Enhancement of the degradation efficiency of dimethyl phthalate by microwave-induced wet oxidation with lower energy consumption

Abstract

Dimethyl phthalate, a common ingredient in the manufacture of plastics, is a typical persistent substance in the organic wastewater environment owing to its lipophilic and refractory properties. To achieve higher degradation of dimethyl phthalate, this study uses an experimentally constructed high-pressure resistant microwave-catalyzed experimental system, which can establish a coupling between the microwave and pressure fields in the wet oxidation process. Three types of catalysts are investigated for catalytic degradation, along with the effects of variables, such as reaction temperature, system pressure, and catalyst concentration, on the removal of dimethyl phthalate. Increasing the reaction temperature effectively increases the reaction rate constant. In addition, the COD content reduces from 4161.8 to 1710.5 mg/L within 5 min. Further, the energy flow and economy indices of the entire process are comprehensively analyzed. Finally, the analysis of the degradation intermediate and other characterization techniques reveals that the pollutant is degraded by ·OH.