Polybenzoxazine-based carbon aerogels for Carbon dioxide capture

Abstract

Carbon aerogels developed from a new type of phenolic resin, called polybenzoazine, was considered to be used as an adsorbent for CO2 adsorption. application. In particular, phenol-based PBZs from two different types of amine precursors (ie., diethylenetriamine (DETA) and pentaethylenehexamine (PEHA) were synthesized by a sol-gel technique, followed by carbonization in nitrogen and activation with CO2. Several techniques such as FTIR, DSC, TGA, sorptomatic analyser, CHN, and XPS have been employed to characterize the textural properties, porosity, nitrogen content, and other adsorbent properties on the adsorption performance. The Co2 adsorption capacity of these adsorbents was measured using a simultaneous thermal analyzer (STA) at atmospheric pressure and adsorption temperatures of 40 °C, 75 °C, and 110 °C. The concentrations of benzoxazine monomer were varied at 30, 35, and 40 wt% in order to tune the surface properties of these porous PBZ aerogels. The effects of different amine chain lengths and loading PEG-PPG-PEG block copolymer as non-ionic surfactant on aerogel materials were investigated. The CO2 adsorption performance at all adsorption conditions of DETA-derived PBZ carbon aerogels performed higher than PEHA-derived PBZ carbon aerogels due to a larger surface area and a higher pore volume; moreover, both types of carbon aerogels exhibited higher CO2 adsorption capacity compared to those activated carbons from PBZ prepared by bulk polymerization. Furthermore, 30 wt% DETA-based carbon aerogel at activating temperature of 900 °C provided the highest CO2 uptake at 1.79 mmolco2/gadsorbent at adsorption condition of 40 °C and I bar.