Dielectric barrier discharge induced the degradation of the emerging contaminant ibuprofen in aqueous solutions

Abstract

This study focused on the degradation of the worldwide nonsteroidal anti-inflammatory drug (NSAID) ibuprofen (IBP) by dielectric barrier discharge (DBD). Factors affecting IBP degradation efficiency were examined, such as output power, initial ibuprorfen concentration, solution pH values, and various additives (H₂O₂, t-BuOH, humic acid). When IBP concentration of 18 mg/L and the output power of 70 W were chosen, 95.6% of IBP was removed after 5 min treatment. Humic acid and 0.3% H₂O₂ additives enhanced the IBP degradation process, while 1% H₂O₂ additive restrained the degradation process of IBP. The addition of t-BuOH also hindered the degradation process of IBP. The degradation of IBP was found to be affected by solution pH, with higher degradation efficiency occurring under strong acidic condition than alkaline and neutral conditions. The solution pH values became lower with the increasing of discharge time. High-performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESMS) techniques were employed to identify the IBP derivatives. The mono-hydroxylates of IBP, and the products due to the oxidation of propanoic acid, and isobutyl substituents of IBP were identified.

Keywords:

• Degradation
• Ibuprofen
• Dielectric barrier discharge

Acknowledgment

This work has been supported jointly by the National Natural Science Foundation (Grant No. 11075039).