452 453 454 455 and 456 when the secondary parallel path 409 is active heat transferred in third coil 457 and fourth coil 458 while water vapor is adsorbed in first desiccant material 412 and hydrogen is absorbed in first absorbent material 413 similarly product hydrogen is desorbed from second absorbent material 463 flowing through valve 456 toward product line 442 in one embodiment of the secondary purification system 400 the hydrogen absorbent material 413 and 463 is a metal hydride type material the material absorbs h 2 molecules into the metal lattices and has the capacity to absorb approximately 150 to 300 times the volume of hydrogen at standard conditions in comparison to the volume of metal any absorbent or adsorbent materials can be used which preferentially remove h 2 gas from a mixture the method described is very simple in that all the open valves are closed and all the closed valves are open uniformly more complex and potentially more effective cycles are embodied for example the purge valve 434 positioned between the second h 2 absorbent material 463 and the first desiccant material 412 can be opened after the starting the process parallel path 408 to maintain the pressure of the process gases in absorbent material 463 and thereby enhance the percentage of the process hydrogen gas in the flow stream that is absorbed in the material 463 similarly the open valves of parallel path 408 can be closed except for purge valve 434 and exhaust.