Pore classification in the characterization of porous materials: A perspective

Abstract

Classification of pores is one of the basic requisites of comprehensive characterization of porous solids. There are various categorizations of pores described in the literature, but it is difficult to give a consistent global classification of porous substances including catalysts, adsorbents, oxides, carbons, zeolites, organic polymers, soils etc. The purpose of each of these classifications is to organize pores in classes by grouping them on the basis of their common characteristics like structure, size, accessibility, shape etc. In this study, a summary of the most used classifications of porous materials is done. Some common properties or behavior for individual classifications could be found, but many differences mainly in pore size are still subject of intensive discussions. Therefore, it is the purpose of this review to provide a general description of the concept and classification of pores in porous solids, to deal with complexity of the matter and to organise our knowledge in decision-making proccesses of pore characteristics determination.

Magnetic resonance analysis of carbon content in paper mill sludge–soil mixtures used in remediation practices

“…In soil science literature, there is no univocal definition of the terms micropores, mesopores and macropores, probably due to the large number of different techniques used to determine the pore size distributions (Zdravkov et al 2007). This ambiguity suggested the use of the typical petrophysical cut-off method to identify micropores by NMR.…”

Porous microsphere and its applications

“…According to the International Union of Pure and Applied Chemistry classification, 3 porous materials can be classified according to their pore sizes: microporous materials (less than 2 nm), mesoporous materials (2-50 nm), macroporous materials (50-200 nm), and gigaporous materials (more than 200 nm). The diversities in pore sizes meet requirements in many practical applications and are intensively studied for their promising virtues.…”

“…For high deposition of inhaled proteins throughout the lung, the porous microspheres' aerodynamic diameter should be about 5 µm. 62 Briefly, microspheres fitted for pulmonary drug delivery should have a low mass density (,0.4 g/cm 3 , aerodynamic diameter of 1-5 µm) and a large size (.5 µm) which allows for a high accumulation of protein particles in the periphery of the lung, thus preventing phagocytic clearance and realizing a controlled release. 63,64 Other applications New fields that microspheres can be applied to have been discovered.…”

Synthesis, Properties and Potential Applications of Porous Graphene: A Review

“…Generally, porous materials contain holes either with random or high regularity. Depending on their diameters, the pores can be classified in micropores (diameters below 2 nm), mesopores in the range 2-50 nm, and for diameters above 50 nm, the pores are labeled macropores [22]. Porous carbons are the most employed porous materials, for their high surface areas, hydrophobic nature, and low cost manufacture.…”