NaOH-Modified Activated Carbon Materials for Hydrogen Sulfide Removal

A high-surface-area activated carbon material (RG) is used as a platform to create highly concentrated NaOH composites. These materials are tested for the removal of H2S under industrially relevant conditions (800 ppm H2S in CO2-, H2O- and O2-containing streams). The experimental results show that the breakthrough performance highly depends on the amount of NaOH incorporated and the experimental conditions used (e.g., relative humidity). The most promising material (RG-NaOH-30) reaches a saturation uptake of up to 800 mgH2S/g at 25 °C and atmospheric pressure. This value is among the most promising results reported in the literature for H2S removal, and it is well above traditional commercial samples. Breakthrough column tests confirm the promoting role of humidity in the reaction mechanism. Analysis of the adsorbents after H2S confirms the formation of well-defined sulfur (Sn) microcrystals as the main reaction product.