INFLUENCE OF LIQUEFIED AND CCB CONTAINING LIQUEFIED WOOD ON GROWTH OF WOOD DECAY FUNGI

D Hrastnik,F Budija,M Humar,M Petrič

doi:10.4067/s0718-221x2013005000010

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.

Highlights

Due to a threat of shortage of fossil based sources and especially due to negative impacts of their usage on the environment, utilisation of renewable natural resources, including biomass, is becoming more and more important
Liquefaction of CCB containing black poplar wood Concentrations of copper and chromium in UBP, LRIBP and HRIBP sawdust are shown in table 1
The study showed that almost 100% of sawdust was liquefied if the ratio between sawdust and diethylene glycol (DEG) was higher than 1: 2. Further increasing of the ratio did not have influence on liquefaction yield (LY)

Summary

Introduction

Due to a threat of shortage of fossil based sources and especially due to negative impacts of their usage on the environment, utilisation of renewable natural resources, including biomass, is becoming more and more important. Beside its applications in a natural - solid form, liquid and gas biomass based products can be produced and used as a fuel or for further organic syntheses (Lin et al 1997). The conversion technologies into a liquid or gas state can be separated into four basic categories: direct combustion processes, biochemical, thermochemical and agrochemical processes (Demirbas 2001). The most important ones are biochemical and thermochemical processes (Tsoul et al 2004). Biochemical processes are anaerobic digestion (decomposition through bacterial action in the absence of oxygen) and alcoholic fermentation (ethanol can be produced from certain materials which contain sugars, starch, hemicellulose or cellulose). Further categories of thermochemical processes are pyrolysis, gasification, supercritical fluid extraction, hydro thermal upgrading process and liquefaction.

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