Characterization of Copper Based Nanoparticles in Treated Wood

There are multiple industrial processes capble of incorporating malachite green particles in wood; the copper continaing compound serves as a preservative from microbial damage to wood products. However, they use a variety of pressure, environments, and temperature for getting the copper-carbonate into the structure of the wood, which may alter the structure and location of the copper-containing compounds between lumens and cell walls. This study aimed to investigate how three wood processing methods impact the incorporation of malachite green particles in wood. We examine both the the crystal structure and long-range order of the copper-containing compounds as well as particle morphology. Three different types of commercially available treated wood, as well as a novel patented processed wood were examined for copper compounds, structure, and location. Electron microscopy revealed particulate features and chemicals in the wood that chemically matched malachite, but in general x-ray diffraction demonstrated an absence of the crystalline malachite structure upon infiltration in the wood post high pressure processing. The amorphoization of copper carbonate appears to occur both when "micronized" powders are infused into the sturcutre, or when copper and carbonate environments are used to precipitate the copper carbonate in situ. This suggests that the pressure and temperatures used to infiltrate wood with copper containing compounds, or the pressure and chemistry swings needed to precipitate the copper may alter formation pathways or of malachite. While all methods examined show similar copper chemistries, the location and distribution of copper including particles does show differences between the processes in relationship to the nanoparticle positioning in early to late wood.