A resistant and stable HKUST@MC composite for highly efficient gas adsorptive desulfurization

Abstract

HKUST-1 is a well-known copper-based metal–organic framework (MOF), promising to be used in separation processes, however its industrial usage remains confined due to its difficult handling and low mechanical stability when in powder form. In this work, we have synthesized and analyzed the mechanical properties of novel HKUST-1 shaped composites based on methylcellulose (MC) and poly(vinyl formal) (PVMF), using a simple and inexpensive extrusion technique. The composites were characterized using different techniques, such as Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) analysis, which demonstrated that their structure and crystallinity were not compromised by the shaping process. Their mechanical properties were investigated by compressive strength measurements and scanning electron microscopy (SEM). The composite with methyl cellulose showed good mechanical resistance, with an average crushing strength value of 40 N. Nitrogen sorption measurements showed that the specific surface area reduction due to the shaping process for HKUST@MC was only 8.6%. The greater hydrolytic stability after heat activation of HKUST@MC compared to that of the pure MOF was also verified. The adsorptive capacity of HKUST@MC towards organosulfur compounds found in sour gas was evaluated in a desulfurization test using a realistic multicomponent gas mixture. HKUST@MC exhibiting a high efficiency to adsorb organosulfur outperformed the benchmark sulfur adsorbent Norit RGM 3 in the adsorption of ethanethiol and dimethyl disulfide. Therefore, in this work we present a technically feasible and cost-effective method to produce a novel HKUST-1 shaped composite with good mechanical and water resistance properties preserving the MOF porosity and gas adsorption properties.