Preparation equilibrium adsorption

C,4—C20 AOS surfactants were laboratory-prepared by Tuvell et al. [2]. Table 3 shows the CMC values of these single-carbon-cut AOS surfactants and of reference compounds, their areas per molecule at the water-air interface inferred from plots of surface tension vs. In (concentration), and the surface tension at the CMC, all at 23°C. The area of the molecule is proportional to the equilibrium adsorptivity, which in turn is taken as a comparative measure of the surface activity of the molecule. Tuvell et al. [2] argue that the greater the... 

Many commercial activated carbons have been prepared with various sources of raw materials and different processing conditions. As a result, the micropore structures and specific surface areas of activated carbons, which are the most profound influences on the extent of adsorption, vary, and in general, activated carbons have a surface area of up to 3000 m2/g. The rate of adsorption increases with some function of the inverse of the radius of the activated carbon even though the adsorption capacity (i.e., equilibrium adsorption) is relatively independent of the particle diameter. However, for a highly porous adsorbent such as activated carbon, the... 

Fig. 13. Procedures for the preparation of alumina-based hydrotreating catalysts containing phosphorus, molybdenum, and cobalt or nickel, a. Impregnation or equilibrium adsorption method (coimpregnation) b, impregnation or equilibrium adsorption method (sequential impregnation) c, precipitation or hydrogel method d, sol-gel method [adapted from Iwamoto and Grimblot 40). ...

Table 5 shows the excellent adsorption characteristics of the home prepared carbons, in comparison with 3 of the 10 commercial carbons tested. The results obtained in the equilibrium adsorption study of phenol, pentachlorophenol, dodecylbenzenesulphonate, and p-toluenesulphonate were discussed in a previous paper [9 ]. Also this study showed a very good performance of the home produced carbons. Based on these results carbon J 23 and J 32 were selected for further research. 

The more common methods for preparing supported oxide catalysts involve the dispersion of the active species or its precursor onto the surface of a preformed support. This has been accomplished using procedures referred to as equilibrium adsorption, incipient wetness or dry impregnation.9,20... 

Gil Llainbias, EJ. et al.. Hydrodesulfurization activity of WOj/y-alumina prepared by the equilibrium adsorption method, Appl. Catal.,, 59, 185, 1990. 

Surface tension. CTAB solutions of various concentrations in a KH2P04-Na0H buffer at pH 7 and 0.1N ionic strength were prepared. At their surface egg-lecithin monolayers of various surface densities were spread from a cyclohexane solution, and the surface tensions were measured at equilibrium adsorption of CTAB. 

An alternative method used for preparing supported catalysts is the Equilibrium Deposition Filtration (EDF) technique, otherwise called equilibrium adsorption. Following this technique the support is immersed in a large volume of a dilute aqueous solution of the TMIS, ideally at fixed pH and ionic strength. Equilibration of the suspension follows for several hours under stirring. During equilibration the TMIS are deposited at the interface developed between the support surface and the aqueous solution. We call this mode of deposition interfacial deposition. In the filtration step the interfacially deposited TMIS are practically separated from the non-deposited ones. 

In this study, precursors of the active phase have been introduced by equilibrium adsorption of alumina as well as of functionalized alumina with Co2Moio(Co) based impregnating solutions in order to maximize CoMoS phase formation. Characterization and catalytic performances in toluene hydrogenation of catalysts prepared on both functionalized and bare supports are presented in this work. 

Calculation from mass balance is convenient but depends upon synthetic recipe and is susceptible to significant experimental errors. For instance, mass balance calculations are reasonable approximations for catalyst preparations that incorporate -100% of the added surface oxide precursor (e.g., incipient wetness impregnation) however, mass balance is not suitable for preparation methods that retain less than 100% of the precursor (e.g., equilibrium adsorption, where a significant concentration... 

Similar to Iglesia and coworkers, Scheithauer et al. [29, 39] prepared WO /ZrOj from amorphous zirconium oxyhydroxide, but they used equilibrium adsorption at 383 K instead of incipient wetness impregnation. They considered ML coverage to occur at 6.4 W/nm, although this was not explicitly stated [39] (Section 11.4.1). They used a different metric called WO, surface coverage Equation 11.3), in which the surface density values were normalized to the ML coverage value. 

For purposes of comparison a Mo( DA) catalyst was prepared via equilibrium adsorption. An aqueous Mo-EDA solution (200ml) was added to lOg of alumina and the mixture was vigourously shaken during 4h then the extrudates were washed. This catalyst will be referred hereafter Mo EDA. 

Fig. 14 shows adsorption isotherm of ethylene on the sol-gel derived CuCl/ y-AhOij sorbent (Sample 2 in Table 8). The isotherm is of type I. The equilibrium adsorption data of C2H4 at 1 atm pressure and 14-18°C on CuCl/ Y-AI2O3 (prepared by the solid state mixing method) was previously reported in the literature [68]. The amount of ethylene adsorbed on CuCl/ y-AUOs was only about 0.29 mmol/g. Yang and Kikkindes [72] reported very good data of adsorption of 0.73 mmol/g of ethylene on CuCl/y-AhOa adsorbent with support surface area of 340 m /g. The result of our sorbent is similar to the best result reported. 

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