Elsevier

Pedosphere

Volume 16, Issue 6, December 2006, Pages 718-725
Pedosphere

Interactions of Heavy Metal Ions with Paddy Soils as Inferred from Wien Effect Measurements in Dilute Suspensions1

https://doi.org/10.1016/S1002-0160(06)60107-0Get rights and content

ABSTRACT

Interactions of three heavy metal ions, Cu2+, Cd2+, and Pb2+, and, for comparison, Na+ with electrodialytic clay fractions (less than 2 μm in diameter) of four paddy soils as well as a yellow-brown soil as a control soil were evaluated based on measurements of the Wien effect in dilute suspensions with a clay concentration of 10 g kg−1 in four nitrate solutions of 2 × 10−4/z mol L−1, where z is the cation valence, and a nitric acid solution of 3 × 10−5 mol L−1. Field strengths ranging from 15 to 230 kV cm−1 were applied for measuring the electrical conductivities (ECs) of the suspensions. The mean free binding energies between the various cations and all of the soils determined from exchange equilibrium increased in the order: Na+ < Cd2+ < Cu2+ < Pb2+. In general, the ECs of the suspensions in the sodium nitrate solution were smaller than those of the suspensions in the heavy metal solutions because of the lower electrophoretic mobility of sodium compared to the divalent cations. In terms of relative electrical conductivity-field strength relationships, relative electrical conductivity (REC) of suspensions containing various cations at field strengths larger than about 50 kV cm−1 were in the descending order: Na+ > Cu2+ > Cd2+ > Pb2+ for all tested soils. A characteristic parameter of the REC-field strength curves, ΔREC200, REC at a field strength of 200 kV cm−1 minus that at the local minimum of the concave segment of the REC-field strength curves, characterized the strength of adsorption of the cations stripped off by the applied strong electrical field, and for all soils the values of ΔREC200 were generally in the order: Na+ < Cu2+ ≤ Cd2+ ≤ Pb2+.

References (29)

  • C.H. Weng

    Modeling Pb(II) adsorption onto sandy loam soil

    J. Colloid Interface Sci.

    (2004)
  • Q.W. Yang et al.

    Lead in paddy soils and rice plants and its potential health risk around Lechang Lead/Zinc Mine, Guangdong, China

    Environment International

    (2004)
  • H. Bergseth et al.

    Selectivity of humus materials for some heavy metal ions

    Acta Agriculturae Scandinavica

    (1976)
  • N. Cavallaro et al.

    Copper and cadmium adsorption characteristics of selected acid and calcareous soils

    Soil Sci. Soc. Am. J.

    (1978)
  • Cited by (6)

    • Wien effect in suspensions and its application in soil science: A review

      2013, Advances in Agronomy
      Citation Excerpt :

      The Wien Effect in soil suspensions, that is, the increase of the suspension EC with increasing E—the subject of this chapter—is more pronounced than in electrolyte solutions (Li et al., 2002), and was successfully applied to characterizing and quantifying the interactions between ions and soil particles (Li and Friedman, 2003; Li et al., 2005; Wang et al., 2007). The above-mentioned studies and others carried out in the past decade (Jiang et al., 2006; Wang et al., 2008, 2009, 2010, 2011, 2013a; Zhu et al., 2009a,b) proved that the energy relationships, that is, the binding and adsorption energies between ions and soil particles can be evaluated, which seems to be a significant step forward in our ability to characterize and quantify soil particle–ion interactions. The present chapter introduces this recently developed experimental Wien Effect method and describes its application to several soil particle–ion interactions.

    1

    Project supported by the National Key Basic Research Support Foundation of China (No. 2002CB410808) and the National Natural Science Foundation of China (No. 40401030).

    View full text