Highly Efficient Removal of Alizarin Yellow R Dye from Aqueous Solution Using a Synthetic Hydrocalumite-Type LDH (caal–no 3 )

CaAl-Layered double hydroxide (LDH) of hydrocalumite-type with nitrate anions in the inter-lamellar region was synthesized via the co-precipitation method at fixed pH and with a selected Ca/Al molar ratio of the starting salts equal to two. The obtained CaAl–NO 3 compound was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). In this context, this material has been employed as an adsorbent for the retention of the reactive azo dye, alizarin yellow R (AYR), from an aqueous solution. To further investigate the practical potential of CaAl–NO 3 for AYR dye adsorption, the effects of various parameters such as temperature, the concentration of dye, pH, adsorbent dose, and contact time on adsorption capacity were separately exanimated. The findings results suggest that a pH of 9 is more suitable for the AYR dye adsorption process. The adsorption kinetics was better explained by the pseudo-first-order model, and equilibrium was achieved after 30 min of contact. The equilibrium adsorption data of AYR dye on the prepared CaAl–NO 3 was well fitted to the Langmuir model, and it was characterized by an excellent adsorption capacity of 2107 mg/g at 293 K. Thus, due to the 2D structure and its positively charged layers, CaAl–NO 3 material exhibits an exceptional ability to remove alizarin yellow R dye from aqueous solutions.