Electroosmosis in the Remediation of Tropical Soils Contaminated with Cadmium: Effect of the Incubation Time

Abstract

This paper addresses the effect of cadmium incubation time on the electroosmotic decontamination of three residual soils from the Zona da Mata Norte, Minas Gerais State, Brazil. The laboratory testing program included the following: (i) materials, encompassing a lateritic clayey silty sand (soil 1), a non-lateritic clayey silty sand (soil 2), and a non-lateritic sandy silty clay (soil 3) impregnated with an aqueous solution of cadmium nitrate in the concentration of 100 mg.L-1; (ii) soils and mixtures specimens compaction at the Standard AASHTO compaction effort; (iii) mixtures contaminant incubation times of 1, 10 and 20 days before performing the electroosmotic decontamination tests; (iv) sequential extraction analysis in order to identify the different contaminant chemical forms in the mixtures specimens. The results support that incubation time and soils chemistry and mineralogy were significant and influential factors in the decontamination process, as well as the 20 days incubation period was the optimum among the tested times.