title: Mechanisms of heavy-metal removal by activated sludge.
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 properties 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.
authors.affiliation: Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy. francesca.pagnanelli@uniroma1.it
authors.forename: F
authors.initials: F
authors.lastname: Pagnanelli
authors.forename: S
authors.initials: S
authors.lastname: Mainelli
authors.forename: L
authors.initials: L
authors.lastname: Bornoroni
authors.forename: D
authors.initials: D
authors.lastname: Dionisi
authors.forename: L
authors.initials: L
authors.lastname: Toro
mesh_terms: D000327:Adsorption; D000465:Algorithms; D018533:Biomass; D002104:Cadmium / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007854:Lead / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry*; D011199:Potentiometry; D012722:Sewage / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D012722:Sewage; D014874:Water Pollutants, Chemical; D002104:Cadmium; D007854:Lead