The invention relates to device for enriching and depleting materials in a liquid. Said device comprises a pump for advancing the liquid and said pump comprisesa displaceable transport element (1) which transports the liquid. Said deviceis advantageous in that it comprises an insertable and retractable transportand drive unit and it is particularly advantageous in that the flow guiding elementeffectively enriches and depletes material in the liquid. The invention alsorelates to a fluidic rotor bearing for mounting the transport element. It isalso possible to connect a two lumen cannula by means of a concentric connectionmodule. Due to said device, a compact oxygen generator system, which is basedon an integrated and re-usable blood-pump, is produced which can be used in blood.