We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Effects of Anions on the Capacity and Affinity of Copper Adsorption in Two Variable Charge Soils.
- Authors
Yu, S.; He, Z.; Huang, C.; Chen, G.; Calvert, D.
- Abstract
Effects of nitrate,(NO) chloride (Cl−), sulfate (SO, and acetate (Ac−) on Cu2+ adsorption and affinity of the adsorbed Cu2+ were evaluated in two Fe and Al enriched variable charge soils from Southern China. The maximum adsorption of Cu2+ ( M, a parameter from the Langmuir isotherm model) in the presence of different anions decreased in the order Cl− > Ac− > NO > SO for both soils. The clayey loamy soil (mixed siliceous thermic Typic Dystrochrept, TTD), developed on the Arenaceous rock, adsorbed less Cu2+ than the clayey soil (kaolinitic thermic Plinthudults, KTP), derived from the Quaternary red earths, regardless of anion type present in the medium. The affinity of adsorbed Cu2+ to both soils could be characterized by the Kd (distribution coefficient) values and successive extraction of the adsorbed Cu2+ with 1-mol NH4Ac L−1. The log10 Kd value was smaller for the TTD soil than for the KTP soil and decreased in the order of Cl− > NO > SO > Ac− at low initial Cu2+ concentrations (≤40 mg Cu2+L−1), whereas at 80 mg Cu2+L−1, the log10 Kd value was similar for NO, SO, and Ac−, but was slightly higher for Cl−. Complete extraction of Cu2+ adsorbed in the presence of Ac− was achieved. Influence of NO and SO on the affinity of adsorbed Cu2+ was similar, but the effects of Cl− depended on the initial Cu2+ concentrations. The extracted percentage of the adsorbed Cu2+ in the presence of NO or SO increased with increasing Cu2+ adsorption saturation. The presence of Cl−, NO, or SO markedly decreased the equilibrium solution pH for both soils with increasing initial Cu2+ concentrations, and the delta pH values at the highest Cu2+ level were 0.5, 0.63, and 0.55 U for the TTD soil and 0.79, 0.84, and 0.93 U for the KTP soil, respectively for the three anions. The presence of Ac− had a minimal influence on the equilibrium solution pH because of the buffering nature of the NaAc/HAc medium which buffered the released protons. The effects of anions on Cu2+ adsorption and affinity of the adsorbed Cu2+ were dependent on anion types and were apparently related to the altered surface properties caused by anion adsorption and/or the formation of anion– Cu2+ complexes.
- Subjects
CHINA; ANIONS; COPPER; SOIL absorption &; adsorption; VARIABLE charge soils; NITRATES; CHLORIDES; SULFATES; ACETATES
- Publication
Biogeochemistry, 2005, Vol 75, Issue 1, p1
- ISSN
0168-2563
- Publication type
Article
- DOI
10.1007/s10533-003-5549-2