Facile Fabrication of Ni-Fe-Layered Double Hydroxide for Boosted Adsorption of Alizarin Red S Dye in Water

This work aims to design layered double hydroxide (Ni-Fe-CO3) via a simple co-precipitation route for the elimination of Alizarin Red S (ARS) dye from water. The physicochemical properties of Ni-Fe-CO3 adsorbent were studied using different spectroscopic and analytical techniques. The adsorptive ability of Ni-Fe-CO3 was evaluated for the removal of ARS under different conditions in order to understand the mechanistic pathways. Ni-Fe-CO3 showed a high adsorption capacity of up to 454.45 mg/g within just 1 h. It was found that the rise in the medium temperature from 20°C to 40°C boosts the adsorption ability, while above this value, there was no change in the adsorption capacity. The capacity of adsorption was found to be 157.97 to 55.38 mg/g at pH 2 to 9, respectively. The surface chemistry of the adsorbent and the dye charge in the solution are significantly responsible for the pH dependency of dye adsorption. The analysis of adsorption data utilizing different isotherm models shows that Freundlich isotherm is the most pertinent to the adsorption process. By the kinetic studies, the pseudo-second-order kinetic model, which also takes into account intra-particle diffusion in the adsorption process, may adequately describe the behavior of adsorption. The thermodynamic characteristics, such as ΔH°, ΔS°, and ΔG°, were found to be endothermic, spontaneous, and practicable. Even though the synthesis process is simple via the use of low-cost elements, the adsorption ability was comparatively high compared to the previously reported materials. Bridging between the lost cost of the process and high effectiveness is the best way to transfer the use of emerging materials to real-world use.