Mechanical strength and reliability of the porous materials used as adsorbents/catalysts and the new development trends

Purpose: This paper aims to provide an understanding on some aspects of the porous material strength and reliability and to present future trends of the research on the mechanical properties of this solid porous materials. Design/methodology/approach: It shows that a multitest approach must be designed in order to measure the particle strength and then optimise the production process to enhance its strength. This approach combines measurements reproducing the different types of stress generated in the separation or catalytic process with an extensive characterisation of the physical and mechanical properties of the porous solid, such as hardness, fracture toughnes, brittle, crushing, attrition, etc. The methodology outlined here on alumina single particle or bulk goes beyond the common practice of evaluating mechanical strength based on a comparative study using a single-crushing test and a bulk-crushing test. Findings: Some recent developments on the basic mechanics of solid porous materials are shown. The main concepts presented are the brittle fracture which leads to the mechanical failure of the porous materials, the measurement and statistical properties of the strength data, the mechanical reliability of the porous material pellets, the mechanical properties of the adsorbent or catalyst packed beds, etc. The use and use limitations of inorganic binders for increasing the mechanical strength is discussed and the most binder systems are presented. Research limitations/implications: The scientific basis for the issues on the adsorbent/ catalyst mechanical properties calls yet for further elucidation and development. Practical implications: It is pointed out that porous materials used as adsorbents/ catalysts, with a high and uniform distributed mechanical strength are beneficial to industrial, energetic and environmental applications. Originality/value: A new route for improving mechanical strength of adsorbents/catalysts will become an unavoidable task not only for their manufacturing but also for to improve the efficiency of separation and catalysis processes