Synthesis and application of pure and modified TiO₂ for photocatalytic remediation of fractionated crude oil

Oil spills have been a major source of concern due its harmful effect on the environment. To reduce the effect of oil spills, new remediation strategies need to be developed whiles enhancing the efficiency of existing remediation ones. In this study, the potential of TiO₂ and its modified form (Fe-TiO₂) as a stand-alone or as an add-on remediation strategy was explored. This was carried out by accessing the how TiO₂ and Fe-TiO₂ photo degrades crude oil fractions (aromatics, paraffins, asphaltenes) under sunlight, visible (400W) and UV light with four (4) hours irradiation time. The TiO₂ and the Fe-TiO₂ used were synthesized with the mild hydrothermal method and characterized with XRD, UV-Vis, DRS, SEM, EDX, TGA, DSC and FTIR. These characterization techniques confirmed the production of the anatase phase TiO₂ and Fe-TiO₂ with estimated bandgap of 3.12 eV and 2.90eV, respectively. The Debye Scherrer's equation was used to compute the crystallite size from the XRD patterns as 4.10 nm and 3.85 nm for TiO₂ and Fe-TiO₂, respectively. The photodegradation experiments on the aromatics, paraffins and asphaltenes showed that Fe-TiO₂ is better at degrading the fractions than TiO₂ under visible light and sunlight irradiation. These conclusions were arrived at from the analysis of the photoproducts using UV-Vis, FTIR and GC/MS. The GC/MS spectra showed the formation of new compounds, diminishing in the concentration of existing compounds and the disappearance of existing compounds. It was revealed that, photocatalysis is effective in remediating aromatics than asphaltenes and paraffins. The results from the study showed the potential of photoremediation as a stand-alone or add-on oil spill response strategy. (Author)