Method to recover and reuse chromated copper arsenate wood preservative from spent treated wood

• Published in: Waste management (Elmsford) Vol. 26; no. 2; pp. 182 - 188
• Main Authors: Kazi, Feroz Kabir M., Cooper, Paul A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2006; New York, NY Elsevier Science
• Subjects: Applied sciences; Arsenates - chemistry; Arsenates - isolation & purification; Arsenic - chemistry; Arsenic - isolation & purification; Chromium - chemistry; Chromium - isolation & purification; Conservation of Natural Resources; COPPER; Copper - chemistry; Copper - isolation & purification; Environmental Pollutants - isolation & purification; Exact sciences and technology; EXTRACTION; GEOSCIENCES; Hot Temperature; HYDROGEN PEROXIDE; Hydrogen Peroxide - chemistry; LEACHING; Other wastes and particular components of wastes; Oxidation-Reduction; Pollution; PRESERVATIVES; WASTE MANAGEMENT; Waste Products; Wastes; WOOD; Waste treatment; Wood preservative; Wood waste
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2004.12.025

The volume of chromated copper arsenate (CCA) treated wood products coming out of service is expected to increase dramatically during the next decade. There is a need for an alternative waste management approach to landfilling. This paper investigates the variables affecting extraction of CCA components from wood particles and the potential to oxidize and reuse the recovered chemicals. Most of the CCA components could be extracted by 10% H 2O 2 at 50 °C in 6 h with an average extraction efficiency of 95% for Cr, 94% for Cu and 98% for As. The extract containing Cr III, Cu II and As V could be oxidized in several stages by aqueous 2.5% w/w H 2O 2 in less than 2 h to a condition where it was compatible with CCA treating solutions and could be reused for treating new wood. When the recovered extract was mixed with fresh CCA solution in different ratios, the mixed CCA-C solutions had similar solution stability as freshly prepared CCA-C solution and treated wood had similar leaching properties as wood treated with fresh solution.