Waste derived biochar for water purification: the roles of redox properties

Biochar, derived from the waste pyrolysis process, is a promising class of functional materials for environmental remediation owing to its large surface area, abundant surface functionalities and redox properties. This review focuses on the compositions, structures and electron transfer abilities of biochar and their roles in pollutant transformation in environmental remediation. First, the redox properties of biochar are systemically introduced, and the influencing factors are thoroughly discussed. Furthermore, biochar-involved redox reactions for pollutant reduction are distinctly classified on the basis of the different oxidants and reaction conditions. The reactive species in each system are comprehensively introduced, while the roles of biochar are adequately analyzed. This review aims to address the growing need for a comprehensive understanding of the role of biochar in pollutant transformation. Moreover, it also seeks to guide future research and the design of biochar materials for advanced water purification, highlighting the need for precise control of redox properties to achieve improved environmental outcomes.

Graphical abstract