Recent progress in layered double hydroxides (LDH)-containing hybrids as adsorbents for water remediation

With rapidly growing industrial development worldwide, the need for a new class of nanoparticles and techniques for treating wastewater remains a major concern to protect the environment. Layered double hydroxides and particularly LDH-containing hybrids are emerging as potential nano-sized adsorbents for water treatment. Recent studies have demonstrated LDH-containing hybrids as promising multifunctional materials for potential utilization in various applications such as, photo-catalysis, energy storage, nanocomposites and water purification. This article reviews the recent applications of LDH-containing hybrids as adsorbents for water remediation. The maximum adsorption capacities of various toxic heavy metals and dyes on different LDH hybrids were reported as 483mg/g for Pb²⁺, 95mg/g for Cd²⁺, 181mg/g for Cu²⁺, 649mg/g for Cr⁶⁺, 180mg/g As⁵⁺, 813mg/g for Hg²⁺, 450 for Ag⁺, 277mg/g for U⁶⁺, 1062mg/g for methyl orange, 185mg/g for methylene blue, and 1250mg/g for Congo red, which is comparatively higher than other commercial adsorbents. This review discusses the adsorption performance of manifold LDH-containing hybrids for treating various pollutants such as heavy metals and dyes. The mechanisms of interaction of LDH-containing hybrids with pollutants and the influence of key adsorption parameters such as pH, contact time, adsorbent dose and temperature have been comprehensively discussed. Moreover, the regeneration potential and reuse of spent LDH-containing hybrids and its toxicity effects have also been reviewed.