Highly efficient adsorption of ethyl mercaptan on hierarchical porous carbon derived from rice husk

Abstract

In this work, rice husk-derived hierarchical porous carbon (HPC) was developed as a high-performance adsorbent for ethyl mercaptan removal. Various characterization methods were used to comprehensively characterize the HPC adsorbent. HPC-2 exhibited an adsorption capacity of 118.1 mg/g for ethyl mercaptan at 500 ppm and a space velocity of 12000 h⁻1, outperforming similar materials reported previously. The high adsorption capacity was attributed to the material’s well-developed microporosity and the abundance of hydroxyl groups (–OH) on its surface, facilitating the chemisorption of ethyl mercaptan. Given the chemically adsorbed nature of sulfur compounds, N₂ thermal regeneration was insufficient to fully recover the adsorbent’s performance. However, oxidative regeneration using O₂/N₂ (3/97 v/v) at 250 °C successfully removed these compounds and restored desulfurization efficiency, likely due to oxygen-assisted reactions on the adsorbent surface. This study provides valuable insights for effectively treating sulfur-containing odorous gases in the air.