Alterations in the anatomy and chemical structure of archaeological wood from a tomb of northern china due to different fungal rots

This paper aims to identify the decay types and investigate the chemical alterations in the three types of fungal decayed archaeological wood from Dongshan Han Tomb M6 (ca. 200-100 B.C.) in Taiyuan City, China. Microscopy, FT-IR, 13C NMR and XPS were adopted to reveal the features of the samples. The results show that from the microscopic and chemical perspectives, these samples are consistent with the characteristics of brown-rot, white-rot and soft-rot. However, all the samples show the accumulation of carboxylic acids or carboxylate salts from extensive oxidation of lignin, which were not observed in artificial fungal decayed wood. Moreover, different fungal decay types and pH values of the samples corresponding to the alternative forms of carboxylic acid or carboxylate salt are considered to be influenced by combined factors, such as the position in the tomb, groundwater level, moisture content, oxygen availability, etc. This study may provide a reference for the deterioration and conservation of fungal decayed wooden artifacts in the tomb of northern China where alkaline loess is the main soil type.

Characterization of lignins from the black liguor of Australian eucalyptus kraft of the nail

Lignin samples were separated from the black liquor of Australian eucalyptus kraft pulping by ethanol-acid precipitation or acid precipitation. Elemental analysis, FT-IR, and 1H NMR were conducted to compare their structural characteristics. The thermal behaviors were studied by TGA and heating value was examined with oxygen bomb calorimeter. The obtained C9 expanded formulas for acid-extraction lignin and ethanol-acid-extraction lignin were C9H9.52O2.96 and C9H9.58O3.18, respectively. According to FT-IR and 1H NMR analyses, the two lignins were similar to hardwood lignin of type GS. However, the acid-extraction lignin showed a high proportion of syringyl (S) unit. TG results showed that degradation process of the two lignins was similar, but their degradation temperatures were different. The weight loss rate reached its maximum value of 8.49 wt% / °C and 4.39 wt% / °C for ethanol-acid-extraction lignin and acidextraction lignin, whose temperature of maximum weight loss was 371°C and 356°C respectively. Results of oxygen bomb calorimeter tested showed the incendiary heat of ethanol-acid-extraction lignin was higher than that of acid-extraction lignin.