1 Use of CeO 2 , TiO 2 and Fe 3 O 4 nanoparticles for the removal of lead from water. Toxicity of nanoparticles and derived compounds. Sonia Recillas 1 , Ana García 1 , Edgar González 2 , Eudald Casals 2 , Victor Puntes 2,3 , Antoni Sánchez 1,* , Xavier Font 1 1. Department of Chemical Engineering, Escola d’Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain 2. Institut Català de Nanotecnologia, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain 3. Insitut Català de Recerca i Estudis Avançats, Passeig Lluís Companys, 23, 08010 Barcelona, Spain *Corresponding author: Antoni Sánchez Phone: 34-935811019 Fax: 34-935812013 E-mail address: antoni.sanchez@uab.cat Pre-print