Self-indicating colorimetric response materials for removal and sensing of toxic chemicals and narcotics
Inventors
Soliz, Jennifer R • Emge, Darren K • Pardoe, Ian J. • Peterson, Gregory W
Assignees
United States Department of the Army • Government of the United States of America
Publication Number
US-10732098-B1
Publication Date
2020-08-04
Expiration Date
2035-06-18
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Abstract
Processes, compositions, and sensors for sensing a variety of toxic chemicals based on colorimetric changes. Exemplary process for sensing a toxic chemical includes contacting a toxic chemical, or byproduct thereof, with a sorbent that includes a porous metal hydroxide or a porous mixed-metal oxide/hydroxide and a transition metal reactant suitable to react with a toxic chemical or byproduct thereof. The sorbent is contacted with the toxic chemical or byproduct thereof for a sampling time. A difference between a post-exposure colorimetric state of the sorbent and a pre-exposure colorimetric state of the sorbent is determined to thereby detect exposure to, or the presence of, the toxic chemical or byproduct thereof.
Core Innovation
The invention provides compositions, methods, and devices for sensing a variety of toxic chemicals via colorimetric changes using sorbents that include porous metal hydroxides or porous mixed-metal oxides/hydroxides combined with transition metal reactants capable of reacting with toxic chemicals or their byproducts. These sorbents undergo visible colorimetric state changes upon exposure, allowing detection of toxic chemicals in liquid, solid, and vapor/gas phases.
The invention addresses the need for improved detection and quantification of toxic chemicals, particularly acidic or acid-forming contaminants, that degrade the capacity of existing filtration media such as activated carbons. Existing end-of-service-life indicators (ESLIs) for filters have significant shortcomings including poor sensing of reactive gases and insufficient reactivity, leading to undetected degradation of filter effectiveness. The invention provides methods to monitor toxic chemical presence and filter residual life through colorimetric responses of the sorbent materials, thereby alerting users when filter replacement is necessary.
Claims Coverage
The patent includes one independent claim encompassing a chemical sensor with key inventive features related to sorbent composition and detection methods.
Sorbent composition with porous metal or mixed-metal oxides/hydroxides incorporating transition metal reactants
A sorbent comprising a porous metal oxide/hydroxide or porous mixed-metal oxide/hydroxide combined with a transition metal containing reactant configured to react with one or more toxic chemicals or their byproducts. The sorbent is applied as a film across a substrate surface.
Dual optical and electrical property changes upon toxic chemical binding
Detection of toxic chemical presence is achieved by measuring changes in both optical and electrical properties that occur when the toxic chemical binds to the sorbent film.
Specific metal oxide/hydroxide materials and defined metal ratios
The porous metal oxide/hydroxide can be selected from silicon-aluminum oxide/hydroxide, silicon-aluminum-titanium oxide/hydroxide, silicon-aluminum-titanium-phosphorus oxide/hydroxide with specified metal-to-metal ratio ranges, and other metal oxides/hydroxides such as zirconium, vanadium, iron, manganese, cobalt, copper, nickel, niobium, tantalum, molybdenum, tungsten, chromium, or mixtures thereof.
Transition metal reactants include specific salts and compounds
Transition metal reactants incorporated in the sorbent comprise salts, nitrates, sulfides, chlorides, oxides, or oxyhydroxides of cobalt, copper, iron, manganese, nickel, chromium, lanthanides, or mixtures thereof.
Diverse substrate materials for sorbent film deposition
The sorbent film may be fabricated, deposited, or spray-coated on substrates such as fabrics, stainless steel, glass, wood, cement, ceramic, graphite, asphalt, vehicle bodies, fiber optic cables, and insulating, semi-conducting, or conducting substrates.
Use of arrays of sorbents for multi-analyte detection
A plurality of such sorbents can be disposed as an array to detect or sense various toxic chemicals.
The independent claim covers a chemical sensor employing a sorbent film composed of porous metal oxides/hydroxides with transition metal reactants that exhibits measurable optical and electrical changes upon exposure to toxic chemicals, enabling versatile, sensitive detection across various substrate types and through arrays for multi-analyte detection.
Stated Advantages
Provides a sensitive and robust colorimetric response to a variety of toxic chemicals and their byproducts.
Enables real-time detection of toxic chemicals in liquid, solid, and vapor phases, including chemical warfare agents and narcotics.
Allows determination of residual life and end-of-service-life of filtration media through visually observable color changes.
Capable of integration into wearable sensors, films, and collective protection filters for continuous monitoring.
Facilitates rapid and reliable sensing, including quantification and identification of exposure to acidic/acid-forming and oxidizable gases.
Documented Applications
Use in films, wearable chemical sensors, and chemical detection devices for sensing toxic chemicals.
Incorporation into individual and collective protection filtration systems as end-of-service-life (ESLI) or residual life indicators (RLI).
Applications in catalysis, decontamination, sensing, detection, separations, and gas storage.
Use in optical, spectral, and electronic sensors for real-time toxic chemical detection.
Application as flexible colorimetric indicators for toxic gas leak confirmation.
Integration into substrates of various materials including fabrics, glass, steel, wood, cement, asphalt, and vehicle surfaces.
Military applications including camouflage with color-indicating materials.
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