Comparison of solutions for the homogeneous surface diffusion model applied to adsorption systems

2004 ◽  
Vol 98 (3) ◽  
pp. 255-264 ◽  
Author(s):  
Vinci K.C. Lee ◽  
Gordon McKay
Keyword(s):  
Surface Diffusion ◽  
Diffusion Model ◽  
Homogeneous Surface ◽  
Adsorption Systems

User-oriented batch reactor solutions to the homogeneous surface diffusion model for different activated carbon dosages

2009 ◽  
Vol 43 (7) ◽  
pp. 1859-1866 ◽  
Author(s):  
Qiong Zhang ◽  
John Crittenden ◽  
Kiril Hristovski ◽  
David Hand ◽  
Paul Westerhoff
Keyword(s):  
Activated Carbon ◽  
Surface Diffusion ◽  
Diffusion Model ◽  
Batch Reactor ◽  
Homogeneous Surface

Adsorption of pentachlorophenol (PCP) by activated carbon in fixed beds: application of homogeneous surface diffusion model

1998 ◽  
Vol 38 (7) ◽  
pp. 227-235 ◽  
Author(s):  
A. J. Slaney ◽  
R. Bhamidimarri
Keyword(s):  
Activated Carbon ◽  
Surface Diffusion ◽  
Diffusion Model ◽  
Freundlich Isotherm ◽  
Breakthrough Curves ◽  
Orthogonal Collocation ◽  
Homogeneous Surface ◽  
Diffusion And Convection ◽  
Film Transfer ◽  
Fixed Beds

The adsorption of pentachlorophenol (PCP) from aqueous solutions was investigated using fixed beds of activated carbon. The equilibrium behaviour was shown to fit a Freundlich isotherm with the values of parameters K and l/n of 95 and 0.180 respectively, which are comparable to those of other substituted phenolics. The surface diffusion coefficient was evaluated from batch kinetic adsorption experiments and was found to be 2.26 × 10−9 cm2s−1. The film transfer coefficient in the fixed beds was estimated using Gnielinski’s correlation. A Homogeneous Surface Diffusion Model (HSDM) was proposed to predict the PCP adsorption breakthrough curves in the fixed beds. The diffusion and convection equations were integrated using a combination of orthogonal collocation and Runge-Kutta techniques. The experimental results on the adsorption of PCP in activated carbon columns proved that the HSDM can predict the column performance satisfactorily and therefore can be used in the design of fixed beds for removal of PCP.

scholarly journals Design of adsorption column for reclamation of methyldiethanolamine using homogeneous surface diffusion model

2020 ◽  
Vol 75 ◽  
pp. 82
Author(s):  
Pravin Kannan ◽  
Priyabrata Pal ◽  
Fawzi Banat
Keyword(s):  
Mass Transfer ◽  
Surface Diffusion ◽  
Diffusion Model ◽  
Scale Up ◽  
Breakthrough Curves ◽  
Design Parameters ◽  
Model Parameters ◽  
Transfer Coefficients ◽  
Homogeneous Surface ◽  
Composite Adsorbent

A predictive simulation model was applied to design a fixed-bed adsorber for studying the removal of Total Organic Acid (TOA) anions from lean Methyldiethanolamine (MDEA) solution using Calcium Alginate Bentonite (CAB) clay hybrid composite adsorbent. Unlike other conventional techniques typically used for packed bed design, the predictive Homogeneous Surface Diffusion Model (HSDM) does not require any test column breakthrough curves a priori. Mass transfer coefficients and isotherm model parameters are provided as input data to HSDM for simulating column breakthrough curves. Various isotherm models were fitted to batch equilibrium data for TOA adsorption on CAB composite adsorbent. Based on Akaike Information Criterion (AIC), Freundlich isotherm was selected and the model parameters were obtained by non-linear regression. Film transfer coefficients and surface diffusivities were determined using appropriate empirical correlations available in the literature. HSDM predictions were first validated using lab-scale column adsorption data generated at lower residence times. The effects of dimensionless numbers (Biot and Stanton) on breakthrough times were investigated using the dimensionless HSDM system and a suitable scale-up regime (Bi& ~& 1 and St& >& 10) was established wherein the sensitivity of mass transfer parameters would be minimal. Using similitude rules on key design parameters, a pilot-scale adsorption column was designed and breakthrough curves were generated using the validated HSDM. The appropriateness of the design technique was verified by comparing the estimated breakthrough data and column design parameters with conventional scale-up and kinetic approaches.

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