Electrolytic remediation of chromated copper arsenate wastes

While chromated copper arsenate (CCA) has proven to be exceptionally effective in protecting wood from rot and infestation, its toxic nature has led to the problem of disposal of CCA-treated lumber and remediation of waters and soils contaminated by process wastes. The active ions in water-based CCA are hexavalent chromium, divalent copper, and pentavalent arsenic. The objective of this study was to develop the underlying engineering science for remediation of aqueous CCA wastes via electrolytic deposition of neutral arsenic, chromium, and copper in order to evaluate the technical feasibility of this process. The specific approach focused on electrochemical stability analysis of the metals; development and testing of a copper sulfate reference electrode (CSE); electrolytic deposition of arsenic, chromium, and copper from model aqueous CCA wastes; and characterization of the resulting deposits. The electrochemical stability analysis of the individual components, As, Cr, and Cu, in an aqueous system was used to determined the most thermodynamically stable forms of the metals as a function of pH and electrochemical potential. This analysis predicted that under the conditions of codeposition of all three metals, hydrogen and arsine would also be produced.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Stern, Heather A. G. (Heather Ann Ganung)

Advisor dc:contributor.advisor

• Donald R. Sadoway and Jefferson W. Tester.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/35284

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/35284