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Cuban and Mexican zeolites are of particular interest from economic outlook because of their exceptional properties and abundance. Here, we present the results of the comparative study of the elemental, structural, morphological, thermal and textural properties of natural zeolites: clinoptilolite, mordenite and erionite from various deposits. Despite a complex phase and element compositions of the studied materials, some general features were detected. The observed dehydration steps are related to water desorption from porosity of different size ranges: mesopores, main and small zeolite voids. This dehydration pattern interferes with the exchangeable cation composition that also affects the general trends. Thermochemical properties of samples are influenced by the geographical location of the deposits. Depending on the origin of the sample, the dehydration enthalpy varies in quite a wide range, which is a function of both zeolite framework structure and exchangeable cation composition. The study of meso- and macropore systems reveals that all the samples exhibit multimodal pore size distribution and possess significant amounts of mesoporosity and even macroporosity. Among the studied samples, the mordenite from Palmarito de Cauto, the clinoptilolite from Etla and the erionite from Agua Prieta (Sonora) have a significant number of pores with average size of about 3 nm. All the samples, except erionite from Agua Prieta, show macroporosity with rather well-defined pore size between 0.3 and 2 μm. The porosity over mass does not change noticeably from one sample to other and varies from 0.32 to 0.65 cm3 g−1.

The derivative of 1,2,4-thiadiazole (TDZ) can be considered as a perspective agent for the Alzheimer’s disease prevention. Due to a highly lipophilic character, the compound reveals good membrane permeability properties and poor solubility in aqueous media. In order to solve this problem, water-soluble biodegradable polymers: PEG 6000 (PEG), PVP K29-30 (PVP) and linear (A–B–A type) ethylene oxide-propylene oxide block copolymer Pluronic F127 (F127) were used in the present investigation to obtain binary and ternary TDZ composites (solid dispersions) with improved solubility and dissolution rate. Composites were prepared by a mechanical grinding procedure. Differential scanning calorimetry and FTIR spectroscopy were used to characterize the obtained samples. The interaction of TDZ with PVP after the grinding procedure was revealed. Shake-flask method was applied to measure the solubility of the composites. A dramatical increase in the solubility was shown for the solid dispersion with F127 above the critical micelle concentration. The dissolution behavior was studied with the help of the basket method at pH 1.2 and pH 6.8. The dissolution of TDZ/polymer solid dispersions was substantially accelerated as compared to pure TDZ and physical mixtures. The dissolution mechanism was estimated through the Korsmeyer–Peppas model equation. Franz diffusion cell and new Permeapad™ barrier were applied for the permeability assay. The permeability of TDZ in solid dispersions through the Permeapad™ barrier was shown to decrease in comparison with the pure TDZ. It was concluded that composites with PEG, PVP and F127 are an effective tool for increasing the solubility and dissolution of 1,2,4-thiadiazole derivative.

A lanthanum zirconate La2Zr2O7 was synthesized by soft mechanochemical method using zirconium oxynitrate ZrO(NO3)2·6H2O and lanthanum carbonate La2(CO3)3·8H2O as reagents. Mechanical activation of the reagents was carried out in a centrifugal planetary ball mill. The processes occurring during calcination of the jointly and the separately mechanically activated salt mixture were studied using DSC, TG coupled with mass spectrometry, XRD analysis, and FTIR spectroscopy. It was shown that in the course of joint mechanical activation in the mill alongside with intimate mixing of the reagents and their amorphization exchange reaction occurred, producing lanthanum nitrate, basic lanthanum nitrate, basic zirconium carbonate, and hydrated zirconium oxide. The DSC curve of the jointly mechanically activated salt mixture showed a strong exothermic peak at 878 °C which was not associated with mass loss. This peak was attributed to La2Zr2O7 crystallization in agreement with XRD data. Nanocrystalline lanthanum zirconate synthesized by annealing of the jointly mechanically activated salt mixture was characterized using XRD analysis, scanning, and transmission electron microscopy.

This article is devoted to the investigation of water sorption by the layered perovskite-type titanate K2Nd2Ti3O10 and its intercalated protonated derivatives HxK2−xNd2Ti3O10·yH2O in a humid atmosphere. K2Nd2Ti3O10 was synthesized by the solid-state reaction. Metastable HxK2−xNd2Ti3O10·yH2O compounds were obtained by water flushing. The determination of the samples composition was carried out by XRD and TG analysis. The stability in a humid atmosphere was investigated by a water vapor sorption analyzer. It was found that humid atmosphere has influence only on K2Nd2Ti3O10 while HxK2−xNd2Ti3O10·yH2O phases are stable under experimental conditions. The study of K2Nd2Ti3O10 in humid atmosphere has shown that the intercalation process proceeds with a rate constant kint = 3.2 × 10−6 min−1 at 0–95% RH, and the protonation process takes place at RH more than 80%.

The article presents results of the complex study of hydration and protonation processes of promising photocatalysts K2Nd2Ti3O10, belonging to the family of perovskite-type layered Ruddlesden–Popper phases. K2Nd2Ti3O10 was synthesized by solid-state method and was monitored using powder X-ray diffraction. The behavior in water has been studied by means of thermogravimetric analysis, simultaneous thermal analysis and differential scanning calorimetry. The substitution of potassium cations for protons and the water intercalation into the interlayer space of the crystal structure were observed. Proton-containing layered oxides with general formula HxK2−xNd2Ti3O10·yH2O (0.07 ≤ x ≤ 1.7, 0.06 ≤ y ≤ 0.44) have been obtained.

The behavior in aqueous solutions of the two types of layered perovskite-like structures, NaLnTiO4 titanates (Ln = Nd, La) belonging to the family of Ruddlesden–Popper phases and ANdTa2O7 tantalates (A = Na, Cs, H) belonging to the family of Dion–Jacobson phases, has been studied by means of thermogravimetric analysis and powder X-ray diffraction. In the case of NaLnTiO4 compounds, the substitution of protons for sodium cations and the water intercalation into the interlayer space of the crystal structure were observed and proton-containing layered oxides with general formula H x Na1−x LnTiO4·yH2O (0.63