Reuse of EDTA after washing contaminated soil

摘要

The procedure "Reuse of EDTA after washing contaminated soil" solves the problem of reusing EDTA washing solution after extraction or washing of soil or sediment contaminated mainly with toxic metals and semi-metals as well as organic pollutants. EDTA forms water-soluble complexes with metals so that they can be removed from the soil or sediment with a washing solution. Excipients in the washing solution remove organic pollutants from the soil or sediments. At alkaline pH, Fe as insoluble hydroxide is removed from the washing solution used. The majority of EDTA is then removed from the washing solution by acid precipitation. The EDTA remaining in the washing solution is decomposed, together with organic pollutants, by anodic oxidation in the electrolytic cell, removing the released metals and half-metals as insoluble salts and by electrodeposition on the cathode. By dissolving the precipitated EDTA in NaOH or Ca (OH) 2 solution, a new washing solution is generated with recycled EDTA.