Hexavalent chromium removal using metal oxide photocatalysts

Qian Cheng, Chengwei Wang, Kyle Doudrick, Candace Chan

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Photocatalysis is an attractive treatment method for removing hexavalent chromium (Cr(VI)) from water. Thus far, photocatalytic reduction of Cr(VI) has been investigated mostly using TiO2 photocatalysts in acidic water solutions. Here we investigate Cr(VI) removal using zinc oxide (ZnO), tungsten trioxide (WO3), and sodium tantalate (NaTaO3), metal oxides that display good activity for other photocatalytic reactions such as water splitting, as well as titanium oxide (TiO2, Evonik P90). The efficiency for Cr(VI) removal using these photocatalysts was investigated in synthetic neutral and alkaline water, as well as in cooling tower blowdown water. The effect of several additives used in water treatment processes on the Cr(VI) removal rate was also studied. For NaTaO3, citric acid was found to have a detrimental effect to Cr(VI) removal, while sodium formate, ammonium chloride, and sodium sulfite were beneficial. While sulfite alone could chemically reduce Cr(VI), sulfite in combination with a photocatalyst resulted in faster and complete removal of Cr(VI) in 10min using a SO32-/Cr(VI) ratio >35 in pH~8 solutions. NaTaO3 was found to display the highest Cr(VI) removal rates on a photon basis at pH 3 and in the presence of sodium sulfite, while ZnO and TiO2 showed the best performance in pH 7 and cooling tower blowdown water.

Original languageEnglish
Pages (from-to)740-748
Number of pages9
JournalApplied Catalysis B: Environmental
Volume176-177
DOIs
Publication statusPublished - Oct 1 2015

Fingerprint

Photocatalysts
Oxides
chromium
Chromium
Metals
sulfite
Water cooling towers
Sodium
sodium
oxide
Zinc oxide
Water
water
zinc
Zinc Oxide
Sulfites
formic acid
alkaline water
Photocatalysis
Titanium oxides

Keywords

  • Cooling tower blowdown
  • Hexavalent chromium
  • NaTaO<inf>3</inf>
  • Photocatalyst
  • Photoreduction

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology
  • Environmental Science(all)

Cite this

Hexavalent chromium removal using metal oxide photocatalysts. / Cheng, Qian; Wang, Chengwei; Doudrick, Kyle; Chan, Candace.

In: Applied Catalysis B: Environmental, Vol. 176-177, 01.10.2015, p. 740-748.

Research output: Contribution to journalArticle

Cheng, Qian ; Wang, Chengwei ; Doudrick, Kyle ; Chan, Candace. / Hexavalent chromium removal using metal oxide photocatalysts. In: Applied Catalysis B: Environmental. 2015 ; Vol. 176-177. pp. 740-748.
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