Hierarchical zeolites

Three kinds of hierarchical Mordenite Framework Inverted (MFI)-type nanozeolites including Si-MFI, Al-MFI and Ti-MFI were successfully synthesized by two-stage varying temperature hydrothermal treatment. Taking toluene as the probe molecule, a series of methods were used to evaluate the adsorption properties of as-synthesized hierarchical zeolites samples including the adsorption breakthrough curves, simulation of adsorption isotherms as well as kinetics models and toluene-TPD (the temperature programmed desorption of toluene).

10p vironald 15-12-2022 3 3   Download

Hierarchical zeolites containing ruthenium oxide nanoparticles were applied in the reaction of dihydroxyacetone isomerization to alkyl lactates and lactic acid. The synthesis of these materials was performed by dispersing the specified amount of two microporous zeolites (HFAU and NaBEA) withan ultrasound bath for 30 min, in a mixture containing cetyltrimethylammonium bromide, water, ethanol and ammonia.

5p vironald 15-12-2022 2 2   Download

Cell-penetrating peptides (CPPs), and metal-organic frameworks (MOFs) are promising as next-generation for the delivery of gene-based therapeutic agents. Oligonucleotide (ON)-mediated assembly of nanostructures composed of hierarchical porous zeolitic imidazolate framework (ZIF-8), and nanoparticles such as graphene oxide (GO), and magnetic nanoparticles (MNPs) for gene therapy are reported.

10p vironald 15-12-2022 4 2   Download

Synthesis of Low Silica X zeolite (LSX) with hierarchical porosity was achieved. The low silicon/aluminum ratio of this zeolite allowed to increase the number of active sites, as cationic positions (>25%) respect to the previous mesoporous X zeolite.

11p vironald 15-12-2022 6 2   Download

The formation of micro/mesoporous zeolites by treating zeolite crystals with alkaline hydroxides has received a lot of interest, but fundamental understanding is still lacking. Here, we study the reactivity of a crystalline zeolitic material with various alkaline hydroxides, to close this knowledge gap.

9p vironald 15-12-2022 3 2   Download

In the context of CO2 removal from biogas, a series of binderless zeolite LTA adsorbents with a macroscopic bead format (0.5–1.0 mm) and with hierarchical porosity (i.e. with the zeolitic micropores being accessible through meso- and macropores mainly in the 10–100 nm range) was synthesized with a variety of Si/Al ratios (1.2–3.9) using Amberlite IRA-900 anion-exchange resin beads as a hard template.

11p vironald 15-12-2022 7 2   Download

One-step facile synthesis of boron containing ZSM-5 microspheres is developed using 1,6-diaminohexane as the structure-directing agent and cetyltrimethylammonium bromide as the mesoporogen. High boron incorporation up to Si/B ratio of 38 is achieved and evidenced by the stretching vibrations of B–O–Si at 667cm−1 and 917cm−1 using Fourier-transform infrared spectra. The morphology of the crystals resembles berry-like spheres with sizes approximately 15 µm, which is composed of aggregated nanocrystals having sizes around 450 nm, is observed using scanning electron microscopy.

18p tudichquannguyet 29-11-2021 11 1   Download

ZSM-5 zeolites are widely used as catalysts in the oil refi ning and petrochemical industry due to their outstanding catalytic performance. Despite their undisputed applications, the relative small pore size of ZSM-5 zeolites often imposes intra-crystalline diff usion limitations for reactant molecules, provoking the lower catalyst utilisation. To alleviate such limitations, in this work, an additional network of mesopores has been introduced by the post-synthesis modifi cation.

6p quenchua 27-09-2019 23 0   Download