Facile synthesis of Fe3O4/SiO2/molecularly imprinted hydroxyapatite nanocomposite and its enhanced photocatalytic degradation of target contaminant

A novel composite photocatalyst of core-shell structured Fe3O4/SiO2/molecularly imprinted hydroxyapatite with molecularly recognitive photoactivity has been successfully fabricated by a facile wet chemical process. Compared with Fe3O4/SiO2/hydroxyapatite, the Fe3O4/SiO2/molecularly imprinted hydroxyapatite exhibited a much higher photocatalytic selectivity for the degradation of template molecules in aqueous suspension. The excellent selectivity can be ascribed to the chemical interaction and size matching between template molecules and imprinted cavities. The photocatalytic activity of Fe3O4/SiO2/molecularly imprinted hydroxyapatite towards template molecules was enhanced significantly, a combined result of the decrease in the migration of photogenerated charge carriers to the inter layer by SiO2 interlayer and selective photodegradation of template molecules on the imprinted nanocomposites. The superparamagnetic properties of the Fe3O4/SiO2/molecularly imprinted hydroxyapatite provide a convenient route for separation of the catalyst from the reaction mixture by an external magnetic field. The spent catalyst could be recycled without appreciable loss of catalytic activity.