Process intensification of Tetrabromobisphenol S removal with a bubble-film hybrid plasma reactor

Abstract

In order to improve the efficiency of removal of organic contaminants in wastewater treatment, a bubble-film hybrid plasma reactor has been designed in this study. Both the generation and mass transfer processes of active species can be intensified with the presence of water film. On one hand, the water film makes streamer discharge and surface dielectric barrier discharge initiated simultaneously, which reduces the initiation voltage and increases the intensity of electric discharge, and then improves the production efficiency of active species. On the other hand, the water film expands the plasma-water interface, which improves the utilization efficiency of active species by enhancing the mass transfer process. The results show that, benefiting from the water film, the maximum yield of active species can be increased by over 80%, and the efficiency of gas–liquid mass transfer can be improved by over 20%. For the initial Tetrabromobisphenol S (TBBPS) concentration of 0.5 mg/L, the time needed to get a nearly 100% removal is about 1 min at the discharge voltage of 12.8 kV. This time increases with the increase in TBBPS concentration, and increases to 9 min for 50 mg/L. The maximum energy efficiency is 700 mg/kWh and decreases with the increase in discharge voltage.The results demonstrate that the bubble-film multistage process is of great significance to the enhancement of removal of organic pollutants in wastewater with plasma.