Floating TiO 2 -Cork Nano-Photocatalysts for Water Purification Using Sunlight

In the present study, titanium dioxide (TiO 2 ) nano-photocatalysts were synthesized through microwave irradiation. In a typical microwave synthesis, TiO 2 nanomaterials were simultaneously produced in powder form and also directly covering cork substrates. The TiO 2 nanopowder was analyzed by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM), revealing that the solvothermal microwave synthesis resulted only in the TiO 2 anatase phase. From Fourier-transform infrared spectroscopy (FTIR), cork’s organic species, along with bands of TiO 2 , were detected. UV–VIS absorption spectrum revealed an absorption extension to the visible region, since a brown powdered TiO 2 product was obtained. Very fine nanoparticles were observed displaying a nearly spherical shape that agglomerates in larger particles. These larger particles fully covered the surface of the honeycomb cork cells, originating TiO 2 functionalized cork platforms. The TiO 2 functionalized substrates were further tested as floating photocatalysts and their photocatalytic activity was assessed from rhodamine B degradation under solar simulating light and natural sunlight. Reusability tests were also performed under natural sunlight. The strategy applied in this research work allowed the production of green and low-cost cork platforms based on TiO 2 photoactive materials with the ability to purify polluted water under natural sunlight.