Effect of the shape of a solid on the kinetics of external mass transfer

1978 ◽  
Vol 35 (1) ◽  
pp. 833-836
Author(s):  
G. A. Aksel'rud ◽  
I. I. Feiginberg
Keyword(s):  
Mass Transfer ◽  
External Mass Transfer ◽  
Kinetics Of

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 KINETICS OF FORMALDEHYDE FROM AQUEOUS SOLUTIONS BY CARBON POROUS MATERIALS IN PRESENCE OF PHOSPHORIC ACID

2017 ◽  
Vol 60 (2) ◽  
pp. 4
Author(s):  
Grygori A. Ovchinikov ◽  
Valentina A. Gorski ◽  
Ilyana I. Fasalova ◽  
Denis A. Kirilov ◽  
Vadim S. Tukhvatshin ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Phosphoric Acid ◽  
Aqueous Solutions ◽  
Porous Materials ◽  
Adsorption Kinetics ◽  
Internal Mass ◽  
External Mass Transfer ◽  
Sorption Equilibrium ◽  
Kinetics Of ◽  
Formaldehyde Adsorption

In this paper we studied the adsorption kinetics of formaldehyde on porous carbon nanotubes and glassy carbon from aqueous solutions in the presence of phosphoric acid. The values of the external and internal mass transfer diffusion coefficients were obtained. We found the influence of the contribution of external mass transfer and internal diffusion on the process of formaldehyde adsorption. The time of establishment of sorption equilibrium was determined.For citation:Оvchinikov G.А., Gorski V.А., Fasаlova I.I., Кirilov D.А., Тukhvatshin V.S., Тalipov R.F., Кraikin V.А. Adsorption kinetics of formaldehyde from aqueous solutions by carbon porous materials in presence of phosphoric acid. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 2. P. 4-6.

scholarly journals ADSORPTION KINETICS OF FORMALDEHYDE FROM AQUEOUS SOLUTIONS BY CARBON POROUS MATERIALS IN PRESENCE OF PHOSPHORIC ACID

2017 ◽  
Vol 60 (2) ◽  
pp. 4
Author(s):  
Grygori A. Ovchinikov ◽  
Valentina A. Gorski ◽  
Ilyana I. Fasalova ◽  
Denis A. Kirilov ◽  
Vadim S. Tukhvatshin ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Phosphoric Acid ◽  
Aqueous Solutions ◽  
Porous Materials ◽  
Adsorption Kinetics ◽  
Internal Mass ◽  
External Mass Transfer ◽  
Sorption Equilibrium ◽  
Kinetics Of ◽  
Formaldehyde Adsorption

In this paper we studied the adsorption kinetics of formaldehyde on porous carbon nanotubes and glassy carbon from aqueous solutions in the presence of phosphoric acid. The values of the external and internal mass transfer diffusion coefficients were obtained. We found the influence of the contribution of external mass transfer and internal diffusion on the process of formaldehyde adsorption. The time of establishment of sorption equilibrium was determined.For citation:Оvchinikov G.А., Gorski V.А., Fasаlova I.I., Кirilov D.А., Тukhvatshin V.S., Тalipov R.F., Кraikin V.А. Adsorption kinetics of formaldehyde from aqueous solutions by carbon porous materials in presence of phosphoric acid. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 2. P. 4-6.

scholarly journals Kinetics of Iron (II) Removal from Aqueous Solution Using Activated Dolomite

2007 ◽  
Vol 1 (1) ◽  
pp. 23-29 ◽  
Author(s):  
G.M. Walker ◽  
G. Connor ◽  
S.J. Allen
Keyword(s):  
Mass Transfer ◽  
Removal Rate ◽  
Bulk Solution ◽  
Experimental Investigations ◽  
Particle Diffusion ◽  
External Mass Transfer ◽  
Experimental Conditions ◽  
Intra Particle Diffusion ◽  
Stage Process ◽  
Kinetics Of

Experimental investigations were undertaken in batch kinetic systems, for the removal of iron (II) from aqueous solutions using activated dolomite. The effect of the extent dolomite activation on the dissolution of magnesium and calcium from the dolomite lattice was determined. Under optimum experimental conditions there was a direct linear relationship between magnesium dissolution and iron (II) removal from bulk solution. The experimental data were mathematically described using empirical external mass transfer and pseudo-intra-particle diffusion models. The data show conformity with a three stage process, with the iron (II) removal rate showing good correlation with external mass transfer (t < 1 min) and two rates of pseudo-intra-particle diffusion (1 < t < 90mins, and t < 90mins).

scholarly journals Adsorption Kinetics of Cationic Dyestuffs on to Natural Clay

1996 ◽  
Vol 13 (4) ◽  
pp. 295-303 ◽  
Author(s):  
Mohammad S. El-Geundi
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Size Range ◽  
External Mass Transfer ◽  
Natural Clay ◽  
Particle Size Range ◽  
Design Variables ◽  
Step Model ◽  
Kinetics Of

A three-step model has been proposed for the adsorption of cationic dyestuffs (Basic Blue 69 and Basic Red 22) from aqueous solutions on to natural clay. The rate of adsorption is controlled initially by the boundary layer film and an external mass-transfer coefficient Ks has been determined for this process under the influence of a number of design variables. Two approaches, designated methods 1 and 2, are available for determining the external mass-transfer coefficient. Using log-log correlations, the external mass-transfer coefficient was found to vary linearly with the agitation speed, the clay particle size range and the mass of clay employed.

Mass Transfer Coefficients during Steel Decarburization in a RH Degasser

2008 ◽  
Vol 273-276 ◽  
pp. 679-684
Author(s):  
Roberto Parreiras Tavares ◽  
André Afonso Nascimento ◽  
Henrique Loures Vale Pujatti
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Flow ◽  
Vacuum Chamber ◽  
Volumetric Mass Transfer Coefficient ◽  
Gas Flow Rate ◽  
Rh Process ◽  
Kinetics Of

The RH process is a secondary refining process that can simultaneously attain significant levels of removal of interstitial elements, such as carbon, nitrogen and hydrogen, from liquid steel. In the RH process, the decarburization rate plays a very important role in determining the productivity of the equipment. The kinetics of this reaction is controlled by mass transfer in the liquid phase. In the present work, a physical model of a RH degasser has been built and used in the study of the kinetics of decarburization. The effects of the gas flow rate and of the configurations of the nozzles used in the injection of the gas have been analyzed. The decarburization reaction of liquid steel was simulated using a reaction involving CO2 and caustic solutions. The concentration of CO2 in the solution was evaluated using pH measurements. Based on the experimental results, it was possible to estimate the reaction rate constant. A volumetric mass transfer coefficient was then calculated based on these rate constants and on the circulation rate of the liquid. The logarithm of the mass transfer coefficient showed a linear relationship with the logarithm of the gas flow rate. The slope of the line was found to vary according to the relevance of the reaction at the free surface in the vacuum chamber. A linear relationship between the volumetric mass transfer coefficient and the nozzle Reynolds number was also observed. The slopes of the lines changed according to the relative importance of the two reaction sites, gas-liquid interface in the upleg snorkel and in the vacuum. At higher Reynolds number, the reaction in the vacuum chamber tends to be more significant.

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