a method of purifying a hydrogen stream using an electrochemical cell having a tightly wound leak resistant metal spring and a hollow wet polymeric membrane located within and concentric with the metal spring which provides an inner compartment and an outer compartment . a porous metal electrode in a form of a tubular sintered metal filter is located within the inner compartment and is spaced from the hollow polymeric membrane . a gas inlet for feeding a hydrogen stream that is to be purified communicates with the inner compartment and a gas outlet is provided for passing purified hydrogen gas thru the metal spring . the electrode within the inner compartment is connected to an anode terminal of a dc supply with an electrical conductor and the metal spring is connected to a cathode terminal of the dc supply with another electrical conductor .