Amine-Appended Hyper-Crosslinked Polymers for Direct Air Capture of CO₂.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Direct air capture (DAC) is crucial for climate change mitigation.
• Efficient, scalable, low-cost adsorbents are needed for DAC.
• Understanding adsorbent structure-performance relationships is key for optimization.

Purpose of the Study:

• Synthesize novel hyper-crosslinked polymers (HCPs) for CO2 capture.
• Investigate the impact of synthesis conditions on pore structure and CO2 uptake.
• Evaluate CO2 sorption kinetics and compare with existing adsorbents.

Main Methods:

• Grafting a microporous support with diethylenetriamine to create HCPs.
• Varying polymerization duration to control pore structure.
• Assessing CO2 uptake at 400 ppm and sorption kinetics using gravimetric analysis.

Main Results:

• Shorter polymerization times yielded higher accessible micropore volume and increased CO2 uptake.
• The best HCP sample showed an equilibrium uptake of 0.43 mmol/g.
• The synthesized adsorbent exhibited a CO2 sorption rate 5.5 times faster than benchmark Lewatit VP OC 1065.

Conclusions:

• Synthesis conditions significantly influence pore structure and adsorption properties of porous polymers.
• Optimizing pore structure is vital for enhancing both CO2 uptake capacity and kinetics.
• This work provides a foundation for designing improved and faster DAC adsorbents.