Academic literature on the topic 'Cadmium cesium bromides mixed'

Mn2+and Cd2+form a family of isostructural hexacyanoferrates(II,III). Their crystal structures, including those of mixed compositions containing K+and Cs+as charge balance cations, were resolved and refined from XRD powder patterns. The crystal structures of M3[Fe(CN)6]2⋅xH2O and MCs2[Fe(CN)6] (where M=Mn, Cd) were refined in the space group Fm3m. The mixed salts, MK2[Fe(CN)6]⋅2H2O, were found to be orthorhombic (space group Pmn21). The orthorhombic structure results from a local distortion due to monohydrated potassium ions located in interstitial sites. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+is a large ion, which practically fills the available interstitial voids stabilizing the cubic structure. In solutions of K+and Cs+the single salts, M2[Fe(CN)6]⋅8H2O (monoclinic P21/n) also transform, in this case liberating M2+ions and forming the corresponding mixed salts. An analogous but slow structural transformation was also observed in the anhydrous forms of these single salts. These structural transformations could be relevant to the use of these compounds as ion exchangers and particularly for the sorption of137Cs+from radioactive waste solutions. The XRD data were complemented with structural information from infrared (IR), Mössbauer and water vapor adsorption techniques. ©2004 International Centre for Diffraction Data.

Recently, the release of some metal ions to the environment has been observed to cause serious damages to human health and the environment. Herein, a chromium(VI)- and zinc(II)-selective adsorbent (CB18crown6/SBA-15) was successfully fabricated through the covalent attachment of 4′-carboxybenzo-18-crown-6 (CB18crown6) as a ligand on mesoporous silica support (SBA-15). The CB18crown6/SBA-15 adsorbent was characterized by Fourier-transform infrared (FTIR) spectrometry, X-ray diffraction (XRD), N2 adsorption–desorption, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). To evaluate its ability to selectively capture Cr(VI) and Zn(II), adsorption experiments were conducted. The influences of pH, initial concentration of metal ions, and coexisting metal ions on the adsorption process were examined. The CB18crown6/SBA-15 selectively adsorbed Cr(VI) at pH 2 and Zn(II) at pH 5, respectively, from the mixed aqueous solutions of chromium, zinc, lithium, cadmium, cobalt, strontium, and cesium ions. The data for the adsorption of Cr(VI) onto the CB18crown6/SBA-15 were well explained by the Langmuir adsorption isotherm. In addition, the recycling and reuse of CB18crown6/SBA-15 was successfully achieved, and 71 and 76% reuse efficiency of Cr(VI) and Zn(II), respectively, was obtained after five cycles. This study suggests that the use of the CB18crown6/SBA-15 can be a feasible approach for the selective remediation of Cr(VI) and Zn(II) contamination.

Photoluminescence spectroscopy is a nondestructive optical method that is widely used to characterize semiconductors. In the photoluminescence process, a substance absorbs photons and emits light with longer wavelengths via electronic transitions. This paper discusses a method for identifying substances from their photoluminescence spectra using machine learning, a technique that is efficient in making classifications. Neural networks were constructed by taking simulated photoluminescence spectra as the input and the identity of the substance as the output. In this paper, six different semiconductors were chosen as categories: gallium oxide (Ga2O3), zinc oxide (ZnO), gallium nitride (GaN), cadmium sulfide (CdS), tungsten disulfide (WS2), and cesium lead bromide (CsPbBr3). The developed algorithm has a high accuracy (>90%) for assigning a substance to one of these six categories from its photoluminescence spectrum and correctly identified a mixed Ga2O3/ZnO sample.

High effectiveness of the granulated glauconite and nickel-cadmium sorbent modified with mixed ferrocyanide on its basis application as a filter bed for water solution purification from cesium radio nuclides has been demonstrated. Meeting of the developed sorbents mechanical strength of the GOST requirements to filtering grained materials has been stated. Results of the investigation of the sorption concentration of 137Cs radio nuclide from water solutions with experimental samples in static and dynamic conditions have been presented. The modified sorbent has shown an increased specificity in respect of 137Cs. The developed sorbents’obtained static exchange capacity in terms of 137Cs is estimated by the value >30 mg/g. Cesium sorption with the sorbents under study time dependencies have been obtained. It has been stated that the sorbent modification causes the process speed constant increase at the starting section of the kinetic curve. Output curves of the cesium sorption with the developed sorbents in dynamic regime are presented. Distribution coefficients for 137Cs obtained in dynamic conditions for the modified sorbent are one order of magnitude higher than that for granulated glauconite. During filtration of 34500 ml of water solution (≈ 8600 unit’s volumes) the fault did not exceeded 6 %. The obtained experimental data enable to recommend both granulated glauconite and its modified analog as a filter bed. For the first time it has been shown that the use of the modified sorbent allows to increase the treatment facilities filtering cycle. The sorbents developed on the basis of local natural materials can be applied in the water system treatment techniques for purification from cesium radio nuclide.

L'etude des proprietes optiques de cscdbr::(3) a montre l'existence de centres br::(2)**(2-). L'excitation des echantillons par des rayonnements ionisants (rx, faisceau d'electrons) et des experiences d'absorption a deux photons ont permis d'associer les differentes bandes d'emission et d'absorption observees a des transitions appartenant a ces centres. L'existence de ces centres br::(2)**(2-) est attribuee a la presence de defauts d'empilement. L'effet d'une pression hydrostatique, le dopage par des ions pb**(2x) et le recuit des cristaux confirment l'hypothese

Etude par une methode d'excitation selective sur cdcsbr::(3) dope par nd**(3+) et liyf::(4) dope par nd**(3+), pr**(3+) et ho**(3+), er**(3+), tm**(3+); etude de la redistribution de l'excitation optique entre deux ions constituant une paire, chemins de desexcitation. Mise en evidence du role dominant de l'interaction de superechange dans les processus de transfert