Removal of cadmium from aqueous solution by the filamentous cyanobacterium Tolypothrix tenuis

Cadmium removal was investigated using the filamentous cyanobacterium, Tolypothrix tenuis, which exhibited a high level of Cd tolerance and had the highest Cd removal ability among 17 cyanobacterial strains obtained in Thailand. The removal of Cd was equilibrated within 30 min, and the type of Cd removal could be described by the Langmuir isotherm. Cadmium removal by T. tenuis is thus suggested to be caused by adsorption of Cd onto the cell surface. T. tenuis showed consistent Cd adsorption ability over a wide range of temperature and pH. The adsorption of Cd was not strongly affected in the presence of Na, K, Ca, and Mg ions. These results suggest that T. tenuis may be applicable to the removal of Cd from surface and ground water in certain outdoor situations.