Enhanced wastewater treatment using biochar-supported layered-double-hydroxide composites

With industrialization advances, the volume of wastewater produced has increased considerably. In recent years, biochar-loaded layered double hydroxides (BC–LDHs) have emerged as a low-cost, sustainable composite material with promising applications in wastewater treatment. Improving the adsorption performance of materials is a central focus in the field of wastewater treatment. Currently, most studies emphasize the adsorption applications of BC–LDHs. However, this study not only discusses existing mainstream methods for enhancing adsorption performance but also shifts the focus from BC modification to LDH synthesis. Building on this, new potential modification methods are proposed to achieve improved adsorption performance. One such method involves obtaining new anion-intercalated BC–LDHs through ion exchange. Another approach is to synthesize BC–LDHs via electrodeposition, which involves using an LDH as the working electrode and then loading BC onto it or using BC as one of the electrodes with a mixed metal salt solution as the electrolyte. Different synthesis methods often result in distinct material properties. The electrodeposition method is used to synthesize BC–LDHs with the aim of achieving material modification. In addition, the factors influencing BC–LDHs are analyzed. Through meta-analysis, the study identifies notable factors affecting the adsorption properties of pollutants, including different synthesis methods, the specific surface area of BC–LDHs, adsorbent dosage, and initial pH. This analysis offers a more intuitive foundation for guiding subsequent research by focusing on these critical factors. Finally, the main adsorption mechanism of BC–LDHs is summarized, and future research directions for BC–LDHs are proposed.