CdS quantum dots embedded in PVP: Inorganic phosphate ion sensing in real sample and its antimicrobial activity.

Polyvinyl-pyrrolidone capped spherical cadmium sulphide quantum dots (CdS-PVP QDs), 2-6 nm in size, were developed as a selective turn-on fluorescence nanosensor for monohydrogen phosphate ion (HPO42-) in aqueous medium. Fluorescence intensity of CdS-PVP QDs significantly increased with addition of HPO42- ions, whereas the other common inorganic ions had very little effect on the fluorescence intensity. The proposed sensor may be efficiently used for the detection of HPO42- ions at a low level of concentration up to 213 nM in real urine sample. Cell imaging study indicates that the CdS-PVP QDs are cell permeable and can detect the intracellular distribution of HPO42- ions under fluorescence microscope. The CdS-PVP QDs showed considerable activity against Staphylococcus aureus also.

Study on size dependent ion exchange property of nanosilica as green inorganic exchanger in radiochemical separation.

Silica nanoparticles (SiNPs) of different sizes were synthesized using different concentration of precursor material tetraethylorthosilicate (TEOS). The structural and morphological details of the material were obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM study was followed by energy dispersive spectroscopic analysis (EDS) for elemental analysis of the sample. The particle sizes were determined by dynamic light scattering (DLS) method. Ion exchange capacity was measured for different metal ions with sizes of the SiNPs and size-dependent ion exchange property of the material was investigated thoroughly. The nanomaterial of the smallest size of around 13.54 nm was used to separate carrier-free 90Y from 90Sr in column chromatographic technique using 1% aqueous EDTA as eluting agent at pH 6.

A new chelating resin containing azophenolcarboxylate functionality: synthesis, characterization and application to chromium speciation in wastewater.

The synthesis of a new stable chelating resin from the polystyrene divinylbenzene copolymer is reported. The polystyrene is first functionalized with a phenolic group and then allowed to couple with diazotized anthranilic acid through the --N==N-- bond. The resulting polymer containing azophenolcarboxylate with an ONO chelating environment has been characterized by elemental analysis, hydrogen ion capacity, and water regain value. Its stability towards thermal and different chemical environments has been evaluated. The sorption capacity of the chelating resin for Cr(III) and Cr(VI) as a function of pH has been studied. The interesting point is that chromium(III) is selectively retained at ca. pH 5.0 and chromium(VI) at ca. pH 2.0. When packed in a column, the new material is able to separate Cr(III) from Cr(VI). Five replicate determinations of 10 microg Cr(III) and 10 microg Cr(VI) present in 100 mL solution gave recoveries of 96.9+/-2.9% (for Cr(III)) and 96.2+/-2.1% (for Cr(VI)) at the 95% confidence level. Calibration graph was linear over the concentration range of 0-250 microg L(-1) of chromium species with correlation coefficient (R) of 0.99994. The detection limits based on 3sigma criterion were determined to be 0.6 microg L(-1) for Cr(III) and 0.9 microg L(-1) for Cr(VI). The developed method was successfully used for the speciation of chromium in wastewater.

A chelating resin containing bis(2-benzimidazolylmethyl)amine: synthesis and metal-ion uptake properties suitable for analytical application.

A new stable chelating resin was synthesized by incorporating the bis(2-benzimidazolyl methyl)amine into Merrifield polymer through CN covalent bond and characterized by elemental analysis, IR and thermal study. The sorption capacity of the newly formed resin for Ag(I), Cu(II), Fe(III), Hg(II) and Pb(II) as a function of pH have been studied. The resin exhibits no affinity for alkali or alkaline earth metals. In column operation it has been observed that Ag(I) in trace quantities can be separated from different complex matrices and Hg(II) can be removed from the river water spiked with Hg(II) at usual pH of natural waters.