LDH-based Nanocomposites: Structure and Role in Sustainable Water Clean-up – A Review

Today, water pollution is a serious global environmental issue, largely driven by rapid population growth, expanding industries, and unplanned urban development. Day by day, the deposition of hazardous contaminants in the environment is increasing due to ongoing discharge of household sewage, agricultural surplus, pharmaceutical residues, and unprocessed seepages. All these activities lead to the accumulation of dangerous substances in the environment. Predominantly, organic contaminants such as dyes, pesticides, antibiotics, and pharmaceuticals are primarily responsible for bioaccumulation, antimicrobial resistance, and long-term ecological disturbance. Among the most prevalent, hazardous, and persistent pollutants are heavy metals like arsenic, lead, cadmium, and chromium. To address these issues, new materials and methods are being developed for improve water purification efficiency. Layered Double Hydroxides (LDH), sometimes referred to as "hydrotalcite- like nanocomposites," have gained considerable interest as potential catalysts and adsorbents for contaminant removal. Carefully regulating the material’s composition, surface area, and layer structure can enhance its ability to eliminate a broad spectrum of water contaminants. Thus, this approach provides a sustainable and environmentally friendly method to minimize water pollution. In addition, many LDH systems exhibit high selectivity and maintain satisfactory regeneration performance over multiple adsorption-desorption cycles, demonstrating their potential for practical water treatment applications. To ensure global water security, LDH-based nanocomposite materials offer opportunities for environmentally benign approaches, safe water reuse, and the development of much cleaner technology. This review provides a comprehensive overview of LDH synthesis strategies, adsorption mechanisms, pollutant removal performance, regeneration characteristics, and recent advances in LDH-based nanocomposites for water purification.