title: Removal of Cd, Cu, Pb, and Zn from aqueous solutions by biochars.
abstract: Sorption and desorption of heavy metals (Cd, Cu, Pb, and Zn) was evaluated in biochars derived from sugarcane bagasse (SB), eucalyptus forest residues (CE), castor meal (CM), green coconut pericarp (PC), and water hyacinth (WH) as candidate materials for the treatment of contaminated waters and soils. Solid-liquid distribution coefficients depended strongly on the initial metal concentration, with K d,max values mostly within the range 10(3)-10(4) L kg(-1). For all biochars, up to 95 % removal of all the target metals from water was achieved. The WH biochar showed the highest K d,max values for all the metals, especially Cd and Zn, followed by CE (for Cd and Pb) and PC (for Cd, Pb, and Zn). Sorption data were fitted satisfactorily with Freundlich and linear models (in the latter case, for the low concentration range). The sorption appeared to be controlled by cationic exchange, together with specific surface complexation at low metal concentrations. The low desorption yields, generally less than 5 %, confirmed that the sorption process was largely irreversible and that the biochars could potentially be used in decontamination applications.
authors.affiliation: Department of Chemistry, Federal University of Paraná-UFPR, 81531-990, Curitiba, PR, Brazil.
authors.forename: M E
authors.initials: ME
authors.lastname: Doumer
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain. annarigol@ub.edu.
authors.forename: A
authors.initials: A
authors.lastname: Rigol
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Vidal
authors.affiliation: Department of Chemistry, Federal University of Paraná-UFPR, 81531-990, Curitiba, PR, Brazil.
authors.forename: A S
authors.initials: AS
authors.lastname: Mangrich
mesh_terms: D000327:Adsorption; D002606:Charcoal; D019216:Metals, Heavy / Q000302:isolation & purification*; D031786:Saccharum; D012987:Soil; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification; D015032:Zinc / Q000302:isolation & purification
chemical_list: D019216:Metals, Heavy; D012987:Soil; D014874:Water Pollutants, Chemical; C540010:biochar; D002606:Charcoal; D015032:Zinc
keywords: Biochar; Desorption; Metal removal; Slow pyrolysis; Sorption; Waste biomass