Process for dehumidifying a moist gas mixture G, in particular moist air, in an apparatus V 1 , comprising the steps of: (a) contacting the moist gas mixture G with a liquid absorption medium A VE comprising a mixture of at least one additive selected from the group consisting of compounds of the structure ( I ) with and at least one salt S selected from the group consisting of Q + A - , Q + (R 1 O) 2 PO 2 - , (Q + ) 2 R 2 OPO 3 2- , Q + M + R 3 OPO 3 2- , wherein the liquid absorption medium A VE at least partially absorbs water from the moist gas mixture G, to obtain a liquid absorption medium A VE1 having an elevated water content compared to the liquid absorption medium A VE and a gas mixture G 1 having a relatively low water content compared to the moist gas mixture G, (b) at least partially removing water from the liquid absorption medium A VE1 to obtain a liquid absorption medium A VE2 having a relatively low water content compared to the liquid absorption medium A VE1 , wherein the apparatus V 1 at least partially comprises a surface made of a metal material of construction O Al and in the apparatus V 1 at least one of the liquid absorption media selected from the group consisting of A VE , A VE1 , A VE2 contacts the surface made of a metal material of construction O Al via at least one contact surface, characterized in that Q + is a dialkylimidazolium cation, wherein A - is an anion selected from the group consisting of R*COO - , R'SO 3 - , HSO 4 - , R"SO 4 - , wherein R*, R', R" are each independently of one another an alkyl group, wherein R 1 , R 2 , R 3 are each independently of one another an alkyl group, wherein R is hydrogen or methyl, and wherein M + is an alkali metal ion, and wherein x is an integral number in the range of 1 to 5, wherein y is an integral number in the range of 0 to 5, and wherein z is an integral number in the range of 1 to 15, wherein the metal is selected from aluminium, steel, copper, noble metals, titanium. (a) contacting the moist gas mixture G with a liquid absorption medium A VE comprising a mixture of at least one additive selected from the group consisting of compounds of the structure ( I ) with and at least one salt S selected from the group consisting of Q + A - , Q + (R 1 O) 2 PO 2 - , (Q + ) 2 R 2 OPO 3 2- , Q + M + R 3 OPO 3 2- , wherein the liquid absorption medium A VE at least partially absorbs water from the moist gas mixture G, to obtain a liquid absorption medium A VE1 having an elevated water content compared to the liquid absorption medium A VE and a gas mixture G 1 having a relatively low water content compared to the moist gas mixture G, and at least one salt S selected from the group consisting of Q + A - , Q + (R 1 O) 2 PO 2 - , (Q + ) 2 R 2 OPO 3 2- , Q + M + R 3 OPO 3 2- , wherein the liquid absorption medium A VE at least partially absorbs water from the moist gas mixture G, to obtain a liquid absorption medium A VE1 having an elevated water content compared to the liquid absorption medium A VE and a gas mixture G 1 having a relatively low water content compared to the moist gas mixture G, (b) at least partially removing water from the liquid absorption medium A VE1 to obtain a liquid absorption medium A VE2 having a relatively low water content compared to the liquid absorption medium A VE1 , characterized in that Q + is a dialkylimidazolium cation, wherein A - is an anion selected from the group consisting of R*COO - , R'SO 3 - , HSO 4 - , R"SO 4 - , wherein R*, R', R" are each independently of one another an alkyl group, wherein R 1 , R 2 , R 3 are each independently of one another an alkyl group, wherein R is hydrogen or methyl, and wherein M + is an alkali metal ion, and wherein x is an integral number in the range of 1 to 5, wherein y is an integral number in the range of 0 to 5, and wherein z is an integral number in the range of 1 to 15, wherein the metal is selected from aluminium, steel, copper, noble metals, titanium. <EOS>