Electrokinetic remediation is an in-situ technique in which a direct current is applied across a water-saturated contaminated soil. As a result, metal ions are transported through the soil from the anode toward the cathode by electromigration, electroosmosis and diffusion. Electrokinetic remediation experiments were performed with Bentonite clay contaminated with Pb and/or Zn under a constant current. The clay bed was cylindrical with a diameter of 5 cm and a length of 15 cm. / The electroosmotic flowrate decreased with time due to a significant increase in the concentration of H+ ions in the bed. Without cathode rinsing the clay bed cracked and the voltage increased. Rinsing the cathode prevented cracking and decreased the voltage applied across the bed. The acid front generated at the anode advanced across the clay bed at a speed of approximately 1.4 mm/hr. When there was no rinsing, most of the metals precipitated in the cathode region. With rinsing, the metals which reached the cathode compartment were removed by the effluent at constant rates over four days. For clay contaminated with Zn, the rate of removal was 15 mg/hr; for clay contaminated with Pb, the rate of removal was 54 mg/hr. For clays with single contaminants and cathode rinsing, the energy consumption was approximately 1.3 x 106 kJ/m3 of clean soil for zinc removal and 1.8 x 106 kJ/m3 for lead removal. For clays contaminated with both metals, the rates of removal were 11 mg/hr for Zn and 26 mg/hr for Pb. After four days, 23% of Pb and 67% of Zn was removed. The efficiency of current utilization was 32% for removal of Zn alone and 40% for removal of Pb alone. For removal of mixed contaminants the efficiency was 40%. (Abstract shortened by UMI.)
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.20198 |
| Date | January 1997 |
| Creators | Chen, Huan, 1971 Mar. 8- |
| Contributors | Weber, M. E. (advisor), Mujumdar, A. S. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Chemical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001609554, proquestno: MQ44000, Theses scanned by UMI/ProQuest. |
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