Advances and prospectives of iron/biochar composites: Application, influencing factors and characterization methods

In recent years, iron/biochar composite materials have been developed and efficiently used for pollutant removal in environmental matrices due to their excellent capability of absorbing pollutants, optimized structures, and flexible application properties. In this review, we evaluated the application value and benefits of iron/biochar composites in soil, hydrology, climate, and energy. The key factors affecting the important iron/biochar composite properties for various applications were analyzed. Besides, the advantages and disadvantages of current iron/biochar composite characterization methods were also summarized. We found that iron/biochar composite materials have been efficiently used for soil remediation, water treatment, carbon sequestration, and long-term storage, as well as energy storage due to their better physicochemical, surface properties, and storage capacity when compared with biochar. The feedstock, pyrolysis temperature, C/Fe mass ratio, and preparation method were crucial to the properties of iron/biochar composite materials. The N2-BET, XRD, XPS, SEM, TEM, EDS, FTIR, and NMR provide information including surface area, structure, functional groups, and chemical elements, which facilitate their beneficial production and potential utilization.