Theoretical adsorption capacity

The theoretical sorption capacities of three sorbents calculated based on stoichiometric equations and experimental sorption capacities calculated taking the HCI sorbed before breakthrough are presented in Table 18.5. Theoretical adsorption capacities of Ca-C, Fe-C, and K2CO3-C were 0.73 g/g, 0.95 g/g, 0.53 g HCl/g sorbent respectively. Observed sorption capacities of three sorbents (Table 18.5) until steady state level shows that the Ca-C (0.48) has higher sorption capacity per gram of sorbent than Fe-C (0.23) and K2CO3-C (0.17 g/g). Table 18.5 shows that the sorption capacity of Ca-C until the breakthrough... 

A remarkable adsorption capacity on high surface area ACs under a hydrogen pressure has been reported for the first time at the beginning of the 1980s [55,56], Whereas hydrogen is absorbed in the interstitial sites of metallic alloys, the main storage mechanism in carbon materials is the adsorption in micropores [57,58], Depending on the authors, theoretical studies found that the optimum pore... 

From XIM = k[C], as [C] increases, XIM increases, such that, theoretically, XIM could become infinite. Practically, this means that equilibrium concentrations of C must be determined experimentally until found. The data do not reflect this. Therefore, the adsorption capacity would have to be solved using the Langmuir isotherm thus,... 

Table 18.5 Theoretical sorption capacities, consumed theoretical capacities during HCl reaction, and adsorption time consumed until steady state time for various sorbents . (Reproduced with permission from the American Chemical Society)...

Sorbent (A) theoretical (B) amount of HCl Theoretical Observed adsorption Adsorption time adsorption capacity adsorbed before the consumed capacity capacity until continued until [HCl(g)]/[ads(g)] breakthrough (B)/(A)100 [%] steady state steady state, h [HCl(g)]/[ads(g)] [HCl(g)]/[ads(g)]... 

The effect of particle size on the HCl sorption capacity of Ca-C was studied varying the particle sizes i.e. 0.25, 1.0, and 2.0 mm. The other reaction parameters such as sorbent weight (2 g), total gas flow (535 mL/min), linear gas velocity (0.18 m/s), inlet HCl concentration (1820 ppm), and temperature of adsorption (350°C) were kept constant. Figure 18.12 shows that with increase of sorbent particle size the breakthrough of HCl was found to increase from 11 h (0.25 nun) to 2 h (2 mm). The results calculated from the adsorption isotherms, such as amount of HCl adsorbed before breakthrough, observed HCl adsorption until steady state level and adsorption time until steady state are presented in Table 18.6. The adsorption capacity of Ca-C was 63% with particle size 0.25 mm. The increase of particle size from 0.25 to 2 mm decreased the theoretical consumed capacity from 63 to 11%. These studies clearly indicated that calcium-based sorbents are effective for the dechlorination of PVC mixed waste plastics pyrolysis process. 

The activation energy for intra-crystalline diffusion for n-butane is 30 kj mol" [72,74,89], For the isosteric heat of adsorption values of =38 kJ mol" are reported by Kapteyn and by Vroon, which value is considerably lower than other values (=50 kJ mol ) reported in literature. For CH4 a good agreement between Ccdculated and measured fluxes is obtained, for n-butane the agreement is reasonable to bad at low pressure and good at higher pressure. A difficult problem is the value of the saturation concentration. In many cases no reliable experimental data are known and theoretical estimates have to be made usually imder the questionable assumption that is independent of temperature. For n-butane the theoretical sorption capacity of MFI/silicalite equals about 2.1x10 mol g" (equivalent to 12 molecules per unit cell). 

It should be checked whether Sn affects the dispersion of Rh particles or not. We have already studied the effect of Sn addition on the dispersion of Rh by comparing the XPS intensity and the adsorption capacity of H2 and CO [11]. The relative XPS intensity of Rh3d5/2 to a monolayer catalyst was larger than the theoretical value calculated from the adsorption capacity of H2 and CO by the method of Kerkhof and Mouljin [13]. These results indicated that the decrease of the adsorption capacity of Rh-Sn/Si02 catalysts was ascribed not to the increase of isolated Rh particle size, but to surface composition of Rh-Sn bimetallic... 

The frequent good fit of adsorption data to this equation is undoubtedly influenced by the insensitivity of log-log plots and by the greater flexibility in curve fitting afforded by the two empirical constants K and ) in the Freundlich equation. The Freundlich equation has no sound theoretical basis, but is an empirical relationship used to describe the adsorption of ions or molecules from liquid onto a solid phase. The major limitation of the Freundlich equation is that it does not predict a maximum adsorption capacity (Bohn et al., 1985). 

ABSTRACT Based on low-temperature nitrogen adsorption principle, the pore structure of coal particles is tested and adsorption isotherms of coal particles with different size are obtained by Quantachrome Autosorb-iQ automatic specific surface area and pore size distribution analyzer. Then, microstructure characteristic parameters such as specific surface area, pore volume and average pore size of coal particles are calculated. Besides, fractal dimension of the internal surface of coal particles is calculated with FHH fractal theory. The relationship between fractal dimension and pore structure parameters together with the adsorption capacity of coal particles is analyzed. Studies show that fractal dimension can characterize the variation of characteristic parameters such as specific surface area and total pore volume of coal particles. In addition, with the increase of fractal dimension, the surface heterogeneity of pore structure is strengthened and so is adsorption capacity. The findings can provide a certain theoretical foundation for mechanism study on coal gas adsorption, desorption and seepage. 

The theoretical free diameter of the pores in the VFI framework is 1.2 run [5]. The pores of the AET framework are elliptic with dimensions of 0.87 x 0.79 nm [2]. Table 3 provides a list of literature data on adsorption capacities of VFI and AET samples for molecules with increasing kinetic diameter. The adsorption capacities of VPI-5 and MCM-9 are comparable and decrease monotonically with increasing adsorbate size. It is not clear whether the perfluorotributylamine molecule with a kinetic diameter of 1.05 nm is adsorbed in WI-5 [31]. 

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