Removal of Strontium, Cobalt, and Cesium from an Aqueous System Containing Each Metal Ion Using Arthrobacter nicotianae Cells

Abstract

Akira Shiga and Takehiko Tsuruta*

In recent years, research on removal of radioactive elements from contaminated sources by using microorganisms, has gained momentum. This study was focused on assessing the feasibility of removing cobalt, strontium, and cesium ions from an aqueous solution using microorganism. Arthrobacter nicotianae known for its ability to remove cationic metal ions, was used for removing each metal. The metal-ion removal efficiency of A. nicotianae was affected by the solution pH, concentration of metals, and cell content. The amount of each metal ion removed increased with increasing pH (1–5) of the solution. The amount of each metal ion removed (μmol metal ion/g dry wt. cells) increased with external metal ion content (μmol metal ion), whereas the amount of each metal ion removed (%) decreased. By contrast, the each removed metal ion content (%) decreased with decreased cell content, whereas each metal removed (μmol metal ion/g dry wt. cells) increased. The amounts of each metal removed (μmol metal ion/g dry wt. cells) were fitted with a Langmuir isotherm. The removal of strontium by A. nicotianae was fast, and the removed amount almost reached equilibrium within 5 min. The amounts of cobalt and strontium removed were higher than that of cesium.

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