Efficient Adsorption of Hydrogen Sulfide at Room Temperature using Fumed Silica-supported Deep Eutectic Solvents

ABSTRACT Supported deep eutectic solvents (SDESs) using fumed silica as the supporting material and TAECuCl3 as the loading substance, were developed for H2S removal. The highest breakthrough sulfur capacity, 9.97 mg g–1, was achieved when the molar ratio of the TEACl to the CuCl2 was 1:1, the loading rate of the DES was 10%, and the temperature was 30°C. TAECuCl3 proved to be a more effective loading substance than pure TEACl, pure CuCl2, or blends of these substances at other ratios. Due to the high utilization rates of the metal-activated sites, the SDESs were more economical. The excellent capacity for H2S removal was attributable to the formation of a thin layer of DES, nano-sized in thickness, on the fumed silica. The XRD and XPS analysis showed that the products of desulfurization were S and Cu2S, the latter of which was then oxidized to S and SO42– by air at room temperature. After regenerating 4 times, the breakthrough sulfur capacity of the SDESs was still as high as 7.39 mg g–1. The nonlinear curve fitting demonstrated that the adsorption kinetics followed those of the Bangham kinetic model.