scholarly journals Recent progress on hygroscopic materials for indoor moisture buffering

2021 ◽  
Vol 2069 (1) ◽  
pp. 012003
Author(s):  
Xu Zhang ◽  
Menghao Qin ◽  
Kan Zu
Keyword(s):  
Water Vapour ◽  
Recent Progress ◽  
Humidity Control ◽  
Moisture Control ◽  
Water Vapour Diffusion ◽  
Vapour Adsorption ◽  
Environment Control ◽  
Water Vapour Adsorption ◽  
Adsorption Desorption ◽  
Moisture Buffering

Abstract Once in contact with the indoor air, hygroscopic materials can moderate the indoor humidity fluctuation by adsorbing or releasing water vapour, and then improve the moisture regulation and thermal management of buildings. It is desirable to explore the characterized properties of these materials about moisture buffering behaviour. In this regard, we review various hygroscopic materials used for the built environment control. The hygrothermal properties of hygroscopic materials often can be characterized by some parameters, such as water vapour adsorption/desorption capacity, water vapour adsorption/desorption rate, water vapour diffusion coefficient, and so on. To provide an insight on the existing research on humidity control materials, different research studies and the recent progress on humidity control materials have been summarized. The materials include traditional and conventional building materials, some natural materials, and novel humidity control materials. Besides, the relevant parameters are considered as well as the improvement suggestions to enhance the application of humidity control materials in building environments. Finally, new multifunctional materials and intelligent moisture control materials together with the corresponding systems are collated to summarize the latest research trends. The overview of the application of hygroscopic materials can provide current and future researchers guidelines for the science-oriented design of moisture control systems for new energy-efficient buildings.

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.

Synthetic allophane from highconcentration solutions: nanoengineering of the porous solid

Clay Minerals ◽  
2002 ◽  
Vol 37 (3) ◽  
pp. 451-456 ◽  
Author(s):  
F. Ohashi ◽  
S.-I . Wada ◽  
M. Suzuki ◽  
M. Maeda ◽  
S. Tomura
Keyword(s):  
Water Vapour ◽  
Particle Diameter ◽  
Amorphous Structure ◽  
Water Vapour Pressure ◽  
Transmission Electron ◽  
Bet Specific Surface Area ◽  
Relative Water ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
Adsorption Desorption

AbstractThe amorphous aluminosilicate allophane was synthesized by rapid mixing of inorganic solutions with high initial concentrations (10 – 100 mmol/l) followed by hydrothermal treatment. X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed homogeneous products having a hollow spherical amorphous structure with a particle diameter of 3 – 5 nm. The amorphous products had a high BET specific surface area (490 – 552 m2/g) in comparison with natural allophane and had a narrow pore-size distribution (2 – 5 nm in diameter). The results of water vapour adsorption isotherm studies showed a gradual increase over the range of relative water vapour pressure of 0.6 – 0.9 and reached a maximum of ∼85 wt.%. The synthetic allophane shows promise as an adsorbent material because of its high adsorption-desorption capacity and its unique structure.

Effect of Salt Contamination on Water Vapour Sorption Hysteresis of Ceramic Bricks

2015 ◽  
Vol 1126 ◽  
pp. 87-92
Author(s):  
Olga Koronthalyova
Keyword(s):  
Sodium Chloride ◽  
Relative Humidity ◽  
Water Vapour ◽  
Additive Model ◽  
Water Vapour Sorption ◽  
Sodium Chloride Solutions ◽  
Moisture Contents ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
Adsorption Desorption

An effect of the presence of sodium chloride on water vapour adsorption/desorption loop was quantified for two types of commonly used ceramic bricks with different hygroscopic ability. The measurements were carried out for salt free materials and saline materials contaminated with sodium chloride solutions of two different concentrations. It was found out that at relative humidity higher than deliquescence point, the hysteretic effects of the saline bricks were similar or less significant as the ones of the salt free bricks. In this range of relative humidity the desorption moisture contents did not exceed the values predicted using the simply additive model. However, for the relative humidity lower than deliquescence point the hysteretic effects of the saline bricks were more significant than the ones of the salt free bricks. The effect was of importance in the case of hygroscopic ceramic brick where obtained desorption moisture contents of the saline bricks were noticeably higher than for the salt free brick.

Synthesis of small Fe2O3 nanocubes and their enhanced water vapour adsorption–desorption properties

RSC Advances ◽  
2015 ◽  
Vol 5 (103) ◽  
pp. 84587-84591 ◽  
Author(s):  
Feng Cao ◽  
Duanyang Li ◽  
Ruiping Deng ◽  
Lijian Huang ◽  
Daocheng Pan ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Water Vapour ◽  
Critical Radius ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
Adsorption Desorption

Uniform ordered Fe2O3 nanocubes showed an excellent humidity-controlling ability, due to their appropriate pore size distribution near the condensation critical radius.

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