Biosorption of nickel and copper ions from synthetic solution and electroplating effluent using fixed bed column of immobilized brown algae

In this study, the immobilized biosorbent prepared from brown algae Sargassum sp. was used for removal of Ni2+ and Cu2+ ions in a fixed bed column. Initially, the experiments were carried out using synthetic solutions, and the linear driving force model was fitted to the breakthrough curves. The equilibrium relations in continuous system was well-adjusted by the Langmuir model, in which the maximum biosorption capacity was 1.404 mmol L-1 for Ni2+ ions and 1.656 mmol L-1 for Cu2+ ions. In addition, biosorption/desorption cycles were performed using acidified calcium chloride solution as eluent. After the first cycle, the biosorption were on average 75% of the initial uptake capacities of Ni2+ and Cu2+ ions. Posteriorly, the biosorbent was evaluated for the removal of metal ions from pre-treated electroplating effluent by chemical precipitation and cyanide oxidation. Due to the high concentrations of light metals (Na, K, Ca, Mg) in the effluent, the biosorption capacities were reduced by an average of 28% and the shape of the breakthrough curves were strongly affected. These behaviors were attributed to the simultaneous removal of metal ions and the multicomponent biosorption equilibrium.