Abstract
The present study aimed to evaluate the efficiency of marine algae for removal of metals
from the aqueous solution. The green alga, Ulva lactuca, collected from the intertidal zone of the
Suez Bay, northern part of the Red Sea was used to reduce cadmium levels from the aqueous
solutions. The biosorption mechanisms of Cd2+ ions onto the algal tissues were examined using
various analytical techniques: Fourier-transform infrared spectroscopy (FT-IR) and Scanning electron
microscopy (SEM). Results indicated that at the optimum pH value of 5.5; about 0.1 g of U.
lactuca was enough to remove 99.2% of 10 mg L1 Cd2+ at 30 C in the aqueous solutions. The
equilibrium data were well fitted with the Langmuir and Freundlich isotherms. The monolayer
adsorption capacity was 29.1 mg g1. The calculated RL and ‘n’ values have proved the favorability
of cadmium adsorption onto U. lactuca. The desorption test revealed that HCl was the best for the
elution of metals from the tested alga. In conclusion, the seaweed U. lactuca was the favorable alternative
of cadmium removal from water.