Catalytic Supercritical Water Oxidation for the Destruction of Quinoline Over MnO2/CuO Mixed Catalyst

Abstract

This article presents the results of the oxidation at supercritical conditions of a nonbiodegradable and highly stable nitrogen containing heterocyclic organic compound (quinoline) over a mixed catalyst in a tubular fixed-bed reactor. The effect of operating conditions namely temperature, pressure, oxygen concentration, and initial quinoline concentration were studied to evaluate their effect on the removal of the organic compound. The results showed that the catalytic reaction depended strongly on temperature and pressure; nevertheless it was very efficient at milder operating conditions close to the critical point of water. A power-law kinetic model was proposed to quantify the catalytic oxidation of quinoline. Three Langmuir−Hinshelwood−Hougen−Watson reaction rates models were also explored to fit the experimental data. However, the kinetic data were better represented by the power-law kinetic model. The catalyst was able to maintain its activity, and thus it can be used as an alternative to reduce the severity of the process.