Gas mixtures can be separated by different types of membranes. In comparison to the cryogenic methods for gas separation, membranes offer higher gas selectivities and are more energy-efficient. For hydrogen separation we have developed Pd-coated alumina capillary membranes. If the operating temperature is high, dense perovskite capillaries can be implemented in the process e.g. for oxygen separation from air, CO2 capture and storage or catalytic reactions such as syngas production. A new research field of our group is the development of membrane-supported ionic liquids for CO and CO2 separation e.g. from biogas.