Method for separating a gaseous mixture that comprises as main ingredients H2S and CO2, wherein the gaseous mixture is contacted in a first device with a solvent comprising a weak Lewis-acid, wherein H2S is absorbed in the solvent and the remaining CO2 is abducted, and wherein the at least partially saturated solvent is regenerated subsequently, in at least one second device wherein the weak Lewis-acid comprises copper aluminum chloride (Cu[AlCl4]) and wherein the solvent comprises monochlorobiphenyl (MCB).