Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (06): 1425-1431.doi: 10.3866/PKU.WHXB201203091

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Acid-Base Properties and Adsorption Behaviors of Heavy Metal Ions at the Surface of γ-Al2O3/SiO2 Nano-Mixed System

HUANG Pei-Pei, SUN He-Yun, FAN Jia-Ni, SUN Zhong-Xi   

  1. School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
  • Received:2011-12-17 Revised:2012-03-02 Published:2012-05-17
  • Contact: SUN Zhong-Xi
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (50874052, 20677022) and National Key Basic Research Program of China (2011CB933700).

Abstract: The surface acid-base properties of a γ-Al2O3/SiO2 nano-mixed system were studied by potentiometric titration technique. Based on experimental data complemented by surface complexation theory of Constant Capacitance Model, the relevant equilibrium constants of surface acid-base reactions in the nano-mixed system were calculated using the WinSGW program as: ≡XOH+H+⇔≡XOH2+ (lgK1=5.06± 0.05); ≡XOH⇔≡XO-+H+ (lgK2=-8.45±0.10). Furthermore, the adsorption of heavy metal ions (Cu2+ , Pb2+ , Zn2+ ) at the surface of the γ-Al2O3/SiO2 nano-mixed system was studied as a function of pH. Again using WinSGW software, the surface complexation constants of Cu2+, Pb2+ and Zn2+ ions in aqueous suspensions of γ-Al2O3/SiO2mixed systems were established respectively as: ≡XOH+M2+⇔≡XOM++H+ [lgK=-2.20, -1.72, -2.90 (M=Cu, Pb, Zn)]

Key words: γ-Al2O3/SiO2 nano-mixed system, Cu2+, Pb2+, Zn2+, Acid-base, Surface complexation, Equilibrium constant