Interaction between the water adsorption ability of aluminium-oxide-based sorbents and their chemical composition, acid-base properties of the surface, and textural characteristics has been analysed. Alumina desiccants were synthesized with the centrifugal–thermal activation of gibbsite followed by the hydration of the gibbsite under mild conditions. It was demonstrated that the multicyclic adsorption regeneration of samples under realistic conditions results in structural transformations and changes in the acidity of their surfaces and water adsorption ability. The modification of pseudoboehmite with alkali ions increases surface basicity and the dynamic capacity of adsorbents relating to water vapours. Equations have been presented that describe the adsorption and desorption processes taking place during water vapour adsorption with the materials studied.

The production of nitric acid is one of the main industrial sources of nitrous oxide entering the atmosphere, which is an ozone-depleting gas with a potential 310 times higher than that of CO

Heterogeneous photo-Fenton process with structured catalyst was investigated in the removal of two typical food azo dyes, red allura (RED) and tartrazine (TRZ). The influence of LaFeO3 loading (with and without Pt) on corundum honeycombs monolithic support was evaluated in the discoloration and mineralization of the target azo dyes. The results for discoloration were reported for different experimental conditions: UV, UV+H2O2, UV+H2O2+structured catalysts. In the case of UV alone the discoloration occurs very slowly and not completely (approximately 36 and 20% in 120 min of irradiation for RED and TRZ, respectively); but the process efficiency has been enhanced in the presence of H2O2 (approximately 77 and 80% in 5 min of irradiation for RED and TRZ, respectively). The best efficiency in RED dye discoloration and mineralization by heterogeneous photo-Fenton process was observed for a LaFeO3 loading equal to 4.5% by weight (complete discoloration and 95% of TOC removal in 60 min of irradiation time...

The effect of alkali metal (Li, Na, K) incorporation on the morphology and water vapor uptake properties of mesoporous Al₂O₃ has been studied. The modification of the raw material, pseudoboehmite, represented a mixture of low-temperature phases (γ + η + χ)-Al₂O₃, and has been done at low-temperature that does not change the phase ratio. A decrease in specific surface values and an average pores size increase were observed as a result of the introduction of metal cations by impregnation and subsequent thermal treatment. The influence of the content of the modifying metal on the adsorption ability of the obtained samples in relation to water vapours has been studied. It has been established that alkaline modification Al₂O₃ with the lithium cations did not result in adsorption ability improvement, whereas samples that were modified with sodium or potassium in the amount of 1.2 weight % and 2.6 weight %, respectively, possess a higher equilibrium capacity (by ~40%), as compared to that of the initial sample (Al₂O₃), and a sufficiently high adsorption rate.

The paper considers the influence of the temperature of calcination (350–550°C) of alumina-based water adsorbents prepared from bayerite-containing aluminum hydroxide on the static water sorption capa

Methane oxidative coupling (OCM) is considered a potential direct route to produce C₂ hydrocarbons. Layered perovskite-like Sr₂TiO₄ is a promising OCM catalyst. Mechanochemical activation (MA) is known to be an environmentally friendly method for perovskite synthesis. Sr₂TiO₄ were synthesized using MA of the mixtures containing SrCO₃ or SrO and TiO₂ or TiO(OH)₂ and annealing at 900 and 1100 °C. XRD and FT-IRS showed that MA leads to the starting component disordering and formation of SrTiO₃ only for SrO being pronounced when using TiO(OH)₂. After annealing at 900 °C, Sr₂TiO₄ was mainly produced from the mixtures of SrCO₃ or SrO and TiO(OH)₂. The single-phase Sr₂TiO₄ was only obtained from MA products containing SrCO₃ after calcination at 1100 °C. The surface enrichment with Sr was observed by XPS for all samples annealed at 1100 °C depending on the MA product composition. The OCM activity of the samples correlated with the surface Sr concentration and the ratio of the surface oxygen amount in SrO and perovskite (O_o/O_p). The maximal CH₄ conversion and C₂ yield (25.6 and 15.5% at 900 °C, respectively), and the high long-term stability were observed for the sample obtained from (SrCO₃ + TiO₂), showing the specific surface morphology and optimal values of the surface Sr concentration and O_o/O_p ratio.