Lead Extraction from Soils as Affected by Lead Chemical and Mineral Forms

Abstract

Soil washing is one of several technologies for the removal of lead (Pb) from soil. Recent studies have focused on washing efficiency using artificially contaminated soils; however, data may not reflect the efficiency of Pb removal for aged, field-contaminated soils. A Glynwood silty clay loam, a river sediment and a sand were artificially contaminated with PbSO4. These, and soil material from a battery recycling/smelting Superfund site, were washed in batch tests with ethylenediaminetetraacetic acid (EDTA), pyridine-2,6-dicarboxylic acid (PDA) (0.0225 M, 0.0375 M, and 0.075 M) or hydrochloric acid (HCl) (0.1 and 1.0 N). Using a sequential extraction procedure, 96% or more of the Pb in the artificially contaminated soils and 65% of the Pb in the Superfund soil were determined to be extractable. X-ray diffraction techniques revealed the presence of both anglesite (PbSO4) and hydrocerrusite (Pb3[CO3]2[OH]2Pb) in the Glynwood and sand, and in the river sediment, massicot (PbO) was also detected. Metallic Pb ...