Docket # 15-3063-1
Researchers at Princeton University have developed a new catalytic method to produce chlorine dioxide quickly and efficiently from easily transportable chlorite salts. This method operates under mild conditions without the input of external energy or the use of harsh chemicals, circumventing the major concerns of large-scale production of ClO2 as well as providing a low-tech, green option for water purification.
This invention uses water-soluble iron porphyrazine catalysts capable of rapid conversion of ClO2- to ClO2. They are more sustainable and superior to the first generation catalysts, which are their manganese counterparts, in terms of catalytic activity. Initial Fe catalyst concentration as low as 0.125 μM is capable of converting 5 mM solution of ClO2- to ClO2. In doing so, Fe catalyst is capable of on average 15,000 turnovers. The evolved ClO2 is isolated in good yield when monitored by UV-Vis spectroscopy.
• Catalytic method to produce ClO2 on a small or large scale
• Portable kit in the form of a cartridge for small-scale water treatment
• Large-scale process for water treatment in the form of a flow system
• Requires no additional power, electricity, or harsh chemicals
• Catalytic method is fast and energy-efficient under mild operating conditions
• Catalyst is reusable and easily recoverable
Umile, T., Groves, J.T. “Catalytic Generation of Chlorine Dioxide from Chlorite Using a Water-Soluble Manganese Porphyrin”, Angew. Chem., 2011, 50(3), 721-724
Chlorine dioxide gas (ClO2) is a potent oxidizing agent for the bleaching of paper, the disinfection of water and air, and the treatment of wastewater. The dangers and energy costs of the production of ClO2, however, have limited its use.
ClO2 offers a number of advantages compared with the use of chlorine gas as an oxidizing agent for water treatment. ClO2 is a stronger oxidizing agent above pH 7 and in the presence of other chemicals such as ammonia and amine, and is less corrosive. ClO2 is more effective than chlorine for killing water-borne pathogenic microbes including viruses, Legionella and other bacteria, and protozoa including the cysts of Giardia and the oocysts of Cryptosporidium. In addition, disinfection with ClO2 does not form the toxic organochlorine byproducts produced during the chlorine disinfection process.
Current methods for the production of ClO2 in large quantities require extreme reaction conditions, hazardous reagents such as strong acids or oxidants, or an energy-intensive electrochemical process. ClO2 gas is highly unstable when high concentrations are reached in air, decomposing explosively into Cl2 and O2. Thus ClO2 gas is typically produced on-site, dissolved in cold water at low concentrations, and used immediately rather than transported. Safer, low-tech kits for the production of ClO2 are available only for small-scale production and typically require long wait periods.
The method developed by Professor John T. Groves at Princeton University utilizes the chemistry of a water-soluble manganese porphyrin catalyst to produce ClO2 from chlorite ions. The manganese porphyrin catalyst consumes chlorite ions, an undesirable byproduct in other methods producing ClO2. The catalyst is also active when immobilized on clay materials, allowing for facile recovery of the catalyst. The clay-immobilized catalyst could be used for the construction of flow systems which continually produce chlorine dioxide on a larger scale.
John T. Groves is the Hugh Stott Taylor Chair and Professor of the department of Chemistry at Princeton University. Professor Groves’ research efforts focus at the interface of organic, inorganic, and biological chemistry, and one major focus is the design and characterization of novel biomimetic catalysts. He received the Hans Fischer Award in Porphyrin Chemistry in 2010.
Intellectual property and technology status
Industrial collaborators are sought to further establish this opportunity as a green alternative for the purification of water and production of chlorine dioxide. The research in this area continues in the identification of more effective and economical catalysts.
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