Journal article
Sludge-derived Cu and Zn in a humic-gley soil: effect of dissolved metal-organic matter complexes on sorption and partitioning
Soil and Sediment Contamination, Vol.12, pp.23-46
2003
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Abstract
<p>A sequential extraction scheme was combined with sorption isotherm analysis in order to investigate sorption of sewage sludge-derived Cu and Zn to the A-horizon of a humic-gley soil as a whole, and to the operationally defined exchangeable (1 M MgCl<sub>2</sub>), carbonate (1 M NaOAc), Fe/Mn oxide (0.04 M NH<sub>2</sub>OH.HCl), and organic (0.02 M HNO<sub>3</sub>+30% H<sub>2</sub>O<sub>2</sub>) soil fractions. Sorption parameters were compared for a sample of sludge leachate (with 97.4% of Cu and 63.2% of Zn present as dissolved metal-organic matter complexes, as calculated by geochemical modelling involving MINTEQA2 and verified using an ion exchange resin method) with that of a reference solution exhibiting the same chemical characteristics as the leachate, except for the presence of dissolved organic material. Dissolved metal-organic matter complexes were found to significantly (P<0.05) depress sorption to the bulk soil and each fraction. The greatest depression of Cu and Zn sorption was observed for the exchangeable, carbonate, and Fe/Mn oxide fractions, while the organic fraction of the soil was the least affected. This reflects a greater affinity for the exchangeable, carbonate, and Fe/Mn oxide fractions by the free divalent metal (Cu<sup>2+</sup>, Zn<sup>2+</sup>), with sorption by these fractions attributed to cation exchange, chemisorption, and co-precipitation processes. The sorption characteristics of the organic fraction indicated that Cu and Zn sorption by soil organic matter mostly involved dissolved metal-organic matter complexes. This may be attributed to hydrophobic interactions between nonpolar regions of the dissolved metal-organic matter complexes and solid-phase soil organic matter.</p>
Details
- Title
- Sludge-derived Cu and Zn in a humic-gley soil: effect of dissolved metal-organic matter complexes on sorption and partitioning
- Creators
- Edward D Burton - Southern Cross UniversityDarryl W Hawker - Southern Cross UniversityM R Redding
- Publication Details
- Soil and Sediment Contamination, Vol.12, pp.23-46
- Identifiers
- 1357; 991012821979602368
- Academic Unit
- Science; Faculty of Science and Engineering; School of Environment, Science and Engineering; Southern Cross GeoScience
- Resource Type
- Journal article