Design and engineering of layered double hydroxide-based composites for efficient wastewater treatment

Layered double hydroxides (LDHs), often referred to as hydrotalcite components, have gained popularity as wastewater treatment solutions due to their distinct lamellar structure, changeable metal arrangement, excellent anion exchange efficiency, and notable memory effect. However, problems including particle agglomeration, inadequate structural stability, and restricted selectivity toward certain pollutants frequently limit the practical use of pure LDHs. The creation of LDH-based composite materials has been the focus of significant research efforts to address these issues. The synthesis techniques, modification strategies, and sewage treatment uses of LDHs and their composites are all thoroughly evaluated in this review. The effectiveness of several LDH-based composite classes in a variety of contaminants, including dyes, heavy metals, nutrients, medications, and new toxins, is critically investigated. Adsorption, ion exchange, surface complexion, photocatalytic degradation, and redox reactions are among the fundamental removal mechanisms that are methodically examined. Additionally, a summary of the impact of operational factors on the effectiveness of treatment is provided, including temperature, coexisting ions, solution pH, and material regenerating. Lastly, the analysis explores future prospects for the logical design of effective and sustainable LDH-based materials for sewage treatment and underlines major issues related to large-scale operation, recyclable properties, and safety for the environment.