U : adsorption

Khan, S.U. Adsorption of 2,4-D from aqueous solution by fulvic acid-clay complex. Environ. Sci. Technol, 8(3) 236-238, 1974. 

A literature search reveals that Cu isotherms for different soils as well as clay fractions often exhibit a nonlinear shape. Moreover, most investigations do not consider the kinetic retention behavior of Cu retention during adsorption. Since the nonlinear nature of Cu retention directly influences its mobility in soils, knowledge of the time-dependence nature of Cu behavior is significant. Therefore, the primary objective of this investigation was to study the kinetics oft u adsorption as well as... 

Karlsson, M. Martensson, L. G. Jonsson, B. H. Carlsson, U. Adsorption of human carbonic anhydrase 11 variants to silica nanoparticles occur stepwise binding is followed by successive conformational changes to a molten-globule-like state. Langmuir, 2000, 76(22), 8470-8479. 

Miinstermann, U. Adsorption von CO2 aus Reingas nnd aus Luft am Molekularsieb-Einzelkom und im Festbett, Beriicksichtigum von Wiirmeeffekten und H20-Pra adsorption, Ph D. Thesis TU Miinchen 1984... 

Eiden, U., and Schlunder, E.U., Adsorption equilibria of pure vapors and their binary mixtures on activated carbons, Chem. Eng. Process., 28( 1), 1 -22 (1990). 

Pershina, V., Borschevsky, A., Eliav, E., Kaldor, U. Adsorption of inert gases including element 118 on noble metal and inert surfaces from ab initio Dirac-Coulomb atomic calculations. J. Chem. Phys. 129, 144106(9) (2008)... 

A rather different approach is to investigate possible adsorption isotherm forms for use with Eq. X-43. As is discussed more fully in Section XVII-7, in about 1914 Polanyi proposed that adsorption be treated as a compression of a vapor in the potential held U x) of the solid with sufficient compression, condensation to liquid adsorbate would occur. If Uq(x) denotes the held necessary for this, then... 

A still different approach to multilayer adsorption considers that there is a potential field at the surface of a solid into which adsorbate molecules fall. The adsorbed layer thus resembles the atmosphere of a planet—it is most compressed at the surface of the solid and decreases in density outward. The general idea is quite old, but was first formalized by Polanyi in about 1914—see Brunauer [34]. As illustrated in Fig. XVII-12, one can draw surfaces of equipo-tential that appear as lines in a cross-sectional view of the surface region. The space between each set of equipotential surfaces corresponds to a definite volume, and there will thus be a relationship between potential U and volume 0. 

Returning to multilayer adsorption, the potential model appears to be fundamentally correct. It accounts for the empirical fact that systems at the same value of / rin P/F ) are in essentially corresponding states, and that the multilayer approaches bulk liquid in properties as P approaches F. However, the specific treatments must be regarded as still somewhat primitive. The various proposed functions for U r) can only be rather approximate. Even the general-appearing Eq. XVn-79 cannot be correct, since it does not allow for structural perturbations that make the film different from bulk liquid. Such perturbations should in general be present and must be present in the case of liquids that do not spread on the adsorbent (Section X-7). The last term of Eq. XVII-80, while reasonable, represents at best a semiempirical attempt to take structural perturbation into account. 

Fig. XVII-30. Adsorption of Na on a silica gel at 77.3 K, expressed as a u-/ plot, illustrating a method for micropore analysis. (From Ref. 230.)...

Mintz M H, Atzmony U and Shamir N 1987 Initial adsorption kinetics of oxygen on polycrystalline copper Surf. Sc/. 185 413-30... 

Calorimetry is the basic experimental method employed in thennochemistry and thennal physics which enables the measurement of the difference in the energy U or enthalpy //of a system as a result of some process being done on the system. The instrument that is used to measure this energy or enthalpy difference (At/ or AH) is called a calorimeter. In the first section the relationships between the thennodynamic fiinctions and calorunetry are established. The second section gives a general classification of calorimeters in tenns of the principle of operation. The third section describes selected calorimeters used to measure thennodynamic properties such as heat capacity, enthalpies of phase change, reaction, solution and adsorption. 

Weinelt M, Huber W, Zebisch P, Steinruck H-P, Ulbricht P, Birkenheuer U, Boettger J C and Rdsch N 1995 The adsorption of acetylene on Ni(110) an experimental and theoretical study J. Chem. Phys. 102 9709... 

Fig. U (o) Isopotential curves for the adsorption of He on the (100) face of solid Xe. The interval between the isopotential lines is 1-24 x 10 J. [b) Isopotential curves for the adsorption of He on the (III) face of solid Xe. The interval between the isopotential lines is 1-66 x 10 J. (After...

Fig. 2.12 Plot of the calorimetric difTeFential enthalpy of adsorption A h) against amount adsorbed (n), for (u) n-pentane, (f)) /i-hexane, (c) n-heptane, d) n-octane, all adsorbed on graphitized car n black. The point corresponding to n = is marked on each curve. (Courtesy Kiselev.)...

Another example of vims clearance is for IgM human antibodies derived from human B lymphocyte cell lines where the steps are precipitation, size exclusion using nucleases, and anion-exchange chromatography (24). A second sequence consists of cation-exchange, hydroxylapatite, and immunoaffinity chromatographies. Each three-step sequence utilizes steps based on different properties. The first sequence employs solubiUty, size, and anion selectivity the second sequence is based on cation selectivity, adsorption, and selective recognition based on an anti-u chain IgG (24). 

Water and Waste Water Treatment. PAG products are used in water treatment for removal of suspended soHds (turbidity) and other contaminants such as natural organic matter from surface waters. Microorganisms and colloidal particles of silt and clay are stabilized by surface electrostatic charges preventing the particles from coalescing. Historically, alum (aluminum sulfate hydrate) was used to neutralize these charges by surface adsorption of Al cations formed upon hydrolysis of the alum. Since 1983 PAG has been sold as an alum replacement in the treatment of natural water for U.S. municipal and industrial use. 

Sulfonation Plant Operations and Gas Effluent. Standards governing U.S. sulfonation plant gas effluents differ depending on whether or not the plant is equipped with a H2SO4 scmbbing system for adsorption of SO gas (see Fig. 3). The installation of the SO adsorber system qualifies the plant as a sulfuric production plant which has stringent regulations. Limitations and typical effluent from the sulfonation system are as follows ... 

R. A. Dobbs, R. J. Middendorf, and J. M. Cohen, Carbon Adsorption Isotherms for Toxic Organics, Municipal Environmental Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio, EPA-600/8-80-023, 1980. 

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