The Application of Biochar for CO2 Capture: Influence of Biochar Preparation and CO2 Capture Reactors

Abstract

This work investigates three types of biochar (bamboo charcoal, wood pellet, and coconut shell) for postcombustion carbon capture. Each biochar is structurally modified through physical (H₂O, CO₂) and chemical (ZnCl₂, KOH, H₃PO₄) activation to improve carbon capture performance. Three methods (CO₂ adsorption isotherms, CO₂ fixed-bed adsorption, and thermogravimetric analysis) are used to determine the CO₂ adsorption capacity. The results show that a more than 2.35 mmol·g^-1 (1 bar, 298 K) CO₂ capture capacity was achieved using the activated biochar samples. It is also demonstrated that the CO₂ capture performance by biochar depends on multiple surface and textural properties. A high surface area and pore volume of biochar resulted in an enhanced CO₂ capture capacity. Furthermore, the O*/C ratio and pore width show a negative correlation with the CO₂ capture capacity of biochars.