Abstract: Commonly available carbon dioxide may contain unacceptable amounts of compounds containing greater than about ten carbon atoms, sulfur-containing materials, and nitrogen-containing materials which are particularly detrimental to semiconductor and silicon wafer processing-related uses of carbon dioxide. These impurities can be effectively removed by an apparatus containing a combination of metal oxide, silica gel, and activated carbon, thus permitting an on-site, on-demand, convenient, and economic method of purifying carbon dioxide ranging from laboratory scale operations to tank car scale operations.