CO₂ adsorption performance of polyethyleneimine-modified ion-exchange resin

ABSTRACT

A series of solid amine adsorbents were prepared by the template method with ion-exchange resin (D001) as the carrier and polyethyleneimine (PEI) as the modifier. The absorbents were characterized by energy disperse spectroscopy (EDS), scanning electron microscope (SEM), N₂ adsorption–desorption, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) techniques. The effects of PEI loading, adsorption temperature and influent velocities on CO₂ adsorption capacity in a fixed-bed reactor were investigated. The results show that the solid amine adsorbent prepared by the template method had a better PEI dispersion, stability and CO₂ adsorption capacity. The maximum CO₂ adsorption capacity was 3.98 mmol·g⁻¹ when PEI loading was 30%, the adsorption temperature was 65°C and the influent velocity was 40 mL·min⁻¹. The CO₂ adsorption capacity decreased only by 9.50% after 10 cycles of adsorption–desorption tests. The study of kinetics indicates that both chemical adsorption and physical adsorption occurred in the CO₂ adsorption process. The CO₂ adsorption process included fast breakthrough adsorption and gradually approaching equilibrium stage. The particle internal diffusion process was the control step for CO₂ adsorption.

KEYWORDS:

• Template method
• Ion-exchange resin
• Polyethyleneimine
• CO₂ adsorption

Funding

This work was supported by the Fundamental Research Funds for the Central Universities (2014XT05), the National Basic Research Program of China (2012CB214902) and the Specialized Research Fund for the Doctoral Program of Higher Education of China (20130095110004).