Zinc-Aluminum Layered Double Hydroxide: High efficient removal by adsorption of tartrazine dye from aqueous solution

The aim of this work is to study the retention of tartrazine dye, from a diluted aqueous solution, by a layered double hydroxide (LDH). This retention required optimization of various parameters such as time, pH, adsorbent dose and initial dye concentration. LDH used as adsorbent in this study is based on Zinc and aluminum (Zn/Al = 2 (molar ratio)) intercalated with chloride ions, and was synthesized by coprecipitation at constant pH, analyzed by Inductively Coupled Plasma (ICP), characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The removal of the dye at room temperature is a fast process. The kinetic equilibrium was reached after 60 min. The modeling of the adsorption equilibrium showed that it is undergone in monolayers according to Langmuir model. Moreover, the characterization by XRD and FT-IR of the adsorbent after dye retention showed that tartrazine has been adsorbed at the adsorbent surface whereas a chemisorption process was confirmed by the kinetic study and activation energy value.