Borazine as Alternative to Benzene-based Organic Linkers for Gas Adsorption on Metal-Organic Frameworks

  • Mostafa Yousefzadeh Borzehandani Universiti Putra Malaysia
  • Emilia Abdulmalek Universiti Putra Malaysia
  • Mohd Basyaruddin Abdul Rahman Universiti Putra Malaysia
  • Muhammad Alif Mohammad Latif Universiti Putra Malaysia
Keywords: HKUST-1; borazine; metal-organic framework; gas absorption; grand canonical Monte Carlo

Abstract

Metal-organic frameworks (MOFs) are porous materials that are extensively used for gas adsorption and storage due to their unique features. The use of borazine in the construction of MOFs (instead of the more common organic fragment, benzene) offers an ideal solution to overcome challenges that arise from functionalizing MOFs. In this study, we modified the original HKUST-1 MOF by replacing the benzene ring in the organic linker with borazine. The adsorption of greenhouse gases by both HKUST-1 and borazine-based HKUST-1 (hB-HKUST-1) were studied. The adsorption of CO2 and CH4 by both MOFs were simulated at 298 K over a range of pressures (0-160 kPa) using grand canonical Monte Carlo simulations. hB-HKUST-1’s surface enhanced the adsorption of CO2 gas, but did not influence the adsorption of CH4. The isosteric heats of adsorption (Qst) demonstrated higher CO2 adsorption by both frameworks compared to CH4. CO2 gas also showed higher loadings of 188.4 and 204.9 mg.g-1, respectively, in HKUST-1 and hB-HKUST-1. Analysis of interaction energies revealed that adsorbent–adsorbate interactions were as much determinative as adsorbate–adsorbate interactions. Snapshots from the simulation indicated that CO2 molecules preferred smaller pores. This valuable information can be a guideline to produce borazine-based MOFs for better gas absorption and storage.

Published
2021-12-31