An adsorption system having at least one adsorber retaining a bed of adsorbent material can be configured to provide enhanced purification of fees having relatively low concentrations of hydrogen or helium. Embodiments can utilize an activated carbon layer between at least one upstream layer and at least one downstream layer. The activate carbon layer can include activated carbon can have a pre-selected surface area (SA), bulk density, total open pore volume (TOPV), and/or ratio of TOPV to surface area (TOPV/SA).