Effects of temperature, oxygen and steam on pore structure characteristics of coconut husk activated carbon powders prepared by one-step rapid pyrolysis activation process

Abstract

Activated carbon powders made from coconut husk (CHCs) were prepared by one-step rapid pyrolysis activation process. Effects of temperature, oxygen and steam on the pore structure of CHCs were investigated. Results showed that high temperature, oxygen and steam all motivated the development of the CHCs pore structure. High temperature accelerated the evaporation of volatiles and led to more micropore structures. Oxygen promoted the development of both micropores and mesopores. CHCs’ porosity separately presented a linear and a logarithmic growth with the increase of the preparation temperature and oxygen content. CHCs prepared under 1000 ℃ with activation agents of 6% oxygen and 20% steam exhibited the largest specific surface area and total pore volume of 415.85 m2/g and 0.1748 cm3/g. Steam can diffuse into the CHC matrix and enhance the formation of more mesopores. Steam over 20% would over-burn the substance and lead to the collapse of some pore structures.