The Rise of Layered Double Hydroxides (LDHs) in Hexavalent Chromium (Cr(VI)) Pollution Treatment: Performance, Optimization, and Challenges

Layered double hydroxides (LDHs), a class of inorganic materials with unique layered structures, exhibit significant potential in environmental remediation. This paper comprehensively reviews recent advances in the application of LDHs for hexavalent chromium (Cr(VI)) removal. First, the fundamental structural characteristics and physicochemical properties of LDHs are elucidated, including their layered architecture, ion‐exchange capacity, thermal stability, and surface chemistry. Subsequently, the adsorption mechanisms of LDHs toward Cr(VI) are critically analyzed, with a focus on microscopic processes such as surface complexation, interlayer anion exchange, and reduction‐driven precipitation reactions. Key factors, such as pH, temperature, adsorbent dosage, and contact time, that influence the Cr(VI) adsorption efficiency of LDHs, are systematically evaluated. Furthermore, modification and performance optimization strategies for LDHs are discussed in depth, encompassing metal ion doping, interlayer anion regulation, nanostructural design, and the fabrication of composite materials. Finally, future research directions and development trends for LDHs in Cr(VI) removal are proposed, including innovative approaches such as the design of porous LDHs, three‐dimensional hierarchical architectures, continuous‐flow reactor synthesis techniques, and integration with self‐healing materials. By synthesizing current research achievements and practical insights into LDHs for Cr(VI) decontamination, this review provides theoretical foundations and technical guidance to advance their large‐scale application in heavy metal pollution control.