Epoxide-Modified Diethylenetriamine for Ambient-Temperature Direct Air Capture

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Small amine-based materials are promising for direct air capture (DAC) of CO2.
• These materials face challenges including evaporation, degradation, and high regeneration temperatures (80-120 °C).

Purpose of the Study:

• To improve the stability and energy efficiency of small amine-based CO2 capture materials.
• To enable ambient temperature regeneration for direct air capture applications.

Main Methods:

• Controlled epoxide functionalization of diethylenetriamine (DETA) using 1,2-epoxybutane at various stoichiometric ratios.
• Characterization of material properties, including molecular weight, thermal stability, oxidative resistance, and CO2 adsorption/desorption kinetics.
• Testing of CO2 capture performance under ambient air conditions and evaluation of long-term cycling stability.

Main Results:

• Functionalized DETA showed enhanced thermal stability and oxidative resistance compared to unmodified DETA.
• Materials exhibited fast CO2 adsorption rates (1.03-1.28 mmol/g/h) and rapid desorption at ambient temperature (66% regeneration in 1 h at 30 °C).
• Optimized material retained 97.8% capacity after oxidative stress and demonstrated stable cycling over 50 cycles with minimal capacity loss.

Conclusions:

• Facile modification of small amines with 1,2-epoxybutane effectively enhances stability and enables energy-efficient CO2 capture.
• This approach addresses evaporative losses and oxidative degradation, facilitating scalable production of improved DAC materials.
• Ambient temperature regeneration achieved through this modification significantly reduces the energy penalty for CO2 capture.