Influence of drying temperature on NO2 sorption ability of cedar timber

Abstract

NO 2 sorption ability of cedar (Cryptomeria japonica) timbers was evaluated using a new measuring system that was developed in our previous study. Four drying conditions were applied, namely natural drying and three kinds of kilndrying at 45, 60, and 105 °C. Aeration experiments were conducted using discoid specimens which had a thickness in the longitudinal direction of 1.5 mm, and a diameter of 10 mm. The moisture content was conditioned to 0 or 9 ± 1.0% in each drying condition. As a result, the NO 2 sorption ability declined as the drying temperature increased. Based on the analysis of extractives, it was shown that the extractives content had a high correlation with the contribution ratio of extractives in the NO 2 sorption volume of the specimens that were dried below 60 °C. Therefore, it was elucidated that the specimen dried naturally has the greatest NO 2 sorption ability. Furthermore, the result of the gas chromatography-mass spectrometry (GC/MS) indicated that abietadiene influenced the NO 2 sorption ability. Also, the NO 2 sorption volume was high especially at the initial stage, which is higher under the condition with moisture.

Effect of the Drying Method of Pine and Beech Wood on Fracture Toughness and Shear Yield Stress

“…It results in extensive hydrolysis when exposed to elevated temperatures in the presence of moisture. Even if the mass loss due to mild thermal modification during drying is negligible, the chemical reconfiguration of hemicelluloses, evidenced as a decrease of hygroscopicity, was observed [15,25,27,57]. It was also reported that thermolysis of hemicelluloses is highly inhibited when drying/thermal modification occurs in vacuum [25,27].…”

“…Furthermore, Borrega and Kärenlampi [ 10 ] noted that the kinetics of the drying process affect an alteration of the mechanical properties of dried wood to the same extent as drying temperature. An effect of the drying method combined with the process temperature on physical properties of dried wood was studied by several researchers [ 3 , 11 , 12 , 13 , 14 , 15 ]. It was also reported that drying of wood may result in an increase of the material porosity, especially after delignification process, as investigated by Vitas et al [ 16 ].…”

Influence of moisture content on NO2 sorption ability of cedar wood

“…In previous studies, it was reported that the terpenoid of cedar wood contributes largely to the NO 2 sorption ability. For the solvent to extract the terpenoid, n-hexane was used [14,21]. 80 discoid specimens were soaked in 150 mL n-hexane at 20 °C for more than 48 h. As with the non-extracted specimens, the MC of the extracted specimens was adjusted to four different levels using each desiccator with saturated salt.…”

“…The following assumptions were made regarding the conditions of water in the specimens at each MC [14]. At 0% MC, it was assumed that water was not present.…”

“…These factors have been evaluated roughly in previous studies [11,12]. We reported precisely the influence of structural features of tissues and extractives using a measuring system to evaluate the NO 2 sorption volume [13,14]. The structure of the tracheids in cedar wood contributed to increase of the interface area, which influenced the NO 2 sorption volume, and the specimen that had been dried naturally had greater NO 2 sorption ability than that dried in a kiln because it had a large amount of extractives.…”