Functional titania–silica/chlorophyllin hybrids: design, fabrication, comprehensive physicochemical characteristic and photocatalytic test

Abstract

Chlorophyllin (which was used as sensitizer) was adsorbed onto a synthetic titania–silica oxide system, prepared via a sol–gel method. It was investigated how the adsorption process was affected by the initial concentration of chlorophyllin and the contact time of the solution. The physicochemical and structural properties of the inorganic support were comprehensively analyzed, including determination of the dispersive properties and morphology of the material (particle size distribution, SEM image), crystalline structure (XRD), chemical composition (EDS), parameters of the porous structure (low-temperature N 2 sorption) and thermal stability (TGA/DTA). The effectiveness of chlorophyllin adsorption on TiO 2 –SiO 2 was examined by Fourier transform infrared spectroscopy. The degree of coverage of the inorganic support with chlorophyllin was calculated from the Berendsen and de Golan equation based on BET and elemental analysis results. The kinetics of the adsorption of chlorophyllin onto the synthetic titania–silica oxide system were also determined. The experimental data correspond directly to a pseudo-second-order model. Moreover, the photocatalytic activity of selected TiO 2 –SiO 2 /chlorophyllin hybrids with respect to the decomposition of C.I. Basic Violet 10 dye was investigated. It was found that the titania–silica hybrids conjugated with chlorophyllin exhibited higher photocatalytic activity in the degradation of C.I. Basic Violet 10 than the pure TiO 2 –SiO 2 material. Moreover, the kinetics of the photocatalytic degradation of selected organic compound was determined based on the Langmuir–Hinshelwood equation, assuming the pseudo-first-order reaction.