scholarly journals Kinetic model of water vapour adsorption by gluten-free starch

2015 ◽  
Vol 29 (1) ◽  
pp. 115-119
Author(s):  
Aneta Ocieczek ◽  
Robert Kostek ◽  
Millena Ruszkowska
Keyword(s):  
Water Content ◽  
Water Vapour ◽  
Adsorption Process ◽  
Starch Granules ◽  
Gluten Free ◽  
First Order ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
Kinetics Of ◽  
Over Time

Abstract This study evaluated the kinetics of water vapour adsorption on the surface of starch molecules derived from wheat. The aim of the study was to determine an equation that would allow estimation of water content in tested material in any timepoint of the adsorption process aimed at settling a balance with the environment. An adsorption isotherm of water vapour on starch granules was drawn. The parameters of the Guggenheim, Anderson, and De Boer equation were determined by characterizing the tested product and adsorption process. The equation of kinetics of water vapour adsorption on the surface of starch was determined based on the Guggenheim, Anderson, and De Boer model describing the state of equilibrium and on the model of a first-order linear inert element describing the changes in water content over time.

scholarly journals Behavioural Change according to the Si/Al Ratio of Successive Na-Mordenites Observed through Their Dielectric Relaxation during Water Vapour Adsorption Process

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Sekou Diaby
Keyword(s):  
Dielectric Relaxation ◽  
Water Vapour ◽  
Adsorption Process ◽  
Behavioural Change ◽  
Exchangeable Cation ◽  
Relaxation Measurement ◽  
Simple Method ◽  
Adsorbed Molecules ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption

The experimental study of water vapour adsorption phenomenon on a zeolite, by dielectric relaxation measurement, makes it possible to determine the variations in the exchangeable cation hopping activation energy, on the surface of the solid, in relation to the number of adsorbed molecules. The present work shows that it is possible to explain the change observed in the energy, by means of simple assumptions based, on the one hand, on the models used in order to simulate the adsorption process and, on the other hand, on the distribution of the molecules adsorbed near the exchangeable cations. Thus, the phenomenological interpretation suggested here, about the change in the exchangeable cation hopping energy, obtained by dielectric relaxation measurement, makes us with a mind to conceive a simple method for explaining the results leading to new information on the organization of the first adsorbed molecules on the surface of the studied zeolite. Then, it can be verified that these conclusions confirm the assumptions already developed for interpreting the inferences from previous experiments carried out by means of other techniques.

scholarly journals Factors Influencing the Kinetics of Water Vapour Adsorption on Activated Carbons

2021 ◽  
Vol 23 (3) ◽  
pp. 191
Author(s):  
Y. Boutillara ◽  
L. Richelet ◽  
L.F. Velasco ◽  
P. Lodewyckx
Keyword(s):  
Water Vapour ◽  
Activated Carbons ◽  
Kinetic Constant ◽  
Ambient Conditions ◽  
Experimental Conditions ◽  
Adsorption Mechanisms ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
The Impact ◽  
Kinetics Of

The performance of porous carbon materials as sorbents is often compromised by the presence of humidity. Studying the kinetics of water vapour adsorption on activated carbons will undeniably help to overcome this issue. This has been approached in this work by evaluating the influence of several operational factors on the dynamic adsorption of water vapour in these materials. Specifically, different carbon types, particle sizes, air flows and ambient conditions (temperature and relative humidity (RH)) were systematically investigated. The impact of each isolated parameter on both the maximum water uptake and the uptake rate was analyzed by fitting the experimental data to the Linear Driving Force (LDF) kinetic model. The results show that except for the particle size, the studied variables play a role in the water sorption kinetics, although to a different extent. It was also confirmed that the LDF model can adequately describe the kinetics of water vapour adsorption independently of the experimental conditions. Finally, the complete water vapour adsorption process can be described by this model, obtaining a different value of the kinetic constant for the sequential stages, involving different adsorption mechanisms.

scholarly journals Applications of Non-Linear Diffusion Equations to the Kinetics of Water Vapour Adsorption by Polymeric Fibres

1992 ◽  
Vol 9 (4) ◽  
pp. 269-275
Author(s):  
B.M. Kats ◽  
V.V. Kutarov ◽  
A.A. Chagodar
Keyword(s):  
Diffusion Coefficient ◽  
Water Vapour ◽  
Exponential Dependence ◽  
Linear Diffusion ◽  
Non Linear ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
Numeric Experiment ◽  
Kinetics Of ◽  
Sorbate Concentration

In order to describe the kinetics of water vapour adsorption by polymeric fibres, a numeric experiment has been carried out using the framework of a non-linear diffusion model which takes into account the exponential dependence of the diffusion coefficient on the sorbate concentration in the sorbent. The results show a good correlation between theoretical and experimental kinetic curves for polymolecular adsorption. They also confirm the exponential decrease of the diffusion coefficient with an increase in polymolecular filling.

Differential heat of water adsorption for montmorillonite, kaolinite and allophane

Clay Minerals ◽  
1989 ◽  
Vol 24 (3) ◽  
pp. 505-512 ◽  
Author(s):  
S. Iwata ◽  
F. Izumi ◽  
A. Tsukamoto
Keyword(s):  
Water Vapour ◽  
Water Adsorption ◽  
Adsorption Process ◽  
Dominant Role ◽  
Equilibrium Constants ◽  
Adsorbed Water ◽  
Differential Heat ◽  
Clay Surface ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption

AbstractDifferential heat of water vapour adsorption for Cs+-saturated montmorillonite, kaolinite and allophane was measured over a low relative humidity range from 10−4 to 10−1. Two interactions (clay surface atom-water and counterion-water) are mainly involved in the water vapour adsorption process. To assess the affinity of water to the clay surface, the amounts of adsorbed water and the differential heat due to Cs+ were estimated from equilibrium constants in the gas phase reactions. It is tentatively concluded that (i) a dominant role of water adsorption due to the Cs+-water interaction in the adsorption process is evident only for montmorillonite; (ii) the affinity of water to the clay surface is strongest for allophane and weakest for montmorillonite.

scholarly journals Changes in the size of the apparent surface area and adsorption energy of the rye roots by low pH and the presence of aluminium ions induced

2016 ◽  
Vol 30 (3) ◽  
pp. 375-381 ◽  
Author(s):  
Alicja Szatanik-Kloc
Keyword(s):  
Surface Area ◽  
Water Vapour ◽  
Adsorption Energy ◽  
High Energy ◽  
Root Surface ◽  
Low Ph ◽  
Vapour Adsorption ◽  
Average Water ◽  
Water Vapour Adsorption ◽  
Adsorption Desorption

Abstract The plant reactions on Al-stress include i.a. change of the surface area of the roots, which in the physicochemistry of plants characterizes the transport of water and ions through the root. The object of this study is the specific surface area of the roots of plants which are tolerant to aluminium, such as rye. Plants of rye were grown in a nutrient solution for 14 days at pH 4.5 in the presence of Al3+ ions of concentration 10, 20, and 40 mg dm−3. The control plants were grown continuously at pH 7 or pH 4.5 without Al3+. The apparent surface area and adsorption energy of the plants roots were determined from water vapour adsorption – desorption data. The apparent surface area of roots growing in the aluminium was (with respect to control) statistically significantly lower. There were no statistically significant differences in the apparent surface area of the roots which grew in pH 7, pH 4.5 without Al3+. The average water vapour adsorption energy of the root surface, under stress conditions decreased. In the roots grown in the presence of Al+3, there was a slight decrease in high energy adsorption centres and an increase in the amount of low-energy centres.

scholarly journals Adsorption purification of waste water from chromium by ferrite manganese

2020 ◽  
Vol 168 ◽  
pp. 00026
Author(s):  
Liliia Frolova ◽  
Mykola Kharytonov ◽  
Iryna Klimkina ◽  
Oleksandr Kovrov ◽  
Andrii Koveria
Keyword(s):  
Adsorption Process ◽  
Uv Spectroscopy ◽  
Second Order ◽  
Waste Waters ◽  
Equilibrium Isotherms ◽  
X Ray ◽  
First Order ◽  
Freundlich Isotherms ◽  
Pseudo Second Order ◽  
Kinetics Of

Plasma method is used to synthesize manganese ferrite. The basic properties of ferrite are determined by IR spectroscopy, UV spectroscopy, X-ray phase analysis, vibration magnetometry. The paper shows that the use of magnetically controlled sorbent allows to purify waste waters from chromium (III). The process of adsorption of chromium cations (III) is investigated. The kinetics of the process is studied. To describe the equilibrium isotherms, the experimental data are analysed by the models of Langmuir, Freundlich isotherms. Pseudo-first order, pseudo-second-order, and Weber-Morris are used to elucidate the kinetic parameters and mechanism of the adsorption process. It has been established that the removal of Cr (III) cations is described by the pseudo-second order of the Langmuir reaction and mechanism.

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