Equilibrium, kinetic and thermodynamic studies of uranium biosorption by calcium alginate beads

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• 作者：Jing Bai ; Fangli Fan ; Xiaolei Wu ; Wei Tian ; Liang Zhao ; Xiaojie Yin ; Fuyou Fan ; Zhan Li ; Longlong Tian ; Yang Wang ; Zhi Qin ; Junsheng Guo
• 关键词：Calcium alginate beads ; Uranium ; Equilibrium ; Kinetics ; Thermodynamics
• 刊名：Journal of Environmental Radioactivity
• 出版年：December, 2013
• 年：2013
• 卷：126
• 期：Complete
• 页码：226-231
• 全文大小：647 K

文摘

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聽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聽kJ/mol and the sorption process had a chemical nature. Thermodynamic constants such as 螖H⁰, 螖S⁰ and 螖G⁰ were also evaluated, results of thermodynamic study showed that the sorption process was endothermic and spontaneous.