Specific adsorptions

S. Greg and K. Sing, Adsorption, Specific Surface, Porosity, (in Russian) Moscow Mir, 1970, 408 p. 

As defined in Chap. 4, the chemisorption energy is the difference between the initial and final energies of the system. Although we could use the expression (4.85) for AE, it is more convenient to work with that of App. L, with a slight modification to account for double adsorption. Specifically, we have... 

The binding energy in field adsorption can be derived from consideration of the kinetics of field adsorption. Specifically, it can be determined from a temperature dependence of the probability of field adsorption on an adsorption site, or the degree of coverage of field adsorption on a plane. As will be shown, a consideration of the probability of field adsorption based on adsorption time and desorption time leads to an equation equivalent to the Langmuir adsorption isotherm, but specific to the problem of field adsorption.112115 Let us focus on one surface atom. The average time it takes to have an image gas atom field adsorbed on the surface atom, ra, is... 

The adsorption of organic ligands onto metal oxides and the parameters that have the greatest effect on adsorption were also studied (Stone et al., 1993). The extent of adsorption was measured by determining the loss of the compound of interest from solution. The physical and chemical forces that control adsorption into two general categories were classified as either specific or nonspecific adsorptions. Specific adsorption involves the physical and chemical interaction of the adsorbent and adsorbate. Under specific adsorption, the chemical nature of the sites influences the adsorptive capacity. Nonspecific adsorption does not depend on the chemical nature of the sites but on characteristics such as surface charge density (Stone et al., 1993). The interactions of specific adsorption can be explained in two ways. The first approach uses activity coefficients to relate the electrochemical activity at the oxide/water interface to its electrochemical activity in bulk solution (Stone et al., 1993). This approach is useful in situations... 

Direct, nonsurfactant-mediated immobilization of metallothionein proteins [207-209] and streptavidin [210] at MWCNTs has also been carried out, the hydro-phobic regions of the proteins probably being responsible for the adsorption. Specific affinity binding of proteins to unmodified SWCNT sidewalls was demonstrated by the adsorption of monoclonal antibodies, IgG, specific for C60 fuller-enes, in aqueous solution. The affinity binding originated from the structural similarity of the tube sidewall graphite network and the C(M fullerene [221]. It was shown that the specific binding site of the IgG antibody is a domain of hydrophobic amino acids. 

Radio frequency heating, 500 Steam stripping, 500 Vacuum extraction, 500 Aeration, 501 Bioremediation, 501 Soil flushing/washing, 502 Surfactant enhancements, 502 Cosolvents, 502 Electrokinetics, 503 Hydraulic and pneumatic fracturing, 503 Treatment walls, 505 Supercritical Water Oxidation, 507 Solid Solution Theory, 202 Solubility products, 48-53 Metal carbonates, 433-434 Metal hydroxides, 429-433 Metal sulfides, 437 Sorption, 167 See Adsorption Specific adsorption, 167 See Chemisorption Stem Layer, 152-154 Sulfate, 261... 

Specific surface area (SSA) by gas adsorption Specific surface areas (expressed in m /g) were measured by Krypton adsorption at 77K (Micromeritics ASAP2400) and calculated using BET equation [3] Prior to measurements, powder specimens were outgassed under vacuum (5 millitorrs) at room temperature. Krypton was chosen as adsorbate because of the low SSA of some samples (SSAphysisorption method allows for measuring the overall surface developed by the powder particles including interparticular porosity (except sealed pores). 

Properties Well-crystallized bayerite, lauric acid adsorption specific surface area 27.9 m /g [1149]. 

Upgrade filters (particulate and adsorption) specific for biological and chemical threat agents. 

Adsorption and wetting Adsorption of gases and vapors, combined with IR spectroscopy, microcalorimetry, and so forth Temperature-programmed desorption of absorbed substances (ammonia, pyridine, and so forth, coupled with mass spectrometry and IR spectroscopy Heats of adsorption, specific surface area, pore size distribution, average pore diameter, and fractal dimension Acidic functional groups, relative acid strength ... 

It is a very simple methdology to investigate the adsorption specificity. In the cases where electrostatic adsorption or adsorption through hydrogen bonding takes place the surface groups remain practically intact and the pH does... 

Optimizing the catalyst In order to optimize the catalytic properties of titanium oxide impregnated with sulfuric acid, catalysts were prepared with different amounts of added sulfuric acid, with different activation times and activation temperatures. The catalyst was studied by X-ray diffraction, IR spectroscopy, and Na adsorption (specific surface area and pore size distribution). 

Greg , S.J., Sing, K.W., Adsorption. Specific Surface Area. Porosity, Moscow, Nauka, 1970, p. 407. 

When conditions 1 to 3 have been met, the adsorption specific surface area, in the SI units of square meters per kilogram, can be calculated with the equation... 

Typical results of specific surface area determinations on phyllosilicates by nitrogen gas/water vapor or nitrogen gas/CPB adsorption are listed in Table 1.7. For Mg-vermiculite and Na-montmorillonite, the measured adsorption specific surface area is close to that calculated from the unit cell dimensions and structural formula. For illitic mica, the area is about 14 per cent of the ideal crystallographic value, indicating that this mineral forms particles containing about seven phyllosilicate layers that cannot be penetrated by water vapor or CPB. 

Heats of adsorption, specific surface area, pore size distribution, average pore diameter, and fractal dimension... 

Gas chromatography can be used to determine the adsorption isotherms, the standard thermodynamic properties of adsorption, specific surface area and pore dimension distribution, provided that the stationary phase is a substance of large specific surface area (adsorbent). 

On the other hand, the changes caused by specific adsorption of anions in the solution side of the double layer can also be followed through the measurement of TCO4 adsorption. Specifically adsorbed anions depending on the extent of their adsorption compensate the positive charge of a protonated surface therefore, the negative charge on the solution side, i.e., the surface excess concentration of nonspecifically adsorbed anions, should decrease. This effect is well demonstrated by the curve presented in Fig. 9. 

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