Patent ID: 7976725

Claim:
A cyclic process for the in-situ generation of chlorine dioxide from a dilute solution of chlorite anions in a recirculating aqueous system treated with a chlorite anion donor, and wherein the said aqueous system remains substantially free of chlorite anions, the process comprising: addition of an activating oxidant selected from at least one of a free halogen donor comprising at least some portion of free chlorine and peroxymonosulfate donor to the said aqueous system; and sustaining in said aqueous system a bromide anion concentration from about 10 ppm to 1000 ppm by addition of an alkali metal salt of bromide, a chlorite anion concentration necessary to sustain from about 0.2 to 1.0 ppm as chlorine dioxide by addition of an alkali metal salt of chlorite, and a pH of between about 6.8 to 8.0; whereby the activating oxidant reacts with the bromide anion to sustain a free bromine concentration from about 1.5 to 25 ppm reported as Br 2 , subsequent reaction of the free bromine with the chlorite anion to produce chlorine dioxide; and wherein at least some portion of the recovered bromide anions and chlorite anions resulting from the reduction of free bromine and chlorine dioxide are recycled in the cyclic process.