Zinc Biosorption by Seaweed Illustrated by the Zincon Colorimetric Method and the Langmuir Isotherm.

• Autores: Maria Mar Areco, Maria dos Santos Afonso, Erika Valdman
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 84, Nº 2, 2007, págs. 302-305
• Idioma: inglés
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• Resumen

  • Heavy metals are major pollutants in marine, ground, industrial, and even treated waters. Sorption of heavy metals onto live or dead biological materials (biosorption) is a potential method of removing toxic metals. Zinc and two algae, Ulva sp. and Gymnogongrus torulosus, were evaluated in this study. A linear zinc calibration curve in the range 1â��8 mg L-1 was obtained using the zincon colorimetric method. In the biosorption assays, a rapid zinc uptake was observed and kinetic curves stabilized after 60 minutes. Experiments using initial zinc concentrations of 50 mg L-1 showed that 20% and 60% of zinc ions were removed from solution by Ulva sp. and Gymnogongrus torulosus, respectively. Results obtained from varying initial zinc concentrations allowed data fitting to Langmuir model with a good correlation. The maximum zinc uptake capacity and affinity constant obtained for Gymnogongrus torulosus were higher than those for Ulva sp. Maximum zinc uptake capacities were 42.8 x10-3 and 26.8 x10-3 for Gymnogongrus torulosus and Ulva sp., respectively, while the affinity constants were 0.084 L mg-1 and 0.019 L mg-1, respectively. An interesting and simple experiment was developed to show the potential of algae in biosorption processes