Adsorption reduced

The intercept on the adsorption axis, and also the value of c, diminishes as the amount of retained nonane increases (Table 4.7). The very high value of c (>10 ) for the starting material could in principle be explained by adsorption either in micropores or on active sites such as exposed Ti cations produced by dehydration but, as shown in earlier work, the latter kind of adsorption would result in isotherms of quite different shape, and can be ruled out. The negative intercept obtained with the 25°C-outgassed sample (Fig. 4.14 curve (D)) is a mathematical consequence of the reduced adsorption at low relative pressure which in expressed in the low c-value (c = 13). It is most probably accounted for by the presence of adsorbed nonane on the external surface which was not removed at 25°C but only at I50°C. (The Frenkel-Halsey-Hill exponent (p. 90) for the multilayer region of the 25°C-outgassed sample was only 1 -9 as compared with 2-61 for the standard rutile, and 2-38 for the 150°C-outgassed sample). 

The reduced adsorption capacity at ORVR vapor generation rates requires increased efficiency in the canister design, in order to limit the effect on cost and performance of the evaporative control system. 

Iodides can also be determined by this method, and in this case too there is no need to filter off the silver halide, since silver iodide is very much less soluble than silver thiocyanate. In this determination the iodide solution must be very dilute in order to reduce adsorption effects. The dilute iodide solution (ca 300 mL), acidified with dilute nitric acid, is treated very slowly and with vigorous stirring or shaking with standard 0.1 M silver nitrate until the yellow precipitate coagulates and the supernatant liquid appears colourless. Silver nitrate is then present in excess. One millilitre of iron(III) indicator solution is added, and the residual silver nitrate is titrated with standard 0.1M ammonium or potassium thiocyanate. 

Silica stationary phases for exclusion can be used with either organic or aqueous solvents. Some types are bonded phases, others are unmodified. When aqueous phases are used with silica exclusion columns, small amounts of polar mobile phase modifiers (inorganic salts or polar organic solvents) often have to be used to reduce adsorption effects. 

In order to improve the biocompatibility of ISEs and reduce adsorption of cells and polypeptides several approaches have been used. Among them are immobilization of... 

When molecules move from a bulk fluid to an adsorbed phase, they lose degrees of freedom and the free energy is reduced. Adsorption is always accompanied by the... 

When adsorption and condensation can be avoided, both dynamic and static sampling methods can be used. Often rinsing the sampling apparatus or even the whole olfactometer with odorous air is necessary to reduce adsorption. Before using the static method a comparative study should be carried out if possible. On the other hand extreme fluctuating emissions can only be sampled statically. 

In practice, moderate heating of the emitter at constant current serves to reduce adsorption to its surface during FI measurements. Heating at a constant rate (1-8 mA min ) is frequently employed to enforce desorption of analytes from the emitter in FD-MS. To avoid electric discharges resulting from too massive ion de-... 

The core-enzymes (15,16) showed reduced adsorption capacities on Avicel of more than 50%, whereas the adsorptions on amorphous (H3P04-Swollen) cellulose were unaffected. This emphasized the role of the binding domains as described above. 

Between pH 4.S-6.3, Pb strongly reduced adsorption of Cu on hematite, whereas the effect of Cu on Pb uptake was less pronounced when the concentrations of both cations were the same (Christl and Kretsdimar, 1999). Palmquist et al. (1999) noted that uptake of Cu and Zn from equimolar solutions was additive. 

This brief review has attempted to discuss some of the important phenomena in which surfactant mixtures can be involved. Mechanistic aspects of surfactant interactions and some mathematical models to describe the processes have been outlined. The application of these principles to practical problems has been considered. For example, enhancement of solubilization or surface tension depression using mixtures has been discussed. However, in many cases, the various processes in which surfactants interact generally cannot be considered by themselves, because they occur simultaneously. The surfactant technologist can use this to advantage to accomplish certain objectives. For example, the enhancement of mixed micelle formation can lead to a reduced tendency for surfactant precipitation, reduced adsorption, and a reduced tendency for coacervate formation. The solution to a particular practical problem involving surfactants is rarely obvious because often the surfactants are involved in multiple steps in a process and optimization of a number of simultaneous properties may be involved. An example of this is detergency, where adsorption, solubilization, foaming, emulsion formation, and other phenomena are all important. In enhanced oil recovery. 

Scamehorn et. al. (20) also presented a simple, semi—empirical method based on ideal solution theory and the concept of reduced adsorption isotherms to predict the mixed adsorption isotherm and admicellar composition from the pure component isotherms. In this work, we present a more general theory, based only on ideal solution theory, and present detailed mixed system data for a binary mixed surfactant system (two members of a homologous series) and use it to test this model. The thermodynamics of admicelle formation is also compared to that of micelle formation for this same system. 

NOg exceeded the standards. To reduce adsorption of CO and NO 2 on the dust of blasted material, it was recommended to drill... 

Replacement of the column with its equivalent, but using a higher proportion of the same stationary phase (this will not necessarily produce higher efficiency but may reduce adsorption). ... 

More frequently the dependence of adsorption upon pH was related to the formation of colloidal metal hydroxides. Again, some authors expressed the opinion that the formation of colloids promoted the adsorption 31, 32) while some others claimed the opposite (7, 8, 24, 36). However, it was generally agreed that when an adsorption maximum was observed as a function of the pH, the reduced adsorption at higher pH values was explained by the electrostatic repulsion between the colloid particles and glass surface bearing the same charge. 

We have studied above a model for the surface reaction A + 5B2 -> 0 on a disordered surface. For the case when the density of active sites S is smaller than the kinetically defined percolation threshold So, a system has no reactive state, the production rate is zero and all sites are covered by A or B particles. This is quite understandable because the active sites form finite clusters which can be completely covered by one-kind species. Due to the natural boundaries of the clusters of active sites and the irreversible character of the studied system (no desorption) the system cannot escape from this case. If one allows desorption of the A particles a reactive state arises, it exists also for the case S > Sq. Here an infinite cluster of active sites exists from which a reactive state of the system can be obtained. If S approaches So from above we observe a smooth change of the values of the phase-transition points which approach each other. At S = So the phase transition points coincide (y 1 = t/2) and no reactive state occurs. This condition defines kinetically the percolation threshold for the present reaction (which is found to be 0.63). The difference with the percolation threshold of Sc = 0.59275 is attributed to the reduced adsorption probability of the B2 particles on percolation clusters compared to the square lattice arising from the two site requirement for adsorption, to balance this effect more compact clusters are needed which means So exceeds Sc. The correlation functions reveal the strong correlations in the reactive state as well as segregation effects. 

Balazs and Lewandowski (1990) have performed simulations of the adsorption of triblock copolymers onto a planar surface, and examined the conformations of the adsorbed chains. Monte Carlo simulations were performed of the motion of hydrophilic-hydrophobic chains on a cubic lattice. These simulations revealed a complex structure in the interfacial region due to the self-assembly of chains, driven by the solvent-incompatible block, reducing adsorption onto the surface. The influence on the surface coverage of length of the hydrophilic segement, polymer concentration, interaction energy between hydrophilic block and the... 

High humidity reduces adsorption efficiency of silica gel. 

Using the cage implant system, Kim et al. successfully polymerized a phospholipid on to a solid substrate and found reduced adsorption of proteins such as albumin, fibrinogen, and IgG and also reduced macrophage adhesion.80 There has also been widespread interest in the use of PC coats for orthopedic joint implants as well as other biomedical applications.81 3... 

The silylation of all glassware that contacts the plant extract has proven to effectively reduce adsorption losses. As diagrammed in Figure 8, the hydroxyl adsorption sites on the silica surface can be coated with dichlordimethyl silane. The unreacted chloride groups are then displaced with methanol in a substitution reaction. A secondary advantage of the silyation process is that water will not adhere to the glass surface. Aqueous residues bead together, which allows more efficient sample transfers. 

To reduce adsorption of cellulose powder (T2) Flodin introduced ethanol-treated cellulose as a supporting medium for zone electrophoresis columns (FI). The main advantage is low adsorption, so that the column can be eluted and used over and over again. In the large models up to 2 liters of serum are separated, while microcolumns are under development which should give excellent results for clinical work (PI, Tl). 

The matrices used in SEC are either polymeric or silica-based particles with a hydrophilic coating. The disadvantage of silica particles is that they tend to retain solutes by adsorption and may catalyze the degradation of solute molecules. To reduce adsorption, the surfaces of these particles are often modified by reaction with organic substituents. 

CZE separation of sugar isomers in a PMMA chip was enhanced by using a phosphate-based, rather than a borate-based buffer. The resolution enhancement may be caused by a rapid carbohydrate-phosphate complex formation process, as compared to a slow carbohydrate-borate complex formation process. To reduce adsorption of the labeled sugar isomers to the PMMA surface, 0.5% methylcel-lulose (viscosity of 2% aqueous solution at 20°C, 4000 cP) was added to the run buffer [560],... 

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