A process for purifying a by-product stream comprising primarily CO2 that emanates from a an ethylene glycol plant, where the by-product stream may contain organic chlorides and water. The process employs an adsorbent to remove one or more organic chlorides from the by-product stream to produce pure or substantially pure CO2. To improve the efficiency of the organic chloride adsorbent, prior to the organic chloride adsorption process, a moisture adsorbent may be employed to remove at least some of the water from the by-product stream.