Aqueous Solution Of Zinc Acetate Research Articles

Structural, optical and electrical studies on spray deposited highly oriented ZnO films

Thin films of Zinc oxide (ZnO) have been prepared on glass substrates by spray pyrolysis techniques using 0.025 M aqueous solution of Zinc acetate. X-ray diffraction (XRD) reveals that the films are polycrystalline in nature having hexagonal wurtzite type crystal structure. The room temperature resistivity is of the order of 10 −1 Ω cm. Estimated band gap energy from optical absorption data is around 3.27 eV. Thermoemf measurements show that films are of n-type.

Synthesis and characterization of α-hopeite, Zn 3(PO 4) 2·4H 2O

Orthorhombic α-Zn 3(PO 4) 2·4H 2O, α-hopeite, was synthesized from an aqueous solution of zinc acetate and orthophosphoric acid. The synthesis from these starting materials yielded best results with respect to purity and crystallinity. Structural characteristics of the compound were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and thermogravimetric/differential thermal analysis (TG/DTA). Supplemental data came from surface area, particle size distribution, and density measurements. The obtained compound proved to be highly crystalline and stoichiometric. Dehydration of α-hopeite is accompanied by at least two endothermic effects and already starts at temperatures <373 K. This observation has important implications for the technical zinc phosphate coating process. The dehydration behavior can be explained by results from low-temperature diffuse reflectance IR spectroscopy (DRIFT).

Optical and electrical properties of zinc oxide films prepared by spray pyrolysis

Zinc oxide thin films were prepared on glass substrates from an aqueous solution of zinc acetate by spray pyrolysis. These films were characterized using X-ray diffraction, scanning electron microscopy and optical transmission. The films were highly transparent to the visible radiation and electrically conductive. Films deposited at optimum conditions exhibited a resistivity of 3·15×10−3 Ωm along with a transmittance of 98% at 550 nm.

Photoluminescent Mn-Doped ZNS Nanoclusters Synthesized within Block Copolymer Nanoreactors

ABSTRACTMn-doped ZnS nanoclusters were synthesized within microphase-separated films of diblock copolymers containing carboxylic acid units on one of the blocks. Zinc was selectively sequestered into the acid-containing domains by treating the films with diethylzinc or an aqueous zinc acetate solution. Manganese was loaded by subsequent treatment of the films with aqueous manganese acetate solutions. The manganese ions displaced a fraction of the zinc ions, and the extent of loading was controlled by varying the loading time, and the concentration of the manganese acetate solution. The extent of loading was tracked using ICP discharge emission spectroscopy. The doped nanoclusters were formed by subsequent treatment with H2S. The size of the doped ZnS nanoclusters could be varied by carrying out the H2S exposure in the presence of a coordinating base. Photoluminescence measurements revealed that the doped nanoclusters were photoluminescent, and showed the characteristic manganese emission. The universal doped cluster synthesis scheme used is quite general and can be easily modified to produce other doped nanocluster clusters, such as Tb-doped ZnS, or Mn-doped CdS.

Properties of ZnO layers deposited by “photo-assisted” spray pyrolysis

Layers of ZnO have been deposited onto glass substrates by “photo-assisted” spray pyrolysis using zinc chloride and zinc acetate as precursors in aqueous and non-aqueous solutions. The structure of these films has been shown by reflection high energy electron diffraction (RHEED) to be hexagonal, the crystallites exhibiting a pronounced preferred orientation with their (0002) planes lying parallel to the substrate. The transmission properties of layers deposited using an aqueous solution of zinc acetate were found to be superior. In their as-deposited form the films repeatedly exhibited carrier concentration, Hall mobility and resistivity values of ∼(1–2) × 1017cm−3, ∼ 0.1–0.2 cm2V−1s−1 and ∼ 150–600 Ω · cm respectively. However, following annealing at 400°C for 15 min in forming gas (H2 + N2), these parameters improved to ∼ 5 × 1019cm−3, ∼ 29 cm2V−1s−1 and ∼ 1.5 × 10−2 Ω · cm respectively. Annealing did not change the transmittance but there was a noticeable improvement in the degree of preferred orientation. The considerable improvement in the electrical properties after annealing can be largely attributed to the increases in carrier concentration and mobility due to the change in stoichiometry and possibly a reduction in inter-granular potential barriers respectively.

New procedure for determining reactive Fe(III) and Fe(II) minerals in sediments

Sediments from the River Elbe estuary and incubated sediments were extracted with 1 N HCl for 24 h at room temperature. The extracted ferric and ferrous iron was determined with DC and AC polarography. Acid‐volatile sulfide was determined from H2S trapped in aqueous zinc acetate solution. Analysis of sediment samples and extraction residues with Mössbauer spectroscopy demonstrated that the Fe oxidation state was conserved during extraction and polarographic determination, siderite and vivianite were completely dissolved, and Fe(II) in chlorite was partially extracted with HCl. Incubation experiments showed that extractable Fe was almost completely oxidized to Fe(III) at the oxic sediment surface and reduced to Fe(II) in deeper anoxic layers within a few weeks. Reactive Fe(III), i.e. that fraction of Fe which was reducible on the time scale of the incubation experiment, was completely extracted with HCl.

Influence of substrate temperature on the structural, optical and electrical properties of ZnO thin films prepared by spray pyrolysis

The influence of substrate temperature on the structural, optical and electrical properties of ZnO films prepared by the spray pyrolysis method using aqueous solution of zinc acetate has been investigated. The films are polycrystalline and X-ray diffraction measurements show a strong preferred orientation along the [002] plane which is strongly dependent on the substrate temperature. Optical absorption spectra, show high transparency of the film (90–95% transmission) in the visible range, with a sharp absorption edge around 375 nm wavelength of light which closely corresponds to the intrinsic band gap of ZnO (3.3 eV). ZnO films with the lowest resistivity, which is due to the increased mobility resulting from the improvement of the crystallinity of the films, can be prepared at a substrate temperature of 490 °C.

Continuous preparation of activated carbon supported zinc acetate catalyst and industrial synthesis of vinyl acetate from acetylene

AbstractA continuous manufacturing method of an activated carbon supported zinc acetate catalyst has been established. Based on the dipping of a crushed activated palm carbon into a zinc acetate aqueous solution, the catalyst is prepared for the synthesis of vinyl acetate from acetylene in an industrial fluidized reaction vessel.The relationship between the supported amount of zinc acetate and various factors has been studied. Based on these results, an empirical formula was developed. Using this formula, the continuous manufacturing apparatus was designed and constructed for the purpose of preparing the optimum supported fluidized catalyst. To minimize the activated carbon loss due to crushing and wearing, a vibrating conveyor system was employed.This continuous manufacturing process produced a uniform catalyst with an activated carbon feed rate of 0.25 m3 h−1. Using this catalyst, a series of operational tests of the vinyl acetate synthesis was performed for investigating the optimum reaction conditions. These operational tests were carried out using an industrial fluidized reaction vessel of 3.28 m diameter and 50 tons day−1 vinyl acetate production capacity. Based on these test results, the reaction rate constant and the deterioration rate constant were newly introduced, and the optimum operation conditions were then determined.

Generation of fume aerosols of zinc oxide.

Fume aerosols of zinc oxide were generated by nebulization of aqueous solutions of zinc acetate (30 milligrams zinc acetate per milliliter water), with subsequent thermal vaporization and chemical degradation to the oxide. A Retec nebulizer operated with compressed air was used to generate the zinc acetate mists which were passed through a quartz tube furnace (1150 degrees C) to dry the droplets and degrade the acetate to the oxide form. Ultrafine particles were formed in this process, demonstrating that zinc acetate was vaporized as aerosol entered the heated tube prior to thermolysis. The few larger particles probably represent those larger droplets which do not completely vaporize prior to thermolysis. Cascade impactor samples indicated a mass median aerodynamic diameter (MMADar) of 0.8 +/- 0.1 (SD) microns with geometric standard deviation (sigma g) of 2.9 +/- 0.5 (SD). About 25% of the zinc was associated with particles smaller than 0.3 microns in aerodynamic diameter, equivalent to spherical particles smaller than 0.09 microns in geometric diameter.

Ultrasonic studies in aqueous solutions of zinc acetate - II

The ultrasonic absorption in zinc acetate solutions and the anomalous temperature variation of absorption observed at various frequencies is explained on the basis of activated complex formation and the attendant relaxational process. The value of the activation energy of the complex has been calculated.

Ultrasonic Studies in Aqueous Solutions of Zinc Acetate

Aqueous solutions of zinc acetate of different concentrations have been studied in respect of their ultrasonic and other physical properties at various temperatures. It is noticed that in case of zinc acetate the ultrasonic absorption coefficient which was earlier found to be increasing with increase in temperature at a frequency of 20 Mc/s, is found to have a peak in the absorption Vs temperature curve at a lower frequency of 8 Mc/s. With decreasing concentrations the peak loses sharpness and ultimately at very low concentrations there is a reversal in the temperature coefficient of absorption which now decreases with the rise in temperature. The results have been discussed along with observations in aqueous solutions of zinc sulphate and acetic acid.