A plasmonic photocatalyst Ag-AgI supported on mesoporous alumina (Ag-AgI/Al(2)O(3)) was prepared by deposition-precipitation and photoreduction methods. The catalyst showed high and stable photocatalytic activity for the degradation and mineralization of toxic persistent organic pollutants, as demonstrated with 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), and trichlorophenol (TCP) under visible light or simulated solar light irradiation. On the basis of electron spin resonance, cyclic voltammetry analyses under a variety of experimental conditions, two electron transfer processes were verified from the excited Ag NPs to AgI and from 2-CP to the Ag NPs, and the main active species of O(2)(*-) and excited h(+) on Ag NPs were involved in the photoreaction system of Ag-AgI/Al(2)O(3). A plasmon-induced photocatalytic mechanism was proposed. Accordingly, the plasmon-induced electron transfer processes elucidated the photostability of Ag-AgI/Al(2)O(3). This finding indicates that the high photosensitivity of noble metal NPs due to surface plasmon resonance could be applied toward the development of new plasmonic visible-light-sensitive photocatalysts and photovoltaic fuel cells.

was prepared by the deposition-precipitation method and was found to be a novel visible light driven photocatalyst. The catalyst showed high efficiency for the degradation of nonbiodegradable azodyes and the killing of Escherichia coli under visible light irradiation (λ > 420 nm). The catalyst activity was maintained effectively after successive cyclic experiments under UV or visible light irradiation without the destruction of AgBr. On the basis of the characterization of X-ray diffraction, X-ray photoelectron spectroscopy, and Auger electron spectroscopy, the surface Ag species mainly exist as Ag 0 in the structure of all samples before and after reaction, and Ag 0 species scavenged h VB + and then trapped e CB -in the process of photocatalytic reaction, inhibiting the decomposition of AgBr. The studies of ESR and H 2 O 2 formation revealed that • OH and O 2•-were formed in visible light irradiated aqueous Ag/AgBr/TiO 2 suspension, while there was no reactive oxygen species in the visible light irradiated Ag 0 /TiO 2 system. The results indicate that AgBr is the main photoactive species for the destruction of azodyes and bacteria under visible light. In addition, the bactericidal efficiency and killing mechanism of Ag/AgBr/TiO 2 under visible light irradiation are illustrated and discussed.

Photolysis Hydroxyl radicals Kinetics ByproductDegradation mechanism a b s t r a c tThe degradation of four pharmaceutical compounds (PhACs), ibuprofen (IBU), diphenhydramine (DP), phenazone (PZ), and phenytoin (PHT) was investigated via ultraviolet (UV) photolysis and UV/H 2 O 2 process with a low-pressure (LP) UV lamp. For each PhAC tested, direct photolysis quantum yields at 254 nm were found to be ranging from 6.32 Â 10 À2 to 2.79 Â 10 À1 mol E À1 at pH 7. The second-order rate constants of the reaction between the PhACs and OH were determined to be from 4.86 Â 10 9 to 6.67 Â 10 9 M À1 s À1 by using a competition kinetic model which utilized para-chlorobenzoic acid ( pCBA) as a reference IntroductionPharmaceutical compounds (PhACs) are developed and manufactured for specific biological effects, to improve human and animal health care, and livestock farming. PhACs are continuously introduced into the environment and are prevalent at small concentrations (Kolpin et al., 2002), which can affect water quality and potentially impact drinking water supplies, ecosystem and human health (Heberer, 2002b;Roefer et al., 2000;Trussell, 2001). Some of the adverse effects caused by pharmaceutical pollution include aquatic toxicity, resistant development in pathogenic bacteria, genotoxicity, and endocrine disruption (Halling-Sørensen et al., 1998;Kü mmerer, 2004;Sumpter, 1998). The presence of trace pharmaceutical and other xenobiotic compounds in finished drinking water is another public health concern, since little is known about potential chronic health effects associated with long term ingestion of mixtures of these compounds through drinking water (Kü mmerer, 2001;Stackelberg et al., 2004). Thus, it is an emerging issue in environmental science and * Corresponding author. Tel.: þ86 10 62849628; fax: þ86 10 62923541. E-mail address: huchun@rcees.ac.cn (C. Hu).A v a i l a b l e a t w w w . s c i e n c e d i r e c t . w a t e r r e s e a r c h 4 3 ( 2 0 0 9 ) 1 7 6 6 -1 7 7 4