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Wood which underwent a relatively mild thermal treatment according to a one-step process leading to improved dimensional stability and improved timber performance was extracted with organic solvents to determine the presence of potentially toxic compounds produced by the thermal treatment. The extractives were examined by GC-Mass spectrometry as well as by 13 C NMR to determine which type of loose chemical compounds were produced by the thermal treatment. The formation of some toxic polynuclear aromatic hydrocarbons derivatives of phenantrene as well as other classes of polyaromatics compounds was detected. It is most likely that the presence of all such compounds contributes, perhaps to a relatively substantial extent, to the reported resistance of heat treated timber to fungal and other biological attack. Other allegedly nontoxic compounds due to wood constituents degradation were also found, mainly the by-products of lignin pyrolysis. The extent of toxic and non-toxic compounds in the heat treated wood were not quanti®ed, but it can be stated that their proportion appears to be quite small. The lack of quanti®cation of the concentration of these products does not allow to ascertain if the ®nal product is toxic or not, and to what extent. Nonetheless, the amount of polynuclear aromatic hydrocarbon-type derivatives should be quanti®ed and related to the type of heat treatment process undertaken before assigning to this type of wood treatment a completely clean health safety label. Hitzebehandeltes Holz: Mo Ègliche toxische Nebenprodukte und Ausmaû des ZellwandabbausRelativ milde Hitzebehandlung mit einem Ein-SchrittVerfahren fu Èhrte zu verbesserter Dimensionsstabilita Èt und verbessertem Schnittverhalten. Dieses Holz wurde mit organischen Lo Èsemitteln extrahiert um mo Ègliche toxische Nebenprodukte des Verfahrens zu bestimmen. Zu diesem Zweck wurden die Extrakte mittels GC-MS und 13 C NMR untersucht. Einige toxische polykondensierte Aromaten vom Phenantrentyp und andere Polyaromaten wurden gefunden. Es ist mo Èglich, daû diese zur bekannten Widerstandsfa Èhigkeit des hitzebhandelten Holzes gegen Pilze und andere Mikroorganismen beitragen. Gefunden wurden auch andere, vorgeblich nicht-toxische Aubbauprodukte der Holzkomponenten, insbesondere aufgrund der Ligninpyrolyse. Die Substanzen wurden nicht quantitativ bestimmt; ihr Anteil ist jedoch sehr gering. Daraus kann man allerdings nicht schlieûen, ob diese Produkte tatsa Èchlich toxisch sind oder nicht. Denn dazu mu Èûten diese Abbauprodukte quanti®ziert werden und den verschiedenen Methoden der Hitzebehandlung zugeordnet werden, bevor ein Gesundheitsrisiko ausgeschlossen werden kann.

The role of biomass for increasing renewable energy sources mix is considered fundamental, despite some negative environmental impact of first-generation biofuels. The use of biomass obtained in a more sustainable way, as represented by agricultural wastes, should be favoured. The Mediterranean area and Italy in particular offer a large amount of vineyard pruning residues that can be converted into bioenergy. Since vineyards are exposed to treatments based on copper (Cu) and zinc, these metals last in wood residues during pruning and accumulate in the soil. In this study an evaluation of the concentrations of copper and other heavy metals in grapevine pruning wastes, when treated with common plant protection products, was carried out. The study was also extended to the soil, being potentially mixed to the biomass in the case of mechanical collection of pruning residues. The grapevine residues free of impurities that were collected during this study have typical values of copper in pruning wood, varying from 8.5 mg kg -1 when treated with low Cu product, to 19.2 mg kg -1 when treated with high Cu product. It was observed that contaminations during pruning with soil could increase the amount of copper in the residues. More in detail, every percentage point of soil that winds up on pruning residues involves an increase of 1 mg of Cu every kg of biomass. For this reason, we recommend the use of appropriate systems for the harvest of grapevine residues, particularly mechanical systems that avoid soil lifting. Moreover, we suggest the use of pruning residues preferably in large-scale power plants with appropriate emission filters instead of small-scale domestic boilers.

The pellet energy market is expanding rapidly in Europe and also at the global level, in response to the continuously growing energy demand and because of the high degree of reliability, the easy handling, and the cheap and simple logistics, in comparison to other solid biomasses. The fast growth of this market has highlighted the problem of product quality, which has strong repercussions for technical, environmental, and economic aspects. The biomass quality is defined by several chemical–physical parameters that are directly measurable in the laboratory. In addition, there are quality attributes related to origin and source, difficult to investigate through traditional analyses, such as the type of wood (hardwood/softwood) and the presence of bark. The development of a rapid technique able to provide this information could be an advantageous tool for the energy sector proving indications on biofuel traceability and sustainability. More than 90 samples belonging to three of the most common European species for the energy pellet sector (fir, pine, and beech) have been collected and analyzed by means of Fourier transform near-infrared (FT-NIR) coupled with Principal Component Analysis (PCA). The results show that the main variation in the data is due to both differences between bark and wood, as well as differences between hardwood and softwood. The differences are mainly linked to changes in composition and amounts of cellulose, hemicellulose, lignin, and extractives. Moreover, 30 wood/bark blends (2%–20% (w/w)) were analyzed, indicating the ability of the system to recognize blends from pure material. This study has shown that spectroscopy coupled with multivariate data analysis is a useful tool verifying the compliance of producer declarations and assisting experts in evaluation of the biomass quality.

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