## 3 Results
### Treatment Using ZnCl\({}_{2}\)-4H\({}_{2}\)O
Figure 2: XRD profiles of the original biomass, Solid I, Solid II, and Solid III. ((**A**) Barley straw; (**B**) pruning waste; (**C**) vine shoots). Figures 4 and 5 show the spectra of the different solids obtained after treatment compared to the lignin, cellulose, and xylan references in the \"fingerprint\" region of lignocellulosic biomass, i.e., between 1800 and 800 cm\({}^{-1}\). Figure 4 shows the spectrum of commercial alkaline lignin compared with Solid I (the supposedly lignin-enriched solid) and Solid III (obtained after washing Solid II with acetone). Figure 4: FTIR spectra of Solid I, Solid II, Solid III, and lignin ((**A**) B.S. : barley straw; (**B**) P.W. : pruning; waste; (**C**) V.S. : vine shoot). Figure 3: FTIR spectra of Solid I, Solid II, and Solid III and their corresponding lignocellulosic biomasses ((**A**): Barley straw; (**B**): pruning waste; (**C**): vine shoots). When comparing Solid I and Solid III with the alkaline commercial lignin, we can see that Solid I differs from the commercial lignin profile; however, Solid III has many similarities for all biomasses used. The most significant peaks found of lignin are shown in Figure 4[43; 44; 45; 46] and are described in the FTIR part of the Characterization Section in the Supporting Information. Solid I shows bands typical of lignin, but it also shows very intense bands between 900 and 1200 cm\({}^{-1}\), attributed to polysaccharides from cellulose and hemicellulose, especially in barley straw (Figure 4), confirming the results obtained in the mass balance data (Table 3). However, no polysaccharide peaks are found in the spectrum of Solid III, but lignin bands are found for all three biomasses used, this indicates a selective separation of Solid III. Figure 5 shows the spectrum of commercial xylans and cellulose compared with Solid I and Solid II, because Solid I is not pure lignin, as has been verified in Figure 4. In Figure 5, different peaks are assigned, these peaks are described [43; 44; 45; 46] in the FTIR part of the Characterization Section in the Supporting Information. In summary, Solid I and Solid II have a similar infrared spectrum profile, showing typical polysaccharide bands in all three biomass samples; however, in Solid I, we observed that the characteristic bands of lignin are intense and defined, and this observation in Solid II is not as evident. A \({}^{1}\)H NMR analysis was performed for all samples obtained after treatment and was compared with the reference materials [10] using DMSO-d\({}_{6}\) solution. We describe the results for all the solids obtained with the different biomasses [10; 47; 48; 49; 50] after the treatment in NMR part of Characterization Section in the Supporting Information. The compositions of Solids I, II, and III of the three biomass samples were determined using NREL standard methods [34]. The results confirmed the characterization data (Figure 4). Full fractionation was not achieved, but we observed partial fractionation of the biomass. Solid I is a solid enriched in lignin (>39 wt.%) and cellulose (>45 wt.%). Solid II is highly enriched in cellulose (>80 wt.%) and Solid III is pure lignin. The amount of  
Figure 5: FTIR spectra of Solid I, Solid II, xylan, and cellulose ((**A**) B.S. : barley straw; (**B**) P.W. : pruning waste; (**C**) V.S. vine shoot). hemicellulose is very small in all samples, probably due to the slight acidic character of the ZnCl\({}_{2}\)\(\cdot\)4H\({}_{2}\)O liquid that hydrolyzes the hemicellulose and leaves it dissolved in the reaction medium. In summary, we showed a method for obtaining a cellulose-rich solid with a very low amount of hemicellulose and lignin (Solid II) and mainly pure lignin (Solid III), as shown by the characterization results. Based on the composition analysis (Table 4) and the solids recovered from the three biomass materials (Table 3), the amount of cellulose, lignin, and hemicellulose recovered can be calculated.