A Review on the Preparation of LDHs/Biochar Composites and Their Application in Water Pollution Control

This article systematically reviews the structural characteristics of layered double hydroxides and biochar (LDHs/biochar) composites, summarizes the features and optimization strategies of preparation methods such as coprecipitation, hydrothermal synthesis, ball milling, and calcination-reconstruction, analyzes their adsorption performance and mechanisms in controlling various water pollutants including organic contaminants, heavy metals, and nutrients, and provides insights into future research trends and practical applications, aiming to offer references for improving material performance and promoting practical use. The existing research results show that LDHs/biochar composites exhibit good application potential for various pollutants, such as dyes, antibiotics, heavy metal ions, and phosphates. The coprecipitation method is simple and easy to operate, and the LDHs/biochar composites prepared by this method exhibit favorable adsorption performance, with potential for industrial-scale production. The mechanisms of pollutant removal by LDHs/biochar composites primarily include electrostatic attraction, ion exchange, hydrogen bonding, complexation, and π-π electron interactions. Both the biomass type and the LDH type influence the adsorption performance of the composites. Therefore, designing LDHs/biochar composites based on pollutant characteristics and adsorption mechanisms is key to achieving effective pollution control. Currently, research on target pollutant-oriented material design and material regeneration remains underdeveloped and requires further breakthroughs.