Adsorption multiple components

We now consider multiple-component adsorption. If other components, such as B and D, are assumed to be in adsorption-desorption equilibrium along with CO, we add the following two reactions... 

Monte Carlo methods can be used to simulate the adsorption of molecules as a function of temperature and the pressure of the gas in contact with the porous solid. In this way adsorption isotherms of single or multiple component gas... 

Competitive adsorption on active carbon of two organic substances dissolved in water is discussed in two papers by Fritz, Merk, and Schliinder. Experiments were made on aqueous solutions of phenol and p-nitrophenol, and interpreted using the ideal adsorbed solution theory of Radke and Prausnitz. A review in Japanese of the adsorption of multiple component aqueous solutions by activated carbon is presented by Takeuchi. The stability of the sorption properties of active carbons under cyclic operating conditions is discussed by Chubarova et al. ... 

Protein adsorption from protein mixtures can be complex. For example, when plasma proteins from whole blood bind to biomaterials, albumin often binds initially and is later displaced by fibrinogen. Fibrinogen can then be displaced by other blood proteins (5). This is the Vroman Effect. Although the Vroman Effect was discovered for blood proteins, it may take place in other situations in which multiple components can bind. 

MRU [Methanol recovery unit] A process for removing methanol from the unreacted components from the synthesis of methyl /-butyl ether. It uses selective adsorption on multiple beds of a zeolite such as 4A. Developed by Union Carbide Corporation and now licensed by UOP as of 1992, eight units had been licensed. See also ORU. 

The extent of equilibrium adsorption of a given chain, thus, would depend on the counteraction between the three enthalpic and entropic components, plus the negative entropic contribution of the chain restraint. The rate of adsorption should be fairly fast, in fact, accelerated after the first segment was held, while the rate of desorption requiring simultaneous multiple desorption steps should be very slow, so slow indeed as to be barely measurable except when assisted by a displacing species. 

Metal Ion Adsorption in Mixtures of Multiple Solid Phases. One of the arguments put forth for extending the concepts of solution coordination chemistry to heterogeneous systems is the hypothesis that the mineral components of soils or sediments can be considered as ligands which compete for complexation of adsorbates. To this end, it is important to know the relative ability of different mineral surfaces to complex solutes. 

Haaland was also able to resolve the ca. 3040-cm 1 vCH absorption into separate components at 3074, 3048, 3032, and 3011 cm 1. He attributed these to the presence of multiple adsorption sites, although such additional component bands were not observed for the other absorptions. It should be recalled, however, that the MSSR can break down for adsorbates on small-particle Pt catalysts (no mean particle size was given), as in the case of 77-bonded ethene (Part I, Section VI.B.c), leading to all the i>CH modes becoming active. 

Isoenzymes. Multiple forms of citrus PE were reported by Evans and McHale (AO) and Versteeg et al. (Al). PE was purified from West Indian limes and Navel oranges by fractionation of the whole fruit extracts with (NH. SO (AO-65%), adsorption and elution from Sephadex G-75 columns (AO). The PE active fractions were combined and concentrated before separation into two active PEs on the basis of their elution volume from a DEAE Sephadex A-50 column. Orange PEI (OPEI) and lime PEI (LPEI) had the same elution volume also OPEII and LPEII had the same elution volume. A higher concentration of NaCl was required at all pH values for optimum activity of OPEI and LPEI than of OPEII and LPEII. When the component parts of oranges were separately analyzed chromatographi-cally with DEAE-Sephadex A-50, OPEI was detected only in the peel, whereas OPEII was identified in juice sacs and section walls (AO). 

To mimic the PG electrode surface for QCM measurements of layers adsorbed on the gold-quartz resonators, we first chemisorb a mixed monolayer of mercaptopropionic acid/mercaptopropanol. This layer is represented by the first point in Fig. 2, labeled MPA. The second layer is PDDA. Quartz crystal microbalance frequency decreasing in a roughly linear fashion and at regular intervals for the multiple adsorption steps demonstrates repeatable adsorption for the two DNA/en-zyme films. Relative precision of layer formation on multiple resonators within 15% can be achieved. Film thicknesses and component weights in Table 1 were obtained by analyzing the QCM data with Eqs. 1 and 2. 

If enzyme inactivation is not due to covalent changes in structure, the native active structure can be reformed in immobilized enzymes by refolding from a random coil state (22,27). In fact, if they are attached to the matrix by multiple points, even thermally inactivated multichain enzymes can be reactivated (27). Although such regeneration steps apparently have not been used commercially, their use should be considered in certain cases, especially since in many cases the inactivation may result from adsorption onto the enzyme matrix of components in the process stream. For example, we have found that immobilized sulfhydryl oxidase activity can be regenerated numerous times following treatment of UHT milk by washing with 4 M urea (28). 

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