Activated Carbon Filter Pore Structure for Vapor-Phase Smoke Removal
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Solution Overview
Problem
Existing activated carbon filters for smoking articles are inadequate in effectively removing vapor phase components such as carbonyls and volatile organic compounds (VOCs), and they contribute to taste and aroma intensity and irritation.
Innovation Solution
Activated carbon with a specific pore structure comprising micropores (less than 2 nm), mesopores (2-50 nm), and macropores (more than 50 nm) in defined ratios and volumes, along with a BET specific surface area of 2,000 m2/g or more, is used to create a filter that enhances removal of vapor phase components while reducing taste and aroma intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If activated carbon is used to remove vapor phase components, then the removal ability is improved, but taste and aroma intensity and irritation increase
Solution Approach 1:
The patent applies porous materials by precisely controlling the pore structure of activated carbon, including micropore volume (0.8-1.1 cm³/g), mesopore volume (0.2-0.4 cm³/g), and macropore volume (0.01-0.10 cm³/g), along with specific pore diameter distributions. This optimized porous structure enables selective adsorption of vapor phase components while preserving desirable taste and aroma compounds, thereby resolving the contradiction between removal efficiency and sensory quality.
Solution Approach 2:
The patent employs parameter changes by optimizing multiple critical parameters of activated carbon: BET specific surface area (2,000 m²/g or more), micropore ratio (70-80 vol%), mesopore ratio (15-25 vol%), and macropore ratio (1-5 vol%). By systematically adjusting these parameters within specific ranges, the patent achieves both effective vapor phase component removal and maintained taste/aroma quality, resolving the technical contradiction.
2Reliability
If micropore volume is increased to enhance adsorption capacity, then vapor phase component removal is improved, but pore accessibility and mass transfer may be reduced
Solution Approach 1:
The patent applies segmentation by dividing the pore structure into three distinct size categories: micropores (<2 nm) for high-capacity adsorption, mesopores (2-50 nm) for mass transfer, and macropores (>50 nm) for accessibility. This segmented pore structure allows each pore type to fulfill its specific function, resolving the contradiction between adsorption capacity and mass transfer efficiency.
Solution Approach 2:
The patent applies local quality by assigning different functional roles to different pore size regions within the activated carbon structure. Micropores provide high adsorption capacity for vapor phase components, while mesopores and macropores provide pathways for mass transfer and accessibility. This local functional differentiation resolves the contradiction between capacity and productivity.
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 activated carbon filter effectively removes carbonyls and VOCs, reducing their intensity and irritation in smoking articles, achieving low component levels of 30 μg/cig or less for carbonyls and 15 μg/cig or less for VOCs.
Implementation Method 1
activated carbon is widely used to remove vapor phase components and also used in tobacco filters to reduce vapor phase components in tobacco smoke
Data Source
AI summary
Disclosed is activated carbon having an excellent ability to remove vapor phase components. According to one aspect, there is provided activated carbon including a micropore having a pore diameter of less than 2 nm, wherein a ratio of the micropores is from 70 vol % to 80 vol % based on a total pore volume of the activated carbon, and the activated carbon has a BET specific surface area of 2,000 m2/g or more.