Characteristics of Degradation and Product Precipitation of Phenolic Wastewater Enhanced by Ultrasonic Photocatalysis Combined with Discharge

The total amount of phenolic wastewater is large, difficult to degrade, and traditional treatment methods can’t recover and utilize phenolic substances. In this study, air plasma jet and photocatalyst were used to treat phenolic wastewater and produce reactive species in the liquid, and then ultrasonic combined with composite photocatalyst CQDs/TiO2 was further used to enhance the subsequent reaction and produce solid recyclable precipitates. The experimental results show that when the flow speed of gas–liquid two-phase flow is 4.20 m/s, the plasma jet has the best effect of generating reactive species and degrading phenol in water. The continuous flow of liquid phase after discharge treatment is conducive to the degradation of phenolic wastewater, and the best effect is when the liquid phase flow rate is 0.60 m/s. The degradation efficiency of p-nitrophenol solution was increased 18.23% by using ultrasonic coordinated CQDs/TiO2 supported aluminum oxide pellets. This study has certain reference value for the application of plasma combined with photocatalysis in the treatment of phenolic wastewater with high toxicity and difficult degradation.