Study on the factors affecting the immobilization of heavy metals in fly ash-based geopolymers

Internationally, geopolymerisation technique has gradually been one of the most popular methods to dispose wastes due to effective immobilization of toxic metals. However, few studies were conducted on the wastes containing many different heavy metals and determined the factors affecting the immobilization of these heavy metals. In this paper, a series of fly ash-based geopolymeric matrices containing Cd(II), Cu(II), Pb(II) and Cr(III) were investigated. The results show that these heavy metals can be effectively immobilized into the geopolymeric matrices. In addition, the concentrations of alkali activator and different kinds of heavy metals have fairly impact on the immobilization behavior to one metal in the same system, and the heavy metals seem to have fairly large effect on the chemical and physical characteristics of the final products. (c) 2005 Elsevier B.V. All rights reserved.