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.