Facile synthesis of magnetically recoverable Fe3O4/Al2O3/molecularly imprinted TiO2 nanocomposites and its molecular recognitive photocatalytic degradation of target contaminant

Magnetically separable Fe3O4/Al2O3/molecularly imprinted TiO2 nanocomposites with molecularly recognitive photoactivity have been prepared successfully by a multistep wet chemical process. Compared to Fe3O4/Al2O3/non-imprinted TiO2, the Fe3O4/Al2O3/molecularly imprinted TiO2 shows a better photocatalytic selectivity toward the template molecules. The enhanced selectivity can be attributed to the chemical interaction and size matching between template molecules and imprinted cavities. Photocatalytic activity studies for 2-nitrophenol degradation indicate an enhanced activity for the composites when the Al2O3 interlayer and molecularly imprinted TiO2 are present in the composites. The enhanced photocatalytic activity is attributed to the decrease in the migration of photogenerated charge carriers to the inter layer by Al2O3 interlayer and selective photodegradation of template molecules on the imprinted composites. The superparamagnetism of the imprinted composites provides a convenient route for separation of the catalyst from the reaction mixture by an external magnet. The spent catalyst could be recycled without appreciable loss of catalytic activity. (C) 2015 Elsevier B.V. All rights reserved.