Photocatalytic degradation of naphthalene in offshore produced water: comparison of immobilized and suspended TiO2
Offshore oil and gas industry has produced and discharged a considerable amount of produced on a daily basis. However, current treatment methods such as gravity separation are not effective in removing dissolved organic matters before discharge. As the increasing environmental awareness and stringent regulation, it is necessary to develop more effective approaches to remove dissolved organics. Photocatalysis has been introduced in water and wastewater treatment and can effectively remove organic pollutants non-selectively. However, the separation of catalysts after treatment is difficult and costly. Thus, the immobilization of catalyst could be an alter approach that avoids any post-treatment. In this study, produced water was irradiated under UV-C (254 nm) for 12 h with the presence of catalysts. A commercial catalyst, Aeroxide® P25 was immobilized on glass plates by a heat attachment method. The P25 powder was used as a referent catalyst. Naphthalene was selected as an indicator owing to its abundance in produced water and typical chemical property of polycyclic aromatic hydrocarbons (PAHs). The results showed that the immobilized catalyst has a better enhancement to photo-oxidation. The turbidity was significantly reduced compared with suspended system.