Effect of temperature on the equilibrium and kinetics of galactose, glucose, and lactose adsorption on a cation exchanger

2014 ◽  
Vol 68 (12) ◽  
Author(s):  
Łukasz Wiśniewski ◽  
Katarína Vaňková ◽  
Pavel Ačai ◽  
Milan Polakovič
Keyword(s):  
Mass Transfer ◽  
Cation Exchanger ◽  
Enzymatic Reaction ◽  
Breakthrough Curves ◽  
Axial Dispersion ◽  
Effect Of Temperature ◽  
Transfer Resistance ◽  
Adsorption Equilibria ◽  
Intraparticle Mass Transfer ◽  
Kinetics Of

AbstractGalacto-oligosaccharides are typically produced by an enzymatic reaction when the post-reaction mixture contains considerable amounts of lactose and glucose and a smaller amount of galactose. In order to develop a process of chromatographic removal of saccharide impurities, adsorption equilibria and kinetics of these di- and monosaccharides were investigated for Diaion UBK 530, an industrialgrade strong cation-exchanger in the Na+ form. Frontal chromatographic experiments were carried out in the temperature range of 30–70°C and a broad interval of saccharide concentrations up to 350 g L−1. Breakthrough curves were described using the equilibrium-dispersive model with the linear adsorption isotherm. Both the distribution and the axial dispersion coefficient values depended on the saccharide molecule type and size. No significant effect of temperature or concentration on the distribution coefficient was observed. The apparent dispersion coefficients of all saccharides exhibited some decrease with the temperature, which was caused by the decrease of the intraparticle mass transfer resistance. An analysis showed that both the intraparticle mass transfer and the axial dispersion had a significant influence on the front dispersion.

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 Kinetics of Dehydration of Aroids and Developed Dehydrated Aroids Products

2010 ◽  
pp. 19-24
Author(s):  
M Kamruzzaman ◽  
MN Islam
Keyword(s):  
Mass Transfer ◽  
Rate Constant ◽  
Chemical Engineering ◽  
Raw Materials ◽  
Drying Rate ◽  
Chemical Compositions ◽  
Air Velocity ◽  
Transfer Resistance ◽  
Power Law Equation ◽  
Kinetics Of

The study was concerned with the dehydration kinetics of aroids in mechanical dryer at different dryingcondition such as variable air dry bulb temperature and air velocity. Fresh aroids with 3, 5 mm slice and 8mm cube were used as raw materials for drying. The experimental results showed that drying rate constantand thickness can be expressed as power law equation. The exponent of the equation for aroids was 1.15indicating presence of significance external mass transfer resistance. Increasing loading density gavedecreased drying rate constant and when air velocity of dryer was increased, drying rate constant was alsoincreased, as higher air velocity reduces the external resistance to mass transfer and also highertemperature gave faster drying rate. The activation energy of diffusion of water from aroids during dryingas per Arrhenius equation was found to be 5.12 k cal/g-mole. The chemical compositions of fresh and driedaroids were determined and it was observed that all the constituent remained almost constant, only fatdecreased slightly possibly due to oxidation. Organoleptic taste testing showed that “chapatti” preparedfrom aroids powder (aroids powder: wheat flour = 1:4) were adjudged to be the best by the panelists using1-9 hedonic scale and ranked as like moderately securing score 7.3.Journal of Chemical Engineering Vol.ChE 24 2006 19-24

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.

scholarly journals Studies of Adsorption of Heavy Metals onto Spent Coffee Ground: Equilibrium, Regeneration, and Dynamic Performance in a Fixed-Bed Column

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
N. E. Davila-Guzman ◽  
F. J. Cerino-Córdova ◽  
M. Loredo-Cancino ◽  
J. R. Rangel-Mendez ◽  
R. Gómez-González ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Mass Transfer ◽  
Ion Exchange ◽  
Axial Dispersion ◽  
Model Parameters ◽  
Dynamic Adsorption ◽  
Transfer Model ◽  
Transfer Resistance ◽  
Spent Coffee Ground ◽  
Coffee Ground

Equilibrium and dynamic adsorption of heavy metals onto spent coffee ground (SCG) were studied. The equilibrium adsorption of Cd2+, Cu2+, and Pb2+in a batch system was modeled by an ion-exchange model (IEM) based on an ion-exchange of heavy metals with calcium and protons bonded to active sites on SCG surface. The maximum amount of adsorbed metal ions obtained using the IEM was 0.12, 0.21, and 0.32 mmol/g of Cd2+, Cu2+, and Pb2+, respectively. Regeneration of SCG was evaluated using citric acid, calcium chloride, and nitric acid. The observed trend of desorption efficiency through four adsorption-desorption cycles was HNO3> CaCl2> C6H8O7. The effect of process variables such as flow rate and bed height during the dynamic adsorption was evaluated. Moreover, the applicability of a mass transfer model based on external mass transfer resistance, axial dispersion, and ion-exchange isotherm was evaluated, and the results were in good agreement with the experimental data for the adsorption in SCG packed column. The sensitivity analysis of the model parameters showed that axial dispersion coefficient is the most significant parameter in the dynamic simulation. The results obtained showed the potential of SCG as a low-cost material for wastewater metal removal in continuous systems.

scholarly journals Study on drying kinetics of summer onion

2015 ◽  
Vol 39 (4) ◽  
pp. 661-673 ◽  
Author(s):  
Md Masud Alam ◽  
Md Nurul Islam ◽  
Md Nazrul Islam
Keyword(s):  
Activation Energy ◽  
Mass Transfer ◽  
Rate Constant ◽  
Variable Temperature ◽  
Air Flow ◽  
Drying Kinetics ◽  
Effect Of Temperature ◽  
Drying Rate ◽  
External Resistance ◽  
Kinetics Of

The present study was concerned with the kinetics of drying of summer onion. Drying was done in a mechanical dryer at constant air flow using blanched and unblanched onion with variable temperature (52, 60 and 680C) and thickness (3, 5 and 7 mm). Drying rate was increased with increase of temperature and decreased with the increase in thickness in blanched and unblanched onion. Blanched onion showed higher drying rate than unblanched onion. Drying rate constant and thickness can be expressed as power low equations. The value of index “n” were found to be 1.277 and 0.845 for onion indicating that the external resistance to mass transfer was highly significant. The effect of temperature on diffusion co-efficient follows an Arrhenius type relationship. The activation energy (Ea) for diffusion of water was found 5.781 Kcal/g-mole for unblanched and 2.46 Kcal/g-mole for blanched onion when onions were dried in mechanical dryer. DOI: http://dx.doi.org/10.3329/bjar.v39i4.22545 Bangladesh J. Agril. Res. 39(4): 661-673, December 2014

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