{HEAD ~ Process} and adsorbent for the recovery of krypton and xenon from {TAIL ~ a gas or liquid stream} 
{ HEAD ~ Process } and adsorbent for the recovery of krypton and xenon from { TAIL ~ a gas or liquid stream }
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL