Purification of gas streams

A method for removing a first and a second minor component from a gas mixture comprising the first and second minor components and one or more major components, which method comprises the steps of:

• (a) providing a first adsorbent zone containing a first adsorbent material and a second adsorbent zone containing a second adsorbent material, wherein the selectivity of the first adsorbent material for the first minor component relative to the second minor component is greater than the selectivity of the second adsorbent material for the first minor component relative to the second minor component, and wherein the average particle diameter of the first adsorbent material and the average particle diameter of the second adsorbent material are substantially the same;
• (b) passing the gas mixture comprising the first and second minor components and the one or more major components through the first adsorbent zone and subsequently through the second adsorbent zone;
• and
• (c) withdrawing from the second adsorbent zone a purified gas containing the one or more major components and depleted in the first and second minor components.