Low concentrations of adsorbate

It should be mentioned that one can detect two types of equilibrium in the model of charge transfer in the absorbate - adsorbent system (i) complete transition of chemisorbed particles into the charged form and (ii) flattening of Fermi level of adsorbent and energy level of chemisorbed particles. The former type takes place in the case of substantially low concentration of adsorbed particles characterized by high affinity to electron compared to the work function of semiconductor (for acceptor adsorbates) or small value of ionization potential (for donor adsorbates). The latter type can take place for sufficiently large concentration of chemisorbed particles. 

Let us now turn to the case where the steps are locally poisoned in the presence of low concentration of adsorbable impurities in such a way that between the adsorbed impurities die step becomes festooned and is consequently able to carry along the adsorbed impurities during the course of its motion. Then a step of macroscopic radius r will have a much smaller local radius of curvature, in fact, it will be of the order of die average distance between adsorbed impurities along the step. Thus it follows that c(r) will remain small and the "back stress ... 

We have completed the analysis of system with linear isotherm, and local equilibrium between the two phases. The local equilibrium assumption is generally valid in many systems the linearity between the two phases is, however, restricted to systems with very low concentration of adsorbate, usually not possible with many... 

Activated carbon fibers (ACF) and nano fibers (ACNF) are a relatively modem form of porous carbon material with a number of significant advantages over the more traditional powder or granular forms. Advantages include high adsorption and desorption rates, thanks to the smaller fiber diameter and hence very low diffusion limitations, great adsorption capacities at low concentrations of adsorbates, and excellent flexibility [18, 19]. 

Taking into consideration the aforementioned points related to both the column dimensions and packing and the gas flow rate, and working at very low concentrations of adsorbate, symmetric peaks are obtained for many materials. Under these conditions, the hypothesis of infinite dilution can be considered. Due to several both experimental conditions and instrumental problems, broadening of the peaks can be observed—avoiding the use of the Gaussian peak, explained later. Some of these causes are ... 

Polymerization begins in the aqueous phase with the decomposition of the initiator. The free radicals produced initiate polymerization by reacting with the monomers dissolved in the water. The resulting polymer radicals grow very slowly because of the low concentration of monomer, but as they grow they acquire surface active properties and eventually enter micelles. There is a possibility that they become adsorbed at the oil-water interface of the monomer... 

Most volatile organics adsorb on activated carbon in the Hquid state. Low concentrations of biodegradable volatiles can be removed by adsorption and biodegradation on activated carbon. 

The Permeation Process Barrier polymers limit movement of substances, hereafter called permeants. The movement can be through the polymer or, ia some cases, merely iato the polymer. The overall movement of permeants through a polymer is called permeation, which is a multistep process. First, the permeant molecule coUides with the polymer. Then, it must adsorb to the polymer surface and dissolve iato the polymer bulk. In the polymer, the permeant "hops" or diffuses randomly as its own thermal kinetic energy keeps it moving from vacancy to vacancy while the polymer chains move. The random diffusion yields a net movement from the side of the barrier polymer that is ia contact with a high concentration or partial pressure of the permeant to the side that is ia contact with a low concentration of permeant. After crossing the barrier polymer, the permeant moves to the polymer surface, desorbs, and moves away. 

The water removal mechanism is adsorption, which is the mechanism for ad Class 4 drying agents. The capacity of such materials is often shown in the form of adsorption isotherms as depicted in Figures 9a and 9b. The initial adsorption mechanism at low concentrations of water is beheved to occur by monolayer coverage of water on the adsorption sites. As more water is adsorbed, successive layers are added until condensation or capidary action takes place at water saturation levels greater than about 70% relative humidity. At saturation, ad the pores are fided and the total amount of water adsorbed, expressed as a Hquid, represents the pore volume of the adsorbent. 

It has been seen that this resin has also some important advantages over the other resins in the literature like high total ion exchange capacity, easy synthesis, lower cost, simple regeneration. Furthermore, very good sepai ations were obtained using a concentration gradient of elution. In these elutions, very low concentrations of sodium trimetaphosphate were used. As a result, the resin synthesized can be used as an adsorbent for the effective removal of Pb, Cd, Co, Cu, Fe, Ni, Zn and Cr from aqueous solutions. 

It diagramatically represents a silica surface in contact with a low concentration of chloroform in n-heptane where the surface is partly covered with chloroform, the remainder covered with n-heptane. The solute molecules can either rest on the surface of the chloroform layer or on the surface of the layer of adsorbed n-heptane. 

Complete resolution was not achieved due to the carryover of interfering substances which frequently occurs when separating the components of biological samples. The column carried a reverse phase, but as the mobile phase contained low concentrations of lauryl sulfate, some would have adsorbed on the surface of the stationary phase and significantly modified its interacting properties. The retention mechanism is likely to have involved both ionic interactions with the adsorbed ion exchanger together with dispersive interactions with any exposed areas of the reverse phase. 

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