Exfoliated LDH nanosheets for membrane-based wastewater treatment: surface engineering and performance

Abstract

Exfoliated layered double hydroxide (LDH) nanosheets are increasingly recognized as surface-active nanomaterials capable of enhancing membrane-based wastewater treatment. Owing to their large surface area, tunable surface charge, and strong interfacial affinity, LDH-integrated membranes exhibit improved ion permeability, selectivity, and greater resistance to fouling. This review examines nanoscale exfoliation and the characteristics of LDH surfaces on membrane interactions and performance are examined in thin-film nanocomposites (TFNs), mixed matrix membranes (MMMs) and supported LDH membranes. Exfoliation techniques—chemical, mechanical, thermal and electrochemical—are compared concerning their effects on nanosheet morphology, dispersion stability, and surface charge. Particular attention is given to radiation-assisted exfoliation, which offers a scalable, environmentally benign route for producing well-dispersed LDH suspensions. Furthermore, interfacial strategies such as polymeric coatings and layer-by-layer (LbL) assembly are discussed for their role in minimizing nanosheet aggregation and improving compatibility with polymers. The review also addresses current challenges, including nanosheet stability and the seamless integration into membrane fabrication processes. Emerging pathways that connect laboratory-scale findings with industrial implementation are discussed. From a materials engineering and sustainability perspective, exfoliated LDH nanosheets are presented as promising nanomaterials for developing next-generation membranes targeted at efficient water purification and environmental protection.