Process for removing metal-EDTA complex and free EDTA salts from mixed aqueous-organic media

摘要

Ethylenediaminetetraacetic acid (EDTA)-complexed heavy metals alone or together with free EDTA salts are removed from solution in a mixture comprising a solvent for a polyphenylene ether resin, an antisolvent for a polyphenylene ether resin and water, by contacting the mixture with alumina for a time at least sufficient to selectively adsorb the metal-EDTA complex and free EDTA salts and recover the mixture of solvent, antisolvent and water substantially free of the metal-EDTA complex and EDTA salts. The alumina can be regenerated to nearly its full original adsorption capacity by contacting with water at a neutral or nearly neutral pH, to give an aqueous solution of the metal-EDTA complex and free EDTA salts.