A study on the sorption of phenol from aqueous solution by activated red mud derived from alumina processing plant in Tanrai, Lamdong province, Vietnam

Abstract

In the present work, red mud derived from TanRai alumina plant was acivated by HCl acid and using as effective adsorbent of phenol from aqueous sloution. The activated red mud was characterized by physico-chemical mehods including X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle distribution. Phenol adsorption ability from aqueous solution onto activated red mud was investigated. With adsorbent’s dosage of 20 g.L^-1 and at suitable pH of 7, more than 90 % of phenol was removed from aqueous solution containing 50 mg phenol.L^-1. Adsorption isotherm study confirmed Langmuir model well described the experimental data and maximum adsorption capacity was about 3,3 mg.g^-1. The kinetic data indicated that the adsorption followed pseudo second-order equation. The negative value of Gibbs free energies proved that the adsorption was a spontaneous process. The endothermic nature of the adsorption with the increase of the chaotic level on solid – liquid surface after taking place the adsorption was demonstrated by the positive values of standard enthalpy and standard entropy.