The effect of co-precipitation on cadmium(II) adsorption on hydrous aluminium(III) hydroxide in the presence of a range of chelates

The adsorption of cadmium(II) on freshly precipitated aluminium(III) hydroxide in the presence of a range of chelates has been investigated. By precipitating the metal, chelate and adsorbent together it is possible to change the pH variation of the metal-complex adsorption from anionic, ligand-like, binding to cationic binding. This is a general phenomenon and is explained by the formation of a ternary Al-O-Cd-L surface species. As a consequence of the preparation method, the pH edge is found to shift to lower pH values in the presence of the chelate which gives rise to an apparent increase in adsorption of Cd2+. This increase is, in general, most pronounced at [chelate] / [metal] > 1. Computer modelling shows that the observed trends result from the competition between Al-O-Cd-L and Al-L for the available aluminium( III) binding sites. The enhanced adsorption in the presence of phenylenediaminetetraacetate is anomalous since it is observed at a [ chelate] / [metal] approximate to 0.1 and cannot be interpreted by the simple competition model.

Speciation of Chlorometallate Ionic Liquids Based on Gallium(III) and Indium(III)

A range of ionic liquids was prepared by mixing 1-alkyl-3-methylimidazolium chloride with gallium(III) chloride or indium(III) chloride in various ratios, producing both acidic and basic compositions. Their speciation was investigated using Ga-71 NMR or In-115 NMR spectroscopy, as well as extended X-ray absorption fine structure. Polynuclear Lewis acidic anions, [MxCl3x+1](-), were found in chlorogallate(III) ionic liquids, but not in chloroindate(III) systems.

The electronic band structure of indium selenide:Photoemission and theory

The electronic band structure of vacuum cleaved single-crystal indium selenide has been investigated by X-ray and ultraviolet photoelectron spectroscopy. The valence band consists of three well separated groups, one derived from the Se 4s levels, and two derived from p-like wavefunctions. The band structure and valence band density of states has been calculated using a tight-binding single-layer approximation and all the major features in the experimental spectra are well accounted for. The spin-orbit splitting and electron loss structure associated with the In 4d core level is also reported.

The band structures of gallium and indium selenide

The band structures of the group III-VI monochalcogenides GaSe and InSe have been calculated using a semi-empirical tight-binding method in a two-dimensional approximation. Many of the discrepancies between experimental work and previous calculations for GaSe have been resolved. The results for InSe appear for the first time.

Unusual photoresponse of indium doped ZnO/organic thin film heterojunction

Photoresponse of n-type indium-doped ZnO and a p-type polymer (PEDOT:PSS) heterojunction devices are studied, juxtaposed with the photoluminescence of the In-ZnO samples. In addition to the expected photoresponse in the ultraviolet, the heterojunctions exhibit significant photoresponse to the visible (532 nm). However, neither the doped ZnO nor PEDOT: PSS individually show any photoresponse to visible light. The sub-bandgap photoresponse of the heterojunction originates from visible photon mediated e-h generation between the In-ZnO valence band and localized states lying within the band gap. Though increased doping of In-ZnO has limited effect on the photoluminescence, it significantly diminishes the photoresponse. The study indicates that optimally doped devices are promising for the detection of wavelengths in selected windows in the visible. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4704655]

Adsorption of metal cations by hydrous aluminium(III) or iron(III) hydroxide precipitates: enhancement by EDTA and related chelate molecules

Stoichiometrically equivalent concentrations of ethylenediaminetetraacetate, EDTA, and of related chelating anions increase the adsorption of ca. millimolar concentrations heavy metal aqua-ions on amorphous precipitates of aluminium(III) or iron(III) hydroxide and, although higher concentrations decrease the adsorption, poly-EDTA, a polyelectrolyte containing EDTA functional groups, shows no such decrease.

Ionothermal, microwave-assisted synthesis of indium(III) selenide

Microcrystalline indium(III) selenide was prepared from a diphenyl diselenide precursor and a range of chloroindate(III) ionic liquids via a microwave-assisted ionothermal route; this is the first report on the use of either microwave irradiation or ionic liquids to prepare this material. The influence of the reaction temperature, dilution with a spectator ionic liquid and variation of the cation and the anion of the ionic liquid on the product morphology and composition were investigated. This resulted in a time-efficient and facile one-pot reaction to produce microcrystalline indium(III) selenide. The product formation in the ionic liquids has been monitored using Raman spectroscopy. The products have been characterised using PXRD, SEM and EDX. Advantages of this new route, such as the ease of solubilisation of all reactants into one phase at high concentration, the negligible vapour pressure irrespective of the reaction temperature, very fast reaction times, ease of potential scale-up and reproducibility are discussed.