Removal of Hydrogen Sulfide (H2S) Using MOFs: A Review of the Latest Developments

Abstract

: Removal of hydrogen sulfide (H 2 S) from gas streams with varying overall pressure and H 2 S concentration is a long-standing challenge faced by the oil and gas industries. The present work focuses on H 2 S capture using metal-organic frameworks (MOFs), in an effort to shed light on their potential as adsorbents in the field of gas storage and separation. MOFs hold great promise as they make possible the design of structures from organic and inorganic units but also, they have provided an answer to a long-time challenging objective, i.e., how to design extended structures of materials. Moreover, the functionalization of the MOF’s surface can result in increased H 2 S uptake. For example, the insertion of 1% of a fluorinated linker in MIL-101(Cr)-4F(1%) allows for enhanced H 2 S capture. Although noticeable efforts have been made in studying the adsorption capacity of H 2 S using MOFs, there is a clear need for gaining a deeper understanding in terms of their thermal conductivities and specific heats in order to design more stable adsorption beds, experiencing high exothermicity. Simply put, the exothermic nature of adsorption means that sharp rises in temperature can negatively affect the bed stability in the absence of sufficient heat transfer. The work presented herein provides a detailed discussion, by thoroughly combining the existing literature, on new developments in MOFs for H 2 S removal, and tries to provide insight into new areas for further research.