C60 aminofullerene-magnetite nanocomposite designed for efficient visible light photocatalysis and magnetic recovery

A magnetically recyclable photosensitizing system for harnessing solar energy for water treatment and disinfection is reported. This system comprises C60 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 (1O2) probe) under visible-light irradiation along with the kinetic retardation of FFA decomposition in the presence of 1O2 quenchers suggests that the visible-light activity of C60 aminofullerene-derivatized msu-SiO2/mag (C60/msu-SiO2/mag) is related to the photosensitization of 1O2. On the other hand, the use of SiO2 gel and fumed SiO2 as magnetic supports drastically reduced the photosensitized generation of 1O2, 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 1O2 production using C60/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 C60/msu-SiO2/mag, demonstrating its potential for catalytic applications.