An apparatus for the purification of fluids includes a material exchange apparatus which contains a more volatile fluid and a less volatile fluid. The material exchange apparatus contains a structured packing, with the structured packing containing a first packing layer (10) and a second packing layer (100). The first packing layer (10) and the second packing layer (100) have corrugations, with open channels (12, 14, 16, 112, 114, 116) being formed by the corrugations. The channels (12, 14, 16) of the first packing layer (10) cross the channels (112, 114,116) of the second packing layer, wherein the channels (12, 14, 16, 112, 114, 116) can be flowed through by the less volatile fluid so that the channel is wettable by the less volatile fluid, wherein a film of the less volatile fluid is formed on the surface of the channel, so that a purification can be carried out either of the more volatile fluid or of the less volatile fluid by a material exchange between the more volatile fluid and the less volatile fluid. The first packing layer (10) is in touching contact with the second packing layer (100) via spacer elements (24, 34, 44, 134, 144).