Effects of pH, organic acids, and inorganic ions on lead desorption from soils.
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.
Yang
J Y
JY
College of Natural Resources and Environmental Sciences, Huajiachi Campus, Zhejiang University, Hangzhou, China.
Yang
X E
XE
He
Z L
ZL
Li
T Q
TQ
Shentu
J L
JL
Stoffella
P J
PJ
D019342:Acetic Acid / Q000494:pharmacology; D000327:Adsorption; D001673:Biodegradation, Environmental; D002614:Chelating Agents / Q000494:pharmacology; D019343:Citric Acid / Q000494:pharmacology; D003300:Copper / Q000737:chemistry; D004787:Environmental Pollution; D052918:Environmental Restoration and Remediation / Q000379:methods*; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007854:Lead / Q000737:chemistry / Q000633:toxicity*; D008293:Malates / Q000494:pharmacology; D019815:Oxalic Acid / Q000494:pharmacology; D012989:Soil Pollutants / Q000737:chemistry / Q000633:toxicity*; D015032:Zinc / Q000737:chemistry
D002614:Chelating Agents; D006812:Humic Substances; D007477:Ions; D008293:Malates; D012989:Soil Pollutants; D019343:Citric Acid; D007854:Lead; D003300:Copper; C030298:malic acid; D019815:Oxalic Acid; D015032:Zinc; D019342:Acetic Acid