| 摘要 |
PURPOSE:To enable industrial recovery and reutilization of useful complexane known as a strong chelating agent, by lowering the pH of a complexane- containing aqueous solution below a specific level in the presence of a material essentially unwettable with water. CONSTITUTION:The pH of an aqueous solution containing a complexane- containing chelate compound is adjusted to 1.0-2.0 with an acid and the solution is stirred in the presence of a number of small pieces of a synthetic resin essentially unwettable with water, preferably Teflon. Complexane (e.g. ethylenediaminetetraacetic acid, trans-cyclohexanediaminetetraacetic acie, etc.) can be recovered by this procedure. Although the synthetic resin such as Teflon, polyethylene, polypropylene, polystyrene, polybiphenyl chloride, etc., may be used in the form of small pieces, it is preferable to use a reticulate molded material to facilitate the separation of the precipitate from the resin.
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