Research progress on synthesis mechanism and performance evaluation of ball milling biochar-iron based materials

Biochar-iron based material has been recognized as an important soil and underground water remediation material, which successfully achieves by adsorption, reduction, and mediating advanced oxidation. In recent years, the use of ball milling to synthesize biochar-iron based materials has become an emerging and promising method due to its low cost, environmental friendliness, and potential for large-scale production. This article presents an overview of the fundamental principles underlying ball milling technology, encompassing aspects such as ball milling pre-treatment, biochar pyrolysis temperature, ball milling speed, milling time, ball-to-material ratio, milling atmosphere, and other parameters that exert a substantial influence on material properties. Additionally, it summarized the potential governing rules associated with these parameters. The performance variances resulting from ball milling pre-treatment and biochar pyrolysis temperatures were highlighted. The specific performance of ball milling in improving the physical/chemical properties of biochar-iron based materials was summarized respectively. Explaining the respective roles and functions of biochar and iron-based materials in eliminating various pollutants during the physical/chemical adsorption, chemical reduction, and catalytic oxidation. It is pointed out in the outlook that although ball milling has been frequently reported in research, its underlying effect mechanism remains a subject of challenge. While previous studies have demonstrated the versatility of ball milling, there is still a need to actively explore their application in meeting diverse environmental restoration requirements. Ultimately, both ball milling technology and biochar-iron based materials hold a promising prospects and warrant further investigation in future endeavors.