Critical impacts of pyrolysis conditions and activation methods on application-oriented production of wood waste-derived biochar. (December 2021) - He, Mingjing
Graphical abstract: Highlights: Co-impacts of pyrolysis conditions and activation methods on biochar were studied. Pyrolysis temperature was the most influential factor on biochar properties. 750 ℃ was the critical temperature for wood-based biochar to form porous structure. Steam-activated biochar pyrolyzed at 850 ℃ displayed the highest mesopores formation. Fit-for-purpose biochar production is critical for its commercial/environmental benefits. Abstract: Wood waste-derived biochar with tunable carbon structure and surface functionality has a great potential for various environmental applications and circular economy; however, a holistic understanding on the application-oriented production of high-efficacy biochar is lacking. Thus, the co-impacts of different pyrolysis conditions (temperature and duration) and activation methods (steam, CO2, and acid pretreatment) on the biochar properties were first investigated. A temperature of 650 ℃ was effective in forming carbonized structure in biochar, while 750 ℃ was critical for the porous structure development. A longer pyrolysis duration (>60 min) enhanced the pore volume without compromising the yield. The activated biochar exhibited a larger pore volume (2.1- to 2.9-fold of pristine biochar) for potential high-end emerging applications. The acid pretreatment effectively removed dissolved organic carbon and most metals from the biochar. This study provides an essential guidance on the fit-for-purpose designs of biochar production conditions for sustainable wood waste management.