Asadollah Karimi - Department of Chemical Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran
Esmaeil Fatehifar - Environmental Engineering Research Center, Faculty of Chemical Engineering, Sahand University of Technology, Tabriz, Iran
Reza Alizadeh - Department of Chemical Engineering, Ahar Branch, Islamic Azad University, Ahar, Iran
Hadi Soltani

Background: Spent caustic contains noxious components such as sulfide species and also high chemicaloxygen demand content (COD). Oxidation of these materials to caustic and sulfate species is mostly therate-controlling step within catalytic oxidation of spent caustic.Methods: In this study, the kinetics of catalytic oxidation of spent caustic and the regeneration methodologyof the sulfidic spent caustic were investigated. The kinetics of catalytic oxidation of spent caustic was studiedin the presence of a heterogeneous catalyst. The developed mathematical model was verified via the batchbubble column reactor. The elementary and non-elementary models based on the genetic algorithm wereused to obtain the rate coefficient and kinetic order.Results: The experiments were carried out at various conditions. The results indicated that the error ofobjective function of the non-elementary and elementary models was 3.01% and 134.96%, respectively.Conclusion: According to the results, the non-elementary model had rational outcome compared to theelementary one. Also, non-elemental model is more concordance with experimental results.

Caustic, Kinetic, Regeneration, Catalysis