Desorption Kinetics of Yttrium, Lanthanum, and Cerium from Soils
- Bei Wen,
- Xiao-quan Shan *,
- Jin-ming Lin,
- Gui-gang Tang,
- Nai-bin Bai and
- Dong-an Yuan
Study on desorption kinetics of Y, La, and Ce from soils is of importance because it relates to the bioavailability and potential toxicity of rare-earth elements. In the present study, a column-flow method and three models (first-order, two site first-order, and log-normal distribution first-order kinetics models) were used to describe the desorption kinetics of Y, La, and Ce from four Chinese soils with different physicochemical properties. A high desorption percentage of Y (87.1–96.6%), La (89.9–98.5%), and Ce (57.6–96.4%) from Yingtan soil was attributed to the low soil pH 5.43 and low organic matter of 1.53%. In contrast, a low percentage of Y (27.5–45.7%), La (27.6–53.6%), and Ce (1.09–50.8%) sorbed by Beijing, Tongjiang, and Haerbin soils desorbed probably because of the higher soil pH values of 8.24, 7.16, 7.23, and increased organic matter (36.4%) in Haerbin soil. The results also suggest that the first-order kinetics model did not offer an acceptable description of the data (R 2 < 0.90). However, excellent agreements were achieved between the experimental data and fits to the latter two kinetic models (R 2 > 0.99). The parameters derived from the kinetic equations indicated that increasing the initial sorption period from 1 to 20 wk could lead to a strong binding of rare-earth elements, resulting in slower desorption.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2002. Published in Soil Sci. Soc. Am. J.66:1198–1206.