1. Dipartimento di Ingegneria Chimica, Mineraria e delle Tecnologie Ambientali, Università di Bologna Via Terracini, 28 40131 Bologna, Italy, Department of Materials Science and Engineering, School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, GR-15780 Athens, Greece, and Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26500 Patras, Greece