) are efficient for actinide ion extraction from nitric acid feeds. Therefore, the radiolytic stability of three C4DGAs (wide-rim, narrow-rim and both side DGA-functionalized calix[4]arenes) and TODGA (N,N,N′,N′-tetraoctyldiglycolamide) (used for comparison purpose), was evaluated by exposing their solutions in an ionic liquid as well as a 95:5 mixture of n-dodecane + isodecanol to gamma radiation up to an absorbed dose of 1000 kGy. Liquid-liquid extraction studies were carried out using 241Am as a radiotracer. Apart from a decrease in the DAm values, ascribed to radiolytic degradation, FT-IR, EPR and GC-MS studies were carried out to characterize the degraded species. The different extractants are less sensitive to radiolytic degradation in the ionic liquid than in the molecular diluent.

ICP-AES based methodology was developed for the determination of trace metallic constituents in thorium matrix after preferential extraction of thorium using TBP, TOPO and DHOA. The distribution ratio for thorium followed the trend TOPO > TBP > DHOA with the formation of 1:2 complex. Oxalic acid was found to strip Th effectively. La, Ce, Pr, Gd, Dy, Lu can be determined at 0.1 mg L−1 using all the ligands, while common analytes can be determined at 0.1, 0.5 and 1 mg L−1 concentrations by using DHOA, TBP and TOPO, respectively.

Selective separation of uranium using bis(2,4,4-trimethylpentyl)phosphinic acid in xylene and C8mimNTf2 was investigated. For ionic liquid based system, the extraction kinetics was found to be slower with the predominance of ion exchange mechanism through [UO2(NO3)·2L]+, while for xylene based system solvation mechanism. The nature of the extracted species was found to be different in both the media as observed in luminescence study. Ionic liquid based system was more radioresistant than that of molecular diluents. Na2CO3 was successfully used for stripping. The selectivity was investigated by processing simulated high level waste of pressurized heavy water reactor origin.

Isothermal-based air dehumidification results in energy problems, low water vapour permeability and poor selectivity. Graphene oxide framework (GOF) membranes exhibit remarkable advantages in effective air dehumidification. In this work, different crosslinking agents, including glyoxal (GLX), oxalic acid (OXA) and ethylenediamine (EDA), were employed to tune the properties of GOF membranes through the casting knife technique. The physicochemical properties of the as-prepared membranes were investigated by using various techniques. The 2D arrangement of GO-based membranes ensured the frictionless nano-channels with an efficient flow rate and storage of water along with chemical interaction while hydrophilic groups on the GO surface. However, crosslinking restricted the mobility between consecutive GO layers, and the free volume and pore size became tuneable in the crosslinking structure. Given its capacity for low energy-efficient air dehumidification, the GLX-cross-linked GO membrane exhibited an excellent selectivity value of 2.8 × 106, and the less energy-consuming stability performance lasted for 120 h. These results indicate that the GLX-cross-linked GO membrane is suitable for practical applications.

Supported ionic liquid membranes have been tested for fractionation of organic compounds. Imidazolium based ionic liquids; 1-allyl-3-vinylimidazolium bromide, 1-hexyl-3-vinylimidazolium bromide and 1-octyl-3-vinylimidazolium bromide were trapped in the pores of a polypropylene membrane. Fractionation of a feed stream consisting of benzene, naphthalene and phenanthrene in tetradecane and cis- and trans-stilbene in hexane were investigated. The receiving phase was hexane. Differences in the π electron cloud density of the aromatic solutes influence their interactions with the imidazolium cation, which can affect the rates of transport. In the case of the three aromatic solutes, the degree of conjugation and molecular weight increase in order benzene, naphthalene and phenanthrene. These opposing effects result in similar mass transfer coefficients for the three solutes for the three ionic liquids tested. However, for cis-and trans-stilbene, the mass transfer coefficient was larger for all three ionic liquids. It is likely that enhanced aromatic stacking of the trans- isomer led to a higher mass transfer coefficient. In addition, 1-hexyl-3-vinylimidazolium bis(trifluoromethylsulfonyl)imide was used as the liquid membrane phase to fractionate two nucleobases: thymine and cytosine in water. The receiving phase was also water. The membrane mass transfer coefficient for thymine was 5.5 times greater than cytosine indicating the possibility of exploiting multimodal interactions with the imidazolium group to fractionate compounds.

An ICP-AES based methodology was developed for the determination of 22 trace metallic constituents (Ca, Co, Cr, Pb, Cu, Fe, Ga, In, Mg, Mn, Na, Ni, Sr, Zn, Eu, Sm, Gd, Dy, B, Be, Cd and Ag) in high purity neptunium matrix alongwith simultaneous determination of Np. Np 295.660 nm line was found to have the best analytical performance. The spectral interference of Np on other analytes have been investigated which includes identification of interference free line, evaluation of correction factor and tolerance level of neptunium. Presence of U, Th, Zr and Pu on the determination of Np has also been studied. The method was validated using synthetic samples.

An attempt was made to understand the complexation of Eu3+ with structurally modified CMPO-functionalized pillararenes by luminescence spectroscopy. Formation of single species with different numbers of inner sphere water molecules was found to be present for all the complexes. On increasing spacer length between ligating moieties and supramolecular pillararenes, the stereo-chemical crowding around ligating oxygen decreased. Therefore, strong covalent metal–oxygen bond was formed which was reflected in the increasing trend of the computed Ω2 values (Judd–Offelt parameter): LI (4.66×10−20) LII (3.19 ms)>LIII (2.94 ms) while the branching ratio values for all three complexes followed the same trend as β2>β4>β1. The other photo-physical constants like asymmetric factor, quantum efficiency, magnetic and electric dipole transition probabilities were also computed.

(Th,Pu)O2 fuel pellets were synthesised by coated agglomerate pelletization route and characterized for the chemical quality control. (Th,Pu)O2 pellets were characterized for trace metals by spectrometric methods and non metals by ion chromatographic, spectrophotometric, conductometric and manometric methods. H, F, B and Cd contents were found to be less than 1 ppm while that for V and Cl were found to be less than 10 ppm. The pellets were found to contain Cr, Cu, Mo, Na, Ni and Pb in the range of 10–50 ppm whereas Zn, Al, Ca and C in the range of 50–100 ppm. More than 100 ppm Si, Fe and Mg were found to be present in the (Th,Pu)O2 pellets. The O/M content of the pellets were found to be ~2.00. A comparative study on (Infrared) I.R. and microwave (microwave) dissolution were also used to ascertain the Th and Pu content in the (Th,Pu)O2 pellets.