Res. Chem. Intermed.
, Vol. 33, No. 3–5, pp. 421–431 (2007)
Also available online - www.brill.nl/rci
Solar puriﬁcation and potabilization
of water containing dyes
THU-HOAI BUI, MAITHAA KARKMAZ, ERIC PUZENAT,
CHANTAL GUILLARD and JEAN-MARIE HERRMANN
Laboratoire d’Application de la Chimie à l’Environnement (LACE), UMR CNRS 5634,
Université Claude Bernard Lyon 1, Bâtiment J. Raulin,
43 Boulevard du 11 novembre 1918, 69622 Villeurbanne, France
Received 10 December 2005; accepted 10 January 2006
Abstract—Organic pollutant removal is the main ﬁeld of water photocatalytic decontamination.
Molecules such as pesticides (herbicides, insecticides, fungicides, etc.) or dyes are totally destroyed
and mineralized into CO
and innocuous inorganic anions (Cl
). Presently, two
azo-dyes (i.e., containing the –N=N– azo group), Cibacron Brilliant Red 3B-A and Remazol
Black B (Reactive Black 5), were successfully destroyed and totally mineralized. The stoichiometric
coefﬁcients of the total degradation, as well as the mass balances have been established with different
analytical tools: TOC for carbon, DCO for oxygen, ionic-HPLC for heteroatoms (N, S, P) and pH-
metry for hydrogen. Moreover, nitrogen balance has been established during the photocatalytic
degradation of the dyes by considering not only nitrate and ammonium ions in the solution, but
also the formation of N
in the gas phase. The quantiﬁcation of N
molecules suggests that the
photocatalytic degradation of azo-compounds is 100% selective in generating gaseous dinitrogen.
The reaction mechanism was ﬁrst determined in a laboratory photoreactor, before degradation in
larger pilot solar photoreactors, using UV-A radiant ﬂux from the sun in a new sub-discipline called
Keywords: Photocatalysis; titania; dye removal; solar energy; heliophotocatalysis; pilot photoreactors.
Heterogeneous photocatalysis is considered as one of the new Advanced Oxidation
Technologies (AOTs) for air and water puriﬁcation treatment. Several books and
reviews have recently been devoted to this problem [1 –9]. In line with this series of
books, the pioneering role of Mario Schiavello has to be particularly underlined
[1, 2]. He subsequently studied the degradation of various pollutants such as
nitrophenol , phenol , toluene  and acetonitrile .
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