The application of copper and zinc containing ion-exchanged synthesised zeolite in agricultural plant rowing

Foliar application of copper and zinc containing ion exchanged synthesised „zeolon-P4A” type zeolite was used in experiments. Foliar application in winter wheat experiments proved that plants had a better uptake and utilisation of copper and zinc bound on zeolite. As a result of the treatments yields and four quality parameters increased.

Gallery character of porous space in the STI-type zeolite structure

The existence of a specific gallery type of zeolite framework is confirmed. It has been found that similar to HEU-type, STI-type framework can be represented as a layered structure in which two impermeable to water molecules and exchange cations aluminum-silicate layers, separated by diortho-groups, confined gallery-type of porous free space, which is available for extra-framework components migration in all directions in the plane of the interlayer.

Defect Formation, T-Atom Substitution and Adsorption of Guest Molecules in MSE-Type Zeolite Framework—DFT Modeling

We used computational modeling, based on Density Functional Theory, to help understand the preference for the formation of silanol nests and the substitution of Si by Ti or Al in different crystallographic positions of the MSE-type framework. All these processes were found to be energetically favorable by more than 100 kJ/mol. We suggested an approach for experimental identification of the T atom position in Ti-MCM-68 zeolite via simulation of infrared spectra of pyridine and acetonitrile adsorption at Ti. The modeling of adsorption of hydrogen peroxide at Ti center in the framework has shown that the molecular adsorption was preferred over the dissociative adsorption by 20 to 40 kJ/mol in the presence or absence of neighboring T-atom vacancy, respectively.

Direct Etherification Reaction of Glycerol Using Alkali Metal Cation (Li+, Na+ and K+) Containing X-Type Zeolites as Heterogeneous Catalysts: Optimization of the Reaction Conditions

X-type zeolite (XZ-Na) containing Na+ as a cation was synthesized, and XZ-Li and XZ-K were prepared by exchanging the cations of XZ-Na with Li+ and K+, respectively. The specific surface areas, structures, and chemical compositions of the prepared zeolites were analyzed by BET, XRD, and SEM-EDX. The activity of the direct and selective etherifications of glycerol to diglycerol (DG) and triglycerol (TG) were investigated using each zeolite XZ-M (M = Li, Na or K) as a basic heterogeneous catalyst. The etherification reactions of glycerol were carried out at atmospheric pressure while controlling the reaction temperature, reaction time, and the amount of each zeolite. As the amount of each zeolite, reaction time, and reaction temperature increased, the conversion of glycerol also increased, but the selectivities of DG and TG decreased due to the increase in the production of oligomers. When each zeolite was used as a catalyst, the catalytic activity for the conversion of glycerol was observed as XZ-K > XZ-Li > XZ-Na, but the selectivities of DG and TG were observed as XZ-Li > XZ-Na > XZ-K. Especially, 3 wt.% of XZ-Li exhibited the excellent catalytic performance when the etherification of glycerol was optimized and carried out at 280 °C for 2 h: the conversion of glycerol was 89.6% and the yields of DG and TG were 61.2 and 21.2%, respectively.

Effects of Si/Al Ratios on the Bulk-Type Zeolite Formation Using Synthetic Metakaolin-Based Geopolymer with Designated Composition

In this paper, synthetic metakaolin with fixed composition (Al2O3·2SiO2) was produced by a simple chemosynthetic route. The chemosynthetic metakaolin can eliminate the influence of impurities in metakaolin from natural kaolin minerals. The synthetic metakaolin together with NaOH and SiO2-sol were used to prepare Na-based geopolymer precursors with various molar ratios of Si/Al. The molar ratios of Si/Al from 1 to 2 were tailored by adding different contents of SiO2-sol. Zeolite/geopolymer composites or monolith-type zeolite were successfully fabricated from synthetic metakaolin-based geopolymer through a hydrothermal process. The effects of Si/Al ratios on the phase composition and microstructure of the produced zeolite/geopolymer composites or zeolites were studied. The results proved that the composition of synthetic metakaolin and geopolymer precursors can be facilely tuned, and the monolithic geopolymer precursors can be mostly, or even totally, transformed into zeolite after hydrothermal treatment.