Micro and nanocrystalline cellulose derivatives of lignocellulosic biomass: A review on synthesis, applications and advancements

Cellulose Nanofiber-Based Nanocomposite Films with Efficient Electromagnetic Interference Shielding and Fire-Resistant Performance

Cellulose nanofiber (CNF) has been widely used as a flexible and lightweight polymer matrix for electromagnetic shielding and thermally conductive composite films because of its excellent mechanical strength, environmental performance, and low cost. However, the lack of flame retardancy seriously hinders its further application. Herein, renewable and biomass-sourced l-arginine (AR) was used to surface-modify ammonium polyphosphate (APP) and an environmentally friendly biobased flame retardant was synthesized by the coordination of zinc sulfate heptahydrate (ZnSO4·7H2O), which was named AAZ. AAZ was deposited on the surface of CNF by electrostatic adsorption and Zn2+ complexation. The biobased compatibilizer Triton X-100 was employed to assist the exfoliation of graphene nanoplatelets (GNPs) and their dispersion in the CNF matrix. Due to the formation of a dense lamellar layer resembling a shell structure, the CNF/GNPs composite films with a tensile strength of 52 MPa were obtained via vacuum-assisted filtration. Because the phosphorus-containing group produces a protective layer of PxOy compound and promotes the formation of a carbon layer by CNF and the combustion releases ammonia gas, the fire-resistant performance of the composite films was greatly improved. Compared with the pure CNF film, the composite film exhibits 33% reduction in PHRR value and 40% reduction in THR. In addition, the CNF/GNPs composite film with 20 wt % GNPs possessed high conductivity (2079.2 S/m) and electromagnetic interference (EMI) shielding effectiveness (37 dB). The ultrathin CNF/GNPs composite films have excellent potential for use as efficient flame retardant and EMI shielding materials.

Extraction of microcrystalline cellulose from Ficus benghalensis leaf and its characterization

Microcrystalline cellulose (MCC) is a crucial component in various industries, including pharmaceuticals, culinary, and cosmetics. The growing demand for MCC has spurred research into extraction methods. This study focused on extracting MCC from Ficus benghalensis using acid hydrolysis to convert the alpha-cellulose content of its leaves into MCC. The solvent used in this process was recyclable for further use. The extracted MCC was characterized by its physicochemical properties, including density, yield percentage, and structural characteristics. The yield was approximately 39.68 %, and the density was low at 1.518 g/cm3, making it suitable for filler applications. Fourier transform spectroscopy and UV-visible analysis identified functional groups of cellulose. X-ray diffraction analysis revealed a crystallite size of 1.560 nm and a crystallinity index of 66.43 %, indicating suitability for related applications. ImageJ determined a mean particle size of 36.545 μm, while scanning electron microscopy showed distinct surface orientations. Atomic force microscopy revealed surface roughness, root mean square, ten-point average roughness, skewness, and kurtosis. Elemental analysis indicated high concentrations of carbon (20.1 %) and oxygen (34 %). Based on these physicochemical features, the extracted MCC could be a valuable source for applications such as filler in reinforcement technology and coating material in pharmaceutical products.

Green and efficient synthesis of cellulose nanocrystals from Hamelia patens leftover via hydrolysis of microwave assisted-ionic liquid (MWAIL) pretreated microcrystalline cellulose

The efficient bioconversion of the lignocellulosic agro-waste has immense importance in biorefinery processing in extracting the cellulose and saccharide fractions. To achieve this, a series of chemical pretreatments is employed, thus concerning environmental threats limit its use. Therefore, an ionic liquid is employed for pretreatment before sustainable extractions owing to its safe manipulation, recycling, and reusability. Specifically, microwave-assisted ionic liquid (MWAIL) pretreatment has significant importance in extracting high cellulose yield at less thermal power consumption. In this study, the leftover stalks of Hamelia patens were subjected to MWAIL pretreatment at 60, 70, 80, and 90 °C to extract microcrystalline cellulose (MCC). Subsequently, the MCC was fabricated into cellulose nanocrystals (CNC) through hydrolytic treatment using acidic and ionic liquids and denoted as CNC-AH and CNC-ILH. Thus obtained CNC was characterized by FTIR, FESEM, XRD, and TGA to investigate the influence of solvent on its morphology, crystallinity, and thermal stability of CNC. The results support that the CNC-ILH has comparatively more thermal and dispersal stability with a reduced crystallinity index than CNC-AH. The surprising results of CNC-ILH signify its utilization in diverse applications in the food and industrial sectors.

Comprehensive characterization of microcrystalline cellulose from lemon grass (Cymbopogan citratus) oil extraction agro-industrial waste for cementitious composites applications

Presently, the construction industry demands components that are exceptionally strong and long-lasting. The initial important construction material is concrete, which contains between 1 % and 2 % of air voids. The structural damage caused by water that enters through the air spaces are improved with filler material. Chemical filler materials are environmentally harmful; therefore, eco-friendly materials are selected for this study. The environmentally benign character of agro-waste byproduct usage is a driving factor in the field of research. Numerous uses can be found for waste materials, especially after they have been repurposed. We used a byproduct of an essential oil extraction company, an extract made from the leaves of lemon grass (Cymbopogan citrus), in our research. Alkalization, slow pyrolysis, acid hydrolysis, and bleaching are only some of the chemical treatments that could be used to easily extract microcrystalline cellulose from the discarded waste material. In our study the chemicals used are mild harmful to the environment and a surface reactant (linear alkyl benzene sulfonic acid) is utilised to bleach and purify the microcrystalline cellulose. Thermal analysis, scanning electron microscopy, transmission electron microscopy and Fourier transform spectroscopy were all used to learn more about the cellulose that had been extracted. The extracted cellulose powder comprises a high crystallinity index (68.14 %) and low crystallite size (5.13 nm) found using X-ray diffraction analysis. The smooth and porous surface is observable in scanning electron microscope analysis. The Differential scanning calorimeter curve shows the highest degradation temperature at 218.16 °C. The micro sized particles mostly range between 100 and 120 μm and are found using ImageJ. The surface roughness and permissible skewness of cellulose particles were examined using atomic force microscopy. The density of extracted cellulose is 1.092 g/cm3. The microcrystalline cellulose yield % was notably maximum (40.45 %). This cellulose was introduced in a M30 grade cement concrete as fillers up to 5 % by the weight of cement. The fresh and mechanical properties of the concrete was found to get improved with the addition of cellulose up to 3 %. As a result, the characteristics of cellulose boost its utility within the construction sector.

Fabrication of a porous Urea@MIL-100(Fe)/CI-MCC/SA hydrogel for All-In-One adsorption, removal and fluorescence monitoring of nitrite

In this paper, a novel All-In-One Urea@MIL-100(Fe)/CI-MCC/SA hydrogel platform was generated by microcrystalline cellulose (MCC) functionalized with pH-response probe (CI), MIL-100 (Fe) and sodium alginate (SA), which was as a carrier of urea to adsorb, remove and monitor NO2-. Under acidic condition, the fluorescent hydrogel platform could produce N2, CO2 and H2O through the diazotization and redox reaction between urea and NO2- with a removal efficiency up to 99.8%, and could also character a good adsorption property for NO2- due to the positive charges of protonation (the maximum adsorption capacity was 21.67 mg g-1), and the adsorption kinetics conformed to pseudo-second-order model. By carried out the NO2- removal step in fluorescent hydrogel platform, NO2- could also be detected indirectly by sensing the changes of pH within 15 min. The linear response range was 0-0.005 M, and the detection limit (LOD) was 74 μM. These results demonstrated that this All-In-One Urea@MIL-100(Fe)/CI-MCC/SA hydrogel platform had great potential in environment. This strategy for the removal and monitoring of NO2- could be employed to related applications in water purification and environmental protection. ENVIRONMENTAL IMPLICATION: Nitrite is one of the important indicators of water monitoring, which is harmful to human and environment. The removal and monitoring of nitrite in industrial wastewater and surface water is very important, but there are no studies about it at present. Based on the fact that urea can react with nitrite to produce green products, we synthesized a novel functional hydrogel to achieve adsorption, removal and fluorescence monitoring of nitrite for the first time. Besides, the practicability of the material in environmental water samples was verified through the detection of nitrite in simulated wastewater.

Mechanochemically functionalized and fibrillated microcrystalline cellulose as a filler in silicone foam: An integrated experimental and simulation investigation

Fibrillated celluloses have gained significant attention due to their exceptional mechanical properties and eco-friendly characteristics, which make them suitable for various applications. In this study, we designed a precise approach for producing highly fibrillated microcrystalline cellulose (MCC) via ball-milling treatment using four typical silane coupling agents. The empirical data demonstrate that the fibrillization of MCC and the properties of fibrillated MCC are largely affected by the size and geometry of the functional groups of the silanes. After ball-milling, most MCC displayed enhanced e-beam tolerance and thermal stability, whereas the silane loading amount, surface area, and morphology of fibrillated MCC appeared to be random, which was exemplified by the proportional and non-proportional relationship between the loading amount and surface area of methyl silane- and phenyl silane-treated MCC, respectively. Density functional theory calculations and molecular dynamics simulations were employed to obtain the intricate details. The simulation results were in agreement with the experimental results. Finally, fibrillated MCC was incorporated into silicone foams as an additive. The thermal stability of fibrillated MCC with added silicone was greatly improved, and the tensile strength of fibrillated MCC-containing silicone foam was 44.1 and 5.4 times higher than that of the neat and MCC-containing silicone foams, respectively.

Study on mechanism of cellulose nanocrystals on hydrophobic phthalocyanine green in aqueous phase

Phthalocyanine green is a hydrophobic pigment with excellent properties, which is usually dispersed in the organic phase. However, most organic phases are volatile and harmful to the environment and organisms. Therefore, phthalocyanine green dispersed in the aqueous phase has development potential. In this work, cellulose nanocrystals (CNCs) were used as dispersant and stabilizer to disperse phthalocyanine green in the aqueous phase. Phthalocyanine green was added to CNCs colloid to prepare phthalocyanine green suspensions with good dispersibility and stability. The particle size, zeta potential, absorbance and microstructure of the phthalocyanine green suspensions were tested and analyzed. The results showed that CNCs had good dispersibility and stability to phthalocyanine green due to charge repulsion and steric hindrance. The phthalocyanine green suspensions were nano-sized and had well compatibility with different types of coating forming substances. The coatings of the mixture had good water resistance, adhesion and mechanical properties. The suspensions had the application property and could be mixed with coating forming substances to prepare coating materials. As a renewable and easily degraded biomass resource, CNCs are expected to become a new dispersant and stabilizer for pigment.

Isolation and characterization of microcrystalline cellulose from an agro-waste tamarind (Tamarindus indica) seeds and its suitability investigation for biofilm formulation

The exploration of potential bio-fillers for bio-film application is a promising approach to ensure biodegradable, eco-friendly, good-quality materials with high-performance applications. This is a comprehensive study executed to establish the utility of an agro-waste Tamarindus indica seeds for microcrystalline cellulose production and to assess its feasibility for biofilm fabrication. The extraction was carried out through consecutive chemical-mediated alkalization, acid hydrolysis and bleaching. The isolated microcrystalline cellulose from Tamarindus indica seeds (TSMCC) was characterized through chemical, thermal and morphological characterization to validate the cellulose contribution, thermal resistance, and compatibility of the material. The physical parameters as density and yield percentage were assessed to evaluate its light-weight utility and economic productivity. These examinations revealed that TSMCC has good specific properties such as high cellulose content (90.57 %), average density (1.561 g/cm3), feasible average roughness (12.161 nm), desired particle size (60.40 ± 21.10 μm), good crystallinity (CI-77.6 %) and thermal stability (up to 230 °C); which are worthwhile to consider TSMCC for bio-film formulation. Subsequently, bio-films were formulated by reinforcing TSMCC in polylactic acid (PLA) matrix and the mechanical properties of the bio-films were then studied to establish the efficacy of TSMCC. It is revealed that the properties of pure PLA film increased after being incorporated with TSMCC, where 5 %TSMCC addition showed greater impact on crystalline index (26.16 % to 39.62 %), thermal stability (333oc to 389 °C), tensile strength (36.11 ± 2.90 MPa to 40.22 ± 3.22 MPa) and modulus (2.62 ± 0.55GPa to 4.15 ± 0.53GPa). In light of all promising features, 5 % TSMCC is recommended as a potential filler reinforcement for the groundwork of good quality bio-films for active packaging applications in future.

Polysaccharides and proteins based bionanocomposites as smart packaging materials: From fabrication to food packaging applications a review

Food industry is the biggest and rapidly growing industries all over the world. This sector consumes around 40 % of the total plastic produced worldwide as packaging material. The conventional packaging material is mainly petrochemical based. However, these petrochemical based materials impose serious concerns towards environment after its disposal as they are nondegradable. Thus, in search of an appropriate replacement for conventional plastics, biopolymers such as polysaccharides (starch, cellulose, chitosan, natural gums, etc.), proteins (gelatin, collagen, soy protein, etc.), and fatty acids find as an option but again limited by its inherent properties. Attention on the initiatives towards the development of more sustainable, useful, and biodegradable packaging materials, leading the way towards a new and revolutionary green era in the food sector. Eco-friendly packaging materials are now growing dramatically, at a pace of about 10-20 % annually. The recombination of biopolymers and nanomaterials through intercalation composite technology at the nanoscale demonstrated some mesmerizing characteristics pertaining to both biopolymer and nanomaterials such as rigidity, thermal stability, sensing and bioactive property inherent to nanomaterials as well as biopolymers properties such as flexibility, processability and biodegradability. The dramatic increase of scientific research in the last one decade in the area of bionanocomposites in food packaging had reflected its potential as a much-required and important alternative to conventional petroleum-based material. This review presents a comprehensive overview on the importance and recent advances in the field of bionanocomposite and its application in food packaging. Different methods for the fabrication of bionanocomposite are also discussed briefly. Finally, a clear perspective and future prospects of bionanocomposites in food packaging were presented.

Lignocellulosic Biomass for the Fabrication of Triboelectric Nano-Generators (TENGs)-A Review

Growth in population and increased environmental awareness demand the emergence of new energy sources with low environmental impact. Lignocellulosic biomass is mainly composed of cellulose, lignin, and hemicellulose. These materials have been used in the energy industry for the production of biofuels as an eco-friendly alternative to fossil fuels. However, their use in the fabrication of small electronic devices is still under development. Lignocellulose-based triboelectric nanogenerators (LC-TENGs) have emerged as an eco-friendly alternative to conventional batteries, which are mainly composed of harmful and non-degradable materials. These LC-TENGs use lignocellulose-based components, which serve as electrodes or triboelectric active materials. These materials can be derived from bulk materials such as wood, seeds, or leaves, or they can be derived from waste materials from the timber industry, agriculture, or recycled urban materials. LC-TENG devices represent an eco-friendly, low-cost, and effective mechanism for harvesting environmental mechanical energy to generate electricity, enabling the development of self-powered devices and sensors. In this study, a comprehensive review of lignocellulosic-based materials was conducted to highlight their use as both electrodes and triboelectric active surfaces in the development of novel eco-friendly triboelectric nano-generators (LC-TENGs). The composition of lignocellulose and the classification and applications of LC-TENGs are discussed.

Constructing a cellulose based chiral liquid crystal film with high flexibility, water resistance, and optical property

Cellulose nanocrystal (CNC) derived from cellulose can form a liquid crystal film with bright structural color by evaporative-induced self-assembly (EISA). As a new class of photonic liquid crystals material, it has attracted much attention because of its intrinsic unique structural characteristics and excellent optical properties. However, the brittleness and water sensitivity of CNC film have hindered its practical application. Herein, multiple cross-linked networks CNC/(polyethylene glycol diacrylate:polyethylene oxide) (PEGDA:PEO) composite film was prepared through EISA and UV irradiation strategies. The as-prepared film exhibits high-flexibility with a fracture strain of up to 36.40 % and strong water resistance, with water absorption at an equilibrium of only 17.41 %. Moreover, the film retains its structural color in aqueous solution for a long time due to its water stability. The outstanding flexibility and water resistance of CNC composite film are attributed to multiple crosslinked networks (i.e. PEGDA, PEO, and PEDGA-PEO networks), which endow the film with excellent stress dispersion and transferability when stretched and limit film swelling in water without affecting chiral nematic structures of CNC. Overall, this work provides a promising strategy to prepare CNC-based film with high-flexibility, water resistance, and optical property for applications like decoration, sensor, and anti-counterfeiting.

Environment friendly emerging techniques for the treatment of waste biomass: a focus on microwave and ultrasonication processes

In the recent past, an increasing interest is mostly observed in using microwave and ultrasonic irradiation to aid the biological conversion of waste materials into value-added products. This study is focused on various individual impacts of microwaves and ultrasonic waves for the treatment of biomass before the synthesis of value-added products. Following, a comprehensive review of the mechanisms governing microwaves and ultrasonication as the treatment methods, their effects on biomass disruption, solubilization of organic matter, modification of the crystalline structure, enzymatic hydrolysis and production of reducing sugars was performed. However, based on the lab-scale experiments evaluated, microwaves and ultrasonication were studied to be economically and energetically ineffective despite their beneficial effects on the waste biomass. This article reviews some of the difficulties associated with using microwaves and ultrasonic irradiation for the efficient processing of waste biomasses and identified some potential directions for future study.

Preparation, characteristics, and soil-biodegradable analysis of corn starch/nanofibrillated cellulose (CS/NFC) and corn starch/nanofibrillated lignocellulose (CS/NFLC) films

The objective of this study was to produce high-performance and biodegradable starch nanocomposites through film casting by using corn starch/nanofibrillated cellulose (CS/NFC) and corn starch/nanofibrillated lignocellulose (CS/NFLC). NFC and NFLC were obtained by super grinding process and added to fibrogenic solutions (1, 3, and 5 g/100 g of starch). The addition of NFC and NFLC from 1 to 5 % was verified to be influential in enhancing mechanical properties (tensile, burst, and tear index) and reducing WVTR, air permeability, and essential properties in food packaging materials. But, in comparison to control samples, the addition of NFC and NFLC from 1 to 5 % decreased the opacity, transparency, and tear index of films. In acidic solutions, produced films were more soluble than in alkaline or water solutions. The soil-biodegradability analysis showed that after 30 days of exposure to soil, the control film lost 79.5 % of its weight. The weight loss of all films was >81 % after 40 days. The results of this study may contribute to expanding the industrial applications of both NFC and NFLC by laying a basis for preparing high-performance CS/NFC or CS/NFLC.

Optimization of microfibrillated cellulose isolation from cocoa pod husk via mild oxalic acid hydrolysis: A response surface methodology approach

Theobroma cacao L. species, cultivated worldwide for its valuable beans, generates up to 72% weight of the fruit as waste. The lack of reutilization technologies in the cocoa agroindustry has hindered the exploitation of valuable bio-components applicable to the generation of high value added bioproducts. One such bioproduct is microfibrillated cellulose (MFC), a biopolymer that stands out for its desirable mechanical properties and biocompatibility in biomedical, packing, 3D printing, and construction applications. In this study, we isolated microfibrillated cellulose (MFC) from cocoa pod husk (CPH) via oxalic acid hydrolysis combined with a steam explosion. MFC isolation started with the Solid/Liquid extraction via Soxhlet, followed by mild citric acid hydrolysis, diluted alkaline hydrolysis, and bleaching pre-treatments. A Response Surface Methodology (RSM) was used to optimize the hydrolysis reaction at levels between 110 and 125 °C, 30-90 min at 5-10% (w/v) oxalic acid concentration. The cellulose-rich fraction was characterized by Fourier-Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) analyses. Characterization analyses revealed a cellulose-rich polymer with fibers ranging from 6 to 10 μm, a maximum thermal degradation temperature of 350 °C, and a crystallinity index of 63.4% (peak height method) and 29.0% (amorphous subtraction method). The optimized hydrolysis conditions were 125 °C, 30 min, at 5% w/v oxalic acid: with a 75.7% yield. These results compare with MFC obtained through highly concentrated inorganic acid hydrolysis from different biomass sources. Thus, we show a reliable and greener alternative chemical treatment for the obtention of MFC.

Study of Unsaturated Polyester Primer Reinforced by Microcrystalline Cellulose on Mechanical, Adhesion and Corrosion Properties

Addition of Microcrystalline Cellulose (MCC) as filler in to Unsaturated Polyester (UPR) polymer can enhanced the properties of the composite. UPR and MCC was prepared using sonication mixing technique at various loading of (2, 4, 6, 8, and 10 wt %) of MCC at a constant of 60 minutes of sonication. UPR and MCC was mixed in a vial bottle and then immersed in sonication bath for the sonication process. Once the sonication completed, the mixture was added with Methyl Ethylene Ketone Peroxide (MEKP) as curing agent, coated on steel plate and was left for curing process of 7 days. The coating was studied for adhesion, mechanical and corrosive properties using pencil hardness, adhesion tape and immersion tests. 4 wt% of loading showed improvement in mechanical properties where form H grade to 4H grade. It is also recorded there are improvement of adhesion test from 1B grade 35-65% pulled out to 4B grade which is less than 5 % pulled. From the immersion test, it shown that 4 wt % of loading has a good corrosion resistant as compared to the control sample. Thus, it was concluded that 4 wt % of loading filler is suitable to be used because it promotes a better mechanical and adhesion properties and also good corrosion resistant compared to other loading percentage.

Cellulose nanocrystalline from biomass wastes: An overview of extraction, functionalization and applications in drug delivery

Cellulose nanocrystals (CNC) have been extensively used in various fields due to their renewability, excellent biocompatibility, large specific surface area, and high tensile strength. Most biomass wastes contain significant amounts of cellulose, which forms the basis of CNC. Biomass wastes are generally made up of agricultural waste, and forest residues, etc. CNC can be produced from biomass wastes by removing the non-cellulosic components through acid hydrolysis, enzymatic hydrolysis, oxidation hydrolysis, and other mechanical methods. However, biomass wastes are generally disposed of or burned in a random manner, resulting in adverse environmental consequences. Hence, using biomass wastes to develop CNC-based carrier materials is an effective strategy to promote the high value-added application of biomass wastes. This review summarizes the advantages of CNC applications, the extraction process, and recent advances in CNC-based composites, such as aerogels, hydrogels, films, and metal complexes. Furthermore, the drug release characteristics of CNC-based material are discussed in detail. Additionally, we discuss some gaps in our understanding of the current state of knowledge and potential future directions of CNC-based materials.

Graphene composite paper synergized with micro/nanocellulose-fiber and silk fibroin for flexible strain sensor

The fabrication of uniform and strong graphene-based conductive paper is challenging due to easy aggregation and poor film formability of graphene. Herein, on the basis of good dispersing effect of nanocellulose, high content graphene (50 wt%) composite paper with micro/nanocellulose fibers and silk fibroin (SF) was manufactured via simple casting method. The synergistic effects of cellulose microfibers (CMFs), cellulose nanofibers (CNFs) and SF result in the paper with ideal combination of flexibility, electrical conductivity and mechanical strength, where CNFs, CMFs and SF act as dispersing and film forming for GNPs, dimensional stability, and interfacial binding agents, respectively. Extraordinarily, by adding SF, graphene nanosheets are tightly coated on the surface of CMFs. The composite paper shows a tensile strength of 49.29 MPa, surface resistance of 39.0-42.1 Ω and good joints bend sensing performance. Additionally, it is found that CMFs can hinder the micro-cracks from propagating during the cyclic elbow bending test. The graphene-based conductive paper is helpful for the development of smart clothing wearable biosensing devices.

Opposite Roles of Bacterial Cellulose Nanofibers and Foaming Agent in Polyhydroxyalkanoate-Based Materials

In this work, an economically feasible procedure was employed to produce poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-based foams. Thermally expandable microspheres (TESs) were used as a blowing agent, while bacterial cellulose (BC) nanofibers served both as a reinforcing agent and as a means of improving biocompatibility. PHBV was plasticized with acetyltributylcitrate to reduce the processing temperature and ensure the maximum efficiency of the TES agent. The morphological investigation results for plasticized PHBV foams showed well-organized porous structures characterized by a porosity of 65% and the presence of both large pores (>100 µm) and finer ones, with a higher proportion of pores larger than 100 µm being observed in the PHBV nanocomposite containing TESs and BC. The foamed structure allowed an increase in the water absorption capacity of up to 650% as compared to the unfoamed samples. TESs and BC had opposite effects on the thermal stability of the plasticized PHBV, with TESs decreasing the degradation temperature by about 17 °C and BC raising it by 3−4 °C. A similar effect was observed for the melting temperature. Regarding the mechanical properties, the TESs had a flexibilizing effect on plasticized PHBV, while BC nanofibers showed a stiffening effect. An in vitro cytotoxicity test showed that all PHBV compounds exhibited high cell viability. The addition of TESs and BC nanofibers to PHBV biocomposites enabled balanced properties, along with lower costs, making PHBV a more attractive biomaterial for engineering, packaging, or medical device applications.

Recent Developments on Bioinspired Cellulose Containing Polymer Nanocomposite Cation and Anion Exchange Membranes for Fuel Cells (PEMFC and AFC)

Hydrogen fuel cell (FC) technologies are being worked on as a possible replacement for fossil fuels because they produce a lot of energy and do not pollute the air. In FC, ion-exchange membranes (IEMs) are the vital components for ion transport between two porous electrodes. However, the high production cost of commercialized membranes limits their benefits. Various research has focused on cellulose-based membranes such as IEM with high proton conductivity, and mechanical, chemical, and thermal stabilities to replace the high cost of synthetic polymer materials. In this review, we focus on and explain the recent progress (from 2018 to 2022) of cellulose-containing hybrid membranes as cation exchange membranes (CEM) and anion exchange membranes (AEM) for proton exchange membrane fuel cells (PEMFC) and alkaline fuel cells (AFC). In this account, we focused primarily on the effect of cellulose materials in various membranes on the functional properties of various polymer membranes. The development of hybrid membranes with cellulose for PEMFC and AFC has been classified based on the combination of other polymers and materials. For PEMFC, the sections are associated with cellulose with Nafion, polyaryletherketone, various polymeric materials, ionic liquid, inorganic fillers, and natural materials. Moreover, the cellulose-containing AEM for AFC has been summarized in detail. Furthermore, this review explains the significance of cellulose and cellulose derivative-modified membranes during fuel cell performance. Notably, this review shows the vital information needed to improve the ion exchange membrane in PEMFC and AFC technologies.

Review of Functional Aspects of Nanocellulose-Based Pickering Emulsifier for Non-Toxic Application and Its Colloid Stabilization Mechanism

In the past few years, the research on particle-stabilized emulsion (Pickering emulsion) has mainly focused on the usage of inorganic particles with well-defined shapes, narrow size distributions, and chemical tunability of the surfaces such as silica, alumina, and clay. However, the presence of incompatibility of some inorganic particles that are non-safe to humans and the ecosystem and their poor sustainability has led to a shift towards the development of materials of biological origin. For this reason, nano-dimensional cellulose (nanocellulose) derived from natural plants is suitable for use as a Pickering material for liquid interface stabilization for various non-toxic product formulations (e.g., the food and beverage, cosmetic, personal care, hygiene, pharmaceutical, and biomedical fields). However, the current understanding of nanocellulose-stabilized Pickering emulsion still lacks consistency in terms of the structural, self-assembly, and physio-chemical properties of nanocellulose towards the stabilization between liquid and oil interfaces. Thus, this review aims to provide a comprehensive study of the behavior of nanocellulose-based particles and their ability as a Pickering functionality to stabilize emulsion droplets. Extensive discussion on the characteristics of nanocelluloses, morphology, and preparation methods that can potentially be applied as Pickering emulsifiers in a different range of emulsions is provided. Nanocellulose's surface modification for the purpose of altering its characteristics and provoking multifunctional roles for high-grade non-toxic applications is discussed. Subsequently, the water-oil stabilization mechanism and the criteria for effective emulsion stabilization are summarized in this review. Lastly, we discuss the toxicity profile and risk assessment guidelines for the whole life cycle of nanocellulose from the fresh feedstock to the end-life of the product.

Acceleration of Wound Healing in Rats by Modified Lignocellulose Based Sponge Containing Pentoxifylline Loaded Lecithin/Chitosan Nanoparticles

Dressing wounds accelerates the re-epithelialization process and changes the inflammatory environment towards healing. In the current study, a lignocellulose sponge containing pentoxifylline (PTX)-loaded lecithin/chitosan nanoparticles (LCNs) was developed to enhance the wound healing rate. Lecithin/chitosan nanoparticles were obtained by the solvent-injection method and characterized in terms of morphology, particle size distribution, and zeta potential. The lignocellulose hydrogels were functionalized through oxidation/amination and freeze-dried to obtain sponges. The prepared sponge was then loaded with LCNs/PTX to control drug release. The nanoparticle containing sponges were characterized using FTIR and SEM analysis. The drug release study from both nanoparticles and sponges was performed in PBS at 37 °C at different time points. The results demonstrated that PTX has sustained release from lignocellulose hydrogels. The wound healing was examined using a standard rat model. The results exhibited that PTX loaded hydrogels could achieve significantly accelerated and enhanced healing compared to the drug free hydrogels and the normal saline treatment. Histological examination of the healed skin confirmed the visual observations. Overall speaking, the in vivo assessment of the developed sponge asserts its suitability as wound dressing for treatment of chronic skin wounds.

Environmental remediation by tea waste and its derivative products: A review on present status and technological advancements

The rising consumption of the popular non-alcoholic beverage tea and its derivative products caused massive growth in worldwide tea production in the last decade, leading to the generation of huge quantities of waste tea residues every year. Most of these wastes are usually burnt or disposed in landfills without proper treatment which results in serious environmental issues by polluting water, air and soil. In the recent times, 'waste to wealth' is a fast-growing concept for environment friendly sustainable development. Utilization of the large amount of tea wastes for the production of low-cost adsorbents to reduce the expenses of water and wastewater treatment can be a sustainable way of management of these wastes which at the same time will improve circular economy also. This review endeavours to evaluate the potential of both raw and modified tea wastes towards the adsorption of pollutants from wastewater. The production of various adsorptive materials such as biochar, activated carbon, nanocomposites, hydrogels, nanoparticles from tea wastes are summarized. The advancements in their applications for the removal of different emerging contaminants from wastewater as well as potable water, air and soil are exhaustively reviewed. The outcome of the present review reveals that tea waste and its derivatives are appropriate candidates to be used as adsorbents that show tremendous effectiveness in cleaning the environment. This article will provide the readers with an in-depth knowledge on the sustainable utilization of tea waste as adsorbent materials and will assist them to explore this abundant cheap waste biomass for environmental remediation.

Thermochemical Conversion of Lignocellulosic Biomass into Mass-Producible Fuels: Emerging Technology Progress and Environmental Sustainability Evaluation

Lignocellulosic biomass is increasingly recognized as a carbon-neutral resource rather than an organic solid waste nowadays. It can be used for the production of various value-added chemicals and biofuels like bio-oil. However, the undesirable properties of bio-oil such as chemical instability, low heating value, high corrosivity, and high viscosity are greatly restricting the utilization of bio-oil as a drop-in fuel. As a consequence, bio-oil should be upgraded. Recently, several emerging methods, such as electrocatalytic hydrogenation, atmospheric distillation, and plasma-assisted catalysis, have been developed for improving the bio-oil quality under mild conditions. Here, we overview the new knowledge on the molecular structure of lignocellulosic biomass gained over the past years and discuss the future challenges and opportunities for further advances of the bio-oil production and upgrading from lignocellulosic biomass. The development of sustainable biomass resource recycle systems with improved efficiency and minimized environmental impacts is analyzed in details. Also, their environmental impacts and sustainability are evaluated. Lastly, the remaining knowledge gaps are identified, and the future research needs that may lead to massive production of biofuels from lignocellulosic biomass are highlighted.

Bio-nano-composites containing at least two components, chitosan and zein, for food packaging applications: A review of the nano-composites in comparison with the conventional counterparts

Both chitosan and zein are safe industrial biopolymers for the 21St century, respecting environmentally concerns. This review mainly is focused on preparations, properties and applications of a promising food packaging material, chitosan-zein nano-composite (NC). The properties and applications of the NCs were compared with their conventional counterparts. The structure of chitosan- zein composites was proposed. A procedure for preparations of conventional and nano zein-chitosan composites was proposed. The sizes of composites depend on molecular weight of chitosan and zein, the ratio of chitosan/zein, and pH of chitosan-zein solutions. The NCs had superior mechanical, antimicrobial, antioxidant, and barrier properties compared with the conventional ones. The properties of the composites were further improved by introduction of bioactive compounds, fillers or plasticizers. The composites have potential to employ as coatings/packaging materials to protect mushroom, meats, and fresh fruits and vegetables.

Natural Hydrogel-Based Bio-Inks for 3D Bioprinting in Tissue Engineering: A Review

Three-dimensional (3D) printing is well acknowledged to constitute an important technology in tissue engineering, largely due to the increasing global demand for organ replacement and tissue regeneration. In 3D bioprinting, which is a step ahead of 3D biomaterial printing, the ink employed is impregnated with cells, without compromising ink printability. This allows for immediate scaffold cellularization and generation of complex structures. The use of cell-laden inks or bio-inks provides the opportunity for enhanced cell differentiation for organ fabrication and regeneration. Recognizing the importance of such bio-inks, the current study comprehensively explores the state of the art of the utilization of bio-inks based on natural polymers (biopolymers), such as cellulose, agarose, alginate, decellularized matrix, in 3D bioprinting. Discussions regarding progress in bioprinting, techniques and approaches employed in the bioprinting of natural polymers, and limitations and prospects concerning future trends in human-scale tissue and organ fabrication are also presented.

A review on global perspectives of sustainable development in bioenergy generation

Over the last few decades, the globe has much relied on fossil fuels; however, environmental concerns forced the World to look at biofuel as an alternative for stable economic development. Biofuel also facilitates national energy security maintenance and reduces environmental complications. The present study is focused on an in-depth analysis of bioenergy policy measures undertaken by various federal agencies of different countries in order to shed light on the bottlenecks that impede biofuel's growth as a sustainable and alternative fuel. An in-depth assessment of feedstock utilization, blending targets, and policy assistance schemes have been thoroughly reviewed. In addition, the potential of commercial firms for the production of bioenergy is highlighted in order to grasp the current bioenergy market scenario better. Finally, the article is concluded with the viewpoints of the authors to address the standing issues of global bioenergy generation.

An update on microcrystalline cellulose in direct compression: Functionality, critical material attributes, and co-processed excipients

Microcrystalline cellulose (MCC) is one of the most popular cellulose derivatives in the pharmaceutical industry. Thanks to its outstanding tabletability, MCC is generally included in direct compression (DC) tablet formulations containing poor-tabletability active pharmaceutical ingredients. Nowadays, numerous grades of MCC from various brands are accessible for pharmaceutical manufacturers, leading to variability in MCC properties. Hence, it seems to be worthy and urgent to evaluate the influences of MCC variability on tablet quality and to identify critical material attributes (CMAs) based on the idea of Quality by Control. Besides, MCC-based co-processed excipients can effectively combine the functions of the filler, binder, disintegrant, lubricant, glidant, or flavor, and thus have drawn extensive interest. In this review, we focused specifically on the recent advances and development of MCC on DC tableting, including the functions in tablet formulations, potential CMAs, and MCC-based co-possessed excipients, therefore providing a reference for further studies.

Bacterial Cellulose-A Remarkable Polymer as a Source for Biomaterials Tailoring

Nowadays, the development of new eco-friendly and biocompatible materials using ‘green’ technologies represents a significant challenge for the biomedical and pharmaceutical fields to reduce the destructive actions of scientific research on the human body and the environment. Thus, bacterial cellulose (BC) has a central place among these novel tailored biomaterials. BC is a non-pathogenic bacteria-produced polysaccharide with a 3D nanofibrous structure, chemically identical to plant cellulose, but exhibiting greater purity and crystallinity. Bacterial cellulose possesses excellent physicochemical and mechanical properties, adequate capacity to absorb a large quantity of water, non-toxicity, chemical inertness, biocompatibility, biodegradability, proper capacity to form films and to stabilize emulsions, high porosity, and a large surface area. Due to its suitable characteristics, this ecological material can combine with multiple polymers and diverse bioactive agents to develop new materials and composites. Bacterial cellulose alone, and with its mixtures, exhibits numerous applications, including in the food and electronic industries and in the biotechnological and biomedical areas (such as in wound dressing, tissue engineering, dental implants, drug delivery systems, and cell culture). This review presents an overview of the main properties and uses of bacterial cellulose and the latest promising future applications, such as in biological diagnosis, biosensors, personalized regenerative medicine, and nerve and ocular tissue engineering.

Structural Evolution of Graphitic Carbon Derived from Ionic Liquids-Dissolved Cellulose and Its Application as Lithium-Ion Battery Anodes

With an attempt to replace petroleum-derived commercial graphite (CG) with biomass-derived carbon, microcrystalline cellulose (MCC) dissolved in 1-butyl-3-methylimidazolium acetate (BMIMAcO) was facilely carbonized to prepare cellulose-derived carbon under a low-temperature range of 250-1600 °C. TEM and AFM results revealed structural evolution of carbon nanosheets starting from carbon dots. The XRD and Raman results showed that the degree of crystallinity of the MCC-derived carbon was apparently enhanced as the temperature was increased to 93.02% at 1600 °C, while the XPS results revealed that the nitrogen content was greatly reduced with increasing temperature. BMIMAcO not only induced low-temperature graphitization of MCC-derived carbon but also provided nitrogen doping for the carbon. Used as an anode of lithium-ion batteries (LIBs), the carbon synthesized at 750 °C showed the best cyclic stability and reversible capacity (1052.22 mAh g^-1 at 0.5 A g^-1 after 100 cycles and 1017.46 mAh g^-1 at 1 A g^-1 after 1000 cycles) compared to other MCC-derived carbon and CG. In addition, the costs of cellulose-derived carbon are much lower than those of the petroleum-derived graphite, showing environmental and economical merits for LIB anode production.

Construction of a novel electrochemical sensor based on biomass material nanocellulose and its detection of acetaminophen

In this work, acidic sulfated cellulose nanocrystals (CNCs) were used as green carriers, and a novel composite material was synthesized and used to design sensors for paracetamol (AP) detection. There are negatively charged acidic sulfate groups on the surface of CNCs, which can enhance the electrostatic repulsion between nanoparticles, thereby increasing the stability and dispersibility of AgNPs in the system, making them less prone to agglomeration. Cationic pillar[5]arene (CP5) with a strong host–guest effect was used as a stable ligand for silver nanoparticles (AgNPs). AgNPs have good electrical conductivity and large specific surface area, which can significantly increase the peak current. In addition, CP5 has excellent supramolecular recognition performance, which can specifically recognize the guest molecule AP to form an inclusion complex, so that a large number of AP molecules are attached to the electrode surface, which is beneficial to the amplification of electrochemical signals. The prepared sensor is more attractive in terms of sensitivity and recognition performance; the host–guest binding constant was (3.37 ± 0.26) × 10⁴ M⁻¹, which can be obtained with good linearity (R² = 0.996), low detection limit (90 nM, LOD = 3σ/k, S/N = 3) and a wide linear range (0.5–500 μM). The electrochemical sensor showed good performance in quantitative analysis, stability, selectivity, reproducibility, and actual sample detection, providing high feasibility for real-time monitoring of paracetamol; it also provides a new idea for a green sensor.

In this work, acidic sulfated cellulose nanocrystals (CNCs) were used as green carriers, and a novel composite material was synthesized and used to design sensors for paracetamol (AP) detection.

Nanocellulose-based membrane as a potential material for high performance biodegradable aerosol respirators for SARS-CoV-2 prevention: a review

The controversy surrounding the transmission of COVID-19 in 2020 has revealed the need to better understand the airborne transmission route of respiratory viruses to establish appropriate strategies to limit their transmission. The effectiveness in protecting against COVID-19 has led to a high demand for face masks. This includes the single-use of non-degradable masks and Filtering Facepiece Respirators by a large proportion of the public, leading to environmental concerns related to waste management. Thus, nanocellulose-based membranes are a promising environmental solution for aerosol filtration due to their biodegradability, renewability, biocompatibility, high specific surface area, non-toxicity, ease of functionalization and worldwide availability. Although the technology for producing high-performance aerosol filter membranes from cellulose-based materials is still in its initial stage, several promising results show the prospects of the use of this kind of materials. This review focuses on the overview of nanocellulose-based filter media, including its processing, desirable characteristics and recent developments regarding filtration, functionalization, biodegradability, and mechanical behavior. The porosity control, surface wettability and surface functional groups resulting from the silylation treatment to improve the filtration capacity of the nanocellulose-based membrane is discussed. Future research trends in this area are planned to develop the air filter media by reinforcing the filter membrane structure of CNF with CNCs. In addition, the integration of sol-gel technology into the production of an air filter can tailor the pore size of the membrane for a viable physical screening solution in future studies.

A critical review on the techniques used for the synthesis and applications of crystalline cellulose derived from agricultural wastes and forest residues

In order to meet the growing energy crisis of the 21st century, the utilization of bio-based materials has become a field of high research endeavour. In view of that, the present review paper is focused on different techniques that are frequently explored for the synthesis of value-added crystalline derivatives of cellulose like MCC and NCC from agricultural wastes and forest residues. Moreover, a comparative analysis between thermochemical and biochemical methods is carried out for such valorization of biomass considering the mechanism involved with various reactions. Further, a critical analysis is performed on various individual techniques specifically used for the applications of MCC and NCC in different fields including environmental, polymer industry, pharmaceutical and other emerging sectors. This article will assist the readers not only to explore new biomass sources but also provides an in-depth insight on various green and cost-effective methods for sustainable production of crystalline cellulose.

An Overview of Cellulose Derivatives-Based Dressings for Wound-Healing Management

Presently, notwithstanding the progress regarding wound-healing management, the treatment of the majority of skin lesions still represents a serious challenge for biomedical and pharmaceutical industries. Thus, the attention of the researchers has turned to the development of novel materials based on cellulose derivatives. Cellulose derivatives are semi-synthetic biopolymers, which exhibit high solubility in water and represent an advantageous alternative to water-insoluble cellulose. These biopolymers possess excellent properties, such as biocompatibility, biodegradability, sustainability, non-toxicity, non-immunogenicity, thermo-gelling behavior, mechanical strength, abundance, low costs, antibacterial effect, and high hydrophilicity. They have an efficient ability to absorb and retain a large quantity of wound exudates in the interstitial sites of their networks and can maintain optimal local moisture. Cellulose derivatives also represent a proper scaffold to incorporate various bioactive agents with beneficial therapeutic effects on skin tissue restoration. Due to these suitable and versatile characteristics, cellulose derivatives are attractive and captivating materials for wound-healing applications. This review presents an extensive overview of recent research regarding promising cellulose derivatives-based materials for the development of multiple biomedical and pharmaceutical applications, such as wound dressings, drug delivery devices, and tissue engineering.

In-situ growth of zeolitic imidazolate frameworks into a cellulosic filter paper for the reduction of 4-nitrophenol

Whatman® cellulosic filter paper was used as a substrate for the synthesis of two zeolitic imidazolate frameworks (ZIFs); ZIF-8 and ZIF-67 with and without 2,2,6,6-tetramethyl-1-piperidine oxoammonium salt (TEMPO)-oxidized cellulose nanofibril (TOCNF). All synthesis procedures take place at room temperature via a one-pot procedure. The synthesis steps were followed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transforms infrared (FT-IR). Data indicated the formation of metal oxide that converted to a pure phase of ZIFs after the addition of the organic linker i.e. 2-methyl imidazole (Hmim). The materials were characterized using XRD, FT-IR, SEM, energy dispersive X-ray (EDX), nitrogen adsorption-desorption isotherms, and X-ray photoelectron microscope (XPS). Data analysis confirms the synthesis of ZIFs into Whatman® filter paper. The materials were used for the reduction of pollutants such as 4-nitrophenol (4-NP) compound to 4-aminophenol (4-AP). The materials exhibit high potential for water treatment and may open new exploration for hybrid materials consisting of cellulose and ZIFs.

Extraction of Cellulose Polymeric Material from Populus tremula Fibers: Characterization and Application to the Adsorption of Methylene Blue and Crystal Violet

Cellulose is the most widely available biopolymer which is extensively used for several applications including textiles, composites, pharmaceutical, water treatment, etc. In this investigation, cellulose was chemically extracted from Populus tremula seed fibers. Samples were characterized using FT-IR, SEM, XRD, and TGA-DTA analyses. FT-IR spectrum of the extracted cellulose confirmed that hemicellulose and lignin were removed during alkali and bleaching treatments. SEM images showed the partially roughened surface of the fiber due to the removal of non-cellulosic elements and surface impurities during chemical modification. The crystallinity index values for untreated Populus tremula fibers and extracted cellulose were calculated to be 32.8% and 58.9%, respectively. The obvious increase in the crystallinity index for the extracted cellulose confirmed the removal of amorphous compounds present in raw populus. Alkali-treated populus fibers were more thermally stable than raw fibers. All changes observed after alkali and bleaching treatments evidenced the removal of amorphous contents and non-cellulosic components in raw populus fibers. Extracted cellulose exhibited excellent adsorption capacities of methylene blue (140.4 mg g⁻¹) and crystal violet (154 mg g⁻¹). The pseudo second order equation fitted well the kinetic data indicating a chemi-sorption process. The Freundlich model complied well with the experimental data suggesting that the adsorption of the studied dyes was multilayer.

Cellulose nanocrystals in cancer diagnostics and treatment

Cancer is currently a major threat to public health, being among the principal causes of death to the global population. With carcinogenesis mechanisms, cancer invasion, and metastasis remaining blurred, cancer diagnosis and novel drug delivery approaches should be developed urgently to enable management and treatment. A dream break-through would be a non-invasive instantaneous monitoring of cancer initiation and progression to fast-track diagnosis for timely specialist treatment decisions. These innovations would enhance the established treatment protocols, unlimited by evasive biological complexities during tumorigenesis. It is therefore contingent that emerging and future scientific technologies be equally biased towards such innovations by exploiting the apparent properties of new developments and materials especially nanomaterials. CNCs as nanomaterials have undisputable physical and excellent biological properties that enhanced their interest as biomedical materials. This article therefore highlights CNCs utility in cancer diagnosis and therapy. Their extraction, properties, modification, in-vivo/in-vitro medical applications, biocompatibility, challenges and future perspectives are precisely discussed.

Gap-Fillers for Wooden Artefacts Exposed Outdoors—A Review

Conservation of wooden artefacts that are exposed outdoors, mainly in open-air museums, is a very complex and difficult issue that aims to preserve both the integrity and aesthetics of valuable objects. Unceasingly subjected to several factors, such as alternating weather conditions and the activities of microorganisms, algae, and insects, they undergo continuous changes and inevitable deterioration. Their biological and physical degradation often results in the formation of gaps and cracks in the wooden tissue, which creates a need not only for wood consolidation, but also for using specialist materials to fill the holes and prevent further degradation of an object. To ensure effective protection for a wooden artefact, a filling material must both protect the wood against further degradation and adapt to changes in wood dimensions in response to humidity variations. A variety of substances, both organic and inorganic, have been used for conservation and gap filling in historic wooden objects over the years. The filling compounds typically consist of two components, of which one is a filler, and the second a binder. In the case of inorganic fillers, plaster has been traditionally used, while the most popular organic fillers were wood powder, wood shavings, and powdered cork. As with binders, mainly natural substances have been used, such as animal glues or waxes. Nowadays, however, due to the lower biodegradability and better physicochemical properties, synthetic materials are gaining popularity. This article discusses the types of filling compounds currently used for gap filling in wooden artefacts exposed outdoors, outlining their advantages and drawbacks, as well as future perspective compounds. It appears that particularly composite materials based on natural polymers deserve attention as promising filling materials due to their high elasticity, as well as similarity and good adhesion to the wooden surface. Their main shortcomings, such as susceptibility to biodegradation, could be eliminated by using some modern, bio-friendly preservatives, providing effective protection for historic wooden artefacts.