Adsorption of acid dye onto activated Algerian clay

Abstract

In this work, activated clay from Algeria was used as adsorbent for the removal of methyl orange (MO) from aqueous solution, for this, the effects of several parameters such as contact time, adsorbent dose, pH value of aqueous solution and temperature on the adsorption of MO were also studied. The results showed that nearly 30 min of contact time are found to be sufficient for the adsorption to reach equilibrium and the adsorption was favourable at lower pH. The acid dye concentration is measured with UV-visible spectrophotometer at a wavelength of 464 nm. The adsorption capacity of MO found to be 32.57 mg/g. The Pseudo-first-order and pseudo-second-order models were used to fit the experimental data. The adsorption kinetic process was found to follow a pseudo second order model.The Langmuir and Freundlich isotherms models were used to describe adsorption data, the results indicates that Langmuir and Freundlich models provide better correlation of the experimental data. The negative values of ΔG° at different temperatures show that the adsorption process is spontaneous. The values of ΔH and ΔS were found to be 1.04 kJ/mol and 3.35 J/mol.K, respectively. The positive value of ΔH confirms that the adsorption is endothermic and the adsorption process is chemical nature.

KEY WORDS: Dye, Adsorption, Cay, Adsorption kinetics, Adsorption isotherms

Bull. Chem. Soc. Ethiop. 2017, 31(1), 51-62.

DOI: http://dx.doi.org/10.4314/bcse.v31i1.5