A general diffusion model for mass transfer in colloidal liquid aphron systems

2009 ◽  
Vol 338 (1-3) ◽  
pp. 25-32 ◽  
Author(s):  
Yi He ◽  
Zhichun Wu ◽  
Zai-Sha Mao
Keyword(s):  
Mass Transfer ◽  
Diffusion Model

scholarly journals Pore Diffusion Model for the Adsorption of Basic Dyestuffs onto Natural Clay in Batch Adsorbers

1992 ◽  
Vol 9 (2) ◽  
pp. 109-120 ◽  
Author(s):  
Mohammad S. El-Geundi
Keyword(s):  
Mass Transfer ◽  
Diffusion Coefficient ◽  
Diffusion Model ◽  
Sherwood Number ◽  
Pore Diffusion ◽  
Batch Adsorption ◽  
External Mass Transfer ◽  
Natural Clay ◽  
Pore Diffusion Model ◽  
Best Fit

The adsorption of basic dyestuffs (Basic Blue 69 and Basic Red 22) onto natural clay has been studied using a series of batch adsorption runs. The pore diffusion model (PDM) has been developed based on external mass transfer and pore diffusion to predict the performance of a batch adsorber. A computer program has been developed to generate theoretical Sherwood number-time curves and these results were adjusted to experimental Sherwood number-time curves by means of a ‘best fit’ approach. The variables of initial dye concentration and natural clay mass have been successfully correlated using a single external mass-transfer coefficient, Ks, and a single effective pore diffusion coefficient, Deff. The Ks values are 3.3 × 10−5 and 2.6 × 10−5 m/s for Basic Blue 69 and Basic Red 22, respectively. The Deff values are 7.3 × 10−10 and 9.6 × 10−10 m2/s for Basic Blue 69 and Basic Red 22, respectively.

scholarly journals Application of the Film–Pore Diffusion Model to the Sorption of Phenol onto Activated Carbons Prepared from Peanut Shells

2008 ◽  
Vol 26 (9) ◽  
pp. 651-659 ◽  
Author(s):  
Elio E. Gonzo ◽  
Luis F. Gonzo
Keyword(s):  
Mass Transfer ◽  
Diffusion Model ◽  
Effective Diffusion ◽  
Carbon Particle ◽  
Pore Diffusion ◽  
Peanut Shell ◽  
External Mass Transfer ◽  
Transfer Resistance ◽  
Pore Diffusion Model ◽  
The Difference

In this work, the film–pore diffusion model was applied to the adsorption of phenol onto peanut shell activated carbon in a batch stirred vessel. This two-resistance model was applied to predict the phenol concentration decay curves for different initial phenol concentrations, carbon particle sizes and dosages. The predicted concentration decay curves were compared with the experimental findings. The optimum best-fit values of the external mass-transfer coefficient and effective diffusion coefficients were found by minimizing the difference between the experimental and model-predicted phenol solution concentration. It was found that, under the experimental conditions employed in this study, the influence of the external mass-transfer resistance was low. A single value of the mass transport coefficient, kf, of (4.8 ± 1.3) × 10−3 (cm/s) described the whole range of system conditions. The difference between the corresponding values of the effective diffusivity, Deff, was not statistically significant. Consequently, a constant value of the effective pore diffusivity of (4.1 ± 0.4) × 10−6 (cm2/s) was sufficient to provide an accurate correlation of the decay concentration curve.

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