title: Photochemical reactivity of aqueous fullerene clusters: C60versus C70.
abstract: Over the past few years, there has been a strong interest in exploring the potential impact of fullerenes in the environment. Despite that both C60and C70have been detected in environmental matrices, the research on the impact of higher fullerenes, such as C70,has been largely missing. This study evaluated and compared the phototransformation of aqueous C60and C70clusters (nC60and nC70) and their1O2production under sunlight and lamp light irradiation (315nm, 360nm and 420nm). The nC60and nC70samples formed by direct mixing with water adopted a face-centered cubic (FCC) crystal structure. The apparent quantum yields (AQYs) of fullerene phototransformed were relatively constant over the examined wavelengths, while1O2production AQYs decreased with increased wavelengths. The long-term fate studies with outdoor sunlight indicated that both nC60and nC70lost considerable organic carbon contents (>80%) in water after ∼8 months of irradiation and that the intermediate photoproducts of nC60and nC70exhibited a progressively increased level of oxygen-containing functionalities. Overall, the study indicates that nC70can be photochemically removed under sunlight conditions and that the photoreactivity of nC60based on AQYs is greater than that of nC70.
authors.affiliation: Department of Environmental Engineering, National Cheng Kung University, Tainan City, 70101, Taiwan. Electronic address: whou@mail.ncku.edu.tw.
authors.forename: Wen-Che
authors.initials: WC
authors.lastname: Hou
authors.affiliation: Department of Environmental Engineering, National Cheng Kung University, Tainan City, 70101, Taiwan.
authors.forename: Shih-Hong
authors.initials: SH
authors.lastname: Huang
keywords: C(70); Fate; Fullerene; Phototransformation; Quantum yield; Singlet oxygen