The pore surface diffusion model as a tool for rapid screening of novel nanomaterial-enhanced hybrid ion-exchange media

2015 ◽  
Vol 1 (4) ◽  
pp. 448-456 ◽  
Author(s):  
Grigoria Athanasaki ◽  
Laurie Sherrill ◽  
Kiril D. Hristovski
Keyword(s):  
Ion Exchange ◽  
Surface Diffusion ◽  
Diffusion Model ◽  
Screening Tool ◽  
Breakthrough Curves ◽  
Rapid Screening ◽  
Pore Surface

The primary goal of this study was to examine the feasibility of using Pore Surface Diffusion Model (PSDM) as a rapid screening tool to predict breakthrough curves of short bed columns packed with nanomaterial enhanced hybrid-ion exchange media.

Pore-Surface Diffusion Model for Batch Adsorption Processes

Langmuir ◽  
2003 ◽  
Vol 19 (10) ◽  
pp. 4188-4196 ◽  
Author(s):  
Chi-Wai Hui ◽  
Buning Chen ◽  
Gordon McKay
Keyword(s):  
Surface Diffusion ◽  
Diffusion Model ◽  
Batch Adsorption ◽  
Pore Surface ◽  
Adsorption Processes

Coupled Chemical and Diffusion Model for Compacted Bentonite

1994 ◽  
Vol 353 ◽  
Author(s):  
M. Olin ◽  
J. Lehikoinen ◽  
A. Muurinen
Keyword(s):  
Ion Exchange ◽  
Surface Diffusion ◽  
Diffusion Model ◽  
Chemical Equilibrium ◽  
Equilibrium Model ◽  
Binding Constants ◽  
Compacted Bentonite ◽  
Monovalent Ions ◽  
And Diffusion ◽  
Chemical Equilibrium Model

AbstractA chemical equilibrium model has been developed for ion-exchange and to a limited extent for other reactions, such as precipitation or dissolution of calcite or gypsum, in compacted bentonite water systems. The model was successfully applied to some bentonite experiments, especially as far as monovalent ions were concerned. The fitted log-binding constants for the exchange of sodium for potassium, magnesium, and calcium were 0.27, 1.50, and 2.10, respectively. In addition, a coupled chemical and diffusion model has been developed to take account of diffusion in pore water, surface diffusion and ion-exchange. The model was applied to the same experiments as the chemical equilibrium model, and its validation was found pardy successful. The above values for binding constants were used also in the coupled model. The apparent (both for anions and cations) and surface diffusion (only for cations) constants yielding the best agreement between calculated and experimental data were 3.0×10-11 m2/s and 6.0×10-12m2/s, respectively. These values are questionable, however, as experimental results good enough for fitting are currently not available.

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.

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