the evaluation of removal efficiency of cod due to water contaminated by gasoline by granular active carbon

Abstract Introduction: Oil pollution has severe effects on the water resources, environment, soil and human health. One of the most important goals of environmental engineers is removing of contaminants from water. Adsorption process is an effective manner for removing of contaminants in aqueous solutions. In this study, the efficiency of adsorption process by activated carbon granular has been investigated to decrease chemical oxygen demand (COD) due to gasoline in water. Methods: This study was an experimental study that was conducted in laboratory scale. The adsorption process was done batch in 100 ml in closed Erlenmeyer and the effective parameters such as the initial concentration of contaminant (1, 2% V/V) and contact time (2, 5, 10, 20, 30 and 60 min) were adapted. In all experiments, pH of 7.85 and the adsorbent mass of 1g/100mL were fixed. The COD values were measured by return reflux method according to D 5220 method presented in Standard Methods book for water and wastewater examinations. Data were analyzed with Freundlich, Langmuir and Temkin isotherm models for determining of adsorption isotherm. The charts were drawn by Excel software. Results: The results of this study showed that the average of gasoline removal percent in 1 and 2% was 93.64±3.17 and 53.7 ± 22.76, respectively that the difference was significant (P-value0.05). Regression coefficients showed that adsorption data followed by Freundlich isotherm model and pseudo-second order kinetic. Conclusion: We can conclude from this study that the activated carbon is an appropriate adsorbent for decreasing of COD due to gasoline contamination in water. The use of this adsorbent can well decrease COD of water contamination due to gasoline at times of 30 min.