Porous Carbon With Mesopores and Micropores for High-Humidity Adsorption
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Solution Overview
Problem
Current adsorbents, such as activated carbons and silica gels, fail to sufficiently adsorb water vapor on a high humidity side, which is necessary for applications like heat pumps and humidity control, due to insufficient adsorption performance and desorption rates.
Innovation Solution
A porous carbon material with a water vapor adsorbed amount ratio of 1.8 or higher, comprising mesopores and micropores, is developed by mixing a polyamic acid resin with magnesium oxide and heat-treating the mixture, resulting in a structure capable of effectively adsorbing water vapor at high humidity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If activated carbons or silica gels are used as adsorbents, then they are readily available and easy to manufacture, but they cannot sufficiently adsorb water vapor on a high humidity side
Solution Approach 1:
The patent changes the pore size distribution parameter of the adsorbent material. Specifically, it controls the pore size to be 0.003 μm to 0.05 μm (3 nm to 50 nm) with a pore volume of 0.2 mL/g to 2.0 mL/g, and sets the water vapor adsorbed amount ratio at 70% RH to 90% RH to be 1.05 or more. These parameter optimizations enable sufficient water vapor adsorption on the high humidity side while maintaining material availability.
Solution Approach 2:
The patent creates a composite porous structure by combining carbon materials with specific pore characteristics. The composite structure integrates micropores and mesopores in specific proportions, with the pore size distribution and volume ratios optimized to enhance water vapor adsorption capacity at high humidity conditions while maintaining chemical stability.
2Quantity of substance
If the pore volume is increased to enhance adsorption capacity, then more water vapor can be adsorbed, but the adsorption and desorption rates may decrease
Solution Approach 1:
The patent optimizes the pore size parameter to 0.003 μm to 0.05 μm (3 nm to 50 nm) and controls the pore volume to 0.2 mL/g to 2.0 mL/g. This specific parameter range allows sufficient adsorption capacity while maintaining fast adsorption and desorption rates, resolving the contradiction between quantity and productivity.
Solution Approach 2:
The patent creates different pore quality zones within the material structure. It distributes micropores and mesopores in specific proportions throughout the adsorbent, with local pore density and size variations that optimize both adsorption capacity and mass transfer rates, enabling high productivity alongside high adsorption capacity.
3Reliability
If the adsorbent is exposed to high temperatures for heat pump applications, then it must maintain chemical stability, but common adsorbents fail to meet the required adsorption performance
Solution Approach 1:
The patent develops a composite porous carbon material with optimized pore structure that combines chemical stability at high temperatures with enhanced water vapor adsorption capacity. The composite structure maintains structural integrity under thermal stress while the controlled pore distribution ensures sufficient adsorption performance, meeting both reliability and quantity requirements.
Solution Approach 2:
The patent optimizes the pore size parameter to 0.003 μm to 0.05 μm and pore volume to 0.2 mL/g to 2.0 mL/g, which enables the material to maintain both chemical stability at high temperatures and sufficient water vapor adsorption capacity, resolving the contradiction between thermal reliability and adsorption quantity.
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 porous carbon exhibits significant water vapor adsorption capacity at high humidity, ensuring sufficient adsorption and control, with a water vapor adsorbed amount ratio of 2.0 or higher, and a mesopore volume of 0.9 mL/g to 2.0 mL/g, enhancing its performance as an adsorbent in humidity control and heat pump applications.
Implementation Method 1
a porous carbon that can sufficiently adsorb water vapor on a high humidity side
Data Source
Figure 1(a)~1(c)
Figure 2
AI summary
A porous carbon that can sufficiently adsorb water vapor on a high humidity side is provided. A porous carbon is characterized by having mesopores and micropores and having a water vapor adsorbed amount ratio, as defined by the following expression (1), of 1.8 or higher. It is particularly preferable that the water vapor adsorbed amount ratio as defined by the following expression (1) be 2.0 or higher. It is also preferable that the water vapor adsorbed amount at a relative humidity of 70% be 50 mg/g or greater. Water vapor adsorbed amount ratio=water vapor adsorbed amount at a relative humidity of90%/water vapor adsorbed amount at a relative humidity of70%.