Light-activated chlorine dioxide-releasing powder and method of manufacture
Inventors
Barenberg, Sumner • Cameron, Robert • Tian, Xiao
Assignees
Publication Number
US-11957805-B2
Publication Date
2024-04-16
Expiration Date
2042-02-22
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Abstract
Methods of manufacturing a light-activated powder are provided which provide solid-state generation and release of chlorine dioxide without detectable amounts of any toxic by-products such as chlorine gas, chlorites, or chlorates. The powder need not be exposed to moisture, relative humidity, or an acid before or during exposure of the powder to visible light to generate the gas. The powder can also be prepared under conditions that minimize or prevent decomposition or oxidation of sodium chlorite or premature light activation of the powder during the manufacturing process to maximize its activity.
Core Innovation
The invention provides methods of manufacturing a light-activated powder capable of solid-state generation and release of chlorine dioxide without the production of detectable amounts of toxic by-products such as chlorine gas, chlorites, or chlorates. The process consists of forming an aqueous suspension of a light-activated catalyst, a base, and sodium chlorite (with sodium chlorite of 85–99% purity), followed by spray-drying at high temperatures (inlet 482–537° C., outlet up to 143° C.) in darkness to yield the powder.
The resulting powder can generate and release chlorine dioxide gas when exposed to visible light, without requiring exposure to moisture, relative humidity, or an acid before or during light exposure. The method of manufacture is designed to minimize or prevent sodium chlorite decomposition or premature activation, thus maximizing the powder's activity and gas-generating efficacy.
This powder and its manufacturing method address the need for a chlorine dioxide-generating process that does not produce harmful by-products and that operates effectively without the addition of moisture or acid, overcoming the limitations of conventional products and providing an alternative to ethylene oxide-based sterilization processes.
Claims Coverage
There is one independent claim, and its inventive features are outlined below.
Method for making a light-activated powder for solid-state controlled release of chlorine dioxide
The method comprises: - Admixing a light-activated catalyst, a base, sodium chlorite (85–99% purity), and water to form an aqueous suspension. - Spray-drying the suspension at an inlet temperature of about 482 to 537° C. and an outlet temperature of not more than 143° C. to form a powder. - Ensuring the powder does not include sources of moisture that could initiate chlorine dioxide release. - Performing the admixing and spray-drying steps in darkness. - Providing that, when exposed to visible light, the powder generates solid-state controlled release of chlorine dioxide in an amount effective for disinfection, without release of detectable amounts of chlorine gas, chlorates, and/or chlorites.
The inventive features focus on the high-temperature, moisture-free, light-activated manufacturing method for powders capable of on-demand chlorine dioxide release without toxic by-products.
Stated Advantages
Enables solid-state generation and release of chlorine dioxide without detectable amounts of toxic by-products such as chlorine gas, chlorites, or chlorates.
Eliminates the need for exposure to moisture, relative humidity, or acid before or during light-induced gas generation.
Allows manufacturing conditions that minimize or prevent sodium chlorite decomposition or premature light activation, maximizing powder activity.
Provides an alternative to ethylene oxide sterilization with less impact on the environment and public health.
Offers a process that generates chlorine dioxide effective for disinfection, sanitation, and sterilization.
Can be incorporated into a variety of materials and products due to thermal stability of the powder.
Effective for disinfecting electronics without causing corrosion, since the released chlorine dioxide is dry.
Effective against a range of biological contaminants, including bacteria, viruses such as SARS-COV-2 and its variants, mold, and fungi.
Documented Applications
Use in disinfection, sanitation, and sterilization, including control of biological or pathogenic contamination.
Replacement of ethylene oxide in sterilizing medical devices and products.
Incorporation into molded, extruded, or formed products such as films, fibers, coatings, tablets, resins, polymers, plastics, and membranes.
Preparation of injection-molded, compression-molded, thermo-formed, or extrusion-formed products by compounding and pelletizing with polymers or waxes.
Manufacture of multilayered composites or packaging films for generating and retaining gas within a package for medical supplies or food.
Retarding, killing, preventing, or controlling microbiological contamination or biochemical decomposition on surfaces, within materials, or in surrounding atmospheres.
Decontamination of medical waste, personal protective equipment, and other equipment in bags or containers, including 'red bags.'
Disinfection of electronics in dry conditions without corrosion risk.
Deodorizing surfaces or atmospheres, and enhancing freshness of materials.
Controlling chemotactic attraction of organisms to materials.
Impregnation into containers for food, soap, laundry detergent, documents, clothing, paint, seeds, medical instruments, personal care products, waste, shoes, or other articles.
Use in packets or sachets within storage containers to provide a chlorine dioxide micro-atmosphere.
Incorporation into paper or polymeric items such as mats, shoe inserts, bandages, cutting boards, food wrappers, packaging trays, seed packets, and air filters.
Inclusion in desiccant powders for moisture removal, foot powders, bath powders, powders for carpet, or other surface treatments.
Use in animal feed to reduce bacterial load in the intestines of animals consuming treated feed.
Providing deodorization and freshness enhancement in packaging for food, medical supplies, or refrigerated materials.
Deactivation of biological contaminants following biowarfare events, such as anthrax exposure.
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