Evaluation of lead desorption from cement matrices

Abstract

Desorption of lead immobilized into cement and concrete matrices was evaluated in the pH range between 4 and 8 within a period of 2 h to 15 days. Lead-desorbed content in aqueous milieu was monitored by Graphite Furnace Atomic Absorption Spectroscopy, while matrices were directly analyzed by X-ray photoelectronic spectroscopy or Rutherford Backscattering spectrometry. For low pH, higher Pb desorption was observed, about 5–7 times higher than that measured in the case of concrete matrices. The inclusion of polyvinyl alcohol as a matrix modifier was evaluated through a factorial design. Polymer inclusion yielded a reduction in Pb desorption, but its effect cannot be justified in terms of the ability of this polymer to chelate the metal. The resulting modified matrices did not present toxicity to Daphnia magna.

Keywords:

• Cement
• waste
• plumb
• desorption
• polymer

Acknowledgments

This work was partially supported by CNPq.

Notes

^a (+) presence or (−) absence of sand or polymer in the matrices;

^b Pb desorbed amount determined in solution by GF-AAS;

^c elemental analysis of the matrix by XPS.

^a Pb desorbed amount determined in solution by GF-AAS;

^b elemental analysis of the matrix by XPS.