scholarly journals Determination of Moisture Sorption Isotherm of Crosslinked Millet Flour and Oxirane Using GAB and BET

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
M. S. Alamri ◽  
A. A. Mohamed ◽  
S. Hussain ◽  
M. A. Ibraheem ◽  
Akram A. Abdo Qasem
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Sorption Isotherm ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Water Binding ◽  
Moisture Sorption Isotherm ◽  
Water Sorption Isotherm ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures

Epoxy resin was prepared by crosslinking epoxidized oil and millet flour. The reaction was carried out at three different temperatures (25, 40, and 55°C) and zinc chloride levels (1, 2, and 3%). Moisture sorption isotherms were determined at 0.1 to 0.9 water activity (aw) using a gravimetric sorption analyzer (Q 2000). The sigmoidal shape (type II) of the resin isotherms exhibited lower equilibrium moisture content (EMC) at higher temperature. The experimental data were modeled using GAB (Guggenheim–Anderson–de Boer) and BET (Brunauer–Emmett–Teller). The EMC of the resin was significantly lower than that of the flour, which could be attributed to the decrease in the number of water-binding sites due to the creation of dense areas during crosslinking. The low root-mean-square error (RMSE) indicates that GAB and BET were suitable for predicting the water sorption isotherm for millet flour resin. The heat of sorption of the resin was large at low moisture content and increased at higher relative humidity. It is recommended that millet flour resin be used at relative humidity below 60%.

scholarly journals Drying kinetics and determination of water sorption isotherms of corn

2017 ◽  
Vol 15 (2) ◽  
Author(s):  
J Roy ◽  
MA Alim ◽  
MN Islam
Keyword(s):  
Moisture Content ◽  
Sorption Isotherm ◽  
Water Sorption ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Drying Kinetics ◽  
Drying Time ◽  
Moisture Sorption Isotherm ◽  
Water Sorption Isotherm ◽  
Monolayer Moisture

The study was carried out for the purpose of determining the drying kinetics as well as moisture sorption isotherm of hybrid-81 corn. Corn at about 31% moisture content (wb) was dried in a forced convective hot air cabinet dryer at different drying conditions, such as variable air dry bulb temperature (40°C, 50°C and 60°C) and loading density (3.56 kg/m2, 7.12 kg/m2, and 10.68 kg/m2) as well as in shining sun at different layers (3.56 kg/m2, 7.12 kg/m2, and 10.68 kg/m2). The water sorption isotherm of the dried corn was developed using vacuum desiccators, which contained saturated salt solutions in the range of 11-93% RHs. The mono-layer moisture content calculated by the Brunauer–Emmett–Teller (BET) model (6.76 g/100 g solid) was lesser than that calculated by the Guggenheim–Anderson–De Boer (GAB) model (10.53 g/100 g solid). The energy constants were 10.45 and 4.64 as per BET and GAB equation, respectively. Both models gave suitable fits for corn. The activation energy (Ea) for diffusion of water was found to be 11.09 kcal/gm-mole for corn. Furthermore, it was noticed that, with the increase of corn layer, the drying rate decreased in case of both sun and mechanical drying. However, higher loading density resulted in efficient drying, at least up to 10.7 kg/m2. It was shown that the drying time to obtain stability was the lowest for moisture content (12.08 %) corresponding to aw of 0.65 in case of BET or GAB monolayer moisture content. This finding could be helpful in predicting the storage life of corn.J. Bangladesh Agril. Univ. 15(2): 309-317, December 2017

Moisture sorption isotherm of cross-linked wheat gluten and epoxydized oil using GAB and BET

2019 ◽  
Vol 27 (9) ◽  
pp. 536-545
Author(s):  
AA Mohamed ◽  
MS Alamri ◽  
S Hussain ◽  
MA Ibraheem ◽  
Akram A Abdo Qasem
Keyword(s):  
Moisture Content ◽  
Free Volume ◽  
Sorption Isotherm ◽  
Wheat Gluten ◽  
Moisture Sorption ◽  
Cross Linking ◽  
Water Binding ◽  
Clapeyron Equation ◽  
Moisture Sorption Isotherm ◽  
Water Sorption Isotherm

The moisture sorption isotherm of wheat gluten/epoxydized sesame or sunflower oil resin was determined at 25, 40, and 55°C. The resin was prepared by cross-linking epoxydized oil and wheat gluten using 1, 2, and 3% zinc chloride as the catalyst. The experiment was carried out over 0.1–0.9 water activity ( a w) range using gravimetric sorption analyzer (Q 2000, TA Instruments, New Castle, PA, USA). The resin isotherms were found to be type III shape where the equilibrium moisture content (EMC) was higher at lower temperatures. The EMC of gluten epoxy resin was dependent on the degree of cross-linking because more cross-linking decreased EMC. The Guggenheim Anderson-de Boer (GAB) parameters support the theory of the free volume as it relates to monolayer absorption. This could be attributed to the decrease in the number of water binding sites due to the development of dense areas during cross-linking and increase in the free volume. The GAB and Brunauer–Emmett–Teller were found to be suitable for predicting the water sorption isotherm for gluten protein resin because it provided low root mean square error. The heat of sorption based on the Clausius–Clapeyron equation (qst) increased with decrease in moisture content.

scholarly journals Moisture sorption isotherms of castor beans. Part 1: Mathematical modeling and hysteresis

2016 ◽  
Vol 20 (8) ◽  
pp. 751-756 ◽  
Author(s):  
André L. D. Goneli ◽  
Paulo C. Corrêa ◽  
Gabriel H. H. de Oliveira ◽  
Osvaldo Resende ◽  
Munir Mauad
Keyword(s):  
Moisture Content ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Environmental Condition ◽  
Adsorption And Desorption ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures ◽  
The Difference ◽  
The Stability ◽  
And Storage

ABSTRACT Sorption isotherms are of great importance in post-harvest procedures, especially for predicting drying and storage, which help to establish the final moisture content of the product under certain environmental condition. Hysteresis is a phenomenon that occurs due to the difference between adsorption and desorption curves, which aids the evaluation of chemical and microbiological deteriorations, indicating the stability of stored products. Moisture sorption isotherms of castor beans were determined and hysteresis was analyzed. Static gravimetric technique at different temperatures (25, 35, 45 and 55 ± 1 °C) was used. Saturated salt solutions in the range of 37-87% ± 2% were utilized to create the required controlled relative humidity environment. Equilibrium moisture content data were correlated by different mathematical models and the Modified Halsey model presented good adjustment for the data, according to statistical procedures. Hysteresis between adsorption and desorption isotherms is present over the range of 0.2-0.9 of water activity, regardless of the temperature. This phenomenon decreases with temperature increase.

Moisture Sorption Isotherms and Thermodynamic Properties of Carrot

2011 ◽  
Vol 7 (3) ◽  
Author(s):  
Valeria S. Eim ◽  
Carmen Rosselló ◽  
Antoni Femenia ◽  
Susana Simal
Keyword(s):  
Moisture Content ◽  
Dry Matter ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Isosteric Heat ◽  
Nonlinear Regression Analysis ◽  
Mean Relative Error ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures ◽  
Water Sorption Isotherms

The water sorption isotherms of carrot were determined at five different temperatures (at 10, 20, 30, 40 and 50ºC) within wide ranges of moisture content (1.3-78.4 kg water /100 kg dry matter) and water activities (0.165-0.907) by using a standardized conductivity thermohygrometer. The sorption isotherms exhibited the type III behaviour, thus, an increase in temperature promoted a decrease in water activity. The GAB, Halsey, Henderson, Iglesias & Chirife and Oswin models were tested to fit the experimental data by using nonlinear regression analysis. The GAB and Henderson models satisfactorily described the sorption isotherms (mean relative error < 5.6%). The net isosteric heat of sorption (Qstn) and the differential entropy (Sd), estimated as functions of the moisture content, decreased as the carrot moisture content increased.

Water-Binding and Oxygen Permeability in Poly(vinyl alcohol) Films

2002 ◽  
Vol 55 (8) ◽  
pp. 507 ◽  
Author(s):  
L. Lien ◽  
C. M. Fellows ◽  
L. Copeland ◽  
B. S. Hawkett ◽  
R. G. Gilbert
Keyword(s):  
Vinyl Alcohol ◽  
Oxygen Permeability ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Poly Vinyl Alcohol ◽  
Contributing Factors ◽  
Water Binding ◽  
Moisture Sorption Isotherm ◽  
Moisture Sorption Isotherms ◽  
Copolymer Poly

The measurement and interpretation of isotherms for sorption of water onto, and oxygen permeability of, polymer substrates are important for designing polymers in applications such as agricultural seed coatings. In a preliminary study of water sorption in the commonly used copolymer poly(vinyl alcohol–co-vinyl acetate), moisture sorption isotherms were measured for a series of substrates of different comonomer composition at 25°C. The data were fitted to the D'Arcy–Watt model, which gave physically reasonable values for parameters related to the strength of monolayer adsorption to high affinity sites on the substrate and the number of sites for secondary water adsorption per unit mass. The oxygen permeability of poly(vinyl alcohol) films was found to be a function only of the water content of the films, with no other obvious contributing factors. Marked differences were seen in the populations of 'bound' and 'unbound' water characterized by 1H nuclear magnetic resonance (NMR) spectroscopy and moisture sorption isotherm fitting. There was no correlation of oxygen permeability with 'bound' or 'unbound' water measured by any means, a fact suggesting that there is a continuum of water environments within the materials.

scholarly journals Comparison of moisture sorption isotherm models in freeze-dried pineapple pulp

1969 ◽  
Vol 77 (3-4) ◽  
pp. 113-128
Author(s):  
Humberto Vega-Mercado ◽  
Gustavo V. Barbosa-Cánovas
Keyword(s):  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Isotherm Models ◽  
Crystalline Cellulose ◽  
Moisture Sorption Isotherm ◽  
Freeze Dried ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures ◽  
Pineapple Pulp

Moisture sorption isotherms of freeze-dried pineapple pulp were determined at 5, 25, 30, 35 and 55°C. Water activity were controlled by using preselected saturated salt solutions in evacuated glass desskators according to Wolf et al. (20), where micro crystalline cellulose is the reference material for the determination of sorption isotherms. The data were correlated in terms of some empirical models involving two single parameters: models of Henderson, Oswin, Chung-Pfost, Halsey, Iglesias-Chirife, and Smith. Also, the data was correlated by the Guggenheim-Anderson-deBoer (G.A.B.) model involving three adjustable parameters. It was found that the models proposed by Henderson and Iglesias-Chirife were the most useful ones in predicting water activities at different levels and at different temperatures.

scholarly journals Experimental Determination of Moisture Sorption Isotherm of Fecal Sludge

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 303 ◽  
Author(s):  
Catherine Bourgault ◽  
Paul Lessard ◽  
Claire Remington ◽  
Caetano C. Dorea
Keyword(s):  
Relative Humidity ◽  
Water Distribution ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Critical Data ◽  
Moisture Sorption Isotherm ◽  
Fecal Sludge ◽  
Moisture Sorption Isotherms ◽  
Gab Model

Dewatering and drying of fecal sludge (FS) is a key treatment objective in fecal sludge management as it reduces volume (thereby reducing emptying frequency and associated transportation costs), inactivates pathogens, and is beneficial and/or necessary to resource recovery activities such as composting and combustion as fuel. However, studies on dewatering performances of FS are limited. The physical water distribution of such matrices is not fully understood, limiting the progress in the development and optimization of FS dewatering technologies. The objective of this study is to present a gravimetric method intended to assess the dewatering characteristics and associated modelling of FS through moisture sorption isotherms. Samples were placed in airtight jars containing different saturated salt (NaOH, CaCl2, NaCl, KCl, K2SO4) solutions to reproduce a range of relative humidity values (6 to 97%). Results confirmed the achievement of characteristic sigma-shaped moisture sorption isotherms with increasing moisture adsorption at higher values of relative humidity. Furthermore, experimental data best fit the three-parameter Guggenheim–Anderson–de Boer (GAB) model. This method can be replicated to contribute critical data about the characterization of fecal sludge, a seriously under-researched matrix.

scholarly journals Study on water sorption isotherm of summer onion

2015 ◽  
Vol 40 (1) ◽  
pp. 35-51 ◽  
Author(s):  
Md Masud Alam ◽  
Md Nazrul Islam
Keyword(s):  
Moisture Content ◽  
Sorption Isotherm ◽  
Water Sorption ◽  
Moisture Sorption ◽  
Moisture Sorption Isotherm ◽  
Water Sorption Isotherm ◽  
Monolayer Moisture Content ◽  
Using Data ◽  
Monolayer Moisture ◽  
Added Salt

The water sorption characteristics of dehydrated onion and onion solutes composite by vacuum drying (VD) and air drying (AD) were developed at room temperature using vacuum desiccators containing saturated salt solutions at various relative humidity levels (11-93%). From moisture sorption isotherm data, the monolayer moisture content was estimated by Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) equation using data up to a water activity of 0.52 and 0.93 respectively. Results showed that in case of non treated samples the monolayer moisture content values (Wo) of BET gave slightly higher values than GAB (9.7 vs 8.2) for VD, while GAB gave higher value than BET (11.0 vs 9.8) for AD. It is also seen that the treated and non treated onion slice and onion powder absorbed approximately the same amount of water at water activities below about 0.44 and above 0.44 the treated samples begin to absorb more water than the non treated samples. It was observed that 10-20% added of sugar gave no change in water sorption capacity while the amount of sorbed water increases with increasing amount added salt for mix onion product.Bangladesh J. Agril. Res. 40(1): 35-51, March 2015

Comparison of Moisture Sorption Isotherms and Quality Characteristics of Freeze-Dried and Boiled-Dried Abalone

2015 ◽  
Vol 11 (4) ◽  
pp. 573-578 ◽  
Author(s):  
Ji-Yeon Chun ◽  
Yeon-Ji Jo ◽  
Jun-Bo Shim ◽  
Sang-Gi Min ◽  
Geun-Pyo Hong
Keyword(s):  
Moisture Content ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Value Added ◽  
Quality Characteristics ◽  
Lower Shear ◽  
Moisture Sorption Isotherm ◽  
Freeze Dried ◽  
Moisture Sorption Isotherms ◽  
Monolayer Moisture

Abstract This study investigated the moisture sorption isotherm (MSI) profiles of freeze-dried (FD) and boiled-dried (BD) abalone at 15°C, 25°C, and 35°C, and compared the quality characteristics of the abalone after rehydration. The equilibrium moisture content (EMC) and the calculated monolayer moisture content of FD abalone were higher than those of BD abalone. After rehydration, FD abalone showed a higher yield and a lower shear force than BD abalone. Additionally, the appearance of FD abalone was similar to that of fresh abalone, reflecting a potential application of FD to produce value-added dried abalone.

Modeling of the Equilibrium Moisture Content (EMC) of Tarragon (Artemisia Dracunculus L.)

2005 ◽  
Vol 1 (5) ◽  
Author(s):  
Akbar Arabhosseini ◽  
Willem Huisman ◽  
Anton van Boxtel ◽  
Joachim Müller
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Relative Deviation ◽  
Artemisia Dracunculus ◽  
Significant Difference ◽  
Moisture Sorption Isotherms ◽  
The Relationship

The equilibrium moisture content of tarragon, Artemisia dracunculus L. (stem and leaf separately) was determined by using the saturated salt solutions method at three temperatures (25, 50 and 70°C) within a range of 5 to 90% relative humidity. Both adsorption and desorption methods were used for stem and leaf of two varieties: Russian and French tarragon. Experimental curves of moisture sorption isotherms were fitted by modified Henderson, modified Halsey, modified Oswin, modified Chung-Pfost and GAB equations and evaluated by residual sum squares, standard error of estimate and mean relative deviation. The modified Halsey and GAB equations were found to be the most suitable for describing the relationship among equilibrium moisture content, relative humidity and temperature. There was no significant difference between the equilibrium moisture content of the Russian and French tarragon.

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