Details

Autor(en) / Beteiligte

• Benabbou, A.K.
• Guillard, C.
• Pigeot-Rémy, S.
• Cantau, C.
• Pigot, T.
• Lejeune, P.
• Derriche, Z.
• Lacombe, S.

Titel

Water disinfection using photosensitizers supported on silica

Ist Teil von

• Journal of photochemistry and photobiology. A, Chemistry., 2011-03, Vol.219 (1), p.101-108

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2011

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The disinfection efficiency against Escherichia coli in water of new silica-based materials containing aromatic photosensitizers (APS) was compared to that of TiO 2 under UV irradiation. The APS used in these experiments (9,10-anthraquinone-4-carboxylic acid (ANT) and a recently investigated cyanoaromatic, 9,14-dicyanobenzo[b]triphenylene-3-carboxylic acid (DBTP-COOH)) were grafted onto commercial silica materials. The influence of several physical and chemical parameters on the photoinduced inactivation of the microorganisms was considered: amount of catalysts, APS structure and concentration in the host material. While no bacterial inactivation took place in the presence of silica in the dark and in the absence of silica under UVA, a slow bactericidal effect was observed in the presence of pure silica under UVA. ANT and DBTP based-materials improved the bacterial inactivation rate under UVA irradiation. The Chick and Watson analysis of the results (without taking into account the induction period observed with all the silica materials), at the same material concentration allowed to conclude that the bacterial inactivation rate constant, k, is the highest (0.13 L g −1 min −1) for SiO 2–ANT with an anthraquinone concentration of 280 μmol g −1 and no longer increased with ANT concentration. This catalyst was more efficient than SiNH 2–DBTP ( k = 0.02 L g −1 min −1). The latency period for bacterial inactivation with the APS based materials was longer than that observed with TiO 2/UVA, but when using 0.25 g of materials, SiO 2–ANT had a k (0.720 L g −1 min −1) three times higher than TiO 2 (0.256 L g −1 min −1). If the actual photosensitizer or TiO 2 molar concentration were examined, it was concluded that all the k values determined for the sensitizer containing silica are much higher (from 305 to 4717 L mol −1 min −1) than that obtained for TiO 2 (24.5 L mol −1 min −1). This result emphasizes the high catalytic efficiency of the silica materials containing low amounts of aromatic PSs. The influence of adsorption of the materials on the microorganisms was shown and the results discussed according to the possible Reactive Oxygen Species. Different mechanisms were proposed for TiO 2 and for the supported sensitizers.