Coconut-shell-based activated carbon (ACS-1) was used as a sorbent to simultaneously remove H 2 S and SO 2 from simulated Claus tail gas. Adsorption and regeneration tests were performed to systematically investigate the desulfurization performance, regenerability, and stability of the ACS-1 sorbent. The physicochemical properties of ACS-1 before and after adsorption were characterized by nitrogen adsorption, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The experimental results revealed that the ACS-1 sorbent exhibited good desulfurization performance under a feed gas of H 2 S (20 000 ppmv), SO 2 (10 000 ppmv), and N 2 (balance), and the concentrations of H 2 S and SO 2 in the simulated Claus tail gas could be reduced to less than 10 mg/m 3 by ACS-1. The breakthrough sulfur capacity of ACS-1 is 64.27 mg of S/g of sorbent at an adsorption temperature of 30°C and a gas hourly space velocity of 237.7 h −1 . The micropores with sizes of around 0.5 nm in ACS-1 are the main active centers for adsorption of H 2 S and SO 2 , whereas mesopores have little desulfurization activity for deep removal of H 2 S and SO 2 . Both physical adsorption and chemical adsorption coexisted in the process of desulfurization. The majority of sulfides were removed by physical adsorption, and 11% of the sulfur compounds existing in the form of elemental sulfur (ca. 20 atom %) and sulfate (ca. 80 atom %) were derived from the chemical adsorption. The mechanism of H 2 S and SO 2 adsorption on the ACS-1 sorbent is also discussed. H 2 S and SO 2 are first adsorbed on ACS-1 by physical adsorption and then partially oxidized to elemental sulfur and sulfate, respectively, by the oxygen adsorbed on ACS-1. At the same time, the Claus reaction between H 2 S and SO 2 occurs. In addition, the ACS-1 sorbent can be completely regenerated using water vapor at 450°C with a stable breakthrough sulfur capacity during five adsorption−regeneration cycles. ■ INTRODUCTIONAt present, the Claus tail gas still contains 1−4% sulfur species and other gaseous components such as CO, H 2 , CO 2 , water vapor, and N 2 because of the thermodynamic limitations of the Claus equilibrium reaction. The sulfur species consist mainly of H 2 S, SO 2 , COS, CS 2 , and sulfur vapor. The volume fractions of H 2 S and SO 2 in Claus tail gas are in the range of 0.3−1.99% and 0.15−0.89%, respectively. 1,2The Shell Claus off-gas treatment (SCOT) process is the most common tail gas treatment unit of the Claus process. 3 In the SCOT process, all of the sulfur compounds and elemental sulfur are first reduced to hydrogen sulfide at 300°C using typical hydrogenation catalysts such as cobalt−nickel or cobalt−molybdenum. The consequent reducing gas is composed of CO and H 2 . 4,5 H 2 S is absorbed by a selective absorbent such as N-methyldiethanolamine (MDEA) and then stripped from the amine-rich solvent and recycled to the Claus unit. 6 The tail gas of the SCOT unit contains rare H 2 S, which can be treated by a burner. This approach...