Microwave-assisted pyrolysis derived biochar for volatile organic compounds treatment: Characteristics and adsorption...

Biochar derived from corn stalk doping with activated carbon was produced by microwave-assisted pyrolysis and applied to sorb volatile organic compounds (VOCs: benzene and o-xylene). Specific surface area (SSA), total pore volume (TPV) and micropore volume (MV) of microwave biochar increased with increasing microwave power with the maximum values 325.2 m²·g^-1, 0.181 mL·g^-1 and 0.1420 mL·g^-1, respectively. Adsorption capacities of benzene and o-xylene on microwave biochar ranged 6.82-54.75 mg·g^-1 and 7.43-48.73 mg·g^-1, which were separate positively related with SSA, TPV, and MV. Benzene adsorption was mainly dominated by surface interaction and partition mechanisms, while o-xylene adsorption was governed by pore filling. The adsorption capacities of microwave biochar for benzene and o-xylene decreased by only 0.30% and 0.99% on the 5th cycle that illustrated the reasonably good reusability of microwave biochar. The results of this research demonstrate that microwave biochar is a promising adsorbent for VOCs removal.