Effect of Intraparticle Diffusion: Agitated Nonflow Adsorption Systems

Edeskuty, Fred J.; Amundson, Neal R.

doi:10.1021/ie50511a058

Cited by 40 publications

(11 citation statements)

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“…Weber [4,8] based his early intraparticle diffusion explanation largely on the work of Edeskuty and Amundson [18]. These latter two authors developed mathematical equations to calculate intraparticle diffusion coefficients for phenol adsorption by "hugh" carbon particles.…”

Section: Diffusion-controlled Processesmentioning

confidence: 99%

“…The experimental procedure, briefly, consisted of preparing uniform cylinders of carbon particles by means of a mechanical mold [18]. Grade SX A activated carbon was obtained from Carbide and Carbon Chemicals Corp. and was prepared in two sizes: 6/8 mesh (0.25 to 0.31 cm diameter) and 4/6 mesh (0.40 to 0.47 cm diameter).…”

Section: Diffusion-controlled Processesmentioning

confidence: 99%

“…Several parameters were developed from theoretical treatment that are related to the intraparticle diffusion coefficient [18]. There are: (3.5) where W = total mass of particles, a = fractional void volume in particle, ratio of void volume to total volume of a single particle, ρ = particle density, V = volume of external solution, k x = constant in adsorption equilibrium isotherm, D = diffusion coefficient, ω η = Aith root of a transcendental equation, R = external diameter of cylinders, and p n = transform parameter corresponding to t (time).…”

Section: Diffusion-controlled Processesmentioning

confidence: 99%

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Kinetics of Adsorption

Faust¹,

Aly²

1987

Adsorption Processes for Water Treatment

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Section: Diffusion-controlled Processesmentioning

confidence: 99%

Section: Diffusion-controlled Processesmentioning

confidence: 99%

Section: Diffusion-controlled Processesmentioning

confidence: 99%

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Kinetics of Adsorption

Faust¹,

Aly²

1987

Adsorption Processes for Water Treatment

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“…This was the case under our experimental conditions, since the results of the model were not at all affected by very large variations of the mass transfer coefficient through the gas film (k,), using Gamson's (1951) correlation to calculate it, with a boundary condition that equals the molar flux through the gas film (in terms of kg) and the molar flux of diffusion into pores of the particles. This model was solved analytically in a previous work by Costa et al (1971), following the method recommended by Edeskuty and Amundson (1952), to give a dimensionless concentration of the adsorbate in the bulk gas around the particles as a function of time:…”

Section: Mathematical Modelmentioning

confidence: 99%

Adsorption of gaseous hydrocarbons on activated carbon: Characteristic kinetic curve

1985

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The internal diffusion coefficients, Di, of pure methane, ethane and ethylene as well as some of their binary and ternary mixtures, have been calculated at 20°C for solid particles of a commercial activated carbon. It has been observed that the contribution of the surface migration mechanism to the global mass transfer process inside the adsorbent particles can be as much as 7040%. Values for the surface migration coefficient Ds have also been calculated from the relation Di = Dg + KD,, where K is a dimensionless mean slope factor. Values found for both coefficients are of the same order of magnitude as those reported in the literature for similar systems.All the values for the internal diffusion coefficients of these pure components and their mixtures fit into a single correlation curve, the characteristic kinetic curve of the adsorbent. SCOPEThe increasing importance of adsorption processes for the separation of gaseous mixtures is due to the high selectivity and adsorption capacity of solid adsorbents, the less extreme operation conditions needed, and the small energy consumption required. Adsorption is becoming a competitive operation that can advantageously substitute for other separation operations such as distillation or liquid-liquid extraction. The advantages are especially attractive when the problem is the separation of light gases such as methane, ethane, ethylene and other typical hydrocarbons of gaseous refinery streams, since their separation by distillation requires expensive high pressure units.Although there are some commercial processes for the separation of hydrocarbons using gas adsorption (Milton, 1963; Priegnitz, 1973; Yatsurugi, 1974;Broughton, 1977), the extension of this method to other cases of practical interest is generally limited by the lack of reliable fundamental data for estimating the feasibility of a given separation and for reducing the empiricism of the present design of adsorbers. Among these fundamental data, the equilibrium adsorption isotherms and the internal diffusion coefficients of individual species of the mixture should be emphasized. Although substantial attention has been paid in the literature to the adsorp tion isotherms of pure compounds and their mixtures, even to the point of predicting multicomponent adsorption equilibria (Lewis et al., 1950 shown that the adsorption rates of pure propane, n-butane, ibutane, l-butene and other light gases into molecular sieves were lower when these compounds were present in binary mixtures. Feng et al. (1973Feng et al. ( ,1974 have extensively studied the diffusion of gaseous mixtures inside the pores of solid adsorbents, using several diffusion models. Their results, which were achieved by assuming a single pore size for the adsorbent and a reasonable tortuosity factor, were erroneous for not considering surface migration. We present here new values for the internal diffusion coefficients of methane, ethane, and ethylene, both as pure components and as part of the mixtures of methane-ethylene, ethaneethylene, and methane...

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“…Eq. (5) is reported as an intraparticle diffusion model in literature [2,4,17,27,28,56] suggesting that the sorption process is to be controlled by the internal diffusion [44,47,57,58] with a minor effect of the external diffusion [44].…”

Section: Intraparticle Diffusion Modelmentioning

confidence: 96%