Removal of mercury, cadmium and lead in aqueous solution by microalgae

Abstract

Three strains of green algae and two strains of filamentous blue green algae with a high growth rate were tested for Hg, Ph and Cd removal in aqueous solution. The adsorption experiments revealed that Chlorella vulgaris (IFRPD1118),Chlorella vulgaris (CCAP211/11B) and Scendesmus acutus could remove Hg at 74, 75 and 85% efficiency, respectively. The ability to rerpove Cd by these green algae was 86,83 and 88% respectively, and for Pb was 85, 81 and 89% respectively for the former and 50, 88 and 91 % respectively for the latter. The kinetics of three heavy metals removal by five microalgae were similar showing a fast removal in the first five minutes and reaching equilibrium within 10 to 20 minutes. In addition, all five microalge were screend on agar plates for their ability to tolerate these heavy metals. The results showed that most microlgae could well tolerate the toxicity of these these metals and the relative toxicity observed was Hg > Cd > Pb.