The study of operating variables in soil washing with EDTA

Environ Pollut. 2009 Jan;157(1):229-36. doi: 10.1016/j.envpol.2008.07.009. Epub 2008 Sep 6.

Abstract

This study discusses the operating variables for removal of metals from soils using EDTA, including the type of EDTA, reaction time, solution pH, dose, temperature, agitation, ultrasound and number of extractions. For As, Cd, Cu, Pb and Zn, the removal efficiency order was: H(4)-EDTA > Na(2)EDTA > (NH(4))(2)EDTA. At low EDTA concentrations the removal increased progressively with increasing dose while above 0.4 mmol/g only small increases in extraction efficiency were observed. EDTA induced a two-step process including a rapid desorption within the first hour, and a gradual release in the following hours. The extraction efficiency of metals decreased with increasing pH in the range of 2-10. Consecutive extractions using low concentrations were more effective than a single extraction with concentrated EDTA if the same dose of EDTA was used.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Arsenic
  • Cadmium
  • Chelating Agents / pharmacology*
  • Copper
  • Edetic Acid / pharmacology*
  • Environmental Restoration and Remediation / methods*
  • Hydrogen-Ion Concentration
  • Lead
  • Metals, Heavy*
  • Soil Pollutants*
  • Time Factors
  • Zinc

Substances

  • Chelating Agents
  • Metals, Heavy
  • Soil Pollutants
  • Cadmium
  • Lead
  • Copper
  • Edetic Acid
  • Zinc
  • Arsenic