Analysis of the influence of pre-treatment with liquid hot water (LHW) on the chemical composition of wooden chips

The goal of this paper is to analyze the chemical composition of untreated and treated wooden chips from the native narrow-leaved ash (Fraxinus angustifolia Vahl. ssp. Pannonica Soó & Simon). In order to determine the effect of pretreatment with liquid hot water (LHW) on changes in chemical composition, the content of moisture, cellulose, lignin, minerals (ash), extractives soluble in hot water, extractives soluble in organic solvents, for treated and for untreated wooden chips was determined. This was done in accordance with TAPPI and ASTM standard methods. The properties of wooden chips, treated for 30 min and 60 min at a temperature of 100 °C, are compared to untreated wooden chips and changes in the chemical composition that occurred are defined as a result of the applied treatments. The research was performed under controlled conditions in a laboratory, and the results of treatments were the subject of comparative analysis. Applied treatments had a statistically significant effect on decreasing the content of extractives. The content of cellulose and hemicellulose increased in the treated wooden chips compared to untreated wooden chips, while the lignin content did not significantly change.