Process of absorption and desorption of methanol with a 3-dimensional transport through Picea wood

Abstract

The process of absorption of methanol in liquid state by a wood sample, as well as the following step of desorption, is studied. A 3-dimensional transfer takes place within a cubic wood sample, this cube being cut in such a way that the sides of the cube are parallel with the longitudinal, radial and tangential axes of diffusion. A numerical model taking into account all the facts, e. g. diffusion within the solid and constant concentration on the surface during the stage of absorption, and diffusion within the solid and evaporation from the surface during the stage of desorption, is built and successfully tested. A pseudo-equilibrium of absorption is attained after an immersion time of about 3 hours in the liquid, and the whole amount of methanol is evaporated during the stage of desorption. The process can be described by a 3-dimensional diffusion with constant principal diffusivities.

A method for reducing the amount of PCP in wood with less detriment to protection against fungi

“…The kinetics of absorption and desorption of pure methanol with three-dimensional transport through various Picea samples were determined up to a pseudo-equilibrium attained after an absorption time of 150 min as shown previously [8]. These kinetics were performed by using the methanol solution of PCP, giving results identical to those obtained with the pure methanol.…”

“…By considering wood samples of various sizes for the longitudinal axis, and using the following equations for short times [19], the principal diffusivities were obtained. In this calculation, the diffusivities along the radial and the tangential axis were assumed to be of the same order of magnitude as shown previously either for water [7,9,10] or methanol [8]:…”

“…The transport of moisture [3][4][5][6][7] or of liquids such as methanol [8] or water [9,10] was generally assumed to be controlled by diffusion with the gradient of concentration as the driving force, in spite of the fact that some scientists considered the gradient of pressure [11]. The main characteristics of the transport of moisture and liquid were the following.…”

Zur möglichen Kausalität methanol- und methylacetathaltiger Holzstäube an der Entstehung von malignen Nasentumoren

“…Der Holzstaub iibernimmt also eine Art Triiger-und Depotfunktion und fflhrt zu einer verz6gerten aber stetigen Freisetzung yon Methanol an der Nasenschleimhaut, wobei dieser Effekt vermutlich bereits bei Zimmertemperatur eintritt (Haloui et al 1992). ZusStzlich kann die intrazellul/ire Methanolkonzentration durch hydrolytische Methanolbildung aus Methylacetat, ebenfalls ein Holzpy-rolyseprodukt, erh6ht werden (Mizunuma et al 1992).…”