The behavior of native and protonated Sargassum fluitans seaweed biomass packed in a fixed-bed was examined during a continuous removal of Cu2+ from 35 mg/L aqueous solution at pH 5.0. The capacity of native and protonated biomass, based on the dry weight of the native biomass, were determined to be 61.5 and 54.1 mg/g, respectively. During the saturation of the native biomass with heavy metal, first Na+ and K+, followed by Mg2+ and Ca2+, were eluted from the fixed-bed before the breakthrough time of the Cu. The pressure drop across the column varied with the ionic composition of the effluent from the bed, yielding an average permeability coefficient of 2.7 . 10(-12)m(2). The void fraction of the interstices in the bed was estimated to be 0.27. No light metals were eluted from the column containing protonated biomass, and the pressure drop remained constant throughout the saturation.