Microporous Silica Aerogel for Low-Energy CO2 Capture
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Solution Overview
Problem
Existing CO2 capture technologies using liquid and solid sorbents face challenges such as high regeneration energy requirements, corrosion, evaporation, and high synthesis costs, along with issues of thermal instability and chemical degradation.
Innovation Solution
Development of a silica-based microporous aerogel with tailored properties for selective CO2 absorption, capable of capturing CO2 from low concentration gaseous streams, and regenerating for reuse, using a one-pot synthesis process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid alkaline solutions are used for CO2 capture, then CO2 uptake rate is improved, but regeneration energy requirements increase and corrosion/evaporation issues occur
Solution Approach 1:
The patent changes the physical state of the sorbent from liquid to solid aerogel material, and modifies the chemical functionality to be amine-based rather than alkaline. This parameter change maintains high CO2 uptake rates while eliminating the need for high-energy regeneration and avoiding corrosion/evaporation problems associated with liquid alkaline solutions.
Solution Approach 2:
The patent creates a composite aerogel material combining amine functional groups with porous silica or organic framework structures. This composite approach provides both high CO2 affinity (from amine groups) and structural stability (from the aerogel matrix), achieving high productivity with lower regeneration energy compared to liquid alkaline solutions.
2Use of energy by moving object
If solid sorbents such as amine-functionalized silica and MOFs are used, then regeneration energy is reduced, but synthesis costs increase and thermal instability occurs
Solution Approach 1:
The patent optimizes the thermal stability parameter by selecting appropriate aerogel substrates (silica-based or organic frameworks) and controlling the amine functionalization degree. This allows the material to maintain structural integrity at regeneration temperatures while achieving low regeneration energy through the inherent thermal stability of the aerogel matrix.
Solution Approach 2:
The patent utilizes the porous structure of aerogels (with controlled pore sizes and high surface area) to provide thermal stability and mechanical strength. The porous framework acts as a stable matrix that can withstand regeneration conditions while maintaining the functional amine groups for CO2 capture, thus improving reliability without increasing synthesis complexity.
3Quantity of substance
If existing solid sorbents are used, then CO2 capture capacity is improved, but device complexity increases due to multistep operations
Solution Approach 1:
The patent designs the aerogel sorbent to be ready-for-use after simple activation, eliminating the need for complex multistep operations like extractions, filtrations, and washings required by other solid sorbents. The aerogel's porous structure and functional groups are pre-configured to directly capture CO2, making the system self-sufficient and simplifying the overall device operation.
4Manufacturing precision
If aerogel pore size is reduced to enhance CO2 selectivity, then CO2 selectivity is improved, but mass transfer resistance increases
Solution Approach 1:
The patent applies local quality by creating a hierarchical pore structure with different pore size ranges (micropores for selectivity and mesopores for mass transfer). The micropores (<2 nm) provide CO2 selectivity through size exclusion and adsorption, while the interconnected mesopores maintain open channels for rapid gas transport, thus simultaneously achieving high selectivity and fast mass transfer without compromising either parameter.
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 silica-based aerogel effectively captures CO2 from environments with concentrations as low as 0.04 vol.%, achieving adsorption efficiencies of at least 0.47 mmol/g and enabling continuous recycling with minimal performance loss, suitable for industrial applications and direct air capture.
Implementation Method 1
The silica-based aerogel composition can be tailored to provide control and selectivity over the CO2 absorption efficiency. In particular, the silica-based aerogels can capture CO2 from a low CO2 concentration gaseous stream by absorbing CO2 within the aerogel
Implementation Method 2
The absorbed CO2 can then be collected from the silica-based aerogel, and the regenerated silica-based aerogel can be reused to absorb more CO2 (e.g. recycled, continuously cycled)
Data Source
AI summary
The present disclosure generally relates to a microporous aerogel, processes for preparing a microporous aerogel, and applications for the microporous aerogel. The present disclosure also generally relates to an apparatus for capturing carbon dioxide from a gaseous stream or from the atmosphere, the apparatus comprising a microporous aerogel for selectively adsorbing and desorbing the carbon dioxide.