Rotten Eggs Revaluated: Ionic Liquids and Deep Eutectic Solvents for Removal and Utilization of Hydrogen Sulfide

Abstract

Hydrogen sulfide (H2S) is highly toxic and one of the problematic impurities in industrial gas streams, calling for H2S removal down to single-digit ppm levels to protect health and environment, and not to harm to the downstream processes. Here, we discuss the recent developments and challenges of current H2S removal technologies. Furthermore, we present a comprehensive review of H2S removal in ionic liquids (ILs), IL-based solvents/adsorbents/membranes, and deep eutectic solvents (DESs) due to their unique advantages. We analyze theoretical studies to better understand the microscopic details behind H2S removal. We discuss new research on IL/DES-based H2S removal processes from an industrial perspective. Finally, we summarize the utilization of H2S in IL/DES-based systems for the recovery of sulfur and hydrogen, and synthesis of value-added chemicals. This review will provide both general and in-depth knowledge of the achievements, difficulties, and research priorities in developing novel ILs/DESs for efficient and sustainable H2S removal and utilization.