LAUSR

Abstract This paper comparatively studied the preparation of activated biochar from rice husk (RH) via one- and two-step KOH-catalyzed pyrolysis under the CO2 environment. The one-step pyrolysis can produce a higher yield of activated carbon compared to the two-step pyrolysis. Pore development in the biochar was significantly improved by the de-ashing process integrated with the KOH activation. Additionally, more pores with deep channels were formed on the surface of activated carbon via one-step pyrolysis due to the catalyzed oxidation of carbon structure in the precursor under CO2 environment. Therefore, one-step pyrolysis can produce a relatively higher SBET of biochar compared with two-step pyrolysis. Compared with the activated biochar via two-step pyrolysis, the activated biochar via one-step pyrolysis showed better performance on the phenol adsorption.