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Abstract

Mesoporous titanium-containing silicas with different Titania contents were investigated. The structural parameters of the materials were characterized by low-temperature adsorption/desorption of nitrogen and X-ray diffraction analysis. The thermodesorption of water using the quasi-isothermal thermogravimetry as well as the differential scanning calorimetry were used to characterize thermal and surface properties of these materials. The adsorbed water layers and the concentration of weakly and strongly bound water as well as the surface free energy on the adsorbent/water interfaces were calculated. It was stated that the increase of Titania content causes a gradual decrease of specific surface area and formation of biporous structure inside the tested materials. The water thermodesorption from the surface proceeds in two or three stages, which is connected mainly with pore distribution and TiO2 content. One can observe the increase of the total surface free energy (ΔG Σ) with the increasing TiO2 content, but the largest ΔG Σ value at the adsorbent/strongly bound water interface is exhibited by the adsorbent of intermediate content (30%) of TiO2. Freezing temperature of water contained in the pores of the studied materials is connected largely with their porous structure. Due to the well developed porous structure, the water freezing process is a multi-stage one.

Open access
Journal of Thermal Analysis and Calorimetry
Authors: V. Sydorchuk, W. Janusz, S. Khalameida, E. Skwarek, J. Skubiszewska-Zięba, R. Leboda, and V. Zazhigalov

Abstract

Deposited zirconium phosphate samples on the base of silica and titania have been prepared using the sol–gel and mechanochemical methods. Porous structure, phase composition, and electrokinetic parameters have been studied by means of nitrogen adsorption–desorption, XRD, DTA-TG, FTIR, electrophoresis, and potentiometric titration. The compositions possess varied parameters of porous structure, structure of deposited phase, and electrokinetic properties depending on support nature and synthesis conditions.

Open access