Layered double hydroxide separation membranes: advances and prospects in water purification applications

Layered double hydroxides (LDHs) exhibit highly promising applications in membrane separation due to their distinctive characteristics, including tunable interlayer spacing, high specific surface area, interchangeable interlayer anions, positive surface charge, and abundant hydrophilic functional groups. It requires a profound understanding of the intrinsic relationship between their structural attributes and separation behaviors. In this review, we systematically explore the applicability of various LDHs across different separation fields based on their structural advantages, comprehensively summarize current fabrication methods for LDH-based membranes, and critically discuss the merits and drawbacks of each approach. By integrating the unique structural benefits of LDHs with the separation mechanisms of LDH-based membranes, we further elucidate their applications in diverse separation scenarios, such as oily wastewater treatment, dye-containing wastewater purification, pharmaceutical wastewater remediation, and seawater desalination. Finally, we elaborate on the prevailing challenges and limitations of LDH-based separation membranes and propose forward-looking perspectives for future in-depth research.