The biochar produced from pyrolysis of corn stove biogas fermentation residues was used for methylene blue adsorption in aqueous solution. The effects of fermentation time (0, 20,40 d) and the highest treatment temperature (HTT) from 400 to 600 °C on biochar properties and methylene blue adsorption characteristics were investigated. Biochar produced from corn stover was used as control. The result shows that biochar from fermentation residue got a higher yield, larger specific surface area, significantly more attachment particles and surface functional groups than that from corn stover. The specific surface area of biochar increased apparent with the increasing fermentation time of corn stover. However, the microporous specific surface (Smicro) decreased from 3.7558 to 1.9818 m2•g−1, while mesoporous specific surface (Smeso) increased from 1.9901 to 3.8994 m2•g−1. The methylene blue adsorption capacity increased with increasing pH value from 2 to 12. The maximum removal rate of methylene blue increased from 86.8 % to 98.64 % when the BC-F20 loading (produced at 400 °C) increased from 0.3 to 1.2 g, while the equilibrium adsorption capacity of methylene blue decreased from 28.94 to 8.22 mg/g. In addition, the adsorption capacity of biochar decreased as HTT increased from 400 to 600 °C. The results indicate that biochar derived from biogas fermentation residue has enhanced the absorption capacity for methylene blue in aqueous solution
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