Enhanced removal of acid dye under visible light using CNT-modified photocatalyst coated onto PU foam

In the present study, the N-TiO 2 /PANI modified with CNTs was immobilized on the polyurethane (PU) foam and the effect of PU foam as support and CNTs as binder were investigated in terms of photodegradation of Acid Red 73 under visible light. The surface characteristics and optical properties of the as-prepared film were studied based on X-ray diffraction, Brunauer–Emmett–Teller surface, field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR) and diffuse reflectance spectroscopy (DRS) analysis. FT-IR results detected the existence of –COCl on CNTs in the film which can react with the functional groups (–NH–) on the PANI/TiO 2 surface. This can be beneficial for durability of photocatalyst film, as confirmed by FESEM images. Moreover, the presence of carbon in the composite structure leads to the increased surface area and porosity which have contribution to the enhanced photocatalytic performance of the modified sample. Based on DRS analysis, the as-prepared samples exhibit the absorption light into the visible region mainly due to the PANI presence. The proposed mechanism shows that the PANI plays a major role in the enhanced charge separation at the titania surface. Photoactivity evaluation shows the higher efficiency for dye degradation using the N–TiO 2 /PANI/CNTs film comparing to the slurry system which can be attributed to macroporous structure of PU foam as support improving the light penetration and the catalyst interaction with the contaminate molecules. The durability and reasonable photocatalytic performance of the as-prepared film makes to consider it as a favorable alternative for the practical applications.