Uso do líquido pirolenhoso na preservação da madeira de Pinus elliottii.

Abstract

Resulting from the carbonization of wood, the pyroligneous liquid (LP) is considered an organic by-product that is often discarded. On the other hand, research is often carried out through the application of alternative organic products in wood conservation. The purpose is to replace the use of inorganic solutions commonly used for this purpose, which can impact the environment. In this context, the present study aims to evaluate the effectiveness of pyroligneous liquid as a preservative in the treatment of Pinus elliottii wood exposed to the action of xylophagous organisms (termites of the genus Nasutitermes and the fungus Trametes versicolor that causes white rot). For the tests, two impregnation methods were used (autoclaving and immersion). The food preference test with termites showed an average mass loss for control samples of 26.07%, for the autoclaved samples the loss was 14.09%, and for the immersed samples it was 10.47%. In tests with fungi, the standard used in this work, BS EN 113:1997, determines as appropriate the preservative that presents results below 3% in mass loss. However, the results for the loss of mass in the test with the fungi were 26.07% for the control samples, 14.09% for the autoclaved samples and 10.47% for the samples treated by immersion, thus exceeding the established by the norm. However, the results for mass loss allowed us to conclude that, in relation to the attack of xylophagous agents, there was a significant reduction in mass loss. This was more evident in the case of the termite attack. LP, in general, in its raw state, partially inhibited the action of xylophagous agents. The mechanical strength tests, through Janka hardness tests for termites and fungi, showed that both treatment methods did not provide compressive strength to the wood of Pinus elliottii. The fungitoxic test performed showed that the LP inhibited the mycelial growth of the fungus used. The LP tested in the laboratory tests showed different chemical compounds, as verified by the chromatographic analysis, allowing the identification of chemical compounds, the majority being Hydrazine, 2-Carboxamidopyrazine 4-N oxide, 2(1H)-Pyridinethione, 1 -ethyl-6-methyl, which are used for the most diverse purposes, as well as the presence of acetaldehyde, ethylene oxide, among others. Given this, LP is a promising product that can be used with other substances that enhance its effect as wood preservatives