Oxidative Magnetic Modification of Pristine Biochar Assisted by Ball-Milling for Removal of Methylene Blue and Tetracycline in Aqueous Solution

Magnetic modification holds a significant place for regulating the performance of biochar for wastewater treatment, endowing its magnetic separation property and facilitating its wide application. Herein, a ball-milled oxidative magnetic modification of pristine biochar was employed to manufacture magnetic biochar using K2FeO4as a precursor and internal oxidant for removal of methylene blue and tetracycline from aqueous solution. The characterizations showed that magnetic iron oxide and oxygen-containing groups were simultaneously introduced. Moreover, specific surface area and pore volume were remarkably enhanced from 0.7 m2/g to 71.2 m2/g and from 0.001 cm3/g to 0.034 cm3/g, respectively. The magnetic biochar showed that 133.76 mg/g and 58.34 mg/g adsorption capacities for MB and TC, respectively, significantly transcended the pristine biochar. Its adsorption was mainly dominated by oxygen-containing groups and iron species. This would provide an efficient oxidative magnetic modification for the preparation of oxygen-containing group-rich magnetic biochar for the removal of MB and TC.Keywords:ball-milling;oxidative magnetic modification;magnetic biochar;methylene blue;tetracycline