Influence of wood species, treatment method and biocides concentration on leaching of copper–ethanolamine preservatives

Cu–ethanolamine-based preservatives are currently the most important alternatives for classical chromated-copper formulation. However, emissions of Cu from wood impregnated with copper–ethanolamine-based preservatives are still higher compared to emissions from wood preserved with copper–chromium based preservatives. In order to elucidate leaching of copper from specimens treated (brushed, soaked or vacuum-impregnated) with different copper–ethanolamine containing biocides of two different concentrations the following research on specimens made of Norway spruce (Picea abies), Scotch pine (Pinus sylvestris) and Beech (Fagus sylvatica) were performed. The results showed that leaching is significantly affected by the wood species used. The lowest leaching rates were determined in specimens made of spruce, while the highest ones were determined in beech wood. Concentration of active ingredient influences the Cu fixation as well. Unfortunately, ethanolamine at higher concentration causes depolymerisation of lignin macromolecules, which results in increased copper leaching.