scholarly journals Modeling of the adsorption kinetics of zinc onto granular activated carbon and natural zeolite

2006 ◽  
Vol 71 (8-9) ◽  
pp. 957-967 ◽  
Author(s):  
Ljiljana Markovska ◽  
Vera Meshko ◽  
Mirko Marinkovski
Keyword(s):  
Mass Transfer ◽  
Activated Carbon ◽  
Simulation Study ◽  
Natural Zeolite ◽  
Granular Activated Carbon ◽  
Model Parameters ◽  
Mass Transfer Resistance ◽  
External Mass Transfer ◽  
Transfer Resistance ◽  
Kinetics Of

The isotherms and kinetics of zinc adsorption from aqueous solution onto granular activated carbon (GAC) and natural zeolite were studied using an agitated batch adsorber. The maximum adsorption capacities of GAC and natural zeolite towards zinc(II) from Langmuir adsorption isotherms were determined using experimental adsorption equilibrium data. The homogeneous solid diffusion model (HSD-model) combined with external mass transfer resistance was applied to fit the experimental kinetic data. The kinetics simulation study was performed using a computer program based on the proposed mathematical model and developed using gPROMS. As the two-mass transfer resistance approach was applied, two model parameters were fitted during the simulation study. External mass transfer and solid phase diffusion coefficients were obtained to predict the kinetic curves for varying initial Zn(II) concentration at constant agitation speed and constant adsorbent mass. For any particular Zn(II) - adsorbent system, k f was constant, except for the lowest initial concentration, while D s was found to increase with increasing initial Zn(II) concentration.

scholarly journals Adsorption Characteristics of Humic Acids by Granular Activated Carbon

1997 ◽  
Vol 15 (7) ◽  
pp. 507-516 ◽  
Author(s):  
S.H. Lin ◽  
C.M. Lin
Keyword(s):  
Activated Carbon ◽  
Humic Acid ◽  
Surface Diffusion ◽  
Humic Acids ◽  
Granular Activated Carbon ◽  
Model Parameters ◽  
Adsorption System ◽  
Transfer Resistance ◽  
Liquid Phase Mass Transfer ◽  
Continuous Adsorption

The adsorption of humic acids on granular activated carbon has been investigated. A commerically available humic acid and that extracted from the bottom sludge of a dam were employed in the studies. Both batch and continuous adsorption experiments were conducted. A simplified competitive adsorption model in conjunction with the Freundlich isotherm was employed to represent the batch multicomponent adsorption system and a homogeneous surface diffusion model utilized to describe the continuous adsorption system in a packed-bed column. The model parameters were obtained by best fit of the models to the experimental adsorption data. The results indicated that the liquid-phase mass-transfer resistance, surface diffusion coefficient and the amount of adsorption on the activated carbon decreased with increasing molecular weight of the humic acid. It was also found that the adsorption of humic acid on the activated carbon was primarily a surface diffusion-controlled process.

scholarly journals Correction for External Mass-Transfer Resistance in Diffusive Sampling

AIHAJ ◽  
1985 ◽  
Vol 46 (11) ◽  
pp. 648-652 ◽  
Author(s):  
PETER PERSOFF ◽  
ALFRED T. HODGSON
Keyword(s):  
Mass Transfer ◽  
Diffusive Sampling ◽  
Mass Transfer Resistance ◽  
External Mass Transfer ◽  
Transfer Resistance

The Effect of External Mass Transfer Resistance during Drying of Fermented Sausage

2008 ◽  
Vol 26 (12) ◽  
pp. 1543-1551 ◽  
Author(s):  
İsmail Eren ◽  
Gülen Yıldız-Turp ◽  
Figen Kaymak-Ertekin ◽  
Meltem Serdaroğlu
Keyword(s):  
Mass Transfer ◽  
Mass Transfer Resistance ◽  
External Mass Transfer ◽  
Fermented Sausage ◽  
Transfer Resistance

Comparing biofilm models for a single species biofilm system

2004 ◽  
Vol 49 (11-12) ◽  
pp. 145-154 ◽  
Author(s):  
E. Morgenroth ◽  
H.J. Eberl ◽  
M.C.M. van Loosdrecht ◽  
D.R. Noguera ◽  
G.E. Pizarro ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Numerical Solutions ◽  
Heterotrophic Bacteria ◽  
Numerical Models ◽  
Single Species ◽  
Organic Substrate ◽  
Mass Transfer Resistance ◽  
Benchmark Problem ◽  
External Mass Transfer ◽  
Transfer Resistance

A benchmark problem was defined to evaluate the performance of different mathematical biofilm models. The biofilm consisted of heterotrophic bacteria degrading organic substrate and oxygen. Mathematical models tested ranged from simple analytical to multidimensional numerical models. For simple and more or less flat biofilms it was shown that analytical biofilm models provide very similar results compared to more complex numerical solutions. When considering a heterogeneous biofilm morphology it was shown that the effect of an increased external mass transfer resistance was much more significant compared to the effect of an increased surface area inside the biofilm.

The role of the external mass transfer resistance in nitrite oxidizing bacteria repression in biofilm-based partial nitritation/anammox reactors

2020 ◽  
Vol 186 ◽  
pp. 116348 ◽  
Author(s):  
Julio Pérez ◽  
Michele Laureni ◽  
Mark C.M. van Loosdrecht ◽  
Frank Persson ◽  
David J.I. Gustavsson
Keyword(s):  
Mass Transfer ◽  
Mass Transfer Resistance ◽  
External Mass Transfer ◽  
Transfer Resistance ◽  
Partial Nitritation ◽  
Nitrite Oxidizing Bacteria

Experimental determination of the dissolved oxygen boundary layer and mass transfer resistance near the fluid-biofilm interface

1994 ◽  
Vol 30 (11) ◽  
pp. 47-58 ◽  
Author(s):  
Tian C. Zhang ◽  
Paul L. Bishop
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Dissolved Oxygen ◽  
Boundary Layers ◽  
Mass Transfer Resistance ◽  
External Mass Transfer ◽  
Transfer Resistance ◽  
Concentration Boundary ◽  
Concentration Boundary Layers ◽  
Do Concentration

The thickness of the dissolved oxygen (DO) concentration boundary layer and the external mass transfer in a biofilm system were investigated using a microelectrode technique. Theoretical analysis was conducted to elucidate the mechanisms of the technique and to interpret the experimental measurements. The measured thicknesses of dissolved oxygen (DO) concentration boundary layers under different conditions demonstrated directly the effect of several factors on external mass transfer resistance. The experimental results indicated that (a) increasing substrate loading rate, (b) increasing fluid streamwise velocity and (c) increasing the roughness of the biofilm surface would decrease the external mass transfer resistance. The measured thickness of the DO concentration boundary layer was not in full agreement with theoretical correlations because the nonuniform biofilm created velocity and concentration fluctuations which resulted in the compression of concentration boundary layers. The microelectrode technique is a useful tool to study the external mass transfer resistance.

Adsorption of micropollutants onto fibrous activated carbon: association of ultrafiltration and fibers

1996 ◽  
Vol 34 (9) ◽  
pp. 215-222 ◽  
Author(s):  
C. Brasquet ◽  
J. Roussy ◽  
E. Subrenat ◽  
P. Le Cloirec
Keyword(s):  
Aqueous Solution ◽  
Mass Transfer ◽  
Activated Carbon ◽  
Water Treatment ◽  
Batch Reactor ◽  
Breakthrough Curves ◽  
Mass Transfer Resistance ◽  
Transfer Resistance ◽  
Adsorption Capacities ◽  
Original Approach

The adsorption of polluted solutions is performed by different kinds of activated carbon: grains, powder and fibers (cloth or felt). The adsorption is carried out in a batch reactor. Classic models are applied and kinetic constants are calculated. Results showed that the performance of fiber activated carbon (FAC) is significantly higher than that of granular activated carbon (GAC). Moreover, FAC's adsorption capacities of phenol are greater than GAC's. Therefore the application of FAC adsorbers may lead to smaller adsorption reactors. The breakthrough curves obtained with FAC adsorbers are particularly steep, suggesting a smaller mass transfer resistance than GAC. The adsorption zone in the FAC bed is about 3.4 mm and is not dependent on the flow rate within the range 0.67 - 2.07 m.h−1. The selectivity of the FAC between different size of soluble molecules is shown. Then, an Ultrafiltration (UF) membrane is coupled with FAC to remove successively macromolecules (humic substances) and phenols present together in an aqueous solution. This new and original approach to a water treatment compact process successfully put to use. Industrial developments are put forward.

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