Academic Staff, Materials and Nuclear Fuels Research School, Nuclear Science and Technology Research Institute, I.R. Iran
In this research, the ability of economically sawdust adsorbent coated by polypyrrole, a semiconductor polymer, for uranium sorption from aqueous solutions was studied in a batch system. The experiments were performed to investigate the effect of operating parameters such as pH, contact time, adsorbent amount, initial concentration, and temperature on the sorption of uranium, and optimum operating conditions were determined. The adsorption amount of 54.65 mg/g was obtained at operational conditions, i.e., absorbent dosage 1 g/L, 100 mg/L of uranium initial concentration, 15 minutes as equilibrium contact time and pH of 5. The results showed that the rate of uranium sorption increases with the increase in temperature, which indicates the adsorption process is endothermic. The experimental results have been fitted with the Langmuir and Freundlich isotherm models, and the experimental data were in better agreement with the Langmuir model. Based on the Langmuir model the maximum adsorption capacity 93.46 mg/g was obtained. Kinetics analysis of the adsorption process showed that the pseudo-second-order model has a better fit with the experimental data. The thermodynamic parameters such as ΔH0, ΔS0,and ΔG0were investigated so that the results show the adsorption process is endothermic and spontaneous.