Oily Wastewater Treatment by Nano-TiO2-Induced Photocatalysis: Seeking more efficient and feasible solutions

Oil is one our most important energy sources However, the wide use of oil could lead to diverse environmental problems, such as oily wastewater discharge. Oily wastewater is water that has become contaminated through oil and gas production, the refinery process, transportation, or storage. The dispersion and dissolution of oil fractions into water result in its contamination with free oil and grease, aliphatic hydrocarbons, aromatic hydrocarbons (e.g., benzene, toluene, ethylbenzene, and xylenes, known as BTEX), phenols, polycyclic aromatic hydrocarbons (PAHs), and highly soluble organic compounds (e.g., carboxyl acids. Many of these components are toxic, persistent, and bioaccumulative, posing a threat to ecosystems and human beings [6]-[9]. Thus, efficient treatment of oily wastewater is a necessity.