| Results are presented for the characterization of Chlorella vulgaris as a chromium (III) ion adsorbent. Heat-killed Chlorella vulgaris, when suspended in solution, strongly and rapidly adsorbs the chromium ions. Because of the heat-killed cells, the binding does not depend on any biological processes of the cells, and thus, can occur under conditions that are normally toxic to living cells. The binding to the algae was found to be dependent on several factors, including pH, exposure time and the presence of salts. A maximum binding of 70% occurred at pH 3 and was independent of chromium concentration in the 5.0 to 100.0 {dollar}mu{dollar}g/mL range. Recovery of chromium ions from the algae back into solution was achieved by reversing the pH. The algae could be reused at least four times after the chromium ions were stripped. On the basis of high binding capacity, low cost and low technology, Chlorella vulgaris is attractive as an adsorbent for the removal and recovery of chromium ions from aqueous solutions. |
