Kinetic and thermodynamic studies of the degradation of methylene blue by photo-Fenton reaction

Syrian natural magnetite has been utilized for the removal of methylene blue from aqueous solutions by photoFenton reaction. Experiments were carried out to evaluate the kinetic and thermodynamic parameters. Pseudo-first order, pseudo-second-order models were used to analyze the kinetic data obtained at different initial MB concentrations and temperatures. The photo-Fenton degradation process of MB is better described by the pseudo-first-order model. The activation energy Ea 1/4 16.89 and 18.02 kJ/mol for MB degradation at concentrations 40 and 80 mg/l respectively, and that suggesting the degradation reaction proceeded with a low energy barrier, the values obtained (Delta G*, Delta S*, and Delta H*) indicate that the process is endothermic and spontaneous.