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用稀悬液Wien效应测量法来研究重金属离子与水稻土的相互作用
作者姓名:JIANG Jun  LI Cheng-Bao  ZHAO An-Zhen  XU Ren-Kou  WANG Yu-Jun  S. P. FRIEDMAN
作者单位:Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China). E-mail: jjiang@issas.ac.cn;Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China). E-mail: jjiang@issas.ac.cn;Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China). E-mail: jjiang@issas.ac.cn;Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China). E-mail: jjiang@issas.ac.cn;Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China). E-mail: jjiang@issas.ac.cn;Institute of Soil, Water, and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan 50250 (Israel)
基金项目:国家重点基础研究发展计划(973计划);国家自然科学基金
摘    要: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+.

关 键 词:结合能  电导率  磁场强度  重金属  土壤
收稿时间:2006-06-08
修稿时间:2006-09-02

Interactions of heavy metal ions with paddy soils as inferred from wien effect measurements in dilute suspensions
JIANG Jun,LI Cheng-Bao,ZHAO An-Zhen,XU Ren-Kou,WANG Yu-Jun,S. P. FRIEDMAN.Interactions of heavy metal ions with paddy soils as inferred from wien effect measurements in dilute suspensions[J].Pedosphere,2006,16(6):718-725.
Authors:JIANG Jun  LI Cheng-Bao  ZHAO An-Zhen  XU Ren-Kou  WANG Yu-Jun and S P FRIEDMAN
Institution:

aInstitute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)

bInstitute of Soil, Water, and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan 50250 (Israel)

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+.
Keywords:binding energy  electrical conductivity  field strength  heavy metal ions  paddy soils
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