Biosorption of copper and zinc by Cymodocea nodosa

The adsorption of the two metal ions Cu and Zn in a single-component system by Cymodocea nodosa, a brown alga, under different pH conditions was inves tigated. The solution pH significantly affected the exhibited uptake, being maximum at a pH value of 3.5. Multi-component mixture biosorption in aqueo us solutions is also reported. A comparison was made between the single-com ponent saturation uptake and the multi-component uptakes. To evaluate the t wo-metal sorption system performance, simple isotherm curves had to be repl aced by three-dimensional sorption isotherm surfaces. In order to describe the isotherm surfaces mathematically, three Langmuir-type models were evalu ated. The isotherms indicate a competitive uptake with Cu being preferentia lly adsorbed. In addition, different tests were carried out to compare the process efficiency working continuously in small columns. (C) 1999 Federati on of European Microbiological Societies. Published by Elsevier Science B.V . All rights reserved.