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A series of M x O y /SiO 2 (where M = Ni, Zn and Mn) nanocomposites were synthesized at different M x O y contents (0.2, 1 and 3 mmol per 1 g SiO 2) using a deposition method. The samples were characterized using nitrogen adsorption-desorption, X-ray diffraction, Fourier transform infrared spectroscopy, high resolution transmission electron microscopy and photon correlation spectroscopy. The heat of immersion in water (Q w) and n-decane (Q d) were measured using a microcalorimetry method, and the corresponding values of the hydrophilicity index K h = Q w /Q d were analysed. The formation of M x O y on a silica surface leads to diminishing of the Q w and Q d values (calculated per 1 g of nanocomposites) because of the specific surface area reduction. However, the Q w values calculated per 1 m 2 increase for Zn x O y /SiO 2 and Mn x O y /SiO 2 in comparison with the unmodified silica, and it remains unchanged for Ni x O y /SiO 2. Silica modification with M x O y significantly changes the pH dependence of zeta potential and affects the surface charge density. A shift of the isoelectric point (pH IEP) and a character of the zeta potential ζ (pH) curve are affected by the M x O y phase, and pH IEP shifts toward higher values as follows Mn < Zn < Ni. Keywords. Oxide nanocomposites; Zn x O y /SiO 2 ; Ni x O y /SiO 2 ; Mn x O y /SiO 2 ; physicochemical properties; heats of immersion.

The paper presents the studies of effects of TiO 2 amount differentiation on the structural and thermal properties of titania-silica complex oxides prepared by chemical vapor deposition of TiCL 4 onto the Si-40, Si-60, and Si-100 silica gels. The mesoporous materials, characterized by a varied pore structure with highly developed surface and large pore volume, were obtained. The porous structure of materials under investigations was characterized by the low-temperature nitrogen adsorption-desorption method as well as by power spectral density calculated from the calorimetric investigations of water confined in the pores. Moreover, the thermodesorption of water using the quasi-isothermal thermogravimetry was used to characterize their thermal and surface properties. 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 has a significant effect on the porous structure formation. The water thermodesorption from the surface proceeds in few stages because of the porosity created by TiO 2 . The decrease in the total surface free energy (ÁG AE ) can be observed with the increasing TiO 2 content. The largest ÁG AE value at the adsorbent/strongly bound water interface is exhibited by the adsorbents of Si-100 series. The lowering of the freezing/melting points of water contained in the pores of the studied materials is strongly connected with their porous structure.

Mechanochemical and microwave-assisted hydrothermal (MicroWave Treatment [MWT]) procedures were applied to prepare crystalline CaCO3. Mechanochemical process was carried out at different speeds of rotation (500 or 850 rpm/min), different duration times (30 or 60 min) and in the aqueous suspensions or in dry state. MWT synthesis was conducted in a saturated water vapour or under the layer of water. The crystalline and porous structures of the prepared samples as well as their morphology were investigated using N2 adsorption, X-ray diffraction and scanning electron microscopy methods. As a result, the calcium carbonate samples in the form of calcite were obtained. The materials prepared by the mechanochemical route performed in the aqueous suspension are characterized by smaller crystallite sizes as compared to those obtained without the addition of water. The samples obtained hydrothermally have the largest size of crystallites. Powders prepared by energetical milling possess higher values of specific surface area in relation to the parameter for those synthesized hydrothermally. In the process of hydrothermal treatment, macroporous structure of the prepared materials is created. With the increasing specific surface area of the sample, the size of the crystallites decreased.