# Eco-Friendly Preservation of Pharaonic Wooden Artifacts using Natural Green Products
## 3 Results
### Analyses of A. nilotica Experimental Wooden Cubes Treated with Thyme Oil as the Most Effective EO  
The experimental aged wooden cubes treated with thyme essential oil as the most efficient antimicrobial were analyzed using a scanning electron microscope, energy dispersive X-ray analysis (SEM and EDX), and Fourier-transform infrared spectroscopy (FTIR). Scanning electron microscope analysis was performed on the experimental wooden cubes of _A. nilotica_ to examine the changes in the morphology of the wooden cells before and after treatment with the most efficient essential oil (thyme oil). The untreated control samples showed fungal hyphae penetrated the cell lumens of the wood via the pits and began to change the structure of the wood by spreading through the lumens, also dense conidial heads and hyphae were mostly located in the untreated wooden cells, where the walls were almost completely degraded (Figure 4a). On the other hand, there were no remarkable morphological variations in the structure of the thyme oil-treated wooden cells. It was also interesting to observe that SEM analyses of the experimental wooden species impregnated with thyme oil were much more resistant to fungal attack than the untreated samples (Figure 4b). Figure 4: Scanning electron microscope (QUANTA FEG250) images of _Acacia nilotica_ treated and not treated with thyme oil. (**a**) _A. nilotica_ not treated with thyme oil revealed changes in the morphology of the wooden cells and penetration of hyphae between cells; the scale bar image (on the bottom-right of the figure) is 40 \(\upmu\)m; other indications: HV (High Voltage) 20.00 kV; magnification: 3000\(\times\); spot: 3.5; WD: 8.8 mm; det: BSED (Backscattered electron detectors); HPW: 138 \(\upmu\)m; date: 8/23/2022. (**b**) _A. nilotica_ treated with thyme oil observed no remarkable changes in the structure of the wooden cells of standard _A. nilotica_ wood; the scale bar image (on the bottom-right of the figure) is 300 \(\upmu\)m; other indications: HV 20.00 kV; magnification: 400\(\times\); spot  
The elemental composition of _A. nilotica_ wood was analyzed by EDX, where the two main elements that appeared before and after treatment by thyme oil were carbon and oxygen. They constitute the main components of the native wood that indicates no significant changes in the major chemical composition of the wood before and after treatment with thyme essential oil (Figure 5a,b). The FTIR spectra of the experimental aged _Acacia nilotica_ wood samples (standard, untreated, or treated with thyme oil) were investigated (Figure 6). The peaks at 1632, 1452, 1266, and 1031 cm\({}^{-1}\) represent the carbohydrate components. These peaks were different in the wood samples exposed to fungal deterioration if compared to the standard sample and the sample treated with thyme oil. In particular, the absorption peak at 1632 cm\({}^{-1}\) (attributed to lignin components) indicates most of the degradation of the cell wall components occurred with the carbohydrates (hemicelluloses and cellulose). The 1452 cm\({}^{-1}\) band is attributed to C-H deformation in lignin and carbohydrates, while the C-O stretch in lignin appeared at 1266 cm\({}^{-1}\). The band at 1031 cm\({}^{-1}\) is attributed to C-O vibration in cellulose and hemicellulose. Moreover, the characteristic peak of thyme oil appeared in the oil-treated wood at the 2200-2400 cm\({}^{-1}\) absorption band. The lengths of the peaks at 1632, 1452, 1266, and 1031 cm\({}^{-1}\) representing carbohydrate components of the untreated thyme oil wood samples exposed to fungal deterioration were different (Figure 6b) if compared to the standard sample and the sample with treated thyme oil (Figure 6a,c). The synchrotron radiation XRD results on the crystallinity (as the mass fraction of crystalline cellulose) of the standard, thyme oil-untreated, and thyme oil-treated wood samples are reported in Figure 7. A decrease in the crystalline index was observed in the untreated sample. The crystallinity index (Cr.