To demonstrate the feasibility of photocatalysis for the removal of polycyclic aromatic hydrocarbons (PAHs) from offshore-produced water (OPW), the effects of water matrix were studied by comparing the performance of TiO2-induced photocatalysis in distilled water and OPW media. The effects of salinity, insoluble particulate matter, and organic composition were evaluated. The results showed the strong improvements with the addition of catalysts but the enhancement of photocatalysis was restricted by OPW media. The photocatalytic degradation of PAHs with high molecular weights was more sensitive to the variations of salinity and insoluble matter due to their lower solubility. The overall degradation of PAHs was strongly restricted by the organic composition in OPW particularly the aromatic compounds. The aromatic compounds played an important role as ultraviolet-photon absorbents and competed with the photodegradation of PAHs. Because of their abundance in OPW, these species had the most significant...