The Creation of a Water Purification System Based on the Manganese Porphyrazine-Aided Production of Chlorine Dioxide

Abstract

Chlorine dioxide is an effective disinfectant for use in water treatment; however, the compound is currently not in widespread use due to the challenges of its generation. In this work, a new system for chlorine dioxide generation was developed, which relies on the use of manganese(III) tetra-N-methyl-2,3-pyridinoporphyrazine as a catalyst and carbon dioxide as a proton source and carrier gas to convert sodium chlorite to product. This system generates adequate concentrations of chlorine dioxide for use in water treatment systems and was optimized for the highest yield and turnover frequency of the catalyst. The limitations of this system are also addressed, which include the short lifetime of the catalyst. It was found in this work that during the catalytic generation of chlorine dioxide, the catalyst is converted to a new resting state through its reaction with the chlorine dioxide product. This resting state is unstable and quickly degrades as it reacts with the dissolved carbon dioxide in solution. With this in mind, a second ‘generation’ system is proposed here which will theoretically elongate the lifetime of the catalyst by immobilizing it on a solid support. The proposed flow system will allow the quick removal of the chlorine dioxide generated to prevent catalyst degradation. Initial proof of concept work for this improved system has shown promise.