In this paper experimental tests of metal extraction from contaminated sediments are presented and discussed. Sediments were collected from La Spezia harbour and characterised to assess the extent of contamination. A significant heavy metal contamination has been observed: Cu, Pb and Zn concentrations, in particular, were above the limits stated by Italian Environmental Regulation. Following to this characterisation, sediment washing tests with several chelating agents were performed. Aqueous solutions of sodium EDTA and citric acid were added to the sediment at stated liquid/soil ratios (5, 8, 12.5). The investigated parameters were pH, reaction time (up to 144 hours) and chelating agent concentration. Results show that the best removal yield (100% Pb, 80% Zn, 60% Cu) were achieved within 24 hours using sodium EDTA 0.1 M solutions, at a liquid/solid ratio of 12.5. At these conditions, the residue contaminants level in the sediment was below the above cited limits. The use of citric acid resulted in a lower extraction yield for Cu and Pb.
Experimental assessment of metal leaching from contaminated harbour sediments / DI PALMA, Luca; Mecozzi, Roberta; F., Sabatucci; Verdone, Nicola. - ELETTRONICO. - 1:(2006), pp. 45/1-45/10. (Intervento presentato al convegno International Conference BOSICON 2006 - Soil and sediment pollution tenutosi a Roma nel 14-15 febbraio 2006).
Experimental assessment of metal leaching from contaminated harbour sediments
DI PALMA, Luca;MECOZZI, ROBERTA;VERDONE, Nicola
2006
Abstract
In this paper experimental tests of metal extraction from contaminated sediments are presented and discussed. Sediments were collected from La Spezia harbour and characterised to assess the extent of contamination. A significant heavy metal contamination has been observed: Cu, Pb and Zn concentrations, in particular, were above the limits stated by Italian Environmental Regulation. Following to this characterisation, sediment washing tests with several chelating agents were performed. Aqueous solutions of sodium EDTA and citric acid were added to the sediment at stated liquid/soil ratios (5, 8, 12.5). The investigated parameters were pH, reaction time (up to 144 hours) and chelating agent concentration. Results show that the best removal yield (100% Pb, 80% Zn, 60% Cu) were achieved within 24 hours using sodium EDTA 0.1 M solutions, at a liquid/solid ratio of 12.5. At these conditions, the residue contaminants level in the sediment was below the above cited limits. The use of citric acid resulted in a lower extraction yield for Cu and Pb.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
