Study On Ultrasonic Degradation Of Pharmaceutical Wastewater Catalyzed By Compound Bismuth Tungstate

Bi₂WO₆ is an important semiconductor material,which has been widely used in the research of catalytic degradation of organic wastewater in recent years.Sonocatalysis is a kind of advanced oxidation method,which has been applied to the treatment of organic pollutants due to its high efficiency,cleanliness,and reusability.Bi₂WO₆ and acoustic catalysis work together to remove organic matter in pharmaceutical wastewater.This research group has already studied it in the early stage,but the removal effect is not ideal.In order to improve the removal rate,Cu WO₄ and Ag₂O are combined with Bi₂WO₆ to form composite materials.Its structural characteristics can effectively inhibit the recombination of electron（e^-）-hole（h⁺）pairs,generate more active substances,and increase the removal of pharmaceutical wastewater.（1）Bi₂WO₆ and Ag₂O/Bi₂WO₆ composites were prepared by hydrothermal method and one-pot method,respectively,and used to remove ciprofloxacin（CIP）.The synthesized composites were characterized by XRD,BET,XPS and DRS,and their structure and morphology were more clearly understood and understood.Next,we investigated the effects of compound ratio,addition amount,initial concentration,p H value,ultrasonic power and time on the removal of CIP by Ag₂O/Bi₂WO₆,and searched for the best conditions.When the addition amount of Ag₂O/Bi₂WO₆complex is 2.5 g/L,the ultrasonic power is 200 W,the concentration of CIP solution is 5 mg/L,and ultrasonic for 60 min,the removal rate of CIP in the solution can reach 95.46±1.50%.The process conforms to the pseudo-first-order kinetic model,and the kinetic constant k of the reaction is 0.0146 min^-1,which is 1.40 times the k value of Bi₂WO₆ combined with ultrasonic to remove CIP,which can significantly improve the removal efficiency.Scavenger experiments show that h⁺,hydroxyl radical（·OH）and superoxide anion（·O₂^-）are the main active species for removing CIP,and a sonocatalytic reaction mechanism of Z-type heterojunction is proposed.In addition,repeated utilization experiments were also carried out.The Ag₂O/Bi₂WO₆composite was recycled 4 times,and the removal rate of CIP could still reach91.15%±1.28%,and the content of the constituent elements did not change significantly.The material is relatively stable,and it is not easy to cause pollution to the environment.（2）The Cu WO₄/Bi₂WO₆complex was prepared by a one-pot method to remove tetracycline（TET）.The synthesized substances were also verified,and a clearer knowing and understanding of their structure and morphology were obtained.Next,we investigated the effects of compound ratio,addition amount,solution concentration,p H value,ultrasonic power,K₂S₂O₈ addition amount and time on the removal of TET by Cu WO₄/Bi₂WO₆,and searched for the best conditions.When the addition amount of Cu WO₄/Bi₂WO₆complex is 1 g/L,the ultrasonic power is 500 W,the concentration of TET solution is 20 mg/L,the addition amount of potassium persulfate is 2.7 g/L,and ultrasonic wave is applied for 60 min.The removal rate of TET can reach 97.47±0.98%.The reaction process conforms to the pseudo-first-order kinetic model.The kinetic constant k of the reaction is 0.02484min^-1,which is 3.64 times the k value of Bi₂WO₆ combined with ultrasonic removal of TET,which can significantly improve the removal efficiency.The scavenger experiments showed that h⁺,·OH and·O₂^-were the main active substances for removing TET,and a Type-Ⅱtype of sonocatalytic reaction mechanism was proposed.In addition,we also conducted a reuse experiment,Cu WO₄/Bi₂WO₆ has an ideal reuse rate,and the removal rate can still reach 92.10%±1.41%after 4cycles of recycling.All in all,the composites formed by Bi₂WO₆ with Ag₂O and Cu WO₄,respectively,can significantly improve the sonocatalytic performance of Bi₂WO₆,and have a good removal effect on pharmaceutical wastewater such as CIP and TET.It has a very good development prospect and can play a huge role.