Anton I. Lysikov

CaO/Y2O3 pellets for reversible CO2 capture in sorption enhanced reforming process.

Abstract Pellets of a novel, high temperature CO2 sorbent, made of CaO-impregnated porous Y2O3, were prepared. Yttria pellets were synthesized from a mixture of yttria powder and a softener. A combination of ethylene glycol, used as a softener, and a casting method yielded mechanically stable pellets after calcination at 800ºC. Treatment of the Y2O3 support at higher temperatures further increases the pellets strength. The same effect of pellets strengthening was observed after yttria impregnation with CaO. Sorption capacity of the pellets with CaO content of 9 wt. %, measured at isothermal conditions of 740ºC, reaches 7.5 wt. % for shorter recarbonation time of 20 min and 8.5 wt. % for a longer time of 1 hour. In this respect, sorption properties of pelletized CaO/Y2O3 are similar to those of powdered material. A distinctive feature of the pelletized CaO/Y2O3 sorbent pretreated at high temperatures is the increase in capacity during the initial cycles.

Synthesis of Polystyrene Beads for Hard-Templating of Three-Dimensionally Ordered Macroporosity and Hierarchical Texture of Adsorbents and Catalysts

Methods of polystyrene beads producing with properties appropriate for catalyst and adsorbent synthesis have been investigated. Hierarchical silicalite-1 and Fe-silicalite-1 with zeolitic MFI structure, as well as three-dimensionally ordered titania, silica, alumina and zirconia have been prepared by hard-templating method using polystyrene beads. The materials were characterized by X-ray diffraction, scanning and transmission electron microscopies, low-temperature nitrogen adsorption technique and mercury porosimetry. Developed meso- and macroporous structure of the templated materials facilitated the supply of macromolecular reactants to the material surface and reduced the negative effect of byproduct deposition, resulting in favored advantages of the materials in a wide range of processes: hydroconversion of heavy oil, wet hydrogen peroxide oxidation of organic substrates in water, photocatalysis and gas chromatographic analysis. The obtained results of the material applications showed their potential attractiveness as catalysts and adsorbents.

Hierarchically porous materials built of Fe–silicalite nanobeads

Hierarchically porous zeolite materials built of closely and randomly packed uniform Fe–silicalite nanobeads were synthesized. The desired assembly of nanobeads was achieved by the centrifugation and sedimentation of nanozeolite suspension followed by drying and calcination. A micro/meso/macroporous Fe–silicalite material with spongy texture built of closely packed nanocrystals was designed using polystyrene latex as a supramolecular template. Large Fe–silicalite microbeads were synthesized to compare their structure with the nanocrystalline materials. The synthesized samples were characterized by laser diffraction analysis, X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, argon and nitrogen adsorption measurements, inductively coupled plasma optical emission spectrometry, UV visible diffuse reflectance spectroscopy and temperature-programmed desorption of ammonia. Fe–silicalite nanozeolite materials have shown high crystallinity, and possess micro- and meso/macropore surface areas and high specific pore volumes. Pellets built of closely packed nanocrystals have exhibited good mechanical stability in benzene and water. Calcined Fe–silicalite materials built of nanobeads were observed to contain highly dispersed ferric clusters no more than 1 nm in size. The 3 nm ferric clusters in the zeolitic microbeads resulted in the appearance of Lewis acid sites with medium strength, which are absent in the nanobeads. Catalytic performance of hierarchically porous Fe–silicalites was studied in the total oxidation of clarithromycin lactobionate by H2O2 at 323 K compared with Fe–silicalite microbeads. Hierarchical Fe–silicalites are more efficient catalysts vs. Fe–silicalite microbeads due to increased catalytic site accessibility.