It is known that H2S absorption occurs faster than CO2 absorption, as CO2 undergoes a slow hydrolyzing step [10,13] that is given in Eq. (5). This fact can be used to increase the selectivity towards H2S by minimizing the contact time between gas and liquid [11,13,15]. The drawback of this method is that increasing selectivity typically accompanied by lowered removal efficiencies of H2S.