Solar photocatalytic oxidation (PCO) for the degradation of liquid and gaseous pollutants is receiving increasing attention. In the present investigation, an attempt has been made to demonstrate the feasibility of a novel slurry photoreactor for the mineralization of 2,4dichlorophenoxyacetic acid (2,4-D) by using a semiconductor photocatalyst (TiO2), air, and concentrated solar radiation. The photocatalytic degradation (PCD) of 2,4-D using concentrated solar radiation in both batch and continuous bubble column reactors has been studied. The photocatalytic reaction takes place on the surface of the catalyst material. Therefore, the adsorption behavior of 2,4-D on the catalyst has also been investigated. The effects of the presence of anions and the pH of the wastewaters are reported. The photocatalytic degradation studies of 2,4-D in the novel slurry bubble column indicate that this type of reactor can be used commercially for the treatment of wastewater from a plant manufacturing 2,4-D.