Chemisorption of hydrogen sulfide over copper-based metal-organic frameworks: methanol and UV-assisted regeneration

Nishesh Kumar Gupta; Suho Kim; Jiyeol Bae; Kwang Soo Kim

doi:10.1039/d0ra09017d

Chemisorption of hydrogen sulfide over copper-based metal-organic frameworks: methanol and UV-assisted regeneration

RSC Adv. 2021 Jan 27;11(9):4890-4900. doi: 10.1039/d0ra09017d. eCollection 2021 Jan 25.

Authors

Nishesh Kumar Gupta^{1

2}, Suho Kim^{1

2}, Jiyeol Bae², Kwang Soo Kim^{1

2}

Affiliations

¹ University of Science and Technology (UST) Daejeon Republic of Korea kskim@kict.re.kr.
² Department of Land, Water, and Environment Research, Korea Institute of Civil Engineering and Building Technology (KICT) Goyang Republic of Korea.

Abstract

Three copper-based metal-organic frameworks (MOFs) with different organic linkers were synthesized for the removal of H₂S gas at room temperature. The synthesized MOFs were characterized by microscopic and spectroscopic techniques to understand their structural, functional, and optical properties. The H₂S adsorption capacity of MOFs calculated by column studies followed the trend: 105.6 mg g^-1 (CuBDC) > 27.1 mg g^-1 (CuBTC) > 1.3 mg g^-1 (CuBDC-N) in dry conditions. The adsorption capacity increased in moist conditions due to an easy dissolution and dissociation of H₂S in a film of water. X-ray photoelectron spectroscopy confirmed the presence of sulfur bound to Cu-sites and sulfate ions. The spent MOFs were regenerated by the successive effect of methanol and low power UV-C radiation. The regenerated CuBTC showed an exceptionally high adsorption capacity of 95.6 mg g^-1 in the second cycle, which was linked to the reactivation of Cu-sites and improved surface area and porosity. The regeneration process developed in this study is a cost-effective method to recycle chemisorbed MOFs without compromising with their structural and functional integrity.