A new model for soil water vapor sorption isotherms considering adsorption and condensation

2020 ◽  
Author(s):  
Chong Chen ◽  
Emmanuel Arthur ◽  
Hu Zhou ◽  
Xiang Wang ◽  
Jianying Shang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Soil Water ◽  
Sorption Isotherms ◽  
Water Vapor Sorption ◽  
Vapor Sorption ◽  
New Model

THE ADSORPTION OF ALIPHATIC ACIDS FROM AQUEOUS SOLUTIONS BY POROUS CARBONS

1955 ◽  
Vol 33 (2) ◽  
pp. 330-343 ◽  
Author(s):  
John L. Morrison ◽  
David M. Miller
Keyword(s):  
Water Vapor ◽  
Solid State ◽  
Aqueous Solutions ◽  
Pore Size ◽  
Carboxylic Acids ◽  
Sorption Isotherms ◽  
Water Vapor Sorption ◽  
Vapor Sorption ◽  
Melting Points ◽  
General Phenomenon

The maximum adsorptions of the lower members of the mono- and di-carboxylic acids from aqueous solutions were determined for coconut charcoals of different degrees of activation. Based on these results, a method for estimating pore size was applied to the more finely porous charcoals. To corroborate the pore sizes estimated from acid adsorption, pore size – area distributions were calculated from measurements of the water vapor sorption isotherms of the charcoals. An alternation in the maximum amounts of adsorbed acids was observed with the more active charcoals. Acids with an even number of carbon atoms had larger adsorptions than acids with an odd number. The alternation was much more marked for the di- than for the mono-carboxylic acids. A remarkable correlation between the alternation of adsorptions and of melting points of both acid series was observed. An explanation for the general phenomenon of alternation based on rotational motion of molecules in the solid state is given as an alternative to the widely held one based on tilting of molecular chains.

scholarly journals Study of Hydrophilic Properties of Polysaccharides

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Michael Ioelovich
Keyword(s):  
Water Vapor ◽  
Structural Characteristics ◽  
Sorption Isotherms ◽  
Water Vapor Sorption ◽  
Water Molecules ◽  
Vapor Sorption ◽  
Direct Proportion ◽  
Polar Groups ◽  
Sorption Of Water Vapor ◽  
Chitin And Chitosan

In this research, the structural characteristics, specific surface area, sorption of water vapor, and wetting enthalpy of various polysaccharides (cellulose, hemicelluloses, starch, pectin, chitin, and chitosan) have been studied. It was confirmed that crystallites are inaccessible for water, and therefore water molecules can interact only with polar groups in noncrystalline (amorphous) domains of biopolymers. The isotherms of water vapor sorption for various polysaccharides had sigmoid shapes, which can be explained by the absorption of water molecules in heterogeneous amorphous domains having clusters with different packing densities. The method of contributions of polar groups to sorption of water molecules was used, which allowed to derivate a simple calculating equation to describe the shape of sorption isotherms. The wetting of biopolymers with water was accompanied by a high exothermic thermal effect, in direct proportion to the amorphicity degree. The sorption values and wetting enthalpies of amorphous domains of biopolymers were calculated, which allowed to find the hydrophilicity index and compare the hydrophilicity of the various polysaccharides.

Water vapor sorption isotherms of cane sugar

2010 ◽  
pp. 95-101
Author(s):  
Maciej Wojtczak ◽  
Zbigniew Tamborski
Keyword(s):  
Water Vapor ◽  
Water Sorption ◽  
Sorption Isotherms ◽  
Cane Sugar ◽  
Water Vapor Sorption ◽  
Vapor Sorption ◽  
Beet Sugar ◽  
Different Types

The aim of the paper was to determine water vapor sorption isotherms of different types of cane sugar in comparison with beet sugar. Different samples of white beet and cane sugar together with brown cane sugar were the materials for the analysis. The sorption isotherms were determined at temperatures of 5 ºC and 25 ºC for water activities from 0.33 to 0.87. In the analyzed sugars the following parameters were also determined: color, conductivity ash, contents of K, Na, Ca, Mg and dextran. Significant differences in water sorption were found between different types of cane sugar and beet sugar. Brown cane sugars were the most hygroscopic samples of all the researched sugars.

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