Fine, P., Institute of Soils, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, P.O.B. 6, Bet Dagan 50250, Israel
Scagnossi, A., Department of Chimica e Biotecnologie Agrarie, Universita degli Studi di Pisa, Via del Borghetto, 80-56124 Pisa, Italy
Chen, Y., Department of Soils and Water, Faculty of Agriculture, Food and Environmental Quality Sciences, Hebrew University of Jerusalem, Israel
Mingelgrin, U., Institute of Soils, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, P.O.B. 6, Bet Dagan 50250, Israel

A sphagnum peat moss removed Cd from aqueous solutions very efficiently, and its effectiveness in taking up the metal was significantly enhanced by exposure to a 1 N NaOH solution. The capacity of the untreated peat for Cd reached 300 g/kg and that of the NaOH-activated peat was over 400 g/kg. Although saturation was rarely reached, the Cd uptake from concentrated solutions often exceeded 200 g/kg. In column experiments, 1 g of the NaOH-activated peat completely removed the metal from over 0.2 L of a 200-mg/L Cd solution (final Cd concentration < 0.1 mg/L), while 1 g of non-activated peat cleared Cd from less than 25% of that volume. The cation exchange capacity measured for the peat depended on the time of contact with the exchanging solution. After 72 h contact, the value for the NaOH-activated peat was 135 cmolc/kg. In addition to uptake by exchange, a significant amount of Cd was sorbed by non-exchange mechanisms. FTIR spectroscopy revealed the importance of carboxyl groups in the uptake. © 2005 Elsevier Ltd. All rights reserved.