Artemisia annua Stems a New Sustainable Source for Cellulosic Materials: Production and Characterization of Cellulose Microfibers and Nanocrystals

Cellulose nanocrystals from agriculture and forestry biomass: synthesis methods, characterization and industrial applications

Agricultural and forestry biomass wastes, often discarded or burned without adequate management, lead to significant environmental harm. However, cellulose nanocrystals (CNCs), derived from such biomass, have emerged as highly promising materials due to their unique properties, including high tensile strength, large surface area, biocompatibility, and renewability. This review provides a detailed analysis of the lignocellulosic composition, as well as the elemental and proximate analysis of different biomass sources. These assessments help determine the yield and characteristics of CNCs. Detailed discussion of CNC synthesis methods -ranging from biomass pretreatment to hydrolysis techniques such as acid, mineral, solid acid, ionic liquid, and enzymatic methods-are provided. The key physical, chemical, and thermal properties of CNCs are also highlighted, particularly in relation to their industrial applications. Recommendations for future research emphasize the need to optimize CNC synthesis processes, identify suitable biomass feedstocks, and explore new industrial applications.

Development of cellulose-based biosorbents from the residue of the peach palm agribusiness and simulation of industrial scale-up for copper removal from Brazilian spirit

BACKGROUND

Cachaça (Brazilian spirit) is an alcoholic beverage of cultural and economic importance in Brazil. Its artisanal production is usually conducted in copper alembics, which results in contamination. The development of effective biosorbents from cheap matrices is an alternative to minimize both solid waste generation and copper levels in cachaça. The present work evaluates the obtention of nanocellulose-based materials from the major residue generated during the processing of palm heart from the Brazilian peach palm, through different processing techniques. Materials were characterized by physicochemical composition and their sorbent capacities for copper removal from aqueous solutions, and a simulation was conducted to evaluate potential application in the adequacy of cachaça to meet Brazilian legislation requirements.

RESULTS

The different processing methods resulted in different cellulose concentrations, with the highest concentration in the bleached material (B3, 694 g kg-1 of cellulose), and different specific surface areas (1.02-12.4 m2 g-1). Copper adsorption onto nanocellulose obtained from peach palm external sheath is fast, with a predominance of a chemisorption mechanism. Isotherms were best represented by Langmuir's model, suggesting a monolayer adsorption. Simulations indicate that B3 is a suitable material for the removal of copper from cachaça, and small amounts of biosorbent (733.5 g) are required for the reduction of copper concentrations (10 to 3 mg L-1) in 1000 L of cachaça.

CONCLUSION

This study demonstrated that the obtention of biosorbents from peach palm solid residues is promising and this nanocellulose-based material can be used for copper removal from contaminated cachaça. © 2024 Society of Chemical Industry.

Fabrication of a ternary biocomposite film based on polyvinyl alcohol, cellulose nanocrystals, and silver nanoparticles for food packaging

Silver nanoparticles (AgNPs) were loaded on deprotonated cellulose nanocrystals (CNCd) and incorporated into polyvinyl alcohol (PVA) to develop novel active food packaging films. The AgNPs were fabricated using the liquid phase chemical reduction method using the sodium borohydride reductant of AgNO3. The analysis using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), and Ultraviolet-visible spectroscopy (UV-Vis) showed that the CNCd surface had a homogeneous distribution of AgNPs with a diameter of about 100 nm. Additionally, CNCd/Ag was successfully incorporated into the PVA film. The developed PVA/CNCd/Ag film showed significantly improved mechanical properties, thermal stability, and UV barrier properties compared to a neat PVA film. The PVA/CNCd/Ag composite film could significantly preserve bananas for 14 days, preventing deterioration and allowing extended storage periods. This composite film generally shows promise in food packaging and prolongs food's shelf life.

3D/4D printing of cellulose nanocrystals-based biomaterials: Additives for sustainable applications

Cellulose nanocrystals (CNCs) have gained significant attraction from both industrial and academic sectors, thanks to their biodegradability, non-toxicity, and renewability with remarkable mechanical characteristics. Desirable mechanical characteristics of CNCs include high stiffness, high strength, excellent flexibility, and large surface-to-volume ratio. Additionally, the mechanical properties of CNCs can be tailored through chemical modifications for high-end applications including tissue engineering, actuating, and biomedical. Modern manufacturing methods including 3D/4D printing are highly advantageous for developing sophisticated and intricate geometries. This review highlights the major developments of additive manufactured CNCs, which promote sustainable solutions across a wide range of applications. Additionally, this contribution also presents current challenges and future research directions of CNC-based composites developed through 3D/4D printing techniques for myriad engineering sectors including tissue engineering, wound healing, wearable electronics, robotics, and anti-counterfeiting applications. Overall, this review will greatly help research scientists from chemistry, materials, biomedicine, and other disciplines to comprehend the underlying principles, mechanical properties, and applications of additively manufactured CNC-based structures.

Room-temperature self-healing polyurethane-cellulose nanocrystal composites with strong strength and toughness based on dynamic bonds

Self-healing materials suffer from a trade-off relationship between their self-healing ability and mechanical strength, which limits their applications. Therefore, we developed a room-temperature self-healing supramolecular composite based on polyurethane (PU) elastomer, cellulose nanocrystals (CNCs), and multiple dynamic bonds. In this system, the abundant hydroxyl groups on the surfaces of the CNCs form multiple hydrogen bonds with the PU elastomer, yielding a dynamic physical cross-linking network. This dynamic network enables self-healing without degrading the mechanical properties. As a result, the obtained supramolecular composites exhibited high tensile strength (24.5 ± 2.3 MPa), good elongation at break (1484.8 ± 74.9 %), favourable toughness (156.4 ± 31.1 MJ m^-3, which is equivalent to that of spider silk and 5.1-times higher than that of aluminium), and excellent self-healing efficiency (95 ± 1.9 %). Notably, the mechanical properties of the supramolecular composites were almost completely retained after reprocessing three times. Further, using these composites, flexible electronic sensors were prepared and tested. In summary, we have reported a method for preparing supramolecular materials having high toughness and room temperature self-healing ability that have applications in flexible electronics.

Major Phytochemical Compounds, In Vitro Antioxidant, Antibacterial, and Antifungal Activities of Six Aqueous and Organic Extracts of Crocus sativus L. Flower Waste

PURPOSE

After being considered as a neglected product, agricultural waste is nowadays considered of paramount importance. It has become a source of many chemical compounds with industrial, pharmaceutical, and food applications. This study aims to evaluate the primary phytochemical content, the antioxidant properties, and the antimicrobial activities of different extracts of saffron flower waste (SFE) against bacterial and fungal strains involved in diverse pathologies in southern Morocco.

METHODS

Total phenolic and flavonoid contents were determined. The antioxidant potentials were assessed by DPPH, FRAP, and β-carotene assays. The antimicrobial activity against four bacteria and four fungi was also evaluated. The findings in terms of the relationships between phytochemical content and all activities were depicted by PCA analyses.

RESULTS

SFEs contained large amounts of phenolic and flavonoid compounds that contribute to the significant antioxidant activities. Diethyl ether (DE), n-Butanol (n-B), and Ethyl acetate (EA) fractions respectively exhibited more DPPH scavenging capacity, FRAP reducing power, and β-carotene bleaching inhibition. DE and EA have a remarkable effect mainly against Staphylococcus aureus strain, compared to Listeria monocytogenes, Escherichia coli and Klebsiella pneumoniae. Both SFEs showed antifungal antagonism towards key fungi species involved in post-harvest mold and crop yield losses. Botrytis cinerea was more susceptible than Fusarium solani, Penicillium expansum, and Penicillium digitatum.

CONCLUSION

These results reveal new data about extracts obtained from SFE that could be a potential source of natural antioxidant and antimicrobial agents opening new possibilities for their applications in the food system as a natural preservative and a sustainable alternative to conventional ingredients.