Biochar-layered double hydroxide vs biochar-layered double oxide: a critical review on their applications in water pollution control

Water pollution is a growing global challenge, necessitating innovative and sustainable solutions for effective pollutant removal. Among the various strategies, adsorption has emerged as a promising approach because of its simplicity, cost-effectiveness, and efficiency. Biochar, when modified with layered double hydroxides (LDHs) or layered double oxides (LDOs), exhibits enhanced adsorption properties, making it a versatile material for water pollution control. While numerous studies have explored the potential of biochar-LDH and biochar-LDO composites, a systematic comparison of their strengths, limitations, and real-world applications remains unexplored. This review provides a comprehensive analysis of biochar-LDH and biochar-LDO composites, focusing on their synthesis, adsorption mechanisms, and performance in removing contaminants such as heavy metals, phosphates, and organic pollutants. By comparing their adsorption efficiencies, regeneration capabilities, and environmental benefits, this study highlights the unique advantages of each material and identifies key areas for future research. The findings underscore the potential of these composites as next-generation adsorbents for sustainable water treatment, offering valuable insights for researchers, industries, and policymakers aiming to address global water pollution challenges.