Dynamics of Hydrogen Sulfide Adsorption in Pulse Mode on Activated Carbons Produced from Plant Waste

The adsorption of H 2 S impurity in the gas flow on carbon adsorbents produced from coconut shells and sugarcane bagasse was studied. The runs were carried out in pulse mode. An original chromatographic method for determining the degree of H 2 S absorption on carbon adsorbents has been developed, which makes it possible to determine the amount of absorbed H 2 S in air and water environments. The results obtained show that the successive treatment of carbon adsorbents first with a solution of a strong oxidizer (HNO 3 , KMnO 4 ) and then, after washing, with an alkali solution (KOH) leads to a sharp increase in the amount of H 2 S adsorbed. The efficiency of H 2 S absorption on the obtained adsorbent reaches 85.5%, which corresponds to 27.7 mg/g H 2 S and is comparable to the results obtained on commercial coconut carbon (CAU). The data allow one to conclude that the rise in the H 2 S adsorption on the carbon sorbents studied can be due to the increase in the micropores’ volume in the activated carbon, as well as the formation of surface functional groups containing an alkali metal (i.e., C-OK, C-COOK) that promotes irreversible chemisorption of H 2 S impurity on the carbon adsorbent. The absorption of H 2 S occurs through the chemisorption mechanism, which is confirmed by IR spectroscopy data.