Improved efficiency for the removal of cadmium from aqueous solution using cells of the cyanobacterium Phormidium angustissimum pre-treated with sodium hydroxide

Abstract

The filamentous cyanobacterium Phormidium angustissimum was examined for its capacity to remove cadmium from aqueous solution using both non-treated and NaOH-treated cells. For non-treated cells the adsorption equilibrium was attained in 10 min and Cd removal ability was 81% with the optimum pH at 6.5. The maximum adsorption (qmax) of Cd was 116 mg/g dry wt. Pretreatment of cells by NaOH could increase the Cd removal ability and the adsorption equilibrium was also attained in 10 min. The presence of either Ca2+ or Mg2+ reduced the ability of the cells to remove Cd with a higher Cd removal ability observed for the NaOH-treated cells. A 2-fold increase in qmax value of 238 mg/g dry wt.was found for the NaOH treated cells.