Abstract

Intimate coupling of photocatalysis and biodegradation (ICPB) shows promise to remove recalcitrant organic compounds from water, because photocatalysis breaks the compounds into biodegradable intermediates that are immediately mineralized by microorganisms inside a macroporous carrier, where they are protected from UV light and free radicals. Key to successful ICPB is a carrier capable of accumulating biofilm in its interior and strongly adhering photocatalyst on its exterior. We employed a low-temperature sintering method, the O method, to adhere TiO2 to sponge-type macroporous carriers. The O method achieved a 7-fold increase of TiO2 density, compared to the previously used sol-gel method, and it conserved the macropores for biofilm accumulation. Although the O-method carrier met the basic requirements of ICPB when degrading 2,4,5 trichlorophenol, it had low photocatalytic activity for breaking down more complex aromatics, like reactive dyes. Therefore, we improved the sintering method in two steps called the D and DN methods: reducing the TiO2 concentration and then removing trimesic acid in the coating solution. The photocatalytic efficiency towards reactive black 5 increased 5 fold for the D method and 10 fold for DN method, and the DN carrier had superior TiO2 adherence during long-term operation.

Original languageEnglish (US)
Pages (from-to)6489-6496
Number of pages8
JournalWater Research
Volume46
Issue number19
DOIs
StatePublished - Dec 1 2012

Keywords

  • Intimate coupling of photocatalysis and biodegradation
  • Low-temperature sintering
  • Sponge-type carrier
  • Titanium dioxide

ASJC Scopus subject areas

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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