Removal of fluconazole from aqueous solution by magnetic biochar treated by ball milling: adsorption performance and mechanism.

The problem of low adsorption capacity of pristine magnetic biochar for organic pollutants always occurs. It is of great significance to select a suitable method to improve the adsorption performance of magnetic biochar. In this study, magnetic biochar was treated by ball milling and tested for its fluconazole adsorption capacity. The maximum adsorption capacity of ball-milled magnetic biochar (BMBC) for fluconazole reached nearly 15.90 mg/g, which was approximately five times higher than that of pristine magnetic biochar (MBC). Fluconazole adsorption by BMBC was mainly attributed to π-π interactions, hydrogen bonding, and surface complexation with oxygen-containing functional groups. The enhancement in fluconazole adsorption by BMBC was attributed to an increase in oxygen-containing functional groups. Batch adsorption experiments also illustrated that BMBC could be successfully applied in a wide range of pH values. The high efficiency of fluconazole removal confirmed that ball milling was an effective strategy to enhance the adsorptive performance of magnetic biochar.