Background and Objectives: 2, 4-dichlorophenoxy acetic acid is a well-known herbicide which can be dangerous for  both human and animal health in different ways such as its presence in drinking water. This study aimed at Performance of granular activated carbon to 2-4-D removal from aqueous solution and assessing the relationship between COD and 2-4-D concentration
Materials and Methods: This study is a lab-scale study. Firstly, different 2-4-D concentrations were prepared from Stock solution (1000 mg/L), and then their CODs were measured. Optimum pH for 2-4-D removal was determined and its absorption rate at different concentrations was measured.
Results: Results showed a clear relationship between COD and 2-4-D concentration. On the other hand, COD removal increased as time elapsed, so that maximum removal 90% and 84% at initial 2-4-D concentrations of 50 and 100 mg/L were observed at contact time of 50 min respectively. Optimum pH for all concentrations was determined as 6.
Conclusion: According to present study it can be concluded that activated carbon have be up to 90% of 2-4-D removal from water environment. In addition, a significant relationship was observed between COD and 2-4-D concentration, so that direct measurement of COD can be used instead of 2-4-D measurement.