Synthesis of polyethylenimine-impregnated titanate nanotubes for CO2 capture: Influence of porosity and nitrogen content on amine-modified adsorbents

Abstract

Amine-modified adsorbents have been of interest due to their excellent performance for carbon dioxide (CO2) capture. In this work, we have prepared titanate nanotubes (TNTs) with amine modification using polyethylenimine (PEI) for selective CO2 capture under flue gas. TNTs were prepared by the hydrothermal reaction, and PEI-functionalized TNTs (P-TNTs) were prepared by the wet impregnation method. Enhanced CO2 affinity through amine modification on TNTs allows for selective and favorable CO2 adsorption onto adsorbents. To confirm the CO2 capture in the post-combustion step, CO2 adsorption performances were investigated by the gravimetric method under 15% CO2 /85% N2 (binary) and 15% CO2/5% O2/80% N2 (ternary) gases as in flue gas conditions, respectively. Furthermore, our work provides evidence that the amine-modified adsorbents can be influenced by oxygen gas on CO2 capture performances, including regeneration ability.