Influence of Liquefied and CCB Containing Liquefied Wood on Growth of Wood Decay Fungi

Abstract

There are high amounts of post-consumed protected waste wood removed from service every year. The residual biocides, including copper, chromium and boron from CCB (Cu, Cr, B) in post-consumed wood that was protected with biocides may cause environmental problems during waste management, for example during land filling. Therefore, the aim of this study was to find out if Cu and Cr in the processed waste wood, previously treated with CCB, can be re-used as a wood preservative or in coatings made of liquefied wood. Liquefaction of CCB containing waste wood could be as well the first step in the elimination process of metals. So, the optimal conditions for liquefaction of CCB (Cu, Cr and B) containing black poplar (Populus nigra L.) wood were established and compared with liquefaction of uncontaminated black poplar wood. The reactants for liquefaction of black poplar wood sawdust were ethylene glycol (EG) and sulphuric acid. It was observed that in the last stages of the liquefaction process, the presence of Cu, Cr and B did not have any influence on liquefaction yield (LY), while their influence was observed in first stages of the solvolytic reaction. Investigations of fungicidal properties of uncontaminated and CCB containing liquefied wood showed higher antifungal efficacy of liquefied wood without Cu, Cr and B than of liquefied wood that contained CCB. In the tested concentration range, the presence of Cu even promoted the growth of selected wood decay fungi. One of the reasons for higher toxicity of liquefied black poplar sawdust without Cu, Cr and B, was its very low pH value.

Polyurethane coatings from liquefied wood containing remains of a copper‐, chromium‐, and boron‐based wood preservative

“…The concentrations of copper and chromium in IBP‐LS were substantially lower than in CCB containing sawdust prior to liquefaction (around 80 or 60% less copper and chromium in the LS, respectively), which is also summarized in Table . We already noticed and discussed similar behavior previously . As reported, the most likely reasons might lie in dilution during the liquefaction process (the ratio between sawdust and ethylene glycol was 1 : 3), liquefaction yield which is substantially lower than 100% (in some cases even only 90%) and in addition some volatile products evaporate from the mixture during liquefaction .…”

“…Hence, instead of using the authentic samples from service, our experiments were performed with the model systems—CCB impregnated sawdust. Impregnation of sawdust with CCB and preparation of liquefied samples was performed as described previously …”

“…Altogether, CCA and by analogy also CCB fixation in wood is a complex process and various new compounds between wood and Cu, Cr, and/or B may be formed and could therefore influence on the liquefaction process itself, and because of the presence in the liquefied mixtures also on curing and properties of PU films made of contaminated liquefied wood. Hence, it was believed that the use of waste CCB‐treated wood is extremely limited, but our previous studies have demonstrated that liquefaction of CCB‐treated wood is possible and it is supposed that this material could be utilized also for the preparation of wood coatings. Hence, the main aim of this study was to prepare PU films from CCB containing liquefied wood and to clarify the influence of Cu, Cr, and B on film properties.…”

Evaluation of the antioxidant activities of different bio-oils and their phenolic distilled fractions for wood preservation

“…The phenolic compounds derived from lignin played an important role against fungal attack (Yen & Chang, 2008). Antifungal activity of liquefied wood and liquefied wood containing biocide were also tested against the selected wood degrading fungi in several studies (Hrastnik et al, 2013;Humar et al, 2011) 5 Determining major phenolic compounds in the bio-oil and their lignin-rich fraction that potentially have higher antioxidant activity is important. Identification of these chemicals will help to use them directly as antifungal agents for wood preservation.…”