Zinc mobility

Zinc ligands are soluble in neutral and acidic solutions, so that zinc is readily transported in most natural waters (USEPA 1980, 1987), but zinc oxide, the compound most commonly used in industry, has a low solubility in most solvents (Elinder 1986). Zinc mobility in aquatic ecosystems is a function of the composition of suspended and bed sediments, dissolved and particulate iron and manganese concentrations, pH, salinity, concentrations of complexing ligands, and the concentration of zinc (USEPA 1980). In freshwater, zinc is most soluble at low pH and low alkalinity 10 mg Zn/L of solution at pH 6 that declines to 6.5 at pH 7, 0.65 at pH 8, and 0.01 mg/L at pH 9 (Spear 1981). Dissolved zinc rarely exceeds 40 pg/L in Canadian rivers and lakes higher concentrations are usually associated with zinc-enriched ore deposits and anthropogenic activities. Marine... 

Loosemore, N., Straczek, A., Hinsinger, P., Jaillard, B., 2004. Zinc mobilization from a contaminated soil by three genotypes of tobacco as affected by soil and rhizosphere pH. Plant Soil 260, 19-32. 

Vinyl neodecanoate [26544-09-2] is prepared by the reaction of neodecanoic acid and acetjiene in the presence of a catalyst such as zinc neodecanoate. Physical properties of the commercially available material, VeoVa 10 from Shell, are given in Table 4. The material is a mobile Hquid with a typical mild ester odor used in a number of areas, primarily in coatings, but also in constmction, adhesives, cosmetics, and a number of misceUaneous areas. Copolymerization of vinyl neodecanoate with vinyl acetate gives coating materials with exceUent performance on alkaline substrates and in exterior weathering conditions. 

Zinc phosphate cement mixes to a paste which is thin and mobile. Under pressure it flows readily to give a film 24 to 40 pm thick (Table 6.3). This film thickness is adequate to seat restorations, especially as McLean von Fraunhofer (1971) and Dimashkieh, Davies von Fraunhofer (1974) have shown that in practice the gap between tooth and restoration can be as much as 100 pm or more. 

In a typical study of conductivity. Cook (1982) used a cell consisting of two platinum disc electrodes, 12 mm in diameter and 1-5 mm apart. The setting AB cement was examined in this cell which had been calibrated using a standard solution of0 02 M potassium chloride. Plots were recorded of spedfic conductance against time for each of the setting cements. For zinc polycarboxylate there was found to be a rapid drop in spedfic conductance about 10 minutes after the start of mixing. This behaviour was consistent with the replacement of relatively mobile protons by significantly less mobile zinc ions in the polycarboxylate chain. Con-... 

F. Zhang, V, Rdmheld, and H. Marschner, Effect of zinc dehciency in wheat on release of zinc and iron mobilizing root exudates. Z. PJIanzeneniaelir. Bodenk. 152 205 (1989). 

Zinc oxide is a thoroughly studied typical semiconductor of n-type with the width of forbidden band of 3.2 eV, dielectric constant being 10. Centers responsible for the dope electric conductivity in ZnO are provided by interstitial Zn atoms as well as by oxygen vacancies whose total concentration vary within limits 10 - 10 cm. Electron mobility in monocrystals of ZnO at ambient temperature amounts to 200 cm -s". The depth of donor levels corresponding to interstitial Zn and oxygen vacancies under the bottom of conductivity band is several hundredth of electron volt [18]. 

We emphasize that these are rough calculations which depend on validity of approach and assumptions made on the values of mobility of current carriers in zinc oxide. To demonstrate convincingly that there is... 

The method of semiconductor sensors allows one to determine the flux of atoms, to which the sensor was exposed, from electric conductivity measurements (provided coefficients of ionization and reflection of oxygen atoms from zinc oxide films are known). In other words, the sensor technique can be used in this case as an absolute method [21]. Indeed, variation of electric conductivity of a semiconductor film Acrpi due to adsorption is known to be caused by variation of carrier concentration An in the film, rather than by variation of their mobility / [21] ... 

This supposition is experimentally substantiated by Kupriyanov et al. [160], In this work they investigated the influence of RGMAs upon the electrical conductivity of pure zinc oxide films and films activated by microcrystals of gold. The gold was chosen as the activator because of its chemical inactivity and high lateral mobility. This makes it possible to obtain islet films on a ZnO surface at room temperature, thus avoiding probable metallurgical processes. 

Reddy KJ, Wang L, Gloss SP. 1995. Solubility and mobility of copper, zinc and lead in acidic environments. Plant and Soil 171 53-58. 

Hydrogen-donor action involving direct or indirect hydrogenation by solid catalysts has provided partial reductions in the severity of treatment, not sufficient to eliminate waste of coal and of input hydrogen. To lower the temperature sufficiently requires mobile catalysts which can penetrate the coal. Melts such as zinc chloride are therefore a promising medium. 

Kadria E., Michel J. Effects of salinity on toxic element transfers in soils associated to agricultural wastewater reuse mobility and bioavailability of zinc and lead for ryegrass in soils irrigated with saline water. 2004. http //Kuk.uni-... 

Fig. 9. Hole mobility versus temperature for an InP Zn epilayer grown by OMVPE. a) before any hydrogenation, b) after hydrogen plasma for 6 hours at 200°C followed by a 275°C, 5 min. annealing. After hydrogenation, the InP layer is highly resistive and Hall measurements are difficult. The slight annealing is performed to partially reactivate the zinc acceptors to a value of 1.3 x 1016 cm-3, which makes possible Hall measurements. J. Cheval-lier et al., Materials Science Forum, 38-41, 991 (1989). Trans. Tech. Publications Semicond. Sci. Technol. 4, 87 (1989). IOP Publishing Ltd.

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