ADSORPTION OF METHYL ORANGE IN WATER BY COMPOSITE CHITOSAN - MAGNETITE: ISOTHERM, KINETIC, AND THERMODYNAMIC STUDIES

Abstract

The adsorption of methyl orange (MO) into the water by a chitosan-magnetite (CM) composite was investigated in the article. The adsorption process was investigated by parameters, such as pH, contact time, temperature and initial concentration of MO. Langmuir and Freundlich isotherm adsorption models were used to analyze the experimental data. The kinetic adsorption was studied using pseudo-first-order, pseudo-second-order, Elovich, and intra-molecular-diffusion models. The pseudo-second-order and Langmuir models fitted the adsorption of MO onto CM. The maximum adsorption capacity calculated using the Langmuir model decreased from 188.88 to 162.99 mg/g when the temperature increased from 293 to 313K. The adsorption of MO onto CM was an exothermic and spontaneous process. The adsorption was created electrostatic attraction between CM and MO. Because of the material's magnetism, CM could easily recover. After three times of reuse, CM had a quite high adsorption efficiency.