Adsorption on zinc

Butanol, reaction over reduced nickel oxide catalysts, 35 357-359 effect of ammonia, 35 343 effect of hydrogen, 35 345 effect of pyridine, 35 344 effect of sodium, 35 342, 351 effect of temperature, 35 339 over nickel-Kieselguhr, 35 348 over supported nickel catalysts, 35 350 Butanone, hydrogenation of, 25 103 Butene, 33 22, 104-128, 131, 135 adsorption on zinc oxide, 22 42-45 by butyl alcohol dehydration, 41 348 chemisorption, 27 285 dehydrogenation, 27 191 isomerization, 27 124, 31 122-123, 32 305-308, 311-313, 41 187, 188 isomerization of, 22 45, 46 isomers... 

Heat of Adsorption—Some data on the heat of adsorption on zinc oxide by different gases and vapors are presented in Table 42. This... 

The effect of ultraviolet and visible radiation on carbon monoxide adsorption on zinc oxide has also been studied (118). Both photoadsorption and photodesorption have been found, depending on the temperature, and there is a quite different pattern of behavior if oxygen has been preadsorbed. Reaction to give oxidized complexes, presumably of the COa,., or... 

Representation of the variations of the surface excess with the potential of the electrode is more usual than with charge density. Generally, only one part at the expected T(E) curve is observable in the dl region. For instance, for cyclohexanol adsorption on zinc faces, comparison of the three low-index faces for one concentration of cyclohexanol in 100 mM KCl + 0.1 mM H2SO4 is represented in Fig. 44 " the surface excess is the highest for the most densely packed face. 

Table 11. Summary of experimental results obtained for halogen adsorption on zinc blende 111-V semiconductor surfaces. The colunm headings are the same as defined for Table 1. ...

Proteins and other impurities can be removed successfully by adsorption on zinc hydroxide (130), on Lloyd s reagent (130,161), on kaolin (88,130), on bentonite, and on magnesol (188). It must be realized, however, that an excess of these reagents will adsorb hyaluronic acid as well (130). 

Presumably, thiol adsorption on these surfaces involves desorption of surface oxygen and hydroxide groups and the thiol seems to be mainly coordinated to the metal atoms in the oxide, as x-ray photoelectron spectroscopy (XPS) indicates, for instance, for thiol adsorption on zinc-terminated ZnO [86,87], where the thiol reduces the oxygen at the surface and forms a zinc-sulfur bond. O-polar ZnO, on the other hand, seems only to adsorb the thiols molecularly at room temperature [87]. 

This is in clear contrast to thiols on gold. For that system, longer immersion times continuously improve the ordering of the thiol. This is most likely due to the effect that during longer immersion time the corrosiveness of the ethanolic thiol solution overcomes the protective properties of the thiol film. Obviously, thiol adsorption on zinc is much more complicated than on gold and the procedure of film preparation becomes a by far more critical parameter. 

Nagoe, M. Morimoto, T. (1969). Differential heat of adsorption and entropy of water absorbed on zinc oxide surface. Journal of Physical Chemistry, 73, 3809-14. 

Figure 3.15 shows the validity of above simplest equation for adsorption of O-atoms provided that there are different concentrations of interstitial zinc atoms on the zinc oxide surface. In case of oxygen atoms the experiment has been carried out in absence of molecular oxygen so that effect of its adsorption on change in conductivity was ruled out. O-atoms were produced by means of pyrolysis of carbon dioxide. From this figure we notice that zinc atoms (superstoichiometric) applied onto the surface of the zinc oxide film are the active centres of adsorption of... 

Moreover, quantitative relations of stationaiy concentrations of these particles with variation of the electric conductivity of a semiconductor sensor (based on zinc oxide) caused by their adsorption are also similar. 

Zinc dialkyldithiophosphates (ZDDPs), which act as antiwear additives in lubricating oils and were postulated to exist in various molecular forms (monomer, dimer or neutral form, and basic form), were studied by multi-edge (Zn K-, P K- and S K-) XAS for structural assessment [311]. Grazing incidence absorption spectroscopy measurements have provided evidence for breakdown of the ZDDP molecule following its adsorption on to a steel substrate surface [312]. XANES and CEMS were used to study the interaction of per-fluoropolyalkyl ether (PFPAE) additives with Fe-based alloys [313],... 

Carbonate removal decreases the adsorption capacity of calcareous soils for trace elements such as Zn (Martinez and Motto, 2000). Solubility curves of the calcareous soil after removal of carbonates resemble those of noncalcareous soils. Solubility values in calcareous soils are within those found for noncalcareous soils. Zinc is completely desorbed after adsorption on pure CaC03 surfaces by lowering the pH of the solution (Zachara et al., 1989). 

Shuman L.M. Effect of removal of organic matter and iron or manganese-oxides on zinc adsorption by soil. Soil Sci 1988 146 248-254. 

Shuman L.M. Effect of roganic waste amendments on zinc adsorption by two soils. Soil Sci 1999 164 197-205. 

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