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.