Biosorption of Trace metals by Ulva sp.

MARIA DEL MAR ARECO; ERIKA VALDMAN; MARIA DOS SANTOS AFONSO

Foz de Iguazu, Brasil

Conferencia; 11th International Conference on Surface and Colloid Science; 2003

Heavy metals are major pollutants in marine, ground, industrial and even treated waters.  Biosorption, known as sorption of heavy metals onto biological materials, is becoming a potential alternative for the removal of toxic metals.  Ulva sp., known as sea lettuce, is a very common alga found in the Atlantic coast and it is easily collected at the high-tide line along the beach.  The seaweed Ulva sp. and zinc, copper, cadmium, lead and arsenic, were chosen to be evaluated in our study.  In the biosorption assays, a rapid trace metal uptake was observed and kinetic curves tended to stabilize from 90 min on.  After 3 hs, the equilibria concentration of trace metal solutions was achieved. The concentration of free metal ions in the aqueous solution was determined spectrophotometrically It was also possible to calculate the Ulva sp uptake capacity for each trace metal.  Trace metals concentration were varied between 0.5 and 20 mM while the Ulva sp concentration was varied between 1x10-3 to 1x10-2 g of dry biomass/dm3. pH dependence of the adsorption process were measured in the range of 2-6. The adsorption isotherms and the kinetics parameters were calculated.