This paper investigates the chemical mechanisms operating in cadmium and lead removal by activated sludge in sequencing batch reactors. Selective extraction and acid digestion of sludge samples denoted that both Cd and Pb are mainly present as surface-bound metals. Characterisation of sludge samples by potentiometric titrations and IR spectra suggested that carboxylic and amino groups are the main active sites responsible for the binding proper-ties of the biomass. Simulation of metal speciation implemented with complexation constants determined in biosorption tests, showed that cadmium predominates as biosorbed species, while lead was mainly removed by precipitation. (C) 2009 Elsevier Ltd. All rights reserved.
Mechanisms of heavy-metal removal by activated sludge / Pagnanelli, Francesca; Mainelli, Sara; Lorena, Bornoroni; Dionisi, Davide; Toro, Luigi. - In: CHEMOSPHERE. - ISSN 0045-6535. - 75:8(2009), pp. 1028-1034. [10.1016/j.chemosphere.2009.01.043]
Mechanisms of heavy-metal removal by activated sludge
PAGNANELLI, Francesca;MAINELLI, SARA;DIONISI, DAVIDE;TORO, Luigi
2009
Abstract
This paper investigates the chemical mechanisms operating in cadmium and lead removal by activated sludge in sequencing batch reactors. Selective extraction and acid digestion of sludge samples denoted that both Cd and Pb are mainly present as surface-bound metals. Characterisation of sludge samples by potentiometric titrations and IR spectra suggested that carboxylic and amino groups are the main active sites responsible for the binding proper-ties of the biomass. Simulation of metal speciation implemented with complexation constants determined in biosorption tests, showed that cadmium predominates as biosorbed species, while lead was mainly removed by precipitation. (C) 2009 Elsevier Ltd. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
