Synthesis of silica-titania and silica-titania-magnetite hybrids and their functionalization and sensitization with Fe3+ ions for the photodegradation of 4-chlorophenol under UV and visible light

Abstract

Several synthesis routes will be exploited to obtain a silica-titania hybrid of high superficial area. The synthesis will be carried out via sol-gel, using cetyl trimethylammonium bromide as pore template. Afterwards, the process applied to obtain the silica-titania hybrid will be employed to cover magnetite particles, in order to attribute magnetic features to the produced materials. Yet, the hybrid materials will be undergone to functionalization with rubeanic acid and then Fe3+ ions will be immobilized by coordination to the ligand, in order to sensitize the materials' surface for the photodegradation of 4-chlorophenol from aqueous media. At each step, the obtained materials will be characterized through FTIR, 13C and 29Si NMR, elemental analysis of C, N, S and O, X-ray difractometry and SEM, so that their constitution could be elucidated and the efficiency of each step could be assessed. The materials will be applied in batch experiments under UV and visible light to photodegrade 4-chlorophenol with air/O2 bubbling. The 4-chlorophenol concentration may be analyzed even by UV-vis as by determination of the total organic carbon in the media. Finally, the by-products generated in the process will be determined and the influence of parameters such as pH, contact time, temperature and wavelength over the degradation processes will be evaluated prior to the application of the materials to real wastewaters. (AU)