Biosorption of copper, zinc and nickel by grape- stalks and corkbiomasses

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 tlie 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 slalks and 13.4 mg/g with cork and for nickel was 11.1 mg/g with cork. Tlie kinetics of copper biosorption in both biomasses was studied and a second order model was fitted to tlie experimental data. Copper biosorption is a fast process and witliin the first 5 minutes 80% of the maximum capacity was attained. The calculated activation energy for tlie 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 tlie metal diffusion inside tlie particles is the rate controlling step of the reaction.