Calorimetric Heats of Adsorption and Adsorption Isotherms. 1. O2, N2, Ar, CO2, CH4, C2H6, and SF6 on Silicalite

Dunne, J. A.; Mariwala, Ravindra K.; Rao, Meera; Sircar, Shivaji; Gorte, and R. J.; Myers, Alan L.

doi:10.1021/la960495z

Cited by 393 publications

(326 citation statements)

References 28 publications

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“…Just as an example, in the work of Eder et al [29] and De Moor et al [53], adsorption was carried out at p  10 -3 mbar (9.87·10 -7 atm) of (propane to n-hexane) and T  400 K. In an analogous way in the work of Dunne et al [54], Ramachandran et al [28] and Ferreira et al [55], among others, adsorption was always performed at p  9.87·10 -5 atm and T  423 K. From the work presented here, it is clear that by working under those experimental conditions it should be very difficult to unequivocally conclude about the homogeneity or heterogeneity of the surface for adsorption sites. Then, one should either follow the methodology presented here or to perform adsorption measurements under the appropriate range of pressures and temperatures to ascertain the homo or heterogeneity of the zeolite surface for catalytic cracking.…”

Section: Differential Heat Of Adsorption (H Ads )mentioning

confidence: 99%

Catalytic cracking of n-alkane naphtha: The impact of olefin addition and active sites differentiation

Corma

Cuquerella

Miguel

2015

Journal of Catalysis

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An extended dual kinetic model allows to fit the n-heptane cracking results working in a wide range of reaction conditions. The duality of the model is provided by the contribution of monomolecular and bimolecular cracking mechanisms. It takes into account the role played by the olefins formed on the global cracking or added within the feed. Furthermore by means of this model and the kinetic parameters obtained when cracking n-heptane on ZSM-5, it has been observed that, while some characterization techniques show a homogeneous zeolite surface from the point of view of the active sites, rigorous kinetic experiments point to the possibility that the reactant sees a heterogeneous surface with, at least, two group of cracking active sites. Those differentiated active sites give different cracking rates and different activation energies for the process and, in the case of ZSM-5, could be assimilated to sites pointing to the 10R channels and sites pointing into the crossing of the 10R channels, mainly due to differences in acid site location and confinement effects.3

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Section: Differential Heat Of Adsorption (H Ads )mentioning

confidence: 99%

Catalytic cracking of n-alkane naphtha: The impact of olefin addition and active sites differentiation

Corma

Cuquerella

Miguel

2015

Journal of Catalysis

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“…The potential parameters in table 2 were derived from experimental data [25]. Note that these 2028 F. Siperstein et al Figure 4.…”

Section: Portability Of Potential Parametersmentioning

confidence: 99%

Long range corrections for computer simulations of adsorption

2002

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Long range corrections are routinely applied to simulations of bulk¯uids by assuming that the radial distribution function is unity beyond a certain cuto radius for pairwise interactions. Similar long range corrections for gas±solid interactions in adsorption frequently are ignored because of the anisotropic structure of the solid. However, the error associated with assuming isotropy beyond the cuto radius is small compared with the magnitude of the long range correction. The long range correction to the Henry constant for a cuto radius of 13 A Ê is 14% for CH 4 and 70% for SF 6 for adsorption in silicalite at 298 K. The large errors incurred by neglecting long range corrections can be concealed by increasing the well depth of the gas± solid interaction, but this approximation reduces the accuracy and portability of the potential parameters. Consistency in the cuto radius is more important than the inclusion or neglect of long range corrections to the energy. IntroductionMolecular simulation of adsorption is based upon a detailed model of the potential energy of the adsorbate molecules as a function of their location and orientation inside the pores of the solid adsorbent. Assuming pairwise additivity, the total potential energy of a con®gura-tion is obtained by summing gas±gas and gas±solid interaction energies. At the limit of zero loading, the gas±gas interactions are negligible and the energy consists entirely of gas±solid interactions. The total potential energy of a gas molecule adsorbed at a particular location includes interactions between the gas molecule and every other atom in the simulation box, as well as images in the surrounding boxes. This summation contains an in®nite number of terms and is impossible to calculate in practice [1].The approximation for dispersion/repulsion forces in bulk¯uids is to use a spherical cuto radius (r c ). Corrections for the missing long range part of the potential are based on the approximation that the radial distribution function g…r † º 1 for r > r c . Long range corrections can be introduced at the end of the simulation in ensembles where the density is constant. In NPT and ·VT ensembles, the long range corrections must be applied to the instantaneous energies and pressures during the course of the simulation, because the corrections change as the density¯uctuates [2].

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“…Taking advantage of the above sets of isotherms and the Clausius-Clapeyron equation [51], the isosteric heat of adsorption (Q st ) was calculated for the two GOs (Fig. 8).…”

Section: A Alazmi Et Al Inorganica Chimica Acta XXX (2018) Xxx-xxxmentioning

confidence: 99%

The impact of surface chemistry and texture on the CO2 uptake capacity of graphene oxide

Alazmi

Tall

Hedhili

et al. 2018

Inorganica Chimica Acta

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ARTICLE INFO ABSTRACTThe influence of the synthesis route on the surface characteristics and CO 2 uptake of graphene oxide was studied. Powders derived from the classical Hummer's method approach and the so-called improved Hummer's method were benchmarked against zeolite 13X and certified carbon nanotubes. With a specific surface area of 283 m 2 g −1 and a CO 2 adsorption capacity of 2.1 mmol g −1 (at 273 K), the improved Hummer's product was superior to the other two nanocarbons tested.

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Calorimetric Heats of Adsorption and Adsorption Isotherms. 1. O₂, N₂, Ar, CO₂, CH₄, C₂H₆, and SF₆ on Silicalite

Cited by 393 publications

References 28 publications

Catalytic cracking of n-alkane naphtha: The impact of olefin addition and active sites differentiation

Catalytic cracking of n-alkane naphtha: The impact of olefin addition and active sites differentiation

Long range corrections for computer simulations of adsorption

The impact of surface chemistry and texture on the CO2 uptake capacity of graphene oxide

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