Influence of process parameters on the effectiveness of photooxidative treatment of pharmaceuticals

J Environ Sci Health A Tox Hazard Subst Environ Eng. 2018 Mar 21;53(4):338-351. doi: 10.1080/10934529.2017.1401394. Epub 2017 Nov 27.

Abstract

In this study, UV-C/H2O2 and UV-C/[Formula: see text] processes as photooxidative Advanced oxidation processes were applied for the treatment of seven pharmaceuticals, either already included in the Directive 2013/39/EU "watch list" (17α- ethynylestradiol, 17β-estradiol) or with potential to be added in the near future due to environmental properties and increasing consumption (azithromycin, carbamazepine, dexamethasone, erythromycin and oxytetracycline). The influence of process parameters (pH, oxidant concentration and type) on the pharmaceuticals degradation was studied through employed response surface modelling approach. It was established that degradation obeys first-order kinetic regime regardless structural differences and over entire range of studied process parameters. The results revealed that the effectiveness of UV-C/H2O2 process is highly dependent on both initial pH and oxidant concentration. It was found that UV-C/[Formula: see text] process, exhibiting several times faster degradation of studied pharmaceuticals, is less sensitive to pH changes providing practical benefit to its utilization. The influence of water matrix on degradation kinetics of studied pharmaceuticals was studied through natural organic matter effects on single component and mixture systems.

Keywords: Kinetics; natural organic matter; pharmaceuticals; photooxidation; response surface modelling.

MeSH terms

  • Hydrogen Peroxide / chemistry*
  • Hydrogen-Ion Concentration
  • Kinetics
  • Oxidants / chemistry*
  • Oxidation-Reduction
  • Pharmaceutical Preparations / analysis*
  • Pharmaceutical Preparations / radiation effects
  • Ultraviolet Rays*
  • Water Pollutants, Chemical / analysis*
  • Water Pollutants, Chemical / radiation effects
  • Water Purification / methods*

Substances

  • Oxidants
  • Pharmaceutical Preparations
  • Water Pollutants, Chemical
  • Hydrogen Peroxide