Self-purification of marine environments for heavy metals: a study on removal of lead(II) and copper(II) by cuttlebone

The aim of this study was to determine adsorption properties of cuttlebone, cuttlefish bone as dead biomass, for lead(II) and copper(II) from aqueous solutions. Adsorption kinetic, isotherm and effect of pH (in the range of 2.0-7.0) were investigated in a single component batch system at room temperature (25 +/- 1 degrees C). The heavy metal adsorption by cuttlebone was relatively rapid and reached equilibrium in 120 min in all the cases. The pseudo-second order rate equation described the adsorption kinetic of both the ions. The adsorption capacities of Pb2+ and Cu2+ were constantly increased by pH and the optimum condition of pH was determined to be 7.0. The Freundlich model was better fitted than other models with the isotherm data, indicating sorption of the metal ions in a heterogeneous surface. According to the Langmuir model, the maximum adsorption capacities of cuttlebone for Pb2+ and Cu2+ were determined to be 45.9 and 39.9 mg/g, respectively. The results indicated cuttlebone as a promising adsorbent for Pb2+ and Cu2+, which presents a high capacity of self-purification in marine environments and also can be used for removal of the metal ions from water and wastewater.