Journal of Hazardous Materials 252–253 (2013) 171–179 Contents lists available at SciVerse ScienceDirect Journal of Hazardous Materials jou rn al hom epage: www.elsevier.com/locate/jhazmat ZnO supported CoFe 2 O 4 nanophotocatalysts for the mineralization of Direct Blue 71 in aqueous environments Panneerselvam Sathishkumar a,b , Nalenthiran Pugazhenthiran a , Ramalinga Viswanathan Mangalaraja b,∗ , Abdullah M. Asiri c , Sambandam Anandan a,∗∗ a Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620015, India b Advanced Ceramics and Nanotechnology Laboratory, Department of Materials Engineering, Faculty of Engineering, University of Concepcion, Concepcion 407-0409, Chile c Center of Excellence for Advanced Materials Research (CEMAR), King Abdulaziz University, Jeddah 21413, P.O. Box 80203, Saudi Arabia h i g h l i g h t s ◮ Visible light active CoFe 2 O 4 /ZnO nanophotocatalyst was successfully synthesized. ◮ The lattice diffusion of Co and Fe was identified through TEM analysis. ◮ Using CoFe 2 O 4 /ZnO and per- oxomonosulphate, about 71% mineralization was seen for Direct Blue 71 in 5 h. g r a p h i c a l a b s t r a c t a r t i c l e i n f o Article history: Received 16 October 2012 Received in revised form 13 February 2013 Accepted 15 February 2013 Available online 26 February 2013 Keywords: CoFe2O4/ZnO nanocatalysts Direct Blue 71 Photocatalytic mineralization Peroxomonosulphate a b s t r a c t In this study, an attempt was made to render both the magnetic and photocatalytic properties in a semiconductor material to enhance the efficiency of degradation and recycling possibility of magnetic nanophotocatalysts. CoFe 2 O 4 and CoFe 2 O 4 loaded ZnO nanoparticles were prepared by a simple co- precipitation method and characterized using various analytical tools and in addition to check its visible light assisted photocatalytic activity. CoFe 2 O 4 /ZnO nanocatalyst coupled with acceptor, peroxomono- sulphate (PMS) showed 1.69-fold enhancement in Direct Blue 71 (triazo dye; DB71) mineralization within 5 h. The accomplished enrichment in decolorization was due to the production of more number of non-selective and active free radicals at the catalyst surface. © 2013 Elsevier B.V. All rights reserved. 1. Introduction The quantity of wastewater released from the textile industries is increasing every day which leads to unrealizable side effects [1–3]. The used modern synthetic aromatic dyes are more persis- tent and the rate of mineralization efficiency is inadequate upon ∗ Corresponding author. Tel.: +56 41 2207389; fax: +56 41 2203391. ∗∗ Corresponding author. Tel.: +91 431 2503639; fax: +91 431 2500133. E-mail addresses: mangal@udec.cl, rvmangalaraja@hotmail.com (R.V. Mangalaraja), sanand@nitt.edu (S. Anandan). utilizing conventional or biological mineralization methods. Most of these dyes get adsorbed on the surface of adsorbent/catalyst thus prevents its mineralization [4–8]. On the other hand, the interme- diates produced during the degradation of azo dyes are more toxic when compared to its parent compounds [9,10]. Therefore, a com- plete mineralization of azo dyes was aimed by many researchers for the last few decades using various methodologies [11–15]. In particular, semiconductor based heterogeneous photocatalysis has been received greater attention and enormous studies were available in literature so far [16–20]. However separation of these materials is problem after the photocatalytic processes and in order to separate such catalysts, researchers adopted a simple magnetic 0304-3894/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jhazmat.2013.02.030