P. S. Yaremov

Adsorption of nitrogen, hydrogen, methane, and carbon oxides on micro- and mesoporous molecular sieves of different nature

A comparative study was carried out on the adsorption of H2, N2, CH4, CO, and CO2 at 77-273 K (p ≤ 1 atm) by silicate and phosphate zeolites and carbon materials, varying in size, shape, volume, and distribution of the micro- and mesopores. We studied effects of the porosity parameters and nature of the surface on gas absorption, in particular, the increased selectivity related to restrictions in the zeolite micropores, the presence of the cationic and acid protic sites as well as decreasing size of the micropores in the carbon adsorbents. The greatest separation of the methane-containing gas mixtures was found for zeolites with MFI channel structures. The greatest separation of the hydrogen-containing mixtures was found for cavity-type LTA, FAU, and CHA zeolites.

Adsorption Properties of Porous Materials Based on Macrocyclic Nickel(II) Complexes and Benzenetricarboxylate Relative to Water, Methanol, and Hexane Vapor

We have shown that varying the substituents in the cationic component of porous crystal compounds formed by azamacrocyclic nickel(II) complexes and the 1,3,5-benzenetricarboxylate anion has a substantial effect on their adsorption behavior relative to water, methane, and n-hexane vapor. The studied compounds are characterized by reversibility of the changes in the crystal lattices during adsorption/desorption, stoichiometry of the reaction with water vapor with relatively low and hydrolytic stability at high humidity.

Effect of synthesis and doping conditions on the physical and chemical properties of mesoporous tin dioxide

We have studied the effect of doping mesoporous materials and films based on tin dioxide on their physical and chemical properties. We have studied their thermal stability, sorption, acid, and semiconductor properties. We demonstrate the advantages of using nanocomposites to obtain thermally stable layers (thickness ~1 μm) with relatively high porous structural parameters (Vtot = 0.460 cm3/g, SBET = 440 m2/g) and physical and chemical properties that can be varied in a targeted fashion.

Characteristics of Template Formation in Silica in Acidic Media

Characteristics of template formation in silica at pH < 0.1 in the presence of a surface active substance (cetyltrimethylammonium bromide or chloride) have been investigated. Depending on the acidity of the reaction medium and some other factors, the synthesis of spontaneously growing particles of templated silica at interfacial surfaces led to the formation of fibers, spirals, spheres, and other forms, most of which appeared as hexagonally ordered bodies of revolution. It is possible to detemplate these forms of silica and to transform them to mesoporous molecular sieves without destroying their structures.

Effect of Introduction of Aluminum on the Structure and Adsorption Properties of Zeolites of VPI-8 Type

Silicates and aluminosilicate zeolites of the VPI-8 type with wide content range of Si and Al atoms have been synthesized. Introduction of aluminum into the zeolite lattice is accompanied by transition from the cubic to the orthorhombic system while retaining the original architecture of the skeleton, but there is also an increase in the sorption volume and the characteristic adsorption energies of methanol and hexane.