水酸化カルシウム及びリン酸アンモニウムによる水溶液中のPb^<2+>イオンの除去

概要

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The elimination of Pb^<2+> ion from aqueous solution was performed by adding calcium hydroxide solution or ammonium phosphate solution to a solution containing Pb^<2+> ion. The concentration of the filtrate was measured and the data were compared with those of the ferrite formation method. In the case of Ca(OH)_2 addition, the concentration of Pb^<2+> ion in the filtrate was affected by the Ca^<2+>/ Pb^<2+> ratio. The minimum concentration of 0.58 mg/dm^3 was obtained when the Ca^<2+>/Pb^<2+> ratio was 1, where pH of the solution was 11.74. In the case of (NH_4)_3PO_4 addition, ill-crystallized pb-hydroxyapatite was precipitated, and the concentration of Pb^<2+> ion in the filtrate was 0.01 mg/dm^3. The well-crystallized Pb-hydroxyapatite was obtained by the hydrothermal treatment of ill-crystallized one by using solution with pH of 12 at 150℃ for 1h. This Pb-hydroxyapatite has lower solubility than lead hydroxide over a wide pH range. It is concluded that the method for elimination of Pb^<2+> ion from aqueous solution by using calcium hydroxide or ammonium phosphate were more effective than the ferrite formation method.
社団法人日本セラミックス協会の論文
1997-03-01