Batch and column removal of copper from aqueous solution using a brown marine alga Turbinaria ornata

Turbinaria ornata, a brown marine alga, was tested for its ability to remove copper(II) from aqueous solution. Batch equilibrium tests at different pH conditions showed that at pH 6, a maximum copper uptake of 147.06 mg/g was observed according to the Langmuir model. A solution of 0.1 M HCl performed well in eluting copper from copper-loaded biomass and caused no damage to the biosorbent. The ability of T. ornata to biosorb copper in a packed column was investigated, as well. The experiments were conducted to study the effect of important design parameters such as bed height and flow rate. The copper uptake remained relatively constant at approximately 68 mg/g irrespective of the bed height, whereas the uptake decreased as the flow rate increased. The bed depth service time model and the Thomas model were used to analyze the experimental data and the model parameters were evaluated. In regeneration experiments, a loss of sorption performance was observed during seven cycles of sorption-desorption indicated by a shortened breakthrough time and a broadened mass transfer zone. The life-factor for T ornata in terms of critical bed length was found to be 0.603 cm/cycle. The elutant, 0.1 M HCl, provided elution efficiencies greater than 98.8% in all the seven cycles. The pH profiles during both sorption and desorption process were also reported. (C) 2004 Elsevier B.V. All rights reserved.