Efficient photocatalytic removal of aqueous NH4+-NH3 by palladium-modified nitrogen-doped titanium oxide nanoparticles under visible light illumination, even in weak alkaline solutions

Dechen Sun, Wuzhu Sun, Weiyi Yang, Qi Li, Jian Ku Shang

Research output: Contribution to journalArticlepeer-review

Abstract

Aqueous ammonium-ammonia (NH4+-NH3) is a commonly found pollutant in industrial and domestic wastewater, which poses a great threat to both the environment and the human health. Photocatalytic treatment had been proved to be an efficient approach to oxidize aqueous NH4+-NH3 for its removal. However, most current researches still suffer from the requirements of UV illumination and strong alkaline environment, low removal rates, and high ratios of toxic oxidation by-products of NO3- and NO2-. In this study, palladium-modified nitrogen-doped titanium oxide (TiO2-xNx/PdO) nanoparticles were synthesized by a simple sol-gel process, which demonstrated an effective photocatalytic removal of aqueous NH4+-NH3 under visible light illumination. By optimizing the reaction conditions, a high removal rate of over 90% could be achieved by TiO2-xNx/PdO nanoparticles under only visible light illumination with the major product of N2, and the production of toxic photocatalytic oxidation by-products of NO3- and NO2- was minimized. The real time solution pH was found to be critical for the photocatalytic oxidation of aqueous NH4+-NH3. By keeping the solution pH constantly at ~8, the effective photocatalytic removal of aqueous NH4+-NH3 in a weak alkaline solution was achieved for the first time.

Original languageEnglish (US)
Pages (from-to)728-734
Number of pages7
JournalChemical Engineering Journal
Volume264
DOIs
StatePublished - Mar 5 2015

Keywords

  • Aqueous ammonium-ammonia
  • Palladium-modified nitrogen-doped titanium oxide
  • Photocatalytic removal
  • Visible-light
  • Weak alkaline environment

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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