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ARS Home » Research » Publications at this Location » Publication #72506
Title: SORPTION AND DESORPTION OF COPPER ON SOIL CLAY COMPONENTS

Author
item WU, JIGANG - IOWA STATE UNIVERSITY
item Laird, David
item THOMPSON, MICHAEL - IOWA STATE UNIVERSITY

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/8/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The objective of this study was to quantify sorption and desorption of copper on various clay and clay-organic matter fractions separated from the Ap horizon of a Zook soil (Cumulic Haplaquolls) from central Iowa. The clay was separated into four particle size fractions, and portions of each fraction were treated with hydrogen peroxide and/or dithionite-citrate-bicarbonate. A batch-equilibration technique was employed to evaluate sorption of copper at pH 6.0 in the presence of 0.01 M CaCl2. The sorption isotherms showed that Cu is preferentially sorbed on organic matter associated with coarse clay fraction of the soil. After organic matter removal; however, the fine clay (< 0.02 um) showed higher copper retention than the coarse (0.2-2.0 um) and medium clay (0.02-0.2 um) fractions. The results suggest that iron oxides coat surfaces of layer silicates blocking access of copper to sorption sites. Substantial sorption-desorption hysteresis was observed for all samples suggesting that copper forms high-energy bonds with both organic matter and layer silicate surfaces.