## 3 Results and Discussion
### Characterization of Cellulose Fibers
#### 3.1.3 Structural Analysis  
Figure 7 illustrates the FT-IR spectra of the following three distinct cellulose materials: commercial pulp, alkali-treated pulp, and bleached pulp. Across all samples, prominent spectral bands are observed at 3391 and 1061 cm\({}^{-1}\), corresponding to stretching vibrations of single-bonded ester groups -OH and CO-. This persistence indicates the resistance of these groups to chemical-thermal treatment. For instance, [PERSON] et al. (2018) employed chemical-thermal treatments, including TEMPO oxidation, to extract cellulose from cotton stems, yet similar spectral bands at 3340 and 1040 cm\({}^{-1}\) attributed to -OH and CO are evident in all samples. The peaks at 2906 cm\({}^{-1}\) arise from antisymmetric and symmetric stretching vibrations of CH\({}_{2}\). Additionally, all samples exhibit spectra in the region of 1635 cm\({}^{-1}\), attributable to adsorbed water interacting with cellulose. The reduction in or absence of spectra associated with hemicellulose and lignin in all samples post-treatment suggests successful delignification and hemicellulose removal. For instance, the absence of spectra at 1728 cm\({}^{-1}\) (acetyl C=O groups in hemicellulose) (71) and 1509 cm\({}^{-1}\) (stretching of the aromatic C=C ring in lignin) (72) may indicate a decrease in  
Figure 6: EDS analysis with elemental mapping of grass clippings after alkaline treatment and bleaching. or absence of amorphous components in the cellulose structure. Spectral peaks indicative of cellulose bonds at 1372 cm\({}^{-1}\)[73; 74], corresponding to a single bond bend of CH in cellulose, peaks at 898 cm\({}^{-1}\)[75], reflecting the \(\beta\)-glycosidic bond between glucose, and peaks at 1162 cm\({}^{-1}\)[65], corresponding to the C-C ring band and the C-O-C glycosidic ester band, affirm the presence of cellulose in the samples. The absorption intensity ratio of different IR bands helps determine the hydrogen bond intensity (HBI) in cellulose samples, which affects bound water content and structural flexibility. Typically, as HBI increases, crystallinity decreases. HBI was calculated using the absorption ratio of bands at about 3336 and 1320 cm\({}^{-1}\), finding values of 1.3, 2.05, and 0.9 for the bleached, commercial, and alkali-treated cellulose samples, respectively. Figure 8 depicts the acquired XRD spectra for the three samples under investigation (original, alkaline-treated, bleached). To provide a more precise estimation of the crystalline phase content in the material, the peak deconvolution method can be employed [76]. This method utilizes software to separate the amorphous and crystalline contributions to the diffraction spectrum through a curve-fitting process employing the Gaussian, Lorentzian, and Voigt functions [77]. Notably, the Voigt function, which combines characteristics of both the Gaussian and Lorentzian functions, is often preferred for analyzing crystalline peaks [78]. Through a deconvolution process using the Voigt function, crystalline XRD reflections (1-10, 110, 200, and 004) were identified. Then, from the X-ray diffraction patterns of the sample, the areas corresponding to the scattering of crystalline and amorphous domains were isolated. The most intense crystalline reflex (200) correspo  
Figure 8: XRD patterns and crystallinity index of untreated grass clippings and the alkali-treated and bleached samples. Figure 7: FT-IR spectra of commercial cellulose and cellulose extracted via the alkali treatment and bleaching processes. distances between cellulose chains is of particular importance since it is a marker of cellulose crystallinity. The reflections (1-10) and (110) are observed because of scattering from planes located in the diagonal directions of the crystalline lattice. In addition, the reflex (004) refers to X-ray scattering from planes located perpendicularly to the direction of cellulose chains in the crystalline lattice. These findings are consistent with previous studies [79; 80; 81], where four reflections from the crystalline region were identified.