No abstract

Wood preservative properties of a solution of ZnSO 4 and MnSO 4 (Zn/Mn molar ratio: 2 : 1), obtained by a process for household battery recycling were studied. Its effect on the growth and enzymatic activity of wood rotting basidiomycetes (Coriolus versicolor, Phanerochaete chrysosporium, Pleurotus ostreatus, Ganoderma resinaceum, Punctularia atropurpurascens, Pycnoporus sanguineous, Inonotus sp, Gymnopilus spectabilis and Gloeophyllum trabeum) was analysed, based on measurements of initial growth rate, minimum inhibitory growth and decolourisation inhibiting concentration. The study solution inhibited mycelial growth and extracellular ligninolytic activity at concentrations between 0?5 and 2 mM Zn 2z , depending on species. The above results were compared with the effect of solutions of pure sulphates. Study solution inhibited mycelial growth at a lower concentration than that of pure sulphates. Wood preservative effect of the study solution was demonstrated in tests using wood substrate (small blocks of Pinus taeda L. and Eucalyptus grandis), finding a minimum toxic value equivalent to 3% Zn 2z .

Analytical pyrolysis (Py-GC/MS) at 500 ºC was applied to study wood composition of Eucalyptus species (E. grandis, E. dunnii and E. benthamii) which are relevant for pulping in Uruguay. Multivariate data treatments mainly principal component analysis and discriminant analysis with automatic backwards variable selection were used to explore differences between the original wood cultivars. Multivariate analyses with automatic backwards variable selection indicated that simplified methoxyphenol patterns (up to 10 compounds) are sufficient for wood discrimination in terms of species and geographical origin but also with purposes of forecasting the ease of delignification of the resulting pulps measured as active alkali. No additional chemotaxonomical accuracy was achieved when the data sets were enlarged with carbohydrate-derived products. On the other side, discriminant or forecasting models were much less significant when based on individual diagnostic compounds, groups of compounds, or the classical syringyl-to-guaiacyl (SG) ratio. Principal component analysis indicated that the variability in lignin composition due to bioclimatic variations (spatial replications) was more significant than that due to phylogenetic differences (species and cultivars).

The effectiveness was evaluated for an established wood preservative, zinc borate, prepared in an agitating bead mill to extensively reduce its particle size. The generated micro- or nano-particles of zinc borate were characterized by X-ray powder diffraction, and the particle size distribution was determined to evaluate the effect of milling. Then the fungicidal effectiveness of the zinc borate of both milled and unmilled samples were assayed against brown- and white-rot fungi, on culture medium and on conifer and hardwood as substrates. Treated wood samples were subjected to leaching tests. Scanning electron microscopic images of wood samples were examined to analyze the distribution of zinc borate within the wood. The micronized zinc product kept its crystal structure intact, and it increased the proportion of particles with diameters below 100 nm by 25% when compared to the unmilled product. Malt extract-agar medium supplemented with 2.5% of w/w milled and unmilled zinc borate inhibited fungal growth tested. Both milled and unmilled zinc borate protected the wood when not subjected to leaching. The milled sample of zinc borate improved resistance to leaching, which would allow its application in environments of high moisture content; however, it did not improve the fungicidal action against decay fungi.

RESUMENContinuando con el estudio del uso de una solución obtenida en un proceso de reciclado de baterías domésticas como preservante para madera, se estableció un primer cementerio de estacas basado en la norma EN 252, que evalúa la durabilidad adquirida por probetas de Pinus taeda L. Dicha solución es ácida, contiene 32 g l -1 de Zn y 15 g l -1 de Mn como sulfatos, libre de metales pesados; en ensayos de laboratorio ha demostrado propiedades funguicidas e insecticidas especí cos, a concentraciones menores a 3% en Zn (máxima concentración obtenida del reciclado). A las probetas tratadas con la mencionada solución por el método de célula llena, se les realizó un tratamiento posterior antilixiviante con bórax al 2%, por pincelado y por célula. Se comparó la durabilidad natural y la adquirida, con dicha solución (con o sin bórax), con arseniato de cobre cromatado (CCA) a dos retenciones. A 32 meses del inicio del ensayo, las concentraciones de Zn de 3% y mayores con el bórax aplicado por el método de célula llena son las más efectivas. Se analizaron además los agentes de deterioro de madera (insectos, hongos y bacterias) presentes en las probetas.Palabras clave: Zinc, bórax, preservantes para madera, manganeso, cementerio de estacas. ABSTRACTAs part of the study of the application of a solution obtained from a domestic batteries recycling process as a wood preservative, a eld stakes test was established to assess the acquired durability in loblolly pine (Pinus taeda L.) specimens following the internationally accepted standard EN 252. is solution is acidic, containing 32 g l -1 Zn and 15 g l -1 of Mn as sulfates and free of heavy metals; in laboratory tests the solution proved to have speci c fungicidal and insecticidal properties against organisms that degrade wood, at concentrations lower than 3% Zn (the highest concentration obtained from the recycling process). e specimens treated by the full cell method with the mentioned solution were a erwards treated with 2% in borax by the full cell method and by brushing in order to prevent leaching. Natural and acquired durability are compared using di erent concentrations of the studied solution as well as chromated copper arsenate (CCA) at two di erent retention levels. At 32 months, 3 % and higher concentrations of Zn and borax applied by full cell method showed to be the most e ective. Main degrading agents (insects, fungi and bacteria) found in the specimens are also described.