Effect of 300 and 500 MPa pressure treatments on starch–water adsorption/desorption isotherms and hysteresis

2014 ◽  
Vol 34 (4) ◽  
pp. 452-459 ◽  
Author(s):  
Mauro D. Santos ◽  
Pedro Cunha ◽  
Rui P. Queirós ◽  
Liliana G. Fidalgo ◽  
Ivonne Delgadillo ◽  
...  
Keyword(s):  
Water Adsorption ◽  
Desorption Isotherms ◽  
Adsorption Desorption

Changes in Water Adsorption Desorption Isotherms of Cement Mortars Caused by Carbonation Coupled with Humidification-Drying Cycles

2014 ◽  
Vol 989-994 ◽  
pp. 705-709
Author(s):  
Tung Pham Son
Keyword(s):  
Water Adsorption ◽  
Coupling Effect ◽  
Adsorbed Water ◽  
Water Vapor Adsorption ◽  
Adsorption Method ◽  
Cement Mortars ◽  
Pore Size Distributions ◽  
Low Humidity ◽  
Desorption Isotherms ◽  
Adsorption Desorption

The objective of this work was to examine the influence of carbonation on the water vapor adsorption desorption isotherms of cement materials. Two types of Portland mortars, which were CEM I and CEM II, were carbonated at 20°C, 65% relative humidity and 20% of CO2concentration. The pore size distributions were determined from the water adsorption method. We also studied the coupling effect between carbonation and humidification-drying cycles. The results showed a reduction in microporosity and a small increase in the mesoporosity. The pores clogging due to formation of calcium carbonate was highlighted by the reduction of the quantity of adsorbed water and the decrease in the hysteresis isotherms. The results of this study also indicated that the humidification-drying cycles coincide only from the second cycle because of a difficult evacuation of water during desorption, even at low humidity.

Water adsorption–desorption isotherms of two-dimensional hexagonal mesoporous silica around freezing point

2012 ◽  
Vol 367 (1) ◽  
pp. 409-414 ◽  
Author(s):  
Akira Endo ◽  
Toshio Yamaura ◽  
Kyohei Yamashita ◽  
Fumio Matsuoka ◽  
Eiji Hihara ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Water Adsorption ◽  
Freezing Point ◽  
Two Dimensional ◽  
Hexagonal Mesoporous Silica ◽  
Desorption Isotherms ◽  
Adsorption Desorption

scholarly journals Synthesis and Characterization of Nanoporous Monetite Which Can Be Applicable for Drug Carrier

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Esmael Salimi ◽  
Jafar Javadpour
Keyword(s):  
Surface Area ◽  
Cetyltrimethylammonium Bromide ◽  
Drug Carrier ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Plate Shape ◽  
Desorption Isotherms ◽  
Adsorption Desorption

Wormhole-like mesostructured monetite was successfully synthesized using cetyltrimethylammonium bromide (C19H42BrN, CTAB), as a porosity agent. X-ray techniques and FTIR reveal that the crystalline grains consist of highly crystalline pure monetite phase. Monetite rods with diameter around 20–40 nm and length in the range of 50–200 nm were confirmed by FESEM and TEM. Based on N2adsorption-desorption isotherms investigation, surface area increased up to 31.5 m2/g due to the removal of surfactant after calcinations at 400°C. The results indicate that CTAB can not only affect monetite crystallization but also change particles morphology from plate shape to rod-like.

Characterization of mesoporous region by the scanning of the hysteresis loop in adsorption–desorption isotherms

Adsorption ◽  
2021 ◽  
Author(s):  
C. F. Toncón-Leal ◽  
J. Villarroel-Rocha ◽  
M. T. P. Silva ◽  
T. P. Braga ◽  
K. Sapag
Keyword(s):  
Hysteresis Loop ◽  
Desorption Isotherms ◽  
Adsorption Desorption

scholarly journals Effect of Both the Phase Composition and Modification Methods on Structural-Adsorption Parameters of Dispersed Silicas

2018 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
Tatyana Rakitskaya ◽  
Tatyana Kiose ◽  
Kristina Golubchik ◽  
Viacheslav Baumer ◽  
Vitaliya Volkova
Keyword(s):  
Water Vapor ◽  
Water Vapor Adsorption ◽  
X Ray Diffraction ◽  
Adsorption Parameters ◽  
X Ray ◽  
Vapor Adsorption ◽  
Crystallite Sizes ◽  
Desorption Isotherms ◽  
Adsorption Desorption ◽  
Modified Forms

Tripoli from two Ukrainian deposits was studied in its natural and modified forms. The investigation of natural and modified tripoli involves the identification of their phase compositions through X-ray diffraction and the analysis of their water vapor adsorption-desorption isotherms. The obtained results are evidence of changes in the structural-adsorption parameters of tripoli as a result of modification. Their treatment in boiling water or acid causes apparent alterations of contents of the main phases and sizes of their crystallites, whereas their calcination causes not only the dehydroxylation of surfaces and the agglomeration of phases, but even phase transformation in the case of carbonate tripoli. After analyzing water vapor adsorption-desorption isotherms of natural and modified tripolis, some correlations between their adsorption parameters, phase compositions, main phase contents and crystallite sizes have been found.

Mixed-Solvothermal Synthesis of MIL-101(Cr) and Its Water Adsorption/Desorption Performance

2019 ◽  
Vol 58 (8) ◽  
pp. 2983-2990 ◽  
Author(s):  
Bingqiong Tan ◽  
Yanshu Luo ◽  
Xianghui Liang ◽  
Shuangfeng Wang ◽  
Xuenong Gao ◽  
...  
Keyword(s):  
Solvothermal Synthesis ◽  
Water Adsorption ◽  
Adsorption Desorption

Heterogeneous Interactions of Methylamines on porous Adsorbents Part II. Interactions on Silica–Alumina and Silica Gel Surfaces of Di- and Tri-methylamine in the Region of their Boiling Points

1972 ◽  
Vol 50 (15) ◽  
pp. 2451-2456 ◽  
Author(s):  
W. G. Cook ◽  
R. A. Ross
Keyword(s):  
Silica Gel ◽  
Surface Coverage ◽  
Adsorbed Layer ◽  
Silica Gels ◽  
Heats Of Adsorption ◽  
Boiling Points ◽  
Silica Alumina ◽  
Desorption Isotherms ◽  
Adsorption Desorption ◽  
Heterogeneous Interactions

The adsorption of di- and tri-methylamine has been studied at 280 and 276°K, respectively, on a range of silica gels and on silica–alumina. Adsorption–desorption isotherms and isothermal calorimetric heats of adsorption were measured. Heats of adsorption for di-methylamine on silica gel varied from 29.0 kcal/mol at θ = 0.05 to 12.0 kcal/mol at monolayer completion, while for silica–alumina the heats fell from 31.4 to 9.0 kcal/mol between these same values of surface coverage. For tri-methylamine on silica gel, heats fell from 21.0, θ = 0.05, to 10.3 kcal/mol, θ = 1.00, while heats of 21.4 and 9.9 kcal/mol, respectively, were found at these same surface coverages on silica–alumina. The values of the heats of adsorption are discussed in terms of interactions in the adsorbed layer which are believed to be influenced by the pore sizes in the adsorbent and by the basicity of the amine molecules.

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