Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction

Zrinka Švagelj; Vilko Mandić; Lidija Ćurković; Martina Biošić; Irena Žmak; Mattia Gaborardi

doi:10.3390/ma13010227

Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction

Materials (Basel). 2020 Jan 4;13(1):227. doi: 10.3390/ma13010227.

Authors

Zrinka Švagelj¹, Vilko Mandić², Lidija Ćurković¹, Martina Biošić³, Irena Žmak¹, Mattia Gaborardi⁴

Affiliations

¹ Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10000 Zagreb, Croatia.
² Department of Inorganic Chemical Technology and Non-Metals, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 20, 10000 Zagreb, Croatia.
³ Department of Analytical Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 20, 10000 Zagreb, Croatia.
⁴ Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14, 4149 Basovizza, Trieste, Italy.

Abstract

In the present work, alumina (Al₂O₃) foam was prepared by the replica method where a polyurethane (PU) foam (30 pores per inch (ppi)) template was impregnated with a 60 wt.% Al₂O₃ suspension. Sintered Al₂O₃ foam was used as substrate for the deposition of sol-gel derived titania (TiO₂) film using dip coating. For the preparation of TiO₂ sol, titanium(IV) isopropoxide (Ti-iPrOH) was used as the precursor. The common problem of qualification and quantification of a crystalline coating on a highly porous 3D substrate with an uneven surface was addressed using a combination of different structural characterization methods. Using Powder X-ray Diffraction (PXRD) and synchrotron Grazing Incidence X-ray Diffraction (GIXRD) on bulk and powdered Al₂O₃ foam and TiO₂-coated Al₂O₃ foam samples, it was determined Al₂O₃ foam crystallizes to corundum and coating to anatase, which was also confirmed by Fourier Transformed Infrared Spectroscopy (FTIR). Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDS) revealed the structural and microstructural properties of the substrate and coating. Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) were used to clarify the evolution of the porous microstructure. The Al₂O₃-TiO₂ composite was evaluated as a photocatalyst candidate for the degradation of the micropollutant medication memantine. The degradation rate was monitored using a light-emitting diode (LED) lamp operating at electromagnetic (EM) wavelength of 365 nm. The photocatalytic activity of sol-gel-derived TiO₂ film immobilized on the Al₂O₃ foam was compared with commercially available TiO₂ nanoparticles, P25-Degussa, in the form of a suspension. The levels of memantine were monitored by High-Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MS/MS). The efficiency and rate of the memantine photodegradation by suspended TiO₂ nanoparticles is higher than the TiO₂-coated Al₂O₃ foam. But, from the practical point of view, TiO₂-coated Al₂O₃ foam is more appropriate as a valuable photocatalytic composite material.

Keywords: Al2O3 foam; LED lamp; TiO2; memantine; photocatalysis.