Polyethylenimine-Based Solid Sorbents for CO2 Adsorption: Performance and Secondary Porosity

Abstract

The series of polyethylenimine (PEI)-based solid sorbents were prepared by the wet-impregnation of PEI (Mw = 600) on the surface of six porous materials, i.e., mesoporous silicas (MCM-41, SBA-15, and KIT-6), mesoporous carbon (CMK-3), protonated titanate nanotube (PTNT), and fumed silica (FS). The resultant materials, denominated PEI/supports, were characterized by N2 adsorption/desorption at 77 K, mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). CO2 adsorption on the PEI/supports was evaluated using 2 vol % CO2 in flowing air on a self-assembled fixed bed reactor. The observations made here show that relative to the other four sorbent counterparts, PEI/PTNT and PEI/FS exhibit better performance of CO2 adsorption, mainly attributed to their more abundant secondary macropores, together with more homogeneous PEI surface dispersion. For all the PEI/supports, the adsorption data of CO2 at vario...