Hatam Godini - Department of Environmental Health Engineering, Health School, Alborz University of Medical Sciences, Karaj, Iran
Abdollah Dargahi - Department of Environmental Health Engineering, Health School, Hamadan University of Medical Sciences, Hamadan, Iran
Mitra Mohammadi - Department of Environmental Health Engineering, Health School, Kermanshah University of Medical Sciences, Kermanshah, Iran
Ghodratollah Shams - Department of Environmental Health Engineering, Health School, Lorestan University of Medical Sciences, Khorramabad, Iran

Background & Aims of the Study: Nitrogenous compounds could directly create manyproblems for human s health and the environment. Thus, removal of nitrogenous compounds isnecessary. Among the most important problems, decreasing dissolved oxygen, toxicity foraquatics, eutrophication, converting aerobic medium into anaerobic one and corrosion could benoted. The aim of this study was determination of powdered activated carbon absorptionefficiency in ammonia-nitrogen removal from aqueous environments.Materials & Methods: This study was conducted as an experimental laboratory scale. Indiscontinuous system, the effect of parameters including absorbent dose (0.5-1.5 gr), initial Nammoniaconcentration (100-200 mg/l), pH (3-9) and contact time (2-120 min) on systemefficiency evaluated through Response Surface Methodology (RSM). The results were fitted intoFreundlich and Langmuir absorption isotherm and then absorption by the activated carbonabsorbent compared by these models and absorption were analyzed. Also, first order, semisecondorder and particulate infiltration reaction kinetics were evaluated.Results: N- ammonia removal efficiency had a direct relationship with absorbent dose, pH,contact time and reverse relation with initial N-ammonia concentration. Study the isotherms andkinetics process showed that activated carbon followed Freundlich isotherm as well as semisecondorder kinetics. Results from central composition design (CCD) model showed that thestudied system efficiency fitted to linear equation and results from model predictions had a greatagreement with experimental data (R2=0. 98).Conclusion: according to appropriate removal efficiency, powdered activated carbon could beutilized as an efficient and inexpensive absorbent for ammonium absorbance. Decreasing thesystem efficiency by increasing pollutant concentration must be considered.

Powdered Activated CarbonAmmonia NitrogenAbsorption IsothermReaction KineticsAqueous EnvironmentRSM