Antimony in the aquatic environment in north Kyushu district of Japan Available to Purchase

In Japan, the water quality standards for items requiring surveillance for drinking water in 1992 and environmental water in 1993 stipulate that the concentration of antimony is 2 μg/l or less. Recently cases of water contamination by antimony have been reported throughout Japan. We have measured antimony concentrations in the aquatic environment in north Kyushu district of Japan by atomic absorption spectrometry with hydride generation and found them to be in the range 0.0 to 0.8 μg/l all of which were less than the water quality standards at the present time. However, wastewater containing high concentration of antimony may contaminate aquatic environment in future. Studies have since been carried out to remove antimony from polluted wastewater. We tried to use ferric chloride as coagulant and dechlorination tap water containing approximately 10 μg/l antimony as the sample solution. Of the sample solution, pH of which was 7 - 8 and included the ferric chloride, pH was controlled by adding either hydrochloric acid or sodium hydroxide. The efficiency of removal of antimony reached a maximum at pH 4.0 - 5.5. When ferric chloride concentration was more than 30 mg/l at pH 4.5, 80 - 90% antimony was removed. However, when the original antimony concentration was 250 μg/l, up to 200 mg/l ferric chloride had to be added. Therefore, from water originally polluted by antimony at concentrations of 2 - 250 μg/l, almost complete removal of antimony is expected by adding ferric chloride to become 200 mg/l and adjusting the pH to 4.5.