Ultrasonic-assisted ozone degradation of organic pollutants in industrial sulfuric acid

In this work, a combination of ozone (O-3) and ultrasound (US) has been firstly used to decolorize black concentrated sulfuric acid with high organic content. The effect of different reaction factors on the transparency, extent of decolorization, H2SO4 mass fraction, and organic pollutants removal is studied. In addition, the systematic interaction between ultrasound and ozone on the decolorization process is reviewed through comparative experiments of O-3, US and US/O-3. A sulfuric acid product that meets the requirements for first-class products in national standards, with an extent of decolorization of 74.07%, transparency of 70 mm, and a mass fraction of 98.04%, is obtained under the optimized conditions. Under the same conditions, it has been established that the treatment time can be saved by 25% using the US/O-3 process compared to using O-3. Further, the production of oxidative free radicals (center dot OH) in a concentrated sulfuric acid system is enhanced using the US/O-3 process compared with O-3. In addition, the degree of effectiveness of different oxidizing components on the decolorization process is revealed by adding different free radical shielding agents when the US/O-3 process is used.

Automated summary

In this study, a combination of ozone and ultrasound was used for the decolorization of black concentrated sulfuric acid. The effect of different reaction factors on the decolorization process was investigated, and the interaction between ultrasound and ozone was evaluated. Under optimized conditions, a sulfuric acid product meeting the national standards was obtained.