Different types of organic impurities such as dyes, acids, and alcohols are discharged into potable water sources. The removal of these hazardous organic pollutants from wastewater is an important task globally. However, the conventional methods used to remove organic impurities suffer from low efficiency and recycling problems. Photocatalysis is a promising advanced oxidation process for the degradation of organic compounds in aqueous solution. Titanium dioxide (TiO2) is commonly used as a photocatalyst. However, the wide bandgap of TiO2 means that it is activated by ultraviolet light, which restrains its ability to harvest solar energy. In this study, a simple water-based precipitation method was used to synthesize TiO2@nanodiamond composites. The ability of the composites to degrade bisphenol A as a model organic pollutant was investigated. It was found that 10 ppm of bisphenol A was completely degraded in 100 min by the TiO2@nanodiamond photocatalyst under ultraviolet illumination.