Moisture swing co2 sorbents with enhanced capacity and kinetics
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Solution Overview
Problem
Existing direct air carbon dioxide capture technologies face high costs and energy consumption due to limitations in second law efficiencies, large temperature swings, competitive adsorption with water, and oxidative degradation of sorbents, particularly in moisture swing adsorption processes with small surface areas and slow mass transfer kinetics.
Innovation Solution
Development of a porous cross-linked polymer network with quaternary ammonium ions and controlled polymerization methods to enhance surface area, mesoporosity, and qAm group proximity, enabling efficient CO2 capture and desorption through moisture swing adsorption processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If moisture swing adsorption uses solid sorbents with quaternary ammonium, then oxidation resistance and lifetime are improved, but specific surface area is reduced to less than 1 m2/g
Solution Approach 1:
The patent employs highly porous materials with specific surface areas exceeding 100 m2/g, utilizing controlled pore sizes and distributions to maintain both high surface area and quaternary ammonium functionality. The porous structure allows sufficient exposure of qAm groups while preventing aggregation that would reduce effective surface area.
Solution Approach 2:
The invention uses composite materials combining quaternary ammonium functional groups with high-surface-area porous supports, creating a hybrid structure that leverages the oxidation resistance of qAm groups while utilizing the high surface area of the porous support material to overcome the surface area limitation of traditional MSA sorbents.
2Reliability
If temperature swing adsorption uses liquid or solid chemi- or physisorbents, then CO2 capture selectivity is improved, but energy consumption increases to 170-570 kJ/mol CO2
Solution Approach 1:
The patent changes the operating parameter from temperature swing to moisture swing, utilizing humidity variations instead of temperature changes to drive adsorption and desorption cycles. This approach maintains CO2 capture selectivity through qAm group chemistry while significantly reducing energy consumption by avoiding large temperature swings and associated sensible heat loads.
Solution Approach 2:
The invention substitutes the thermal field (temperature-based TSA) with a moisture field (humidity-based MSA), replacing the need for energy-intensive heating and cooling cycles with a moisture-driven process that achieves similar separation performance at much lower energy input.
3Quantity of substance
If temperature swing adsorption uses large temperature swings for selective CO2 uptake, then CO2 capture capacity is improved, but parasitic sensible heat loads reduce second law efficiencies to 4-12 percent
Solution Approach 1:
The patent changes the driving parameter from temperature to moisture content, eliminating the need for large temperature swings. The qAm groups selectively capture CO2 through chemical interaction with water molecules in the gas phase, maintaining capture capacity while avoiding the parasitic sensible heat loads associated with heating and cooling the entire sorbent mass.
4Quantity of substance
If direct air capture is performed at dilute ambient concentrations, then CO2 capture from air is achieved, but competitive adsorption between CO2 and water reduces efficiency
Solution Approach 1:
The patent converts the typically harmful effect of water vapor (which competes with CO2 for adsorption sites) into a beneficial component by utilizing water molecules as part of the CO2 capture mechanism. The quaternary ammonium groups interact with water-CO2 complexes, effectively using the presence of water to enhance rather than hinder CO2 capture at ambient conditions.
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 sorbent achieves high CO2 capture capacity, rapid mass transfer, and improved degradation resistance, reducing energy consumption and costs by optimizing surface area and qAm group distribution, resulting in efficient CO2 capture and desorption.
Implementation Method 1
employing a sorbent comprising a quaternary ammonium ions in a porous cross-linked polymer network in an environment to adsorb CO2
Implementation Method 2
Moisture swing adsorption represents one approach for direct air capture (DAC) that overcomes the limitations of TSA
Implementation Method 3
at least one counter ion in the cross-linked polymer network that is at least one of hydroxide or a counter ion capable of forming hydroxide upon reaction with water
Data Source
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AI summary
A composition of matter having a porous cross-linked polymer network, quaternary ammonium ions in the cross-linked polymer network, and at least one counter ion in the cross-linked polymer network that is at least one of hydroxide or a counter ion capable of forming hydroxide upon reaction with water. A method to produce a porous material includes polymerizing a compound containing quaternary ammonium and a cross-linker using controlled polymerization and ion exchange in the presence of at least one of hydroxide or a counter ion capable of forming hydroxide upon reaction with water. A method to capture CO2, includes employing a sorbent comprising a quaternary ammonium ions in a porous cross-linked polymer network in an environment to adsorb CO2.