Impregnation Isotherms of Linalool on Radiata Pine Wood from Supercritical Carbon Dioxide

摘要

Supercritical impregnation of Radiata pine with linalool using CO_2 as carrier solvent has been studied at lab scale (impregnation vessel ＝ 100 mL). Radiata pine is one of the most common wood species that is originally from Australia and is widely grown in Spain and linalool is a biocide substance using as wood preservative with bactericidal and fungicidal effect obtained from natural extracts (herbs, spices, fruits). In this work, the equilibrium loadings of linalool from supercritical carbon dioxide on Radiata pine at different temperatures (35°C and 45°C) and pressures (8.2 MPa and 9.1 MPa) are reported. The experimental data were obtained with a dynamic method based on measuring the outlet concentration of linalool (UV absorbance) eluted from the impregnation vessel until the effluent reach the output concentration. Impregnation isotherms of linalool on pine wood have typical shapes and can be modelled by classical two parameter models (Langmuir and Freundlich) or by more complex ones (Redlich-Peterson and Toth). The fit of impregnation data showed that Freundlich model could correlate the experimental data for linalool satisfactorily (average absolute deviation ＝ 6-13%) and with more simplicity versus other tested models.