STUDIES ON THE BIOSORPTION OF HEAVY-METALS ONTO CHLORELLA-VULGARIS

The metal binding characteristics of Chlorella vulgaris were investigated. Metal uptake by intact algal cells was found to consist of two processes; (1) a fast, metatbolism-independent surface reaction and (2) metabolism-dependent slow uptake. Results of both the pH and the ionic strength effects on the metal adsorption indicate that the specific interaction accounts for the majority of metal adsorption. Carboxyl and amine surface functional groups of Chlorella vulgaris were modified to assess the role of the surface charge site as the metal binding one. The carboxyl-modified algae showed major decreases in the adsorption capacity of Cd(II) and Zn(II) binding. The amine-modified algae also displayed some decreases in metal adsorptions.