Chitosan-cement matrices for solidification-stabilization of heavy metals

Abstract

Cement matrices have been extensively used to solidify-stabilize hazardous wastes containing heavy metals [1]. However, the presence of some heavy metals such as Pb and Zn modify the rheological properties of the cement due to the interaction with different cement phases [2], [3]. These changes in fresh-state properties of the cement materials may have a negative influence on the applicability of these matrices. Moreover, the hardened-state properties could be affected by the fresh-state changes and, consequently, the long-term stability and leaching of the heavy metals would be jeopardized. The use of some polymeric additives may be interesting in order to solve the aforementioned problems. Polysaccharides have been reported to be efficient cement additives behaving as viscosity-enhancing admixtures and set retarders [4].