Modelling gas adsorption in porous solids

Abstract

Porosity is a vital element in the design and development of porous architectures down to the micro- and nano-scale ranges that mimic structures found in nature (such as hollow bamboo, honeycomb with hexagonal cells, and alveoli in the lungs) in synthesized materials [1]. The International Union of Pure and Applied Chemistry (IUPAC) classi ed porous materials into three categories based on their pore sizes: microporous < 2 nm, 2 nm < mesoporous < 50 nm, and macroporous > 50 nm. Until the mid 1990's, the highly ordered structures among the available organic and inorganic porous materials, were zeolites that had also been utilized as CO2 adsorbents (see Figure 1.1) [2]. However, the disadvantages of these traditional adsorbents are low gas storage capacity, ine ciency in regeneration process [3] and di culties to alter their properties due to rigid bonds in their entire framework. On the other hand, porous organic polymers such as activated carbons have high porosity and surface area but they lack long-range order in their structure [4]. Hence, there was a need for materials that would possess porosity, high surface area as well as long-range ordered structures. Yaghi et al. developed new highly crystalline hybrid porous frameworks, metal-organic frameworks (MOFs) [5, 6] by taking advantage of both organic and inorganic counterparts which is shown in Figure 1.1.