Piezoelectric Ozonation By Barium Titanate For Ibuprofen Degradation In Water

In order to meet the needs of production and life,synthetic organic compounds represented by drugs and personal care products（PPCPs）are widely used.Among them,the ibuprofen（IBP）is discharged into the natural environment in large quantities due to its large usage and difficult to be biodegraded.However,traditional biological,physical,chemical and chemical methods are difficult to achieve effective degradation and degradation of IBP.Mineralization.Therefore,IBP is widely detected in natural waters and organisms worldwide,posing a great potential threat.As a clean and effective strong oxidant,ozone is widely used in water treatment disinfection and organic matter degradation.However,the single ozone method cannot degrade and mineralize IBP effectively.Ozone-based advanced oxidation processes（AOPs）,with hydroxyl radicals（^·OH）as the main active substance,have been proven to effectively degrade a variety of refractory organic pollutants in water,but may involve high energy consumption and secondary pollution.Piezoelectric material is a special material that can convert mechanical energy into electrical energy and chemical energy.Piezoelectric catalysis process has been applied to degrade pollutants in water.However,it is only effective for some easily degradable pollutants.Therefore,this research combined the ozone（O₃）system with the piezoelectric（PE）system,and proposed a piezoelectric ozonation（PE-O₃）water treatment.The PE-O₃ process can efficiently degrade refractory pollutants and save energy without secondary pollution.In this study,the piezoelectric material barium titanate（Ba Ti O₃,BT）was used to catalyze ozone degradation of IBP,and the PE-O₃system’s degradation ability,mineralization ability and synergistic effect were systematically explored.The influencing factors,mechanism and practical application prospects of PE-O₃ process were analyzed and discussed.Compared with the BT and the O₃ system,the PE-O₃ system has significantly enhanced IBP degradation and mineralization,and the synergy coefficient is as high as 3.98.The PE-O₃ system can remove 87.22%of IBP within 15 minutes,and achieve a TOC removal ratio of up to 85.23%within 120 minutes.The influence of ozone concentration,BT dosage,hydraulic gradient and initial pH on the degradation of IBP in PE-O₃ system was explored.The increase of ozone concentration,BT dosage and hydraulic gradient increases the degradation ability of PE-O₃ system to IBP,but the sensitivity of this effect decreases after reaching a certain level.The FLUENT and COMSOL based on finite element method（FEM）were used to simulate the pressure in the flow field and the piezoelectric potential distribution on the BT surface,respectively.And the relationship between hydraulic gradient,piezoelectric potential and degradation effect was analyzed.In addition,the degradation of IBP in the PE-O₃ system is inhibited at pH₀ 3.0,and the effective degradation of IBP can be achieved in the range of pH₀ 5.0～11.0.Electrochemical experiments and quenching experiments were used to explore the mechanism of PE-O₃.Electrochemical experiments demonstrated that hydraulic power can effectively drive BT to produce piezoelectric effect and participate in the reaction with ozone.The quenching experiment shows that there are^·OH,superoxide radicals,e^-and h⁺in the PE-O₃ system.The quantitative calculation of the contribution ratio of each active substance to the degradation of IBP shows that the single electron transfer of ozone is the main way to produce^·OH in the PE-O₃ system.In addition,the degradation pathway of IBP in the PE-O₃ system is proposed.Through degradation test,water matrices test,stability tests and energy consumption analysis,the practical application prospects of the PE-O₃ system are inferred.The PE-O₃system can effectively degrade a variety of pollutants（nitrobenzene,carbamazepine,diclofenac,phenol）,and can also effectively degrade IBP in tap water and surface water matrix.The stability test,XPS and XRD characterization and ion leakage test proved that the stability of the PE-O₃ system is high and the piezoelectric material BT will not change its chemical state without metal leakage.The results of energy consumption calculation show that the energy consumption per unit mass of TOC in PE-O₃ process is reduced by1～2 orders of magnitude compared with other ozone-based advanced oxidation processes.