Equilibrium, kinetic and thermodynamic studies of uranium biosorption by calcium alginate beads.
Calcium alginate beads are potential biosorbent for radionuclides removal as they contain carboxyl groups. However, until now limited information is available concerning the uptake behavior of uranium by this polymer gel, especially when sorption equilibrium, kinetics and thermodynamics are concerned. In present work, batch experiments were carried out to study the equilibrium, kinetics and thermodynamics of uranium sorption by calcium alginate beads. The effects of initial solution pH, sorbent amount, initial uranium concentration and temperature on uranium sorption were also investigated. The determined optimal conditions were: initial solution pH of 3.0, added sorbent amount of 40 mg, and uranium sorption capacity increased with increasing initial uranium concentration and temperature. Equilibrium data obtained under different temperatures were fitted better with Langmuir model than Freundlich model, uranium sorption was dominated by a monolayer way. The kinetic data can be well depicted by the pseudo-second-order kinetic model. The activation energy derived from Arrhenius equation was 30.0 kJ/mol and the sorption process had a chemical nature. Thermodynamic constants such as ΔH(0), ΔS(0) and ΔG(0) were also evaluated, results of thermodynamic study showed that the sorption process was endothermic and spontaneous.
Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China. Electronic address: baijing@impcas.ac.cn.
Jing
J
Bai
Fangli
F
Fan
Xiaolei
X
Wu
Wei
W
Tian
Liang
L
Zhao
Xiaojie
X
Yin
Fuyou
F
Fan
Zhan
Z
Li
Longlong
L
Tian
Yang
Y
Wang
Zhi
Z
Qin
Junsheng
J
Guo
D000327:Adsorption; D000464:Alginates / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D013816:Thermodynamics; D014501:Uranium / Q000737:chemistry*; D018508:Water Purification
D000464:Alginates; D006603:Hexuronic Acids; D014501:Uranium; D020723:Glucuronic Acid
Calcium alginate beads; Equilibrium; Kinetics; Thermodynamics; Uranium