Sorption study of uranium from aqueous solution on ordered mesoporous carbon CMK-3

• Published in: Journal of radioanalytical and nuclear chemistry 2013-01, Vol.295 (1), p.663-670
• Main Authors: Nie, Bin-wen, Zhang, Zhi-bin, Cao, Xiao-hong, Liu, Yun-hai, Liang, Ping
• Format: Article
• Language: English
• Subjects: Adsorption; Carbon; Chemistry; Chemistry and Materials Science; Contact; Diagnostic Radiology; Diffraction; Hadrons; Heavy Ions; Inorganic Chemistry; Mathematical models; Nuclear Chemistry; Nuclear Physics; Physical Chemistry; Recovery; Sorption; Surface chemistry; Uranium; X-rays
• ISSN: 0236-5731; 1588-2780
• DOI: 10.1007/s10967-012-1820-0

The ability of ordered mesoporous carbon CMK-3 has been explored for the removal and recovery of uraium from aqueous solutions. The textural properties of CMK-3 were characterized using small-angle X-ray diffraction and N 2 adsorption–desorption, and the BET specific surface area, pore volume and the pore size were 1143.7 m 2 /g, 1.10 cm 3 /g and 3.4 nm. The influences of different experimental parameters such as solution pH, initial concentration, contact time, ionic strength and temperature on adsorption were investigated. The CMK-3 showed the highest uranium sorption capacity at initial pH of 6.0 and contact time of 35 min. Adsorption kinetics was better described by the pseudo-second-order model and adsorption process could be well defined by the Langmuir and Freundlich isotherm. The thermodynamic parameters, ∆ G° (298 K), ∆ H° and ∆ S° were determined to be −7.7, 21.5 k J mol −1 and 98.2 J mol −1  K −1 , respectively, which demonstrated the sorption process of CMK-3 towards U(VI) was feasible, spontaneous and endothermic in nature. The adsorbed CMK-3 could be effectively regenerated by 0.05 mol/L HCl solution for the removal and recovery of U(VI). Complete removal (99.9 %) of U(VI) from 1.0 L industry wastewater containing 15.0 mg U(VI) ions was possible with 2.0 g CMK-3.