BIOSORPTION OF COPPER, ZINC AND NICKEL BY GRAPE- STALKS AND CORK BIOMASSES

摘要

The removal of copper, zinc and nickel from aqueous solutions by biosorption using grape-stalks and cork biomasses is reported. The adsorption isotherms were determined and the uptake capacity for copper with grape stalks and cork was, respectively, 19.9 mg/g and 16.5 mg/g, while for zinc was 18.3mg/g with grape stalks and 13.4 mg/g with cork and for nickel was 11.1 mg/g with cork. The kinetics of copper biosorption in both biomasses was studied and a second order model was fitted to the experimental data. Copper biosorption is a fast process and within the first 5 minutes 80% of the maximum capacity was attained. The calculated activation energy for the biosorption reaction of copper was 28+-3 KJ/mol for grape stalks and 6+-2 KJ/mol for cork biomass. These low values indicate that the metal diffusion inside the particles is the rate controlling step of the reaction.