Building structures made from fir wood are often attacked by wood-destroying insects for which the terpenes it contains serve as attractants. One of the possibilities for extending the lifetime of structures is to use older wood with a lower content of terpenes and/or thermally modified wood. The study evaluated the levels of terpenes in naturally aged fir wood (108, 146, 279, 287 and 390 years) and their decrease by thermal treatment (the temperature of 60 °C and 120 °C, treatment duration of 10 h). Terpenes were extracted from wood samples by hexane and analyzed by gas-chromatography mass-spectrometry (GC-MS). The results indicate that recent fir wood contained approximately 60 times more terpenes than the oldest wood (186:3.1 mg/kg). The thermal wood treatment speeded up the release of terpenes. The temperature of 60 °C caused a loss in terpenes in the recent fir wood by 62%, the temperature of 120 °C even by >99%. After the treatment at the temperature of 60 °C the recent fir wood had approximately the same quantity of terpenes as non-thermally treated 108 year old wood, i.e., approximately 60–70 mg/kg. After the thermal treatment at the temperature of 120 °C the quantity of terpenes dropped in the recent as well as the old fir wood to minimum quantities (0.7–1.1 mg/kg). The thermal treatment can thus be used as a suitable method for the protection of fir wood from wood-destroying insects.
The aim of the study was to establish and compare the model of the biodegradability and ecotoxicological properties of oil samples in aqueous environment.The unused new mineral oil Turbinol and used (after 1 year of usage) recovered oil Turbinol purified by the electrostatical method were the tested samples. For the determination of the ecotoxicological properties, the test organisms used were seeds of Sinapis alba L. and the small aquatic crustaceans Daphnia magna. Preliminary tests were positive and determined the acute toxicity with the values of IC 50 and EC 50 . Biodegradability was determined by the manometric method, in tests which lasted 28 days. Tests of toxicity were positive, and the samples were found to be hard to biodegrade. Determination of the oil composition by gas chromatography with mass detection (GC -MS); found that the composition of the electrostatically cleaned oil is comparable to the new oil, which is confirmed by the results obtained with the response inhibition in selected tests. Regeneration extends the oil life, reducing the cost of disposal of waste oils, saving fossil raw materials, thus belonging to the environmentally friendly techniques.
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