Effect of pH on the adsorption behaviour of Congo Red Dye on the Mg-Al layered double hydroxide

Abstract

Abstract In the present study, the synthesis of Mg-Al layered double hydroxide at the molar ratio of 3:1 for Mg/Al are determined. One-step hydrothermal technique with slow hydrolysis of urea at a low temperature was employed without further annealing. The study was aimed at determining the effectiveness of Congo Red dye removal in the adsorption process onto Mg-Al layered double hydroxide (LDH) with respect to the change in pH of the solution. The experiment was conducted at concentrations of a sorbent 0.04g with 100 ml of Congo Red and at six values of the reaction, i.e. pH 2.0, pH 4.0, pH 6.0, pH 8.0, pH 10, and pH 12.0. It was found that pH affects the adsorbent surface charge and the degree of anionic dye dissociation. This can be explained to the chemical form of dye in the solution and functional groups present on the adsorbent surface at a specific pH.