Development of metal-organic framework-based systems for H2S removal: A comprehensive review

Biogas is recognized as a source of renewable energy that can substitute for fossil fuels, especially natural gas. Biogas is produced from various organic resources, and it contains mainly methane (CH₄) and carbon dioxide (CO₂). However, several contaminants are found in the biogas flow such as hydrogen sulfide (H₂S), water (H₂O), ammonia (NH₃), and volatile organic compounds (VOCs). Therein, due to its high corrosion, toxicity, and bad odor, H₂S must be eliminated first and intensively to avoid equipment damage and health risks. Among H₂S removal technologies, using the solid adsorbent is viewed as a friendly and effective way. Recently, metal-organic frameworks (MOFs) have been studied with increasing attention for H₂S adsorption thanks to their high surface area, good thermal stability and structural tunability. Although many MOFs-based systems have been designed for H₂S removal, an intensive study to summarize them is missing. This work aims to revise the development of MOFs-based networks for H₂S removal in literature including pristine MOFs, functionalized MOFs, MOF composites, and mixed-metal MOFs. We focus on explaining H₂S adsorption mechanism of MOFs, and material engineering factors that directly affect the H₂S adsorption capacity, the selectivity over other gases, and the ability to regenerate. Furthermore, several perspectives to enhance the removal performance of MOFs are also proposed. Together, this study will provide a comprehensive document on current technologies and perspective development of MOF-derived H₂S adsorbent.