Copper-based compounds are some of the most important biocides for the protection of wood in heavy-duty applications for decades. In the past, copper was combined with chromium compounds to reduce copper leaching, but a next generation of copper-based preservatives uses ethanolamine as a fixative. As wood preservatives that are based on the micronized copper are still not approved in the EU, copper-ethanolamine based wood preservatives remained as the most important wood preservatives for protection of wood in severe applications. One of the drawbacks of copper-based preservatives is leaching that negatively impacts environment and reduces the performance of treated wood in service. To elucidate the leaching of copper biocides from wood, Norway spruce (Picea abies) wood was treated with a commercial copper-ethanolamine solution with two different copper concentrations (cCu = 0.125% and 0.25%). The aim of this research was to compare the leaching of copper from the specimens exposed in above and below ground applications for various periods between 2 weeks and 43 months. The results indicated that the first leaching peak appears in the initial phases of leaching. There was, between 25% and 36% of copper leached from the impregnated wood after 42 months of exposure. Compared to the classical leaching tests (CEN/TS 15119-1 and CEN/TS 15119-2), both exposures resulted in considerably more severe leaching, what should be considered when testing new preservatives.
Keywords: Norway spruce, copper-ethanolamine, leaching, filed tests
Authors
Humar M.
Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana
Thaler N.
Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana
Lesar B.
Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana
Žlahtič M.
Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana
Kržišnik D.
Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana
Login to download the PDF