Oxides adsorption characteristics

Nelson YM, Lion LW, Ghiorse WC, Shuler ML (1999) Production of biogenic Mn oxides by Leptothrix discophora SS-1 in a chemically defined growth medium and evaluation of their Pb adsorption characteristics. Appl Environ Microbial 65 175-180... 

Lion, L. W., Altmann, R. S. and Leckie, J. O. (1982). Trace-metal adsorption characteristics of estuarine particulate matter evaluation of contributions of iron/ manganese oxide and organic surface coatings, Environ. Sci. Technol., 16, 660-666. 

Suzuki, T. M., Tanco, M. L., Tanaka, D. A. P., Yokoyama, T., Matsunaga, H., Yokoyama, T., Adsorption characteristic and removal of oxo-anions of arsenic and selenium on the porous polymers loaded with monoclinic hydrous zirconium oxide, Sep. Sci. Technol., 36, 2001,103-111. 

Therefore, the reaetion rate of corrosive oxidation of jamesonite and its adsorption characteristics are different in different media of adjusting pH at the same pH condition. The oxidation rate of jamesonite is minimal in Na2C03 solution. It is basically the same in Ca(OH)2 solution as in NaOH solution, but Ca(OH) is more easy to adsorb on jamesonite siuface. 

In this chapter we shall focus on the synthesis and adsorption characteristics of a CMS, prepared by a co-condensation or sol-gel route following the S°I° (S°, a neutral amine 1°, a neutral inorganie preeursor) pathway [3,6]. Immobilization of some cobalt(III) oxo clusters on CMS support, characterization of the resultant supported materials, and the use of these Co(III)-CMS materials in eatalytie oxidation rmder enviromnentally friendly conditions are also described. Related results available in the published literatine are also included at appropriate places with a view to broadening the scope of oin discussion. 

Before any further discussion of the implications of these adsorption characteristics, some pertinent properties of zinc oxide as a semiconductor will be reviewed. 

Sorption on oxides and hydrous oxides has been extensively studied both experimentally and theoretically. In order to define an ideal oxide or hydrous oxide exchanger, we will rely on experiments with well-defined sorbents such as chromatographic alumina (1-4). Briefly, the adsorption characteristics of oxides and hydrous oxides are (1) At high pH, they act as cation exchangers but with less sensitivity to the total salt concentration than clay minerals. This behavior is illustrated in Figure 2, where sorption of strontium on alumina is shown. 

Abstract. Several series of pyrocarbon/silica adsorbents were prepared using fumed oxides of different specific surface areas, and mesoporous silica gel Si-100, as inorganic matrices. Different synthetic and natural polymers as well as glucose were used as carbon precursors. Solutions of phosphoric acid at various concentrations were utilized to prepare functionalized hybrid carbon-silica adsorbents. Nitrogen, p-nitrophenol and Cd(II) adsorption isotherms as well as AFM, XRD and XRF methods were used to estimate the structural and adsorption characteristics of the adsorbents. 

Carbon/silica adsorbents with pure or functionalized carbon deposits, or functionalized silica surfaces, are of interest for many purposes, An improvement of the structural and adsorption characteristics of carbon deposits is desirable.1 Pyrocarbon deposits formed by carbonization of low-molecular organic precursors (dichloromethane, cyclohexene, alcohols, acetylacetone, acenaphthene, etc) at oxide surfaces typically possess a low inner specific... 

V. M. Gun ko, J. Skubiszewska-Ziqba, R. Leboda, K. N. Khomenko, O. A. Kazakova, M. O. Povazhnyak, and I. F. Mironyuk, Influence of Morphology and Composition of Fumed Oxides on Changes in Their Structural and Adsorptive Characteristics on Hydrothermal Treatment at Different Temperatures,./. Colloid Interface Sci. 269, 403-424 (2004). 

An interesting avenue for investigation is to examine the adsorption characteristics on single crystals concurrently with electrical measurements. Thus, any relationship which possibly exists between the slow states and the chemisorption might be positively revealed. Examination of the adsorption characteristics of reduced germanium crystals and the effect of the fast states would also be of interest. These studies have been initiated. It remains clear at this time, however, that the semiconductor properties of the germanium influence the surface properties of the thin oxide films supported thereon. The influence is clear in the case of propanol adsorption and the differences are even more dramatic in the case of water adsorption. 

The commonest gel for adsorption purposes is silica gel but measurement have also been carried out on ferric oxide, aluminium oxide, stannous oxide and titanium oxide. The characteristics of adsorption on silica gel differ somewhat from those for charcoal, particularly with respective Freundlich isotherm which holds fairly accurately. Moreover, deviation from Henry s Law even, seems to be much less than for charcoal. Water is somewhat exceptional. Silica and alumina gels are used as adsorbents for removing moisture and for controlling humidities of rooms. 

Although oxidation has been used to purify carbon materials, oxygen-carbon reactions have been shown to drastically alter physiochemical properties, such as wettability and adsorption characteristics. Moreover, oxidation can easily induce damage to carbon materials or even destroy the sample. This is of particular importance in the case of carbon nanostmctures. Thermogravimetric analysis (TGA), which measures changes of mass during oxidation processes, has been widely used to determine the purification conditions [22-24]. However, TGA does not provide information on what type of carbon is removed from the sample or to what extent nanostructures are damaged. 

Blackwell, J.A. Carr, P.W. Study of the fluoride adsorption characteristics of porous microparticulate zirconium-oxide. J. Chromatogr. 1991, 549, 43-57. 

Sanderson (1940) observed up to six-fold differences in the ability of soils to adsorb hydrocarbons in his laboratory. He also noted that the adsorptive characteristics of the colloidal soil systems would vary slowly with moisture content, time and season. Of particular significance was his observation that the adsorptive capacity for hydrocarbons on wet soil was only a small fraction of that for dry soil. A further complication is created by near-surface biological activity that creates wide variations in the content of carbon dioxide, nitrous oxide and other biological gases. Overcoming all these problems is probably impossible however, it will suffice if the gases are liberated in proportion to the amounts present so that the analytical results bear some relationship to one another, and allow identification of potentially prospective areas. 

Performance improvement in 1102 is achieved by doping the titania with platinum or vanadium oxide and copper. In order to improve the adsorption characteristics of Ti02, attempts have been made to support fine Ti02 on the porous adsorbent materials such as silica, alumina, activated carbon, clay, and zeolites. Ti02-supported adsorbent provides higher specific surface area and introduces more effective adsorption sites than bare Ti02. Decomposition rates of the substrates are found to increase due to one or... 

Volatilized sulfides have not yet been utilized for applied separations. In the meantime, Korotkin, at al. [57] reported adsorption characteristics for a number of such compounds a sample chromatogram is shown Fig. 1.14. The deposition temperatures of the investigated sulfides proved to correlate with the sublimation energies of the bulk compounds. Notice an enhanced volatility of the compounds with less than four sulfur atoms in the molecule it seems to be attributable to less polar bonding than that in oxides. The paper offers an extended discussion of the potentialities of sulfides for isolation and radiochemical separations of elements. 

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