A rotating packed bed (RPB) unit comprising one rotor is described. The rotor comprises a first plate and a second plate. The rotor further comprises a plurality of annular permeable packing elements housed in between the first plate and the second plate, wherein a first end of each of the plurality of annular permeable packing elements is attached to the first plate, and wherein a second end of each of the plurality of permeable packing elements is attached to the second plate. The rotor further comprises a shaft coupled to one of the first plate and the second plate for rotating the rotor. Further, the rotor comprises a liquid inlet for receiving a liquid phase and a gas inlet for receiving a gas phase.