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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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Abstract  

Physico-chemical properties (adsorption capacity, desorption energy distribution and pore-size distribution functions) of nanomaterial surfaces from selected materials, based on sorptometric and liquid thermodesorption measurements under quasi-equilibrium conditions, are presented. The fractal dimensions of nanotubes using sorptometric and AFM data have been evaluated. Comparison of thermogravimetric and other data provide new information about the adsorption and pore structure of the studied materials. The fractal dimensions of nanomaterial surfaces using sorptometry are in good agreement with those from AFM.

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Abstract  

Specific surface area and pore size distribution are determined usually from adsorption isotherms at low temperatures using nitrogen or noble gases. These are not absolute parameters and the measuring methods are fraught with serious difficulties. General problems of sorption measurements and recent developments are discussed. To obtain information for practical purposes these measurements need to be supplemented by investigations of the sorbate/sorbent system used in practice. Results of the measurement of nitrogen and water vapour adsorption on different materials are compared.

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Abstract  

Thermodesorption of benzene and water from alumina samples saturated in vacuum dessicator were studied under quasi-isothermal conditions. The Q-TG and Q-DTG curves show multi-step mass losses associated with the evaporation of liquids from pores and physisorbed liquid films from active sites with different energies. The isotherms of adsorption-desorption of nitrogen on porous alumina samples were measured using sorptomatic method and pore size distribution functions have been calculated. The correlation between porosity parameters and the volume of desorbed liquids is presented. A good agreement between above data was obtained.

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Abstract  

The aim of the present study was the pore structure characterization of porous glass derived from a leachable precursor. Two independent techniques were applied on this purpose. The interpretation of the results obtained by these techniques, i.e. thermoporometry and nitrogen porosimetry was indicative for their supplementary character in what concerns the calculation of pore size distributions. The experimental work described in this study gives an example for the monitoring of the compositional evolution of phase separating compact-glass precursors of porous glasses.

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Abstract  

Nitrogen adsorption measured at 77 K was used to characterize the surface heterogeneity of high-temperature superconductor surfaces. Properties relating to adsorption and porosity of the solids (adsorption capacity, specific surface area, radii and volume of the pores, pore-size distribution function) were determined from nitrogen adsorption–desorption isotherms and atomic force microscopy (AFM) for a series of oxide superconductors. It is shown that the adsorption isotherms of all samples are S-shaped and belong to type II according to the IUPAC classification. On the basis of the nitrogen adsorption isotherms and AFM data, fractal dimensions were determined and correlations found with adsorption and porosity parameters.

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Acta Geologica Hungarica
Authors: Tamás Földes, Gizella B. Árgyelán, Péter Bogner, Imre Repa, Balázs Kiss, and Kinga Hips

This paper summarizes the benefits of non-destructive core measurements by medical Computer Tomograph (CT) in integrated 3D reservoir characterization.  A direct relationship exists between CT measurements and petrography, conventional petrophysical analysis and well logs. Based on CT measurements the internal structure of core samples, and the geometry of framework constituents, porosity type and pore size distribution, as well as fracturing, can be described. There is a close connection between distribution of the Hounsfield Unit of CT measurements and pore size distribution detected by conventional petrophysical analysis. Calculation of effective porosity from petroleum saturation experiments provides a new way to determine the porosity of the whole core sample. Beside the description of reservoir parameters, the results of CT measurements can be extended over the surrounding area of the well. By matching the cylinder maps of CT to FMI images and other well logs the original position of the core samples can be reconstructed. Applying high-tech CT measurements in 3D reservoir characterization and modeling of fluid migration significantly reduces the exploration and production risks.

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Abstract  

The present work describes the application of radiotracer technique for studying uptake of arsenic on titanium hydroxide, commercial titanium dioxide (TiO2) powder (anatase) and synthesized mesoporous titania beads in acidic, neutral, and alkaline conditions. Sol–gel templating method was used to prepare titania–polysaccharide composites, with different polymer contents. Mesoporous titania was obtained by heat treatment of the composite beads in a controlled environment. The synthesis process was optimized, using thermogravimetry analysis. X-ray diffraction patterns confirmed the formation of anatase pure phase titania (TiO2) at 700 °C in different environments, and scanning electron microscopy studies confirmed uniform pore size distribution. The effect of surface area, polymer content and pH on uptake of arsenic(III) and (V) on the synthesized titania beads was also investigated. Arsenic(V) was found to be retained quantitatively on the titania beads synthesized from 0.8% polymer content titania–polymer composite precursor in neutral to alkaline conditions. Details of the results obtained are discussed.

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Abstract  

The paper presents evaluation of energy distribution of n-octane and pore-size distribution functions on the alumina oxide surface (e.g. total heterogeneity) of on the basis one experimental run. the Q-TG mass loss and derivative Q-DTG mass loss curves of n-octane thermodesorption from the alumina oxide sample were made using a hungarian derivatograph with an analyser equipped with an automatic ultraslow procedure and a special crucible of maintaining the quasi-isothermal heating procedure to increase the resolution of thermal analysis. a new theoretical and experimental procedure was developed for evaluation of distribution functions of liquid preadsorbed on the mesoporous surface from special thermogravimetry. An example of the approach to quantitative description of the energetic and structural heterogeneities of alumina oxide surface is given.

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Journal of Thermal Analysis and Calorimetry
Authors: Ana Carla S. L. S. Coutinho, Solange A. Quintella, A. S. Araujo, Joana M. F. Barros, Anne M. G. Pedrosa, V. J. Fernandes Jr., and M. J. B. Souza

Abstract

Nanoporous silica with narrow pore size distribution has attracted increasing attention as a novel material for separations and reactions involving large molecules. SBA-15 has been synthesized in an acidic medium using a triblock copolymer as template. In this work, the SBA-15 was synthesized by the hydrothermal treatment at 373 K for 48 h, of a gel with the following overall molar composition: 1.0TEOS:0.017P123:5.7HCl:193H2O, where TEOS is tetraethyl orthosilicate and P123 is poly(ethylene oxide, propylene oxide and 1,4-dioxane). The obtained material was characterized by thermogravimetry, X-ray diffraction, infrared spectroscopy and BET surface area. A kinetic study using the model free model was accomplished in the stage of decomposition of the template (P123). The obtained value of the apparent activation energy was ca. 131 kJ mol−1.

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