PMID- 11695471
OWN - NLM
STAT- MEDLINE
DCOM- 20020305
LR  - 20131121
IS  - 0273-1223 (Print)
IS  - 0273-1223 (Linking)
VI  - 44
IP  - 5
DP  - 2001
TI  - Determination of photonic efficiency and quantum yield of formaldehyde formation 
      in the presence of various TiO2 photocatalysts.
PG  - 279-86
AB  - Illumination of aqueous TiO2 suspentions yields hydroxyl radicals, which can be 
      trapped by methanol producing formaldehyde (HCHO). In this work, the photonic 
      efficiency and quantum yield of HCHO formation in colloidal TiO2 solutions and, 
      P25 and UV 100 suspensions have been determined. Differences in photocatalytic 
      activity of the three photocatalysts have been found and are discussed. The 
      photonic efficiency of HCHO formation in the presence of P25 and UV 100 depends 
      on the concentration of TiO2 and the pH. The critical concentration is 2.5 g/L. 
      Below this, the photonic efficiency with P25 is higher than with UV 100, and vice 
      versa. Optimum pH values for P25 and UV 100 giving the maximum photonic 
      efficiency are 7.7 and 10.4, respectively. Compared to P25 and UV 100, the true 
      quantum yield of HCHO formation in colloidal TiO2 solution varies a little with 
      pH and virtually does not change with the amount of loading of TiO2. The true 
      quantum yield varies as the inverse square root of light intensity. The quantum 
      yield increases from 0.02 to 0.08 when the absorbed photon flux decreases from 
      8.1 x 10(-7) Ein/L s to 4.9 x 10(-8) Ein/L s. A simple model is presented to 
      explain the experimental observation.
FAU - Wang, C
AU  - Wang C
AD  - Institut fur Solarenergieforschung, Hameln/Emmerthal(ISFH), Hannover, Germany.
FAU - Bahnemann, D W
AU  - Bahnemann DW
FAU - Dohrman, J K
AU  - Dohrman JK
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Water Sci Technol
JT  - Water science and technology : a journal of the International Association on 
      Water Pollution Research
JID - 9879497
RN  - 0 (Colloids)
RN  - 0 (Coloring Agents)
RN  - 0 (Disinfectants)
RN  - 15FIX9V2JP (titanium dioxide)
RN  - 1HG84L3525 (Formaldehyde)
RN  - 3352-57-6 (Hydroxyl Radical)
RN  - D1JT611TNE (Titanium)
SB  - IM
MH  - Catalysis
MH  - Colloids
MH  - Coloring Agents/*chemistry
MH  - Disinfectants/*chemistry
MH  - Formaldehyde/*chemistry
MH  - Hydrogen-Ion Concentration
MH  - Hydroxyl Radical/chemistry
MH  - Light
MH  - Photochemistry
MH  - Titanium/*chemistry
MH  - Water Purification/methods
EDAT- 2001/11/07 10:00
MHDA- 2002/03/07 10:01
CRDT- 2001/11/07 10:00
PHST- 2001/11/07 10:00 [pubmed]
PHST- 2002/03/07 10:01 [medline]
PHST- 2001/11/07 10:00 [entrez]
PST - ppublish
SO  - Water Sci Technol. 2001;44(5):279-86.