Determination of Texture- Geometric Parameters of Disperse and Porous Materials

Objects of study

Dispersed and porous materials, first of all catalysts, sorbents, supports.

Applications

Following parameters are defined:

• Total specific surface in the range 0,01 – thousands m²/g.
• Separate surface of the 8th group metals supported onto the inert support.
• Pore size distribution in the range:
  – from 1 up to 100 nm (nitrogen adsorption),
  – from 2 nm up to 200–300 μm (mercury porosimetry).
• Micropore volume and mesopore specific surface.
• Powder particle size distribution in the range from 2 up to 200 ?m.
• True material density.

Instrument facilities

1. The total material surface is defined by express method in the circulating unit by argon adsorption and more precise static methods by isotherms of low temperature adsorption of nitrogen, oxygen and other gases. Determination limits (the lower, the upper): for express methods – 0,01 and hundreds m²/g, for static ones – 1 and thousands m²/g.

2. The separate surface of the supported metals of the 8th group is determined by selective oxygen chemisorption, under circulating conditions by impulse dosing.

3. Pore and surface size distribution are defined:

• for mesopores in the range from 1 nm up to 100 nm – by isotherms of nitrogen adsorption;
• for pores in the range from 2–3 nm up to 200-300 μm – by mercury porosimetry;
• for the micropore volume, volume and surface of mesopores (if necessary, their size distribution), the surface of macropores usually not filled in the adsorption experiments – by nitrogen adsorption.

The measurements by nitrogen adsorption are conducted at 77 K on ASAP-2400 (Micromeritics, USA) and AutoSorb IV (Quantochrome, USA) devices.

Mercury-porosimetric studies are performed on the automatic porosimeters Micromeritics (USA) PoreSizer 9300 (the limiting pressure 200 MPa) and AutoPore 9520 (the limiting pressure 400 MPa).

4. Powder particle size distribution is defined by the laser diffraction method on Laser Diffraction particle size Analyzer SALD-2101 (Shimadzu, Japan). The results are presented as the integral and differential curves of particle number or weight portion distribution versus the size, estimation of the average size and total outer surface of particles.

5. Estimation of the true density is performed by gas pycnometry on Autopycnometer-1320 (Micrometrics, USA) with helium. For the optimal material volume (8–9 cm³) an accuracy of measurement is ± 0.02 cm³.

The general requirement to the samples presenting for estimation of texture-geometric parameters indication by the customer of the admissible temperatures of sample heating in the course of preliminary testing.

Leading scientists and their research interests

Prof. V.B. Fenelonov. Mechanism of formation and simulation of the texture of catalysts and adsorbents, development of adsorption and mercury-porosimetric methods for porous structure study, applied adsorption. The author of monographs “Porous carbon” (1995) and “Introduction in physical chemistry of formation of supramolecular structur of adsobents and catalysts” (2002, 2004).

Prof. V.Yu. Gavrilov. Porous structure genesis for the difficulty crystallizing oxides of the IV group – SiO₂, TiO₂, SnO₂ and ZrO₂ as well as the binary systems on their basis.

Dr. M.S. Mel'gunov. Physics and chemistry of nanomaterials including mesoporous mesophase and carbon composites, synthesis and research.