Removal of reactive dye Procion Red MX-5B from model aqueus solutions using Mg-Al layered double hydroxide

Abstract

Layered double hydroxides (LDHs), known as the anionic clays, have a layered structure and a permanent positive charge due to the partial substitution of bivalent cations with trivalent cations. Therefore, these compounds show anion exchange properties and they are suitable for removing anionic pollutants from water. In this paper, Mg-Al double hydroxide was synthesized and examined in terms of the characterization of its surface and its efficiency of the removal of the reactive dye Procion Red MX-5B from model aqueous solutions. It was found that the initial concentration, the contact time, pH value of solution and the competitive effect of sulfate anion, affect the dye adsorption process at constant temperature. Adsorption kinetics is interpreted by the pseudo second-order kinetics model, while the Temkin model of adsorption isotherm best describes the equilibrium condition. Infrared spectroscopy and surface photomicrography were used for characterization of materials in the native state and after adsorption. The results showed that the dye retention is performed by establishing hydrogen bonds and electrostatic interactions.