Electrochemical Analysis of Ion-Exchange Membranes with Respect to a Possible Use in Electrodialytic Decontamination of Soil Polluted with Heavy Metals^†

^†Dedicated to J⊘rgen Birger Jensen (1937–1995).

Abstract

Transport numbers in different metal chloride solutions were estimated using the emf method for two ion-exchange membranes: Ionics CR67 HMR412 (cation-exchange membrane) and Ionics AR204 SXRA 7639 (anion-exchange membrane). The cation-exchange membrane was found to work nearly ideally for NaCl and CaCl₂ solutions even at high concentrations, whereas deviation from ideality was seen for ZnCl₂ and CuCl₂ solutions. The anion-exchange membrane showed transport numbers for the anion around 0.95 for NaCl, CaCl₂ and ZnCl₂ solutions for the concentration range investigated. Electrodialytic desalting experiments taken as a simplified simulation of the electrokinetic decontamination method showed that it was possible to remove all ions in the simulated soil volume, with a sharp increase in the potential difference over the soil volume as a result, and that it was possible to control the metal content in the different solutions in the electrodialytic decontamination method.

^†Dedicated to J⊘rgen Birger Jensen (1937–1995).

Key Words:

• Ion-exchange membranes
• Electrodialysis
• Transport numbers
• Desalting
• Heavy metals
• Soil decontamination

Notes

^†Dedicated to J⊘rgen Birger Jensen (1937–1995).