UBC Theses and Dissertations
Investigation of reacted copper(II) species in micronized copper treated wood Xue, Wei
Wood preservatives using micronized particulate copper as the active ingredient recently introduced in the USA has generated controversies due to their limited intrinsic solubility compared to the conventional soluble copper treatments. Because the availability of soluble copper ions is essential for these preservatives to provide an effective treatment, concerns are centered on whether they are able to produce soluble copper, and the copper fixation mechanism of the treatment is little understood. In this thesis, micronized copper treated wood were studied using a combination of Electron Paramagnetic Resonance (EPR) spectroscopy and X-ray Fluorescence (XRF) spectroscopy. The identification and characterization of soluble and chemically fixed copper species were discussed. A calibration standard was developed to quantify the solubilized and fixed copper species in the micronized copper treated wood, which also contains unreacted particulate copper. On the basis of the experimental results, the fixation mechanism is thought to be triggered by the reaction between the carboxylic acid protons in hemicellulose and pectin of wood with the particulate copper, and the quantities of the solubilized and fixed copper species are determined by the availability of the acidic protons. Results from the studies on micronized copper treated earlywood and latewood, as well as the effect of monoethanolamine additive provided further support on the theory of the fixation mechanism. Soil exposure experiment suggested that the Cu fixation may be affected by the moisture level, organic content and metal content in the soil. Study on micronized copper treated heartwood showed that the particulate Cu may react with the resin acids in addition to the major wood components. The effects of fungal colonization and bio-incision on the pre-treatment material were also briefly discussed.
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Attribution-NonCommercial-NoDerivs 2.5 Canada