Characterization, physiochemical, controlled release studies of zinc–aluminium layered double hydroxide and zinc layered hydroxide intercalated with salicylic acid

Intercalation of salicylic acid (SA) into the interlayer region of zinc/aluminium-layered double hydroxides (LDHs) and zinc layered hydroxides (ZLH) was studied. Fourier transform infrared-attenuated total reflectance (FTIR-ATR) shows the presence of nanocomposites peak at 3381 cm−1 for OH group, 1641 and 1640 cm−1 C=O vibration mode indicates that SA is intercalated between the layered structures. Powder X-ray diffraction (PXRD) analysis shows the presence of new peak at lower region of 2θ with calculated basal spacing of 16.3 A for LDSA and 16.15 A for ZLSA. CHNS analysis stated that the percentage of carbon was increased from 0 to 15.09% in LDSA and 21.85% in ZLSA . Thermogravimetric analysis/derivative thermogravimetric (TGA/DTG) test shows that SA was thermally stable due to increase in decomposition temperature from 204°C for pure salicylic compound to 405°C in LDSA and 426°C in ZLSA, respectively. Field emission scanning electron microscope (FESEM) images show that the nanocomposites are more compact, flaky non-porous, large agglomerates with smooth surfaces of the intercalated compound. Controlled release was successful which follows pseudo-second order from phosphate > carbonate > chloride.