Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (01): 186-192.doi: 10.3866/PKU.WHXB20110115

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Surface Complexation Reactions in a Mixed α-Fe2O3,γ-Al2O3 and SiO2 Suspension

LIU Jia, ZHANG Wei-Min, HUANG Pei-Pei, FAN Jia-Ni, SUN Ren-Gui, SUN Zhong-Xi   

  1. School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
  • Received:2010-07-12 Revised:2010-09-07 Published:2010-12-31
  • Contact: SUN Zhong-Xi E-mail:sunzx@ujn.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20677022, 50874052).

Abstract:

We systematically studied the surface acid-base properites and complexation behavior of heavy metal ions in aqueous suspensions of α-Fe2O3, γ-Al2O3, SiO2 of mixed oxides and the α-Fe2O3/γ-Al2O3/ SiO2 mixed systems using potentiometric titrations in combination with computer-based calculations using the constant capacitance model (CCM). The experimental and calculated results reveal that the surface chemical reactions in the mixed system are quite different from the sum of the individual single systems. A complicated mutual interaction exists among these mineral surfaces. The surface chemical reaction models and relevant equilibrium constants in the mixed system are: ≡XOH2+?≡XOH+H+(lgKa1=-4.23), ≡XOH?≡XO-+H+(lgKa2=-8.41). The surface complexation model and related equilibrium constants for Cu2+, Pb2+, and Zn2+ in the mixed system can be described by following reaction: ≡XOH+M2+ ?≡XOM++H+, with lgK of -2.20, -1.90, -3.20 for Cu2+, Pb2+, Zn2+, respectively.

Key words: Fe2O3, Al2O3, SiO2, Mixed system, Surface complexation, Surface acid-base property

MSC2000: 

  • O641