Abstract: The proportion of chlorine dioxide to chlorine in aqueous solutions formed from gaseous mixtures of chlorine dioxide and chlorine is improved over conventional separation techniques. The gaseous product stream from a chlorine dioxide generator is scrubbed with an aqueous salt mixture containing an approximately stoichiometric quantity of sodium hydroxide, which reacts preferentially with the chlorine, yielding chlorine dioxide of high purity. The absorption system is operated under such conditions that the chlorine is converted to sodium chlorate and sodium chloride, which may then be recirculated to the chlorine dioxide generating system. The scrubbing salt solution is adjusted so as to produce an R-2 mixture upon reaction with the chlorine in the chlorine/chlorine dioxide stream.