Metal–Organic Frameworks for H2S Removal: Identification of Optimal Adsorbents and Influence of H2S Molecular Models

Abstract

Managing H₂S emissions is essential, given their detrimental impacts on human health, the environment, and industry. Among various techniques, the adsorption process using metal–organic frameworks (MOFs) has garnered significant interest for their energy efficiency. In light of the vast assortment of MOFs, the necessity for efficient screening strategies to identify potential H₂S adsorbents is self-evident. To this end, this study conducts a large-scale computational study to identify top-performing MOFs for H₂S adsorption and provide insights into the design rules for these materials. The findings suggest that optimal MOFs feature relatively confined structures and higher maximum metal charges. Moreover, while molecular simulations have been proven effective, prediction uncertainties may be inevitably involved. Specifically, various molecular models have been developed to date for modeling H₂S, each focusing on reproducing experimental properties such as the electrostatic potential (ESP) and/or vapor–liquid equilibrium (VLE). This study has also investigated the consistency of various H₂S models in identifying optimal H₂S adsorbents. While most models are found to rank MOFs similarly overall with a Spearman correlation exceeding 0.8, the rankings of top candidates can vary significantly. The results suggest that those fitted to both ESP and VLE are strongly recommended for more reliable discoveries, though it is still found that they may lead to distinct atomistic adsorption and diffusion behaviors. Overall, the insights garnered from this study may help steer future research endeavors toward experimental and computational developments of optimal adsorbents for H₂S removal.