Extraction and Characterization of Cellulose Nanocrystals (CNCs) from Jute Fibers and Other By-products Towards a Circular Economy Approach

Materials from renewable resources have gained tremendous attention recently due to environmental concerns and various strict legislations. Cellulose nanocrystals (CNCs) are considered one of the most potential and versatile bio-based nanomaterials for a wide range of applications in multiple fields. Jute is one of the most abundant natural fibers, comprising around 60–65% pure cellulose and 12–15% lignin. In this study, CNCs and other by-products (lignin and Glauber’s salt) were generated using an eco-friendly and sustainable chemical method. Chemical treatment such as alkalization (NaOH), bleaching (H₂O₂), and acid hydrolysis (H₂SO₄) results in the yield of CNCs (38%). Moreover, approximately 12% of the lignin was extracted from the black liquor after the alkalization process, while approximately 17.8% of Glauber’s salt was extracted from the chemicals employed. Scanning electron microscopic (FE-SEM) examination revealed that the average size of the extracted CNCs was around 30 nm, and spherical-shaped particles were observed. From the X-ray diffraction analysis, the crystal size and crystallinity index of CNCs were found to be 3.94–10.27 nm and 85.51%, respectively. From the FTIR (Fourier transform infrared) spectroscopy test, the peak at 1730 cm⁻¹ signifies the carbon and oxygen stretching, and the peak at 1018 cm⁻¹ indicates the lignocellulosic jute fiber, while a broad peak at 1018 cm⁻¹ confirms that CNCs represent higher content of cellulose. The thermogravimetric (TGA-DSC) analysis showed that CNCs were 21.3% stable at 800℃. FTIR and TGA-DSC analysis also identified the by-products, such as lignin and Glauber’s salt.