Immobilization of Aqueous Heavy Metals with Non-apatites-type Apatites

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The summary was described as followed the projects planes submitted. Re.Plane 1 on 2002 : Based on the dissolution precipitation mechanism, it was found that calcium phosphate and calcium hydrogen phosphates could immobilize aqueous heavy metals. Particularly calcium monohydrogen phosphate could immobilize various heavy metals. Re. Plane 2 on 2003 : Magnesium and calcium sulfates revealed the. great removabilities of aqueous lead, indicating that those sulfates could be employed as a immobilization reagent from waste solutions in car-batteries. Re.Plane 1 on 2003 : Sodium and than potassium hydrogen phosphates, which are cheap and possess greater solubilities phosphates ever employed, were supplied as the immobilization reagents. Those alkali hydrogen phosphates afforded the excellent removabilities within 30 mm, indicating that the nature of the immobilization abilities is not unique for calcium hydroxyapatite but common properties for various phosphates. Re.Plane 2 on 2003 : Aqueous phosphate and ammonia, could be favorablely immobilized with magnesia and magnesium chloride to afford magnesium aluminum phosphate (MAP), which can be used as a slow-acting fertilizer. Particularly the adjustment of pH during the immobilization was found to be important to proceed smoothly for the immobilization. Solid state 31P MAS NMR showed that it was rather difficult to obtain high pure MAP although XRD afforded signals only due to MAP. Re.Plane 3 on 2003 : It has been already known that the solids recovered from the immobilization of aqueous heavy metals with various phosphates cannot be identified by XRD due to low crystalline. However the solid recovered from the immobilization of copper (II) ion with potassium hydrogen phosphate could be identified as Cu(P04)(OH)2 by the combination of XRD and solid state 31P MAS NMR.