C-60 aminofullerene-magnetite nanocomposite designed for efficient visible light photocatalysis and magnetic recovery

Abstract

A magnetically recyclable photosensitizing system for harnessing solar energy for water treatment and disinfection is reported. This system comprises C-60 aminofullerene as a sensitizer for singlet oxygenation and functionalized mesoporous silica (msu-f SiO2) encapsulating magnetite nanoparticles (msu-SiO2/mag) as a magnetically separable host. Rapid degradation of furfuryl alcohol (FFA) (a singlet oxygen (O-1(2)) probe) under visible-light irradiation along with the kinetic retardation of FFA decomposition in the presence of O-1(2) quenchers suggests that the visible-light activity of C-60 aminofullerene-derivatized msu-SiO2/mag (C-60/msu-SiO2/mag) is related to the photosensitization of O-1(2). On the other hand, the use of SiO2 gel and fumed SiO2 as magnetic supports drastically reduced the photosensitized generation of O-1(2), which is ascribed to the absence of an ordered pore structure in the alternative silica support, resulting in an uncontrolled growth of Fe3O4 and an aggregation of the fullerenes on the SiO2 gel and fumed SiO2. Significant O-1(2) production using C-60/msu-SiO2/mag led to the effective oxidation of emerging pharmaceutical contaminants and inactivation of MS-2 bacteriophage under visible-light irradiation. Magnetic recovery and the subsequent reuse of the composite did not cause any significant loss in the photosensitizing activity of C-60/msu-SiO2/mag, demonstrating its potential for catalytic applications. (C) 2013 Elsevier Ltd. All rights reserved.