size (pore, particle) distribution (rus. распределение по размерам (пор, частиц)) — dependence of the quantity (volume, mass) of particles or pores on their size in the material, as well as the curve (histogram) which describes this dependence.

Description

Size distribution reflects the dispersion of a system. The case where the distribution curve has the form of a sharp peak with a narrow base, i.e., particles or pores are of almost the same size, is referred to as a monodisperse system. Polydisperse systems are characterised by distribution curves that have broad peaks with no well-defined maxima. In the presence of two or more clearly defined peaks, distribution is bimodal and polymodal, respectively.

The basic methods of studying particle size distribution are statistical processing of data from optical, electronic and atomic force microscopy, as well as dynamic light scattering and analysis of the sedimentation curves. Pore size distribution is usually studied by analysing the adsorption isotherms using a model of mesopore size dependence on the equilibrium gas pressure (Barrett-Joyner-Halenda model, BJH method).

Particles' (pores') size distribution is acquired through interpretation of experimental data and depends on the method and model employed. Therefore, distribution curves constructed according to different methods of determining particle (pore) size, volume and surface area, etc., may differ.

Authors

  • Smirnov Andrey V.
  • Shlyakhtin Oleg A.

Sources

  1. Manual of Symbols and Terminology // Pure Appl. Chem. V. 46. 1976. P. 71.
  2. Setterfield Ch. Practical Course of Heterogeneous Catalysis (in Russian). - Moscow, Mir, 1984, 520 pp.
  3. Karnaukhov A.P. Adsorption. The texture of dispersed and porous materials (in Russian). - Novosibirsk: Nauka, 1999. - 470. p.

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