Evaluation of degradation in chemical compounds of wood in historical buildings using FT-IR and FT-Raman vibrational spectroscopy

Abstract

Vibrational spectroscopy approaches like FT-IR and FT-Raman, as analytical method, can be used to assess chemical changes in historical wood structures. In this study, wood samples of three historical buildings, in Gorgan, Iran, namely Tekie Estebar, Molla Esmaiel Mosque, and the Esmaieli Buildings were selected. Wood species was determined by their macroscopic characteristics which were hornbeam (Carpinus betulus), oak (Quercus castaneifolia), beech (Fagus orientalis), and elm (Ulmus glabra), as hardwood species, and yew (Taxus baccata) as a softwood species. Also, some samples of oak were collected from northern and southern sides of the Esmaieli Building in order to compare deterioration environmental factors.. The approximate assignment of the experimental bands was completed by comparing. For this purpose, the experimental bands with the calculated band frequencies of cellulose, hemicellulose and lignin. In addition, the reported assignment for softwood and hardwood was used to confirm the vibrational assignments. The results of spectroscopy revealed that biodegradation had occurred in all species. Comparison between the most important vibrational band frequencies related to carbohydrates and lignin in hardwood species suggested that degradation of carbohydrates was greater than lignin, which could be attributed to brown rot and hydrolysis. Reduction of chemical compounds in south oak samples was higher and could be associated with prevailing wind and UV ray in this side. In the only softwood species (yew), because of its highest exposure to frequent raining, deterioration was observed in both carbohydrates and lignin.

Decolorization kinetics and mass transfer mechanisms of Remazol Brilliant Blue R dye mediated by different fungi

“…The appearance of sharp and medium peak at 1617.33 cm −1 may be attributed to the formation of C C, C O and C—N functional groups [ 38 , 39 ]. The 1240.83, 726.47 and 625.02 cm −1 bands are due to stretching vibrations of C—O, S O and C—CO—C group characteristics of the RBBR dye [ 39 , 40 ].

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Comparative archaeometric characterization of recent and historical oak (Quercus spp.) wood

“…The findings indicate lower cellulose content and higher lignin content in fossil oak wood relative to recent wood. The proportion of lignin increased at the expense of polysaccharides, which are more sensitive to degradation and loss, especially in waterlogged conditions (Krutul et al 2010;Łucejko et al 2012;Bader et al 2013;Kolář et al 2014;Capano et al 2015;Baar et al 2019;Moosavinejad et al 2019). The disappearance of acetyl side chains and the cleavage of backbones in hemicelluloses are the main chemical alterations of waterlogged cell wall components in wood material.…”

FTIR analysis of chemical changes in wood induced by steaming and longitudinal compression

“…The glass transition temperature decreases till the fiber saturation point FSP and then the temperature remains relatively constant. It reaches approximately 80°C for lignin in beech wood with MC [ 35.6% or oak [ 24.5% MC (Molnár 2004). Hemicelluloses pass their glass transition point already at room temperature if the moisture content exceeds FSP (Lenth and Kamke 2001).…”

“…The average FSP value for wood in general is considered as 30% (Siau 1984;Niemz and Sonderegger 2017;Engelund et al 2013). However, it can vary highly for individual wood species (e.g., guaiacum: 16.0%, robinia: 19.5%, oak: 24.5%, beech: 35.6% or balsa: 63.7%) (Molnár 2004). The water sorption in wood is a complex thermodynamic process related to polymer changes at the molecular level and can be assumed as a threestage process (Niemz and Sonderegger 2017).…”