A rapid and low energy consumption method to decolorize the high concentration triphenylmethane dye wastewater: Operational parameters optimization for the ultrasonic-assisted ozone oxidation process

This research set up an ultrasonic-assisted ozone oxidation process (UAOOP) to decolorize the triphenylmethane dyes wastewater. Five factors – temperature, initial pH, reaction time, ultrasonic power (low frequency 20 kHz), and ozone concentration – were investigated. Response surface methodology was used to find out the major factors influencing color removal rate and the interactions between these factors, and optimized the operating parameters as well. Under the experimental conditions: reaction temperature 39.81 °C, initial pH 5.29, ultrasonic power 60 W and ozone concentration 0.17 g/L, the highest color removals were achieved with 10 min reaction time and the initial concentration of the MG solution was 1000 mg/L. The optimal results indicated that the UAOOP was a rapid, efficient and low energy consumption technique to decolorize the high concentration MG wastewater. The predicted model was approximately in accordance with the experimental cases with correlation coefficients R2 and Radj2 of 0.9103 and 0.8386.

► Apply ultrasonic-assisted ozone oxidation process (UAOOP) to decolorize wastewater.
► Prove UAOOP a rapid and efficient process to treat triphenylmethane dye wastewater.
► Figure out the optimal conditions to decolorize high concentration MG wastewater.
► UAOOP is a low energy consumption method and it cost 4 kW, 0.43 US dollar to decolorize 1 ton simulated MG wastewater.