Competitive adsorption of heavy metals by soils

Journal Article · · J. Environ. Qual.; (United States)

OSTI ID:7190712

Elliott, H A; Liberati, M R; Huang, C P

The competitive adsorption of Cd, Cu, Pb, and Zn from 0.025 M NaClO/sub 4/, solutions onto four soils with differing chemical properties was investigated with batch adsorption experiments. For two mineral soils, adsorption under acidic conditions (pH 5.0) followed the sequence Pb > Cu > Cd, which corresponds to the order of increasing pK for the first hydrolysis product (e.g., PbOH/sup +/) of the metal ions. In contrast, the order of selectivity for two soils containing 20 to 40 g kg/sup -1/ organic C was Pb > Cu > Cd > Zn, suggesting that organic matter (OM) increased Cd retention preferentially over that of Zn. When accompanied by a sizable reduction in cation exchange capacity (CEC), extraction of soil OM markedly reduced adsorption of all four metals. However, only Cd and Cu adsorption were appreciably smaller for a soil that maintained a sizable CEC following OM removal. Lead, and possibly Zn, adsorption by soils with substantial inorganic exchange sites may be unresponsive to organic waste amendments. For Cd and Cu, increased soil OM should restrict mobility and bioavailability, at least under acidic conditions where soluble metal complex formation is limited.

• Research Organization: Pennsylvania State Univ., University Park
• OSTI ID: 7190712
• Journal Information: J. Environ. Qual.; (United States), Journal Name: J. Environ. Qual.; (United States) Vol. 15:3; ISSN JEVQA
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ADSORPTION
BIOLOGICAL AVAILABILITY
CADMIUM
CATIONS
CHARGED PARTICLES
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
CHEMISTRY
COPPER
DATA
DECOMPOSITION
ELEMENTS
EXPERIMENTAL DATA
HYDROLYSIS
INFORMATION
ION EXCHANGE
IONS
LEAD
LYSIS
METALS
NUMERICAL DATA
ORGANIC MATTER
PH VALUE
SOIL CHEMISTRY
SOILS
SOLVOLYSIS
SORPTION
TRANSITION ELEMENTS
ZINC