Photodegradation of emerging micropollutants using the medium-pressure UV/H2O2 Advanced Oxidation Process

Water Res. 2013 May 15;47(8):2881-9. doi: 10.1016/j.watres.2013.02.045. Epub 2013 Mar 13.

Abstract

A medium-pressure (MP) ultraviolet (UV) process has been applied to investigate the direct UV photolysis and UV/H2O2 oxidation of selected model micropollutants (naproxen, carbamazepine, diclofenac, gemfibrozil, ibuprofen, caffeine, 2,4-D, 2,4-DCP, and mecoprop). The quantum yields were found to be between 0.0010 and 0.13 at pH = 7. In the MP UV/H2O2 oxidation, the pseudo first-order rate constants for the selected compounds were found to be dependent on their initial concentrations (at mg/L levels) and on the H2O2 concentration. The UV doses required for 50% and 90% removal at various H2O2 levels varied widely among the compounds tested. Second-order rate constants (ranging from 4.1 × 10(9) to 1.4 × 10(10) M(-1) s(-1)) for the reaction between the selected compounds and hydroxyl radicals were determined using a competition-kinetics approach, where para-chlorobenzoic acid (pCBA) was chosen as the reference compound. Further, as an evaluation of electrical energy efficiency, the Figure-of-Merit, Electrical Energy per Order (EEO) was determined for the selected compounds using a batch reactor at 25 and 50 mg/L H2O2 concentrations. The electrical energy (in kWh) required to reduce a pollutant concentration by 90% ranged from 1.3 to 7.1 kWh m(-3).

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alberta
  • Caffeine / chemistry
  • Chromatography, High Pressure Liquid
  • Herbicides / chemistry
  • Hydrogen Peroxide / chemistry*
  • Oxidation-Reduction
  • Pharmaceutical Preparations / chemistry
  • Photolysis*
  • Pressure
  • Waste Disposal, Fluid / instrumentation
  • Waste Disposal, Fluid / methods*
  • Water Pollutants, Chemical / chemistry*
  • Water Purification / instrumentation
  • Water Purification / methods*

Substances

  • Herbicides
  • Pharmaceutical Preparations
  • Water Pollutants, Chemical
  • Caffeine
  • Hydrogen Peroxide