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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 .

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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.

Zinc borate has long been used as a protector for wood products due to its fungicide, insecticide and flame retardant properties. In this initial study, its capacity as a flame retardant when applied to Eucalyptus grandis wood is evaluated; micronized zinc borate, synthesized from zinc oxide and boric acid in our laboratory was used. The methodology used in the study is the use of the Vandersall tunnel, which allowed analyzing parameters such as the flame spread, the carbonization index, the carbonization area and the wood weight loss. The results show a remarkable improvement in these parameters after the application of micronized zinc borate. For the longest fire exposure time, the percentage decrease of each evaluated parameter is, for tangential and radial plane respectively: 31.27-43.00% for flame spread, 36.66-40.86% for carbonization area, 33.01-52.49% for carbonization index and 19.86-57.80% for mass loss.