Effects of pH, organic acids, and inorganic ions on lead desorption from soils

Environ Pollut. 2006 Sep;143(1):9-15. doi: 10.1016/j.envpol.2005.11.010. Epub 2006 Jan 24.

Abstract

The desorption characteristics of lead in two variable charge soils (one developed from Arenaceous rock (RAR) and the other derived from Quaternary red earths (REQ)) were studied, and the effects of pH value, organic acid, and competitive ions were examined. Desorption of Pb(2+) decreased from nearly 100.0 to 20.0% within pH 1.0-4.0 in both soils, and then the decrease diminished at pH > 4.0. Organic ligands at relatively low concentrations (< or =10(-3) mol L(-1)) slightly inhibited Pb(2+) desorption, but enhanced Pb(2+) desorption at higher concentrations. In this study, citric acid or acetic acid at higher concentrations (>10(-3) mol L(-1)) had the greatest improvement of Pb(2+) desorption, followed by malic acid; and the smallest was oxalic acid. Desorption of the adsorbed Pb(2+) increased greatly with increasing concentrations of added Cu(2+) or Zn(2+). Applied Cu(2+) increased Pb(2+) desorption more than Zn(2+) at the same loading.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetic Acid / pharmacology
  • Adsorption
  • Biodegradation, Environmental
  • Chelating Agents / pharmacology
  • Citric Acid / pharmacology
  • Copper / chemistry
  • Environmental Pollution*
  • Environmental Restoration and Remediation / methods*
  • Humic Substances
  • Hydrogen-Ion Concentration
  • Ions
  • Lead / chemistry
  • Lead / toxicity*
  • Malates / pharmacology
  • Oxalic Acid / pharmacology
  • Soil Pollutants / chemistry
  • Soil Pollutants / toxicity*
  • Zinc / chemistry

Substances

  • Chelating Agents
  • Humic Substances
  • Ions
  • Malates
  • Soil Pollutants
  • Citric Acid
  • Lead
  • Copper
  • malic acid
  • Oxalic Acid
  • Zinc
  • Acetic Acid