Polybenzoxazine sorbents for CO2 capture

Abstract

Adsorption is a promising technique to capture CO2 from flue gases in post combustion. Nitrogen loading has been proposed to increase adsorption performance because the formation of carbamates by nitrogen bonded on the adsorbent surface. Polybenzoxazine (PBZ) is used in this study both as an impregnating material and as the porous adsorbent by carbonizing under nitrogen and activating by CO2. Two amines, diethylenetriamine (DETA), and pentaethylenehexamine (PEHA), were used in the synthesis of PBZ to investigate the effect of amine structure to the CO2 adsorption capacity. Various amine loadings on activated carbon and a number of PBZ activating conditions were studied to evaluate the CO2 adsorption performance. A gravimetric method was used to measure CO2 adsorption capacity and using characterization techniques such as surface area analyzer. FTIR and XPS. The results showed that the synthesis of benzoxazine and PBZ were successful. The CO2 adsorption capacity of impregnated adsorbents with PEHA - derived benzoxazine were higher than impregnated adsorbent with DETA – derived benzoxazine because PEHA contains more nitrogen functional groups and more chain length than DETA, however, both impregnating adsorbents perform lower CO2 adsorption capacity than the untreated activated carbon probably, due to pore blocking. The PBZ-derived activated carbon obtained by carbonizing at 300 ℃ and activating at 800 ℃ showed the highest CO2 adsorption capacity at 1.65 mmolCO2/g adsorbent-