Air permeable substrate structure
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Solution Overview
Problem
Existing methods for producing purified hydrogen peroxide gas (PHPG) face challenges such as the production of hydrated forms of hydrogen peroxide, safety issues due to high concentrations, and inhibition by reactive species in photocatalytic plasmas.
Innovation Solution
The development of a device that uses an air-permeable substrate structure with a catalyst surface, combined with a source of ultraviolet light, to produce non-hydrated PHPG by controlling airflow and humidity levels, thereby minimizing the residence time of hydrogen peroxide and avoiding ozone production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If vaporized aqueous solutions of hydrogen peroxide are used, then hydrogen peroxide can be produced in gas phase, but the hydrogen peroxide molecules become hydrated and their ability to interact with environment is greatly attenuated
Solution Approach 1:
The invention changes the physical and chemical parameters of hydrogen peroxide production by using photocatalytic oxidation of water vapor instead of vaporizing aqueous solutions. This produces non-hydrated hydrogen peroxide gas molecules that maintain their electrostatic interaction capabilities with the environment, directly resolving the hydration problem.
Solution Approach 2:
The invention replaces the mechanical heating/vaporization process with a photocatalytic chemical process. Instead of thermally vaporizing water and hydrogen peroxide (which creates hydration), UV light activates a photocatalyst to oxidize water vapor directly into non-hydrated hydrogen peroxide gas, eliminating the harmful hydration effect.
2Quantity of substance
If vaporized hydrogen peroxide solutions are used, then gas phase hydrogen peroxide is produced, but the concentration is above OSHA safety limits making it unsuitable for occupied areas
Solution Approach 1:
The invention changes the production method to achieve much lower concentrations (parts per billion range) compared to vaporization methods. The photocatalytic process produces hydrogen peroxide at controlled, safe levels that are effective for environmental disinfection while remaining well below OSHA safety limits.
Solution Approach 2:
The invention produces hydrogen peroxide in-situ through photocatalytic oxidation rather than introducing pre-concentrated vapor. This creates a continuous, low-level generation of hydrogen peroxide that maintains effective disinfection concentrations without reaching hazardous levels.
3Productivity
If photocatalytic plasma is used to generate reactive species, then hydrogen peroxide can be produced, but reactive species destroy hydrogen peroxide and inhibit its production
Solution Approach 1:
The invention extracts only the beneficial hydrogen peroxide production aspect of photocatalysis while eliminating the harmful reactive plasma species. By using a photocatalyst-coated substrate with controlled water vapor exposure, the system produces hydrogen peroxide without generating the destructive plasma environment.
Solution Approach 2:
The invention converts the photocatalytic reaction to produce exclusively hydrogen peroxide without generating destructive reactive species. The photocatalyst surface facilitates water oxidation to form hydrogen peroxide directly, turning the potential harm of reactive species into the benefit of selective hydrogen peroxide production.
4Object-affected harmful factors
If organic gases are introduced into photocatalytic plasma, then organic pollutants can be degraded, but hydrogen peroxide production is inhibited by direct reaction and oxidized products
Solution Approach 1:
The invention segments the functions into separate stages: first, photocatalytic oxidation of water vapor produces hydrogen peroxide on the substrate surface; second, the hydrogen peroxide is released into the environment to degrade organic pollutants. This separation prevents organic gases from interfering with hydrogen peroxide production while still achieving pollutant removal.
Solution Approach 2:
The invention uses hydrogen peroxide as an intermediary substance produced by photocatalysis. Instead of using reactive plasma species that destroy hydrogen peroxide, the system generates stable hydrogen peroxide molecules that then serve as the active agent for degrading organic pollutants in the environment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively produces a steady state concentration of PHPG at levels of at least 0.005 ppm in a closed air volume, while maintaining low ozone levels and minimizing the degradation of hydrogen peroxide.
Implementation Method 1
Photocatalysts that have been demonstrated for the destruction of organic pollutants in fluid include but are not limited to TiO2, ZnO, SnO2, WO3, CdS, ZrO2, SB2O4, and Fe2O3. Titanium dioxide is chemically stable, has a suitable bandgap for UV/Visible photoactivation
Implementation Method 2
Light in the ultraviolet range emits photons at a frequency that when absorbed has sufficient energy to break chemical bonds. UV light at wavelengths of 250-255 nm is routinely used as a biocide
Implementation Method 3
an air-permeable substrate structure having a catalyst on its surface... wherein the airflow is through the air-permeable substrate structure
Implementation Method 4
air-permeable substrate structure... mesh having a percentage of open area of between 20% and 60%
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
The present disclosure provides for and includes improved devices and methods for the production of purified hydrogen peroxide gas (PHPG) that is substantially non-hydrated and substantially free of ozone.