Chem. J. Chinese Universities ›› 2010, Vol. 31 ›› Issue (1): 135.

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Adsorption Behavior and Mechanism of Nano-Al2O3 for Ge(Ⅳ)

ZHANG Lei*, LI Hong-Mei, HAN Guang-Xi, KANG Ping-Li   

  1. College of Chemistry, Liaoning University, Shenyang 110036, China
  • Received:2009-04-08 Online:2010-01-10 Published:2010-01-10
  • Contact: ZHANG Lei. E-mail: zhanglei63@126.com
  • Supported by:

    辽宁省教育厅科创新团队项目(批准号: 2007T053)和辽宁省自然科学基金(批准号: 20082049)资助.

Abstract:

The effects of various equilibrium time, temperature and pH on the adsorption of Ge(Ⅳ) on nano-Al2O3 were studied. The results show that the adsorption is fast to reach equilibrium within 2 min. It was found that the adsorption efficiency of Ge(Ⅳ) was more than 95% with pH from 4 to 11. Almost all of Ge(Ⅳ) ions adsorpted onto nano-Al2O3 can be eluted with 0.3 mol/L K3PO4-1 mol/L H2SO4 mixed solution within 5 min, the desorption percentage can reach 97%. The sorption of Ge(Ⅳ) ions onto nano-Al2O3 followed the second-order rate equation, the kinetic experimental data properly correlate with the second-order kinetic model and the values of activation energy(Ea) was 11.63 kJ/mol. The adsorption data are fitted to the Freundlich and the magnitude of sorption energy computed from D-R equation is 10.87 kJ/mol, thus, the type of the adsorption of germanium on nano-Al2O3 is a chemical adsorption. The ΔG0 and ΔH0 values is negative and positive respectively which indicate the adsorption of Ge(Ⅳ) on nano-Al2O3 is spontaneous and endothermic.

Key words: Ge(Ⅳ); Nano-γ-Al2O3; Adsorption; Kinetics; Thermodynamic

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