Extraction of chromium, copper, and arsenic from CCA-treated wood by using wood vinegar.

In the present study, wood vinegar was used to extract chromium, copper, and arsenic from chromated copper arsenate (CCA)-treated wood. The extraction efficiency for CCA elements was evaluated using various concentrations of wood vinegar, extraction temperatures, and extraction periods. The extraction efficiency for CCA elements increased with increasing the concentration of wood vinegar and the extraction conditions, resulting in maximal removal rate of copper (95.7%), followed by arsenic (92.7%) and chromium (86.3%). Since wood vinegar afforded high levels of copper extraction, its use was extended to copper-based preservative-treated wood, wherein significant extraction of copper up to 97.6% and 95.7% was obtained from alkaline copper quats (ACQ)- and copper azole (CuAz)-treated sawdust, respectively. To the best of our knowledge, this is the first study on the application of wood vinegar for the extraction of metal elements from CCA-treated wood.