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Thermoporosimetry

Pore size distribution measurements for microporous glass using differential scanning calorimetry

Journal of Thermal Analysis and Calorimetry
Authors: K. Ishikiriyama, M. Todoki, K. H. Min, S. Yonemori, and M. Noshiro

The pore size distributions (PSDs) of microporous glass, which were controlled by acid leaching subsequent to phase separation of CaO-Al2O3-B2O3-SiO2 glass, were determined via both mercury porosimetry and thermoporosimetry (thermal porosimetry). As a result, the pore radii, the cumulative pore volumes, and the surface areas determined via thermoporosimetry were in good agreement with those determined via mercury porosimetry. It was revealed that thermoporosimetry could be applied to pore structure analysis for porous materials having pore sizes at least up to 58 nm in radius.

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Abstract  

Methods of thermal analysis are employed in a study of the high-temperature properties of three different types of glass fiber reinforced cement composites together with the measurements of their thermal and hygric parameters. First, basic TG and DTG measurements are carried out to get the first insight into the high-temperature behavior of the analyzed materials. Then, mercury porosimetry and scanning electron microscopy of specimens subjected to the temperatures of 600 and 800C are performed and compared to the reference specimens not exposed to any thermal load. Finally, measurements of thermal and hygric parameters of the studied materials are done and matched with the results of the material characterization experiments. Three main effects are found to influence the thermal and hygric properties of the analyzed materials. The first is the decomposition of the cement matrix, which is clearly a negative factor. The second is the positive effect of the presence of fibers that could partially keep the cement matrix together even after significant decomposition of cement hydration products. The third important factor affecting the thermal and hygric properties is the composition of the particular materials. The application of vermiculite aggregates instead of sand is found to be clearly positive because of its porous character leading to the bulk density decrease without worsening the other properties. Also, wollastonite aggregates are a better choice than sand because of its fibrous character that could partially magnify the effect of fiber reinforcement.

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Abstract  

Properties of limestone related to SO2/SO3 reactivity were investigated. Limestone calcined under different conditions (temperature, time and with/without additives) yield calcines of distinctly different physical structures. The amount of pores and the size of the pores formed during calcination is important. The main purpose of the present work was to gain a better understanding and more reliable explanation of the temperature regime for gas desulphurization using Ca-based sorbents in atmospheric fluidized-bed combustors. Pore size, surface area and pore volume of each calcine were determined by mercury porosimetry and BET methods. At higher calcination temperature and during longer time, sintering became significant and the obtained calcine had a smaller internal surface area and thereby the average pore radius increased. The additives such as NaCl also accelerated sintering thus increasing the pore size. The measurements of porosity were supplemented by scanning electron microscopic observations employed for qualitative description of the pore structure. SEM micrographs are presented.

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, S , Svatá , M . Mercury porosimetry: state of the art . Powder Technol . 1981 ; 29 : 1 – 12 10.1016/0032-5910(81)85001-2 . 20. Léon , Y , León , CA . New perspectives in

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Abstract  

Programmed thermodesorption of n-butanol from Na-, La-montmorillonite, natural and commercial zeolite samples in quasi-isothermal conditions made. The new method of fractal dimension calculations from thermogravimetry data has been presented. On the basis of nitrogen adsorption-desorption isotherms from sorptometry and mercury porosimetry data the fractal dimensions of montmorillonites were calculated. The results from above independent and separated techniques were compared and good correlation were obtained.

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Abstract

Thermoporometry is a relatively new method of characterising porous properties of nanostructured materials based on observation of solid–liquid phase transitions of materials confined in pores. It provides several advantages over the conventional characterisation methods, mercury porosimetry and gas sorption. The advantages include possibility of using short measurement times, non-toxic chemicals and wet samples. In addition, complicated sample preparation and specialised instruments are not required. Therefore, it has a great potential of becoming a widely utilised characterisation method, although its potential has not yet been widely realised. In recent years, there has been a significant increase in research activities regarding the method. In the second part of the review, results and conclusions of the recent studies about thermoporometry are surveyed and discussed focusing on the application of thermoporometry in extracting various structural information from the porous materials.

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Studies of surface properties of Na- and La-montmorillonites

Thermogravimetry Q-TG, sorptometry, porosimetry and AFM methods

Journal of Thermal Analysis and Calorimetry
Authors: P. Staszczuk, J. Bazan, M. Błachnio, D. Sternik, and N. Garcia

Abstract  

This paper presents possible applications of thermal analysis, sorptometry and porosimetry to study physico-chemical properties of Na- and La-montmorillonite samples, especially for determination of total surface heterogeneity. The quasi-isothermal thermogravimetric (Q-TG) mass loss and its first derivative (Q-DTG) curves with respect to temperature and time obtained during programmed liquid thermodesorption under quasi-isothermal conditions have been used to study adsorbed layers and heterogeneous properties of the Na- and La-montmorillonites. Calculations of the desorption energy distribution functions by analytical procedure using mass loss Q-TG and differential mass loss Q-DTG curves of thermodesorption under quasi-isothermal conditions of polar and non-polar liquid vapours preadsorbed on a material surface are presented. Parameters relating to porosity of samples were determined by sorptometry, mercury porosimetry and atomic force microscopy (AFM). From nitrogen sorption isotherms from sorptometry and porosimetry methods, the fractal dimensions of montmorillonites have been calculated. Moreover, a new approach is proposed to calculate fractal dimensions of materials obtained from Q-TG curve; this is compared with values obtained by the above methods. The total heterogeneous properties (energy distribution function and pore-size distribution functions) of samples studied were estimated. The radius and pore volume of the tested samples calculated on the basis of thermogravimetry, sorptometry and porosimetry techniques were compared and good correlations obtained.

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S. Modry M. Svata 1981 Mercury porosimetry: State of the art Powder technology 29 1

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characterization of pore size distribution of tilled and orchard soil using water retention curve, mercury porosimetry, nitrogen adsorption, and water desorption methods. Geoderma. 135 . 307–314. Hajnos M

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Journal of Thermal Analysis and Calorimetry
Authors: Dmitar Zorić, Dušan Lazar, Ognjen Rudić, Miroslava Radeka, Jonjaua Ranogajec, and Helena Hiršenberger

96 : 363 – 368 10.1007/s10973-008-8951-0 . 14. Wardlaw , NC , McKellar , M , Yu , L 1988 Pore and throat size distributions determined by mercury porosimetry and direct observation

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