Comparing leaching of different copper oxide nanoparticles and ammoniacal copper salt from wood

Abstract

Copper-based nanoparticle wood preservatives typically contain a mixture of nanoparticles. We test the effect of nanoparticle size on copper leaching, and if the leachate contains nanoparticles, by treating southern pine sapwood with copper oxide nanoparticles with uniform diameters of 10 and 50 nm. Significant numbers of nanoparticles are found in the leachate from the treated wood, and trends show that size is a major factor. The 50 nm nanoparticles leach slightly less than the control (ammonium copper salt), whereas 10 nm nanoparticles leach more. Effects of polymer stabilizers are also tested and they increase nanoparticle leaching compared to unstabilized nanoparticles. Wood specimens are treated with 10 and 50 nm CuO nanoparticles, and a soluble copper salt as a control. Wood treated with 10 nm nanoparticles leaches more copper than the control, and many nanoparticles are found in the leachate. Wood treated with 50 nm CuO nanoparticles leaches less than the control, but nanoparticles are still found in the leachate. Polymer stabilizers enhance leaching. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.