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The surface functionalization of ZnO nanoparticles (ZnO NPs) was carried out by a simple one pot co-precipitation method followed by a facile ligand introduction onto the surface. This technique al...

Determination of trace level of iron in metallic uranium is of great importance. The developed procedure involves online pre-concentration and separation of iron and its determination using flow injection analysis system. The analyte forms complex with mandelic acid and retained in the micro column packed with cation exchanger and matrix goes to waste. The eluted iron was determined and the detection limit of the method is 5 ppb with a precision (RSD) at 100 ppb level of 6.2%.

Analytical evaluation of the effect of alpha fluence and energy on the properties of the irradiated PADC polymers was carried out. The images obtained by alpha irradiation on the films were analyzed using image analysis technique while UV–Vis spectrophotometry was used to understand the changes of the optical properties of the polymer. The results of this study could be applied for estimation of fluence and identification of energy of plutonium bearing sources in nuclear industrial facilities without having to use a dedicated and glove box enclosed equipment.

This article describes one-step synthesis of a singly bridged biscalix[6]arene ( 2 ) and evaluation of its recognition properties towards alkali metal ions for the first time. Synthesis of 2 was accomplished through coupling of two 4-tert-butylcalix[6]arene units with one molecule of diethyleneglycol ditosylate. Both base and linker were found to play a role in the outcome of coupling reaction for the simple and efficient synthesis of 2 . Complexation ability of 2 was studied by liquid-liquid extraction using alkali metal (Na +, K +, Cs +) picrates. Carrier activity of 2 towards the facilitated transport of alkali metal ions across a bulk liquid membrane was also studied and the transport behaviour was mechanistically explained. The predominant role of an ion exchange action mechanism in the transport process was observed.

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.

The present study aims to probe the effect of silver nanoparticles (AgNPs) on the sorption behaviour of boroaluminosilicate glass (BASG). Firstly, BASG was loaded with AgNPs and benzotriazole (BT) and the glass exhibited surface-enhanced Raman spectrum of BT. The loaded BASG was equilibrated with copper (II) chloride solution and was investigated using ICP-AES, Raman spectroscopy, and luminescence measurements. It was observed that the glass matrix along with the sorbed copper ions showed luminescence, with a broad peak centered at ∼400 nm, indicating the presence of copper ions in the Cu (I) state. However, in the absence of AgNPs, the glass matrix containing BT and sorbed copper ions failed to show luminescence implying that the copper ions are in the Cu (II) state. The glass matrix containing copper ions in addition to AgNPs and BT gave an enhanced Raman peak at 240 cm −1 (corresponding to Ag-Cl stretch with overlapping Ag-N stretch mode) and a shift of peak from 1022 (inplane trigonal ring breathing mode) to 1040 cm −1 and a broadening of the ring stretching modes at 1390 and 1575 cm −1 . All these observations could be attributed to the interaction of copper ions with BT and the simultaneous uptake of chloride ions along with copper. The studies suggest that both AgNPs and copper ions bind to the nitrogen atoms of BT and form a nanoarray like assembly AgNPs-BT-Cu which facilitates the diffusion/tunnelling of electrons from AgNPs to Cu (II) ions resulting in the reduction of Cu (II) to Cu (I).

Iron oxide-silica nanocomposite synthesized by one-pot co-precipitation method was evaluated for its applicability as sorbents for removal of toxic species like inorganic metal ions (UO22+, Zn2+, Cu2+, Ni2+, Co2+) and cationic dyes (MB and R6G) from aqueous streams at room temperature. The detailed structural analysis revealed the formation of crystalline iron oxide core with amorphous silica shell. The zeta potential measurements of surface charge helped in assessing the applicability of the sorbents. The magnetic property of the sorbent, as evaluated from magnetic measurements helped in its easy separation from solution using external magnetic field. The high porosity and large surface area of sorbent contributed to its excellent sorption efficiency. The efficiency of magnetic nano-composites was analyzed with respect to sorption kinetics (rate and kinetics order), initial concentration of toxic species (equilibrium conditions) and weight of sorbent. The optimum pH for uptake was in the range of 5–6. Extensive modelling of sorption data helped in getting an insight to the mechanism of metal ion sorption. The selectivity towards uptake of MB (MB) as opposed to that of Rhodamine 6G (R6G) was quite intriguing and detailed studies were carried out to understand this. Since the bare nanosorbent showed no selectivity in sorption of metal ions, modification was carried out to enhance selectivity with respect to uranyl ion.

The surface charge of nanosorbents is a very important factor which affects applications. In the present paper, the surface charge of ZnO NPs was tailored using by adopting different synthesis protocols. The synthesized nanoparticles were characterized and zeta potential measurements showed that the ZnO Nps synthesized by pyrolysis method (ZnO (PY)) and the gel-combustion method (ZnO (GC)) possess a positive charge while the co-precipitation method results in nanoparticles (ZnO (CP)) with negative surface charge.

n-Benzoyl-n-phenylhydroxylamine impregnated Amberlite XAD-4 beads were used for the removal of Th(IV) from a mixture of ions. The impregnated XAD was characterized using different techniques like weight and colour change, IR spectra, surface area and pore size measurements to confirm the presence of n-BPHA within the macroreticular resin structure. The experimental conditions were optimized to make the separation fast and selective. It was seen that the maximum sorption was achieved in the pH range of 3–7.5 and uptake was nearly complete within half an hour. The results obtained in the present study were subjected to extensive modelling in order to get a complete understanding of the sorption process. It is seen that the maximum uptake was calculated to be 500 mg/g and has very fast kinetics it was seen that the process is chemisorption. It was further deduced from the modelling that the overall sorption process was controlled dominantly by external mass transfer. Considering the simplicity this procedure, the present study has a possible application for the removal of thorium from different mixtures.

Antimony phosphate nanoribbons was synthesized and characterized using different techniques. Studies showed that the synthesized antimony phosphate possessed highly crystalline monoclinic SbPO4 phase with an average crystallite size of 14 nm. TEM studies showed that antimony phosphate was present both as nano ribbons and nano particles. It is observed that the nano ribbons have length in the range of 500–700 nm and width around 100–200 nm whereas the nanoparticles size in the range of 1–5 nm. The synthesized nano phosphate was studied for its efficiency as sorbent for uptake of various metal ions including uranyl ion. The results indicated that a clean separation of uranyl ion from its various binary mixtures could be achieved at optimized pH of 4.5 and equilibration period of 1 h using 0.1 g of the sorbent.

Polyaniline (Pani) was synthesized by the chemical oxidation of aniline. The use of persulphate instead of dichromate was desired in order to avoid the incorporation of chromium in the polymer matrix. The presence of chromium in the matrix, when dichromate was used as an oxidant, was confirmed by various techniques. The batch mode experiments showed that Pani could be used for separation of different metal ions. These ions were converted into their anionic complexes using suitable complexing agents. It was found that EDTA was used as a suitable reagent for the separation of Cu2+ from Zn2+ whereas the uranyl ion uptake could be increased to about 95 % when carbonate was used instead of EDTA as complexing agent. A possible application of the above exchange system to preconcentration of uranyl ion from seawater has also been examined.

Nanocrystalline manganese oxide was prepared and characterized using various techniques like XRD, surface area analyzer and zeta potential measurements. The sorption characteristics with respect to uptake of various ions including uranyl have been evaluated. Various experimental conditions which affect the sorption characteristics have been studied. Nanocrystalline manganese oxide was prepared by the hydrolysis of KMnO4 and the nano oxide were found to have a size of 8 nm and surface area of 145 m2/g. Due to the high surface area, the sorption property of the nano oxide was good. It was found that the sorption was achieved at different pH values and with varying time of equilibration. Thus it is seen that the kinetics was an important aspect for the possible separation of metal ions.

Solvent extraction is hoary yet modern technique with great scope of research due to the various intriguing phenomena in the system. Tri-n-butyl phosphate (TBP) is a well known extractant which has been extensively used for separation of uranium matrix prior to elemental profiling. In this paper, one of the impurities namely Fe is being considered as it posed a challenge to the separation due to its co-extraction with TBP along with uranium. In these studies, for the first time, the existence of cation-cation inner sphere complexes between the UO22+and Fe3+ ions in both aqueous and organic phases have been establisted in addition to the selective separation of iron from uranium sample matrix using only TBP. The data from both spectrophotometric and thermophysical studies corroborated one another confirming the presence of cation-cation interactions (CCIs). The developed solvent extraction with only TBP showed almost no interferences on the iron extraction from matrix uranium and other co-ions like aluminum and copper. This has been the first time application of pure TBP for selective removal of iron from uranium samples. The procedure possessed excellent reproducibility and robustness.

were prepared and char-acterized using various techniques like XRD, TEM, surface area analyzer and zeta potential mea-surements. The synthesized oxides were evaluated for their sorption characteristics with respect touptake of lead ion. It was found that depending on the nature of the oxide the maximum sorptioncould be achieved within varying periods of time. However, it was found that for all the sorption,the optimum pH was around 6. It was seen that the oxides could be used as room temperaturesorbents for uptake of Pb

Sodium boroaluminosilicate glasses, (Na2O)0.22(K2O)0.029(B2O3)0.05(SiO2)0.69(Al2O3)0.011 and (Na2O)0.05(K2O)0.029(B2O3)0.22(SiO2)0.69(Al2O3)0.011 having different B2O3 to Na2O mole ratio of 0.23 and 4.4 respectively were investigated for their uptake characteristics of cationic dyes, namely Rhodamine 6G and methylene blue, from aqueous solutions. Both the glasses have been found to adsorb these dyes. However, the glass with B2O3 to Na2O ratio of 0.23 is found to have more uptake capacity with 2.5 and 1.8 mmol of Rhodamine 6G and methylene blue respectively per gram of the glass sample. For Rhodamine 6G dye, the amount of uptake by glass is found to be significantly higher than that of conventionally used activated charcoal (0.1 mmol/g). Based on 29Si and 11B magic angle spinning nuclear magnetic resonance technique, it is confirmed that the increased concentration of Si–O− Na+ and BO4− Na+ linkages present in the glass with B2O3 to Na2O mole ratio of 0.23 is responsible for the increase in its uptake of the dye compared to the glass sample with B2O3 to Na2O mole ratio of 4.4. From fluorescence studies, incorporation of the dye molecules in the glass matrix is confirmed. The present study is quite relevant for the removal of dye molecules present in untreated aqueous solutions generated from the textile industry.

The carrier activity of 8-hydroxy quinoline (oxine) towards the facilitated transport of copper ions through chloroform bulk liquid membrane has been studied. The effects of pH of the source phase, the nature of stripping agents in the receiving phase, presence of other cations, nature of synergistic reagents on the transport were investigated. A solution of 0.1 M nitric acid (HNO 3 ) served as receiving phase for maximum transport of the metal ion. Addition of 2-amino pyridine to the membrane phase had a synergistic effect and caused a pronounced enhancement in the transport, while citric acid or glycine did not change the transport significantly. Maximum transport efficiency was observed for Cu 2+ ion when it was present in the concentration of 10 −4 M. Tolerance to the presence of Pb 2+ , Zn 2+ , Cd 2+ , Ni 2+ , Fe 2+ and Fe 3+ ions was investigated and it was found that Cu 2+ transport was not affected even in the presence of 10-fold concentration of these ions. This system was applied for the recovery of copper in electroplating industrial waste water samples.

Two series of boroaluminosilicate glasses having varying mole ratios of B 2 O 3 /Na 2 O (series 1) and B 2 O 3 /SiO 2 (series II) were prepared by conventional melt-quench method. Based on 29 Si and 11 B MAS NMR studies, it has been established that for series I glasses up to 15 mol% B 2 O 3 content, Na 2 O preferentially interacts with B 2 O 3 structural units resulting in the conversion of BO 3 to BO 4 structural units. Above 15 mol% B 2 O 3 for series I glasses and for all the investigated compositions of the series II glasses, silicon structural units are unaffected whereas boron exist in both trigonal and tetrahedral configurations. Variation of microhardness values of these glasses as a function of composition has been explained based on the change in the relative concentration of BO 4 and BO 3 structural units. These glasses in the powder form can act as efficient room temperature ion exchangers for metal ions like Cu 2+ . It is seen that the ion exchange does not affect the boron and silicon structural units as revealed by IR studies.

Removal of various toxic species from aqueous streams is of great importance. Sorption is one of the important remediation procedures as it involves the use of cheap and easily available materials. Also the advantage of regeneration of the sorbent involves the possibility of using novel sorbents. Nanosorbents are very important as the removal is based on the surface phenomena and this is greatly affected by surface charge and area. Functionalization has been very important to bring about the removal of metal ions with greater selectivity., {"references":["F.W. Pontius, J. Am. Water Works Assoc., 1996, 88:22-27, 30-33.","J. Y. Choi, D. S. Kim, J. Y. Lim, J. Environ. Sci. Health A Tox. Hazard. Subst. Environ. Eng. 2006, 41, 1155-1172.","S. Pacheco, R. Rodriguez, J. Sol-Gel Sci. Technol. 2001, 20, 263–273.","F. M. Koehler, M. Rossier, M. Waelle, E. K. Athanassiou, L. K. Limbach, R. N. Grass, D. Günther, W. J. Stark, Chem. Commun. (Cambridge), 2009, 4862–4864.","S. Singh, K. C. Barick, D. Bahadur, J. Mater. Chem. A. 2013, 1, 3325 -3333.","B. R. White, B. T. Stackhouse, J. A. Holcombe, J. Hazard. Mater. 2009, 161, 848–853.","S. Singh, K. C. Barick, D. Bahadur, J.Hazard. Mater. 2011, 192, 1539-1547.","Jerina Majeed, Jayshree R, S. Chandramouleeswaran, O. D. Jayakumar, A. K. Tyagi , RSC Adv. 2013, 3, 3365-3373."]}

In this study, Fe3O4@SiO2 core-shell structure was synthesized by a one pot co-precipitation method, and its applicability as Low-Cost Abundantly available adsorbent for removal of heavy metal ions from simulated industrial waste water was examined. The detailed characterization of morphology showed that the Fe3O4 nanoparticle was coated with amorphous silica of a shell thickness of 2–3 nm. The core-shell magnetic nanoparticles (MNPs) showed a great removal capability of four different heavy metal ions (Zn (II), Co (II), Ni (II), and Cu (II). These MNPs showed high magnetic saturation values, which ensure the convenience of recovering sorbent for reusability with the assistance of external magnetic field. Specifically, this present study shows the use of MNPs as an effective recyclable adsorbent for environmental remediation.

A rapid and sensitive AAS method is described for the determination of copper, cadmium and lead based upon on-line preconcentration on a microcolumn packed with C18 material. These heavy metals are complexed with dithizone from ammonical solutions in the flow injection system and adsorbed on the column. The preconcentrated species were eluted with acidified methanol (pH ≥ 2) and injected directly into the nebulizer for atomization in an air-acetylene flame for measurement. The retention efficiency was better than 98% resulting in sensitivity enhancement factors of 80, 90 and 60 for 10 ml sample containing copper, cadmium and lead, respectively. The respective detection limits are 1.2, 0.6 and 3.0 ppb for copper, cadmium and lead. The throughput of the samples was found to be 30/h, with a loading time of 1 min. The method has been applied to the analysis of marine sediment samples.

Boroaluminosilicate glass having a specific composition could be successfully used for the selective uptake of thorium from a mixture containing uranium by controlling the solution pH only. Single ion uptake studies showed that the uptake of uranium and thorium was maximum at pH of 4.5 and 7.5, respectively. But uptake studies using mixtures with uranium and thorium showed that irrespective of the pH, the uptake of thorium was higher than that of uranium.

Barium borosilicate (BBS) and sodium borosilicate (SBS) glass samples, prepared by the conventional melt-quench method, were used for the uptake of Rhodamine 6G dye from aqueous solution. The experimental conditions were optimized to get maximum uptake and was found to be 0.4 mg of dye per gram of BBS glass sample. For the same network former to modifier ratio, barium borosilicate glasses are found to have improved extent of uptake for the dye molecules from aqueous solutions compared to sodium borosilicate glasses. Based on 29Si MAS NMR studies on these glasses, it is inferred that significantly higher number of non-bridging oxygen atoms present in barium borosilicate glasses compared to sodium borosilicate glasses is responsible for its improved uptake of Rhodamine 6G dye. 11B MAS NMR studies have confirmed the simultaneous existence of boron in BO3 and BO4 configurations in both barium borosilicate and sodium borosilicate glasses. The luminescence studies have established that the dye molecule is incorporated into the glass matrix through ion exchange mechanism by replacing the exchangeable ions like Na+/Ba2+ attached with the non-bridging oxygen atoms present in the glass.

Barium borosilicate glass was found to have high uptake capacity for many cations. To improve its selectivity, surface modification was carried out. In order to make the glass selective towards uranyl ion, organic ligands like tri-n-octylphosphine oxide (TOPO) and 8-hydroxy quinoline (Oxine) were used. It was observed that the surface modification resulted in the change in uptake property of the glass. The uptake process was faster and within 5 h, 90% of the uranyl ion could be taken up from a 0.01 mM solution. With use of the modified barium borosilicate glass and EDTA as masking agent, uranyl ion could be selectively removed from mixtures of cations.

Zinc oxide nanoparticles were synthesized by two different routes namely pyrolytic and gel combustion methods and characterized using different techniques like XRD, TGA/DSC, diffuse reflectance spectrophotometry, zeta potential, NMR and IR. The efficiency of the nanoparticles with respect to sorption of different toxic species like chromate and rhodamine 6G was evaluated. The studies showed that the synthesis route adopted affects the characteristics of the nanoparticles, thus leading to the difference in sorption efficiency. The mechanism of sorption proposed was based on the different characterization studies and it was found that the sorption was not only an electrostatic interaction but can occur due to the presence of pores or some binding groups. The highly pH-dependent sorption efficiency of the nanoparticles is evident from the results, whereas their kinetics was described by a pseudo-second-order kinetic model and further explained by using Weber–Morris and Boyd models. The overall rate process appeared to be influenced by both external mass transfer and intraparticle diffusion. Considering the simplicity of the synthetic procedure and the possibility of a cost effective catalyst, the developed nanomaterials have great potential for applications in water treatment technologies.