Highly Efficient Removal of Alizarin Yellow R Dye from Aqueous Solution Using a Synthetic Hydrocalumite-Type LDH (CaAl-NO3)

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-NO3 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-NO3 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-NO3 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-NO3 material exhibits an exceptional ability to remove alizarin yellow R dye from aqueous solutions.

Automated summary

CaAl-Layered double hydroxide (LDH) with nitrate anions was synthesized and utilized as an adsorbent for the removal of alizarin yellow R (AYR) dye from aqueous solutions. The effects of various parameters on the adsorption capacity were investigated, and it was found that pH 9, a contact time of 30 minutes, and equilibrium adsorption data fitted well with the Langmuir model. The CaAl-NO3 material exhibited exceptional adsorption capacity of 2107 mg/g at 293 K.