Enhanced Gas Separation of PEBAX with Metal-Doped MOF-5

Abstract

Metal doping strategy is used to prepare MOF based fillers in order to fabricate effective mixed matrix membranes (MMMs) for gas separation. In this regard, two and three metallic MOF-5 is produced by using Co²⁺ and Cd²⁺ doping. Among the result MMMs, the best CO₂ permeability (386.1) and CO₂/N₂ selectivity (73.2) are belonged to those containing Cd-Co-MOF-5 and Cd-MOF-5, respectively. With the aim of upgrading the gas separation ability of the MMMs, (3-Aminopropyl)triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) are employed as linkers to modify MMMs. The result MMMs render promoted behaviors in both gas permeability and selectivity in which APTES modified MMMs possess higher gas permeability (up to 556.0) and the modified ones with TEOS own higher gas selectivity (up to 90.1). Additionally, the effects of feed temperature and pressure on gas separation of membranes are also explored. The most impacts of temperature on CO₂/N₂ selectivity are received in unmodified MMMs while for pressure effects, the modified ones experience the highest changes in CO₂/N₂ selectivity. It should be noted that synthesized MOFs are analyzed by FT-IR, XRD, FESEM and N₂ adsorption–desorption analysis and the prepared membranes are also analyzed by FT-IR, XRD, FESEM, TGA, DSC, stress–strain and water contact angle analysis.