Photocatalytic degradation of fractionated crude oil: potential application in oil spill remediation

Abstract

The current oil spill remediation strategies are costly and may be toxic to aquatic species and clean-up workers. There is, therefore, the need to look for alternative oil spill remediation strategies that are less costly and non-toxic. This paper presents the potential of TiO2 and its modified form (Fe-TiO2) to remediate crude oil fractions under the irradiation of sunlight (UV-Vis), visible (Vis) and ultraviolet (UV) lights. The TiO2 and Fe-TiO2 were synthesized by mild hydrothermal method and characterized with X-ray diffraction (XRD), Ultra-violet-visible spectroscopy (UV-Vis), Diffusion reflectance spectroscopy (DRS), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDX). The DRS result of Fe-TiO2 showed an enhanced absorption in the visible light region. The estimated optical band gaps were ~3.12 and ~2.9 eV for TiO2 and Fe-TiO2, respectively. The potential application of TiO2 and Fe-TiO2 in oil spill remediation was investigated through photocatalytic degradation of benzene soluble fraction, n-hexane soluble fraction and 1:1 volume by volume methanol/benzene soluble fraction in crude oil. The degraded crude oil fractions were characterized with UV-vis, Fourier Transform Infrared (FTIR) Spectroscopy and Gas Chromatography-Mass Spectrometer (GC-MS). The FTIR and UV-vis results showed that the Fe-TiO2 was more effective in photodegrading the crude oil fractions under sunlight light irradiation than TiO2. The GCMS results showed excellent photodegradation of the various crude oil fractions with the formation of new intermediate products. The results from the study show the potential application of TiO2 and Fe-TiO2 in crude oil spills remediation.