Contamination of the food supply from agricultural waste is an increasing concern worldwide. Numerous hazardous chemicals enter the environment from various industrial sources daily. Many of these pollutants, including 2,4-dinitrophenol (2,4-DNP), are water soluble, toxic, and not easily biodegradable. The solar photocatalytic degradation of 2,4-DNP was investigated in a solution of titanium dioxide (TiO2) that was prepared to be an optically clear aqueous solution of nanosized particles of TiO2. In order to achieve optimal efficiency of the photodegradation, the effects of light intensity and pH were conducted. All experiments were carried out in a batch mode. At a pH of 8. maximum removal of 70% of 2,4-DNP was achieved within 7 h of irradiation time. The nearly homogeneous solution of 5.8 nm TiO2 particles, size determined by XDS, were very effective in the photocatalytic degradation of 2,4-DNP. (C) 2008 Elsevier B.V. All rights reserved.