Composite catalyst filter, filtering system including the same, and method of preparing the composite catalyst filter
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Solution Overview
Problem
Existing air-purifying methods using adsorbents, oxidation catalysts, and photocatalysts face limitations such as secondary contamination, low efficiency, and limited activation due to moisture and light exposure, respectively.
Innovation Solution
A composite catalyst filter with a porous substrate coated with particles of photocatalysts, adsorbents, and oxidation catalysts, allowing for widespread catalyst activation and enhanced pollutant removal through simultaneous adsorption and photocatalytic oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If adsorbents with large specific areas are used to remove gaseous pollutants, then pollutant removal capacity is improved, but secondary contamination occurs and performance deteriorates rapidly in moist conditions
Solution Approach 1:
The patent combines adsorbents (activated carbon) with oxidation catalysts (Pt, Pd, Rh, Ru, Ir) and photocatalysts (TiO2, ZnO, ZnS, CdS, Fe2O3) to form a composite catalyst filter. This composite structure allows the adsorbent to capture pollutants while the catalysts decompose them, preventing secondary contamination and maintaining performance in humid conditions through synergistic action.
2Productivity
If oxidation catalyst is coated on honeycomb substrate surface, then pollutant removal is achieved through oxidation, but efficiency is low because only catalyst close to airflow participates in reaction
Solution Approach 1:
The patent uses a porous filter substrate with interconnected pores that allow airflow to penetrate throughout the entire catalyst layer. This porous structure enables oxygen and pollutants to reach catalyst particles deep within the substrate, ensuring uniform utilization of all catalyst material regardless of position, thereby dramatically improving overall catalytic efficiency.
3Productivity
If photocatalyst is used to remove pollutants through oxidation/reduction, then pollutant removal is achieved, but activation is limited to areas exposed to light
Solution Approach 1:
The patent merges oxidation catalysts and photocatalysts in a single composite filter structure. The oxidation catalysts provide immediate pollutant decomposition through chemical oxidation, while photocatalysts activate under light to provide additional oxidation/reduction pathways. This combination ensures comprehensive pollutant removal across the entire filter surface, regardless of light exposure variations.
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 composite catalyst filter significantly increases air pollutant removal rates by ensuring almost all catalyst particles participate in reactions, maintaining efficiency even in humid conditions and without the need for additional light activation.
Implementation Method 1
methods of using a photocatalyst (e.g.: TiO2) are being used to remove pollutants in the air by oxidation/reduction induced by electrons and holes generated by the photocatalyst upon receiving light with a predetermined amount of energy or more
Implementation Method 2
a method of using an oxidation catalyst is used to remove pollutants by oxidation occurring at contact sites between gases and an oxidation catalyst coated on a surface of a honeycomb substrate
Implementation Method 3
methods of adsorbing/removing gaseous pollutants by applying adsorbents having relatively large specific areas (e.g., activated carbon) to air-purifying filters
Data Source
AI summary
A composite catalyst filter includes a porous filter substrate, and particles of at least one type of catalyst on a surface of the porous filter substrate. The particles of the catalyst include particles of a photocatalyst, and particles of at least one type of adsorbent and oxidation catalyst.