Dubinin-Astakhov model for acetylene adsorption on metal-organic frameworks

Graphical abstract: It was demonstrated that Dubinin-Astakhov equation can be exploited as a general isotherm model for C2H2 adsorption on metal-organic frameworks (MOFs), including MOF-5, ZIF-8, HKUST-1, and MIL-53. - Highlights: • Dubinin-Astakhov equation is demonstrated to be a general model for C₂H₂ adsorption on metal-organic frameworks (MOFs). • Surface areas obtained with Dubinin-Astakhov equation from C₂H₂ adsorption on MOFs are consistent with BET surface areas from N₂ adsorption. • C₂H₂ on MOF-5, ZIF-8, and MIL-53 is a physical adsorption, whereas its adsorption on HKUST-1 is due to a chemical bonding. - Abstract: Acetylene (C₂H₂) is explosive at a pressure above 29 psi, causing a safety issue for its storage and applications. C₂H₂ adsorption on metal-organic frameworks (MOFs) has been explored to solve the issue. However, a suitable isotherm equation for C₂H₂ adsorption on various MOFs has not been found. In this paper, it was demonstrated that Dubinin-Astakhov equation can be exploited as a general isotherm model to depict C₂H₂ adsorption on MOF-5, ZIF-8, HKUST-1, and MIL-53. In contrast, commonly used Langmuir and BET models exhibited their inapplicability for C₂H₂ adsorption on those MOFs.