Degradation of antibiotics by modified vacuum-UV based processes: Mechanistic consequences of H 2 O 2 and K 2 S 2 O 8 in the presence of halide ions

Yuqing Sun, Dong Wan Cho, Nigel J.D. Graham, Deyi Hou, Alex C.K. Yip, Eakalak Khan, Hocheol Song, Yaru Li, Daniel C.W. Tsang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

44 Citations (Scopus)

Abstract

In this work, the degradation of cefalexin, norfloxacin, and ofloxacin was examined via various advanced oxidation processes (AOPs). Direct photolysis by ultraviolet (UV) and vacuum ultra violet (VUV) was less effective for the degradation of fluoroquinolone antibiotics such as norfloxacin and ofloxacin than that of cefalexin. Both hydrogen peroxide (H 2 O 2 ) and potassium persulfate (K 2 S 2 O 8 ) assisted UV/VUV process remarkably enhanced fluoroquinolone degradation. The addition of K 2 S 2 O 8 was superior to H 2 O 2 under VUV irradiation, with the best removal efficiency of norfloxacin and ofloxacin being almost 100% within 3 min in the presence of VUV/K 2 S 2 O 8 . The ofloxacin degradation rate was accelerated as concentrations of H 2 O 2 and K 2 S 2 O 8 was increased to 3 mM, but the degradation rate was slightly decreased with excess H 2 O 2 (>3 mM). The performance of modified VUV processes (i.e., VUV/H 2 O 2 and VUV/K 2 S 2 O 8 ) was inhibited at highly alkaline condition (pH 11). The co-existence of halides (Cl and Br ) enhanced antibiotics degradation via the modified VUV processes, but the reaction was almost unaffected in the presence of single halides. This study demonstrated that modified VUV processes (especially VUV/K 2 S 2 O 8 ) are efficient for eliminating fluoroquinolone antibiotics from water, which can be considered as a clean and green method for the treatment of antibiotics-containing industrial wastewater.

Original languageEnglish
Pages (from-to)312-321
Number of pages10
JournalScience of the Total Environment
Volume664
DOIs
Publication statusPublished - 10 May 2019

Keywords

  • Catalytic degradation
  • Chlorides/bromides
  • Fluoroquinolone antibiotics
  • Persulfate radicals
  • Sustainable remediation
  • Vacuum-ultraviolet light

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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