A novel method to delaminate nitrate-intercalated Mg–Al layered double hydroxides in water and application in heavy metals removal from waste water

Nitrate-intercalated Mg–Al layered double hydroxide (LDH) was successfully delaminated in water by a facile and effective method upon reflux at 120 °C for 24 h followed by sonication at 40 °C for 5 h. This process is environmentally friendly since water is the only solvent used. The delaminated nanosheets were characterized by microscopic, spectroscopic, and particle size analyses. The delamination process successfully produced octahedron-shaped single-layer nanosheets 50–150 nm in size. X-ray photoelectron spectroscopy (XPS) data confirmed that the surface elements and their chemical status are consistent with the basic layer of Mg–Al LDH. The delaminated nanosheets displayed higher adsorption capacity for removing heavy metals from waste water than the original powdered LDH. After treating the waste water, a sharp and intense peak in the X-ray powder diffraction (XRD) pattern of the precipitate confirms the restacking of the LDH nanosheets.