Treatment of High Concentration Acid Plasticizer Wastewater by Ozone Microbubble Oxidation

The large use of plasticizers in industry produced large amounts of wastewater. The treatment of industrial wastewater with advanced oxidation processes (AOPs) has attracted widespread interest from scientists in recent years. Comparing with several common AOPs such as activated persulfate, Fenton, UV, and H2O2, the ozone oxidation technology has the advantages of not introducing other chemical reagents, not bringing secondary pollution, lower energy consumption, safety, and non-flammability or explosion. Using the ozone microbubble process to treat high-concentration acidic plasticizer wastewater is in line with the concepts of green, energy-saving, and environment friendly. This work studied the changes of chemical oxygen demand (COD), pH, and dissolved oxygen (DO) in wastewater by adjusting the reaction time, system pressure, and reaction temperature, and revealed the best working conditions of ozone microbubble technology to treat plasticizer wastewater. The experiment shows that with the condition of the reaction time of 45 h, the pressure of 0.150 MPa, the ozone concentration of 100%, and the gas flow of 0.7 L/min, the dissolved oxygen (DO) of the wastewater increased from 3.8 to 4.5 mg/L, while the pH value increased from 3.23 to 7.54, and the COD removal rate reached up to 94.18%. This work discussed the mechanism of ozone microbubble technology to degrade plasticizer wastewater, and also confirmed that ozone microbubble technology can generate high hydroxyl radicals, even under acidic media. In addition, this technology does not require the addition of any additional chemical reagents and does not form a precipitate in the reaction to cause secondary pollution to the environment. Meanwhile, the water treatment costs of unit tons using this technology have also been analyzed. This technique has great practical application prospects in treating high concentration organic acid wastewater.