Emerging technologies for the production of nanocellulose from lignocellulosic biomass

Unveiling potential of cellulose gel electrolyte: Molecular engineering for enhanced electrostatic interactions with Mg adatoms in Mg-ion battery

The Mg-ion battery faces significant limitations due to its liquid electrolyte, which suffers from inherent issues such as leakage and the growth of Mg dendrites. In contrast, gel polymer electrolytes (GPEs) offer heightened safety, a wide voltage window, and excellent flexibility, making them a promising alternative with outstanding electrochemical performance. In this study, a cyano-modified cellulose (CEC) GPE was engineered to aim at enhancing ion transportation and promoting uniform ion-flux through interactions between N and Mg2+ ions. The resulting CEC-based GPE demonstrated a high ionic conductivity of 1.73 mS cm-1 at room temperature. Furthermore, it exhibited remarkable Mg plating/stripping performance (coulombic efficiency ~96.7 %) and compatibility with electrodes. Importantly, when employed in a Mo6S8//Mg battery configuration, the CEC GPE displayed exceptional cycle stability, with virtually no degradation observed even after 650 cycles at 1C, thereby significantly advancing Mg-ion battery technology due to its excellent electrochemical properties. This study provides valuable insights into the molecular engineering of cellulose-based GPEs.

Zwitterionic Cellulose-Based Polymer Electrolyte Enabled by Aqueous Solution Casting for High-Performance Solid-State Batteries

Polyethylene oxide (PEO)-based solid-state batteries hold great promise as the next-generation batteries with high energy density and high safety. However, PEO-based electrolytes encounter certain limitations, including inferior ionic conductivity, low Li+ transference number, and poor mechanical strength. Herein, we aim to simultaneously address these issues by utilizing one-dimensional zwitterionic cellulose nanofiber (ZCNF) as fillers for PEO-based electrolytes using a simple aqueous solution casting method. Multiple characterizations and theoretical calculations demonstrate that the unique zwitterionic structure imparts ZCNF with various functions, such as disrupting PEO crystallization, dissociating lithium salts, anchoring anions through cationic groups, accelerating Li+ migration by anionic groups, as well as its inherent reinforcement effect. As a result, the prepared PL-ZCNF electrolyte exhibits remarkable ionic conductivity (5.37×10-4 S cm-1) and Li+ transference number (0.62) at 60 °C without sacrificing mechanical strength (9.2 MPa), together with high critical current density of 1.1 mA cm-2. Attributed to these merits of PL-ZCNF, the LiFePO4|PL-ZCNF|Li solid-state full-cell delivers exceptional rate capability and cycling performance (900 cycles at 5 C). Notably, the assembled pouch-cell can maintain steady operation over 1000 cycles with an impressive 93.7 % capacity retention at 0.5 C and 60 °C, highlighting the great potential of PL-ZCNF for practical applications.

Transforming textile waste into nanocellulose for a circular future

The expansion of the textile industry and improvements in living standards have led to increased cotton textile production, resulting in a rise in textile waste, with cotton accounting for 24% of total textile waste. Effective waste management through recycling and reuse is crucial to reducing global waste production. Nanocellulose has diverse applications in environmental, geotechnical, food packaging, and biomedical engineering areas. As interest in nanocellulose's unique properties grows, cotton-based textile waste emerges as a promising source for nanocellulose development. However, there is a notable lack of comprehensive reviews on the extraction of nanocellulose from textile waste as a sustainable biomaterial. This paper aims to address this gap by exploring current extraction processes, properties, and recent applications of nanocellulose derived from textile waste. We discussed (1) the potential of nanocellulose resources from different textile wastes, (2) a comparison of the various extraction methods, (3) the functionalization technology and the potential application of such nanocellulose in the textile industry, and (4) the life cycle assessment (LCA) and potential gap of the current technology. It also emphasizes the potential reintegration of extracted nanocellulose into the textile industry to manufacture high-value products, thus completing the loop and strengthening the circular economy.

Lignin-cellulose complexes derived from agricultural wastes for combined antibacterial and tissue engineering scaffolds for cutaneous leishmaniasis wounds

Bacterial infections in wounds significantly impair the healing process. The use of natural antibacterial products over synthetic antibiotics has emerged as a new trend to address antimicrobial resistance. An ideal tissue engineering scaffold to treat infected wounds should possess antibacterial properties, while simultaneously promoting tissue regrowth. Synthesis of hydrogel scaffolds with antibacterial properties using hemp shive (HT1/HT2) lignin, sugarcane bagasse (SCB) lignin and cellulose was carried out. All lignin samples had low molecular weights and were constituted of G-type β-5 dimers, linked by β-O-4 bonds, as determined by MALDI-TOF-MS. Hemp lignin was more cytotoxic to mouse fibroblasts (L929) compared to SCB lignin. All lignin samples demonstrated antibacterial properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis, with greater efficiency against Gram-negative strains. 3D hydrogels were engineered by crosslinking SCB lignin with SCB cellulose in varying weight ratios in the presence of epichlorohydrin. The stiffness of the hydrogels could be tailored by varying the lignin concentration. All hydrogels were biocompatible; however, better fibroblast adhesion was observed on the blended hydrogels compared to the 100% cellulose hydrogel, with the cellulose : lignin 70 : 30 hydrogel showing the highest L929 proliferation and best antibacterial properties with a 24-hour bacterial growth reduction ranging from 30.8 to 57.3%.

Functionalised Fibres as a Coupling Reinforcement Agent in Recycled Polymer Composites

This study addresses the structure-property relationship within the green concept of wood fibres with cellulose nanofibre functionalised composites (nW-PPr) containing recycled plastic polyolefins, in particular, polypropylene (PP-r). It focuses especially on the challenges posed by nanoscience in relation to wood fibres (WF) and explores possible changes in the thermal properties, crystallinity, morphology, and mechanical properties. In a two-step methodology, wood fibres (50% wt%) were first functionalised with nanocellulose (nC; 1-9 wt%) and then, secondly, processed into composites using an extrusion process. The surface modification of nC improves its compatibility with the polymer matrix, resulting in improved adhesion, mechanical properties, and inherent biodegradability. The effects of the functionalised WF on the recycled polymer composites were investigated systematically and included analyses of the structure, crystallisation, morphology, and surface properties, as well as thermal and mechanical properties. Using a comprehensive range of techniques, including X-ray diffraction (XRD), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), zeta potential measurements, and dynamic mechanical analysis (DMA), this study aims to unravel the intricate interplay of factors affecting the performance and properties of the developed nanocellulose-functionalised wood fibre-polymer composites. The interfacial adhesion of the nW-PPr polymer composites, crystallisation process, and surface properties was improved due to the formation of an H-bond between the nW coupling agent and neat PP-r. In addition, the role of nW (1.0 wt%) as a nucleating agent resulted in increased crystallinity, or, on the other hand, promoted the interfacial interaction with the highest amount (3.0% wt%, 9.0% wt%) of nW in the PP-r preferentially between the nW and neat PP-r, and also postponed the crystallisation temperature. The changes in the isoelectric point of the nW-PPr polymer composites compared to the neat PP-r polymer indicate the acid content of the polymer composite and, consequently, the final surface morphology. Finally, the higher storage modulus of the composites compared to neat r-PP shows a dependence on improved crystallinity, morphology, and adhesion. It was clear that the results of this study contribute to a better understanding of sustainable materials and can drive the development of environmentally friendly composites applied in packaging.

Processing factors affecting roughness, optical and mechanical properties of nanocellulose films for optoelectronics

This work aims to understand how nanocellulose (NC) processing can modify the key characteristics of NC films to align with the main requirements for high-performance optoelectronics. The performance of these devices relies heavily on the light transmittance of the substrate, which serves as a mechanical support and optimizes light interactions with the photoactive component. Critical variables that determine the optical and mechanical properties of the films include the morphology of cellulose nanofibrils (CNF), as well as the concentration and turbidity of the respective aqueous suspensions. This study demonstrates that achieving high transparency was possible by reducing the grammage and adjusting the drying temperature through hot pressing. Furthermore, the use of modified CNF, specifically carboxylated CNF, resulted in more transparent films due to a higher nanosized fraction and lower turbidity. The mechanical properties of the films depended on their structure, homogeneity (spatial uniformity of local grammage), and electrokinetic factors, such as the presence of electrostatic charges on CNF. Additionally, we investigated the angle-dependent transmittance of the CNF films, since solar devices usually operate under indirect light. This work demonstrates the importance of a systematic approach to the optimization of cellulose films, providing valuable insight into the optoelectronic field.

Biomass-derived cellulose nanocrystals modified nZVI for enhanced tetrabromobisphenol A (TBBPA) removal

Nano zero-valent iron (nZVI) is an advanced environmental functional material for the degradation of tetrabromobisphenol A (TBBPA). However, high surface energy, self-agglomeration and low electron selectivity limit degradation rate and complete debromination of bare nZVI. Herein, we presented biomass-derived cellulose nanocrystals (CNC) modified nZVI (CNC/nZVI) for enhanced TBBPA removal. The effects of raw material (straw, filter paper and cotton), process (time, type and concentration of acid hydrolysis) and synthesis methods (in-situ and ex-situ) on fabrication of CNC/nZVI were systematically evaluated based on TBBPA removal performance. The optimized CNC-S/nZVI(in) was prepared via in-situ liquid-phase reduction using straw as raw material of CNC and processing through 44 % H2SO4 for 165 min. Characterizations illustrated nZVI was anchored to the active sites at CNC interface through electrostatic interactions, hydrogen bonds and FeO coordinations. The batch experiments showed 0.5 g/L CNC-S/nZVI(in) achieved 96.5 % removal efficiency at pH = 7 for 10 mg/L initial TBBPA. The enhanced TBBPA dehalogenation by CNC-S/nZVI(in), involving in initial adsorption, reduction process and partial detachment of debrominated products, were possibly attributed to elevated pre-adsorption capacity and high-efficiency delivery of electrons synergistically. This study indicated that fine-tuned fabrication of CNC/nZVI could potentially be a promising alternative for remediation of TBBPA-contaminated aquatic environments.

Modified cellulose nanocrystals enhanced polycaprolactone multifunctional films with barrier, UV-blocking and antimicrobial properties for food packaging

The packaging industry demands improved eco-friendly materials with new and enhanced properties. In this context, bio-nanocomposite films with antimicrobial and UV-shielding properties based on modified cellulose nanocrystals/polycaprolactone (MCNC/PCL) were fabricated via solution casting method, and then food packaging simulation was carried out. CNCs were obtained by acid hydrolysis followed by successful functionalization with Quaternary ammonium surfactant, confirmed by FTIR, XPS, XRD, TEM, and DLS analyses. Furthermore, the morphological, physical, antibacterial, and food packaging properties of all prepared films were investigated. Results showed that the mechanical, UV blocking, barrier properties, and antibacterial activity of all composite films were remarkably improved. Particularly, the addition of 3 wt% MCNC increased the tensile strength and elongation at break by 27.5 % and 20.0 %, respectively. Moreover, the permeability of O2, CO2, and water vapor dramatically reduced by 97.6 %, 96.7 %, and 49.8% compared to the Neat PCL. Further, the UV-blocking properties of the composite films were significantly improved. The antimicrobial properties of MCNC/PCL films showed good antimicrobial properties against S. aureus. Finally, cherry packaged with 1 and 3 wt% MCNC films exhibited satisfactory freshness after 22 days of preservation. Overall, the fabricated PCL nanocomposite films can be utilized in the food packaging industry.

Oil palm frond-derived cellulose nanocrystals: Effect of pretreatment and elucidating its reinforcing potential in hydrogel beads

Herein, cellulose nanocrystals were synthesized from oil palm fronds (CNC-OPF) involving two pretreatment approaches, viz. autohydrolysis and soda pulping. The pretreatments were applied individually to OPF fibers to assess their influence on CNCs' physicochemical and thermal properties. CNC-OPF samples were assessed using complementary characterization techniques, which confirmed their purity and characteristics. CP/MAS 13C NMR and TEM studies revealed that autohydrolysis pretreatment yielded CNCs with effective hemicellulose and extractives removal compared to that of soda pulping. XRD analysis demonstrated that autohydrolysis-treated CNC-OPF contained a much higher crystallinity index compared to soda pulping treatment. BET measurement disclosed a relatively higher surface area and wider pore diameter of autohydrolysis-treated CNC-OPF. Autohydrolysis-treated CNCs were applied as a reinforcement filler in alginate-based hydrogel beads for the removal of 4-chlorophenol from water, which attained a qmax of 19.168 mg g-1. BET analysis revealed the less porous nature of CNC-ALG hydrogel beads which could have contributed to hydrogel beads' relatively lower adsorption capacity. The point of zero charge of CNC-ALG hydrogel beads was 4.82, suggesting their applicability only within a short solution pH range. This study directs future studies to unveil the possibilities of functionalizing CNCs in order to enhance the adsorption performance of CNC-immobilized hydrogel beads towards 4-chlorophenol and other organic contaminants.

Oxidation of p-toluenesulfonic acid fractionated hybrid Pennisetum by different methods for carboxylated nanocellulose preparation: The evaluation of efficiency and sustainability

An innovative two-step process with p-toluenesulfonic acid (p-TsOH) and oxidation treatment was proposed for the efficient preparation of carboxylated nanocellulose from hybrid Pennisetum. Approximately 90 % of lignin was dissolved by p-TsOH acid under the optimal condition (80 °C, 20 min). Near-complete delignification (down to 0.5 %) and introduction of carboxylate groups (up to 1.48 mmol/g) could be achieved simultaneously during cellulose oxidation treatments without the requirement for bleaching. However, different oxidation methods expressed different efficiency and sustainability. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) oxidation has higher selectivity for the carboxylation reaction but with detriment to the aquatic environment. Fenton oxidation is more energy-consuming due to the lower carboxylate contents of products (maximum 188 μmol/g), with the carboxylic groups present as carboxylic acids, but competitive in terms of environmental sustainability, especially when renewable energy sources are available. The nanocelluloses obtained by the two oxidation methods differ in morphology and have different application prospects.

Nanocellulose: Structure, modification, biodegradation and applications in agriculture as slow/controlled release fertilizer, superabsorbent, and crop protection: A review

This review investigates the potential of nanocellulose in agriculture, encompassing its structure, synthesis, modification, and applications. Our investigation of the characteristics of nanocellulose includes a comprehensive classification of its structure. Various mechanical, chemical and enzymatic synthesis techniques are evaluated, each offering distinct possibilities. The central role of surface functionalization is thoroughly examined. In particular, we are evaluating the conventional production of nanocellulose, thus contributing to the novelty. This review is a pioneering effort to comprehensively explore the use of nanocellulose in slow and controlled release fertilizers, revolutionizing nutrient management and improving crop productivity with reduced environmental impact. Additionally, our work uniquely integrates diverse applications of nanocellulose in agriculture, ranging from slow-release fertilizers, superabsorbent cellulose hydrogels for drought stress mitigation, and long-lasting crop protection via nanocellulose-based seed coatings. The study ends by identifying challenges and unexplored opportunities in the use of nanocellulose in agriculture. This review makes an innovative contribution by being the first comprehensive study to examine the multiple applications of nanocellulose in agriculture, including slow-release and controlled-release fertilizers.

Nanocellulose Composite Films in Food Packaging Materials: A Review

Owing to the environmental pollution caused by petroleum-based packaging materials, there is an imminent need to develop novel food packaging materials. Nanocellulose, which is a one-dimensional structure, has excellent physical and chemical properties, such as renewability, degradability, sound mechanical properties, and good biocompatibility, indicating promising applications in modern industry, particularly in food packaging. This article introduces nanocellulose, followed by its extraction methods and the preparation of relevant composite films. Meanwhile, the performances of nanocellulose composite films in improving the mechanical, barrier (oxygen, water vapor, ultraviolet) and thermal properties of food packaging materials and the development of biodegradable or edible packaging materials in the food industry are elaborated. In addition, the excellent performances of nanocellulose composites for the packaging and preservation of various food categories are outlined. This study provides a theoretical framework for the development and utilization of nanocellulose composite films in the food packaging industry.

Biotechnological innovations in nanocellulose production from waste biomass with a focus on pineapple waste

New materials' synthesis and utilization have shown many critical challenges in healthcare and other industrial sectors as most of these materials are directly or indirectly developed from fossil fuel resources. Environmental regulations and sustainability concepts have promoted the use of natural compounds with unique structures and properties that can be biodegradable, biocompatible, and eco-friendly. In this context, nanocellulose (NC) utility in different sectors and industries is reported due to their unique properties including biocompatibility and antimicrobial characteristics. The bacterial nanocellulose (BNC)-based materials have been synthesized by bacterial cells and extracted from plant waste materials including pineapple plant waste biomass. These materials have been utilized in the form of nanofibers and nanocrystals. These materials are found to have excellent surface properties, low density, and good transparency, and are rich in hydroxyl groups for their modifications to other useful products. These materials are well utilized in different sectors including biomedical or health care centres, nanocomposite materials, supercapacitors, and polymer matrix production. This review explores different approaches for NC production from pineapple waste residues using biotechnological interventions, approaches for their modification, and wider applications in different sectors. Recent technological developments in NC production by enzymatic treatment are critically discussed. The utilization of pineapple waste-derived NC from a bioeconomic perspective is summarized in the paper. The chemical composition and properties of nanocellulose extracted from pineapple waste may have unique characteristics compared to other sources. Pineapple waste for nanocellulose production aligns with the principles of sustainability, waste reduction, and innovation, making it a promising and novel approach in the field of nanocellulose materials.

Nanofibrillated cellulose originated from Rhododendron ponticum to produce scaffolds using 3D printing for biomedical applications

Rhododendron ponticum is an invasive species that spreads rapidly and is described as one of the biggest threats to peatlands in Ireland. This study offers an innovative approach to utilizing Rhododendron waste. Initially, sawdust was submitted to a bleaching treatment and the nanofibrillated cellulose (NFC) was obtained using two different methods: ultra-fine friction grinding and twin-screw extrusion with the assistance of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) pre-treatment. The samples processed through twin-screw extrusion exhibited the presence of NFC at five intervals, as confirmed by TEM analysis. However, these samples displayed a higher diameter deviation compared to those processed through grinding alone. Notably, after 20 extrusion steps, the NFC diameter became more uniform, reaching approximately 35 nm. Sedimentation tests showed that extrusion produced more homogeneous cellulose size than the grinder method. However, FTIR characterization for the samples showed a unique band related to C-O-C glycosidic linkage. The results showed that grinding breaks these groups resulting in crystallinity values lower than extrusion, 50 % compared 60 %. Therefore, NFC with 20 steps by grinding was blended with polycaprolactone to produce a 3D scaffold using a 3D printer at different ratios of 1-5 % addition. The effect of 1 % of NFC was unique showing significant enhanced mechanical properties compared to pure polycaprolactone (PCL), additionally, the NFC does not exhibit toxicity so these materials show promise for biomedical applications.

Efficient extraction of nanocellulose from lignocellulose using aqueous butanediol fractionation to improve the performance of waterborne wood coating

The highly efficient extraction of cellulose from lignocellulose with an excellent yield of 95.2 % and purity of 96.7 % was demonstrated using acid-catalyzed fractionation with aqueous butanediol. This cellulose was subsequently transformed into cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs) with specific dimensions and surface functional groups through various chemomechanical treatments. The average diameters of CNFs and CNCs produced by sulfuric acid hydrolysis-ultrasonication and deep eutectic solvent treatment-ultrasonication (DES-CNCs) were 29.7, 21.9 and 17.3 nm, respectively. The DES-CNCs were obtained in a good yield of 71 ± 1.27 wt% and exhibited a high zeta potential of -33.5 ± 2.51 mV following posthydrolysis and esterification during the DES treatment. These CNFs and CNCs were used as nanofillers in a waterborne wood coating (WWC), which significantly improved its dynamic viscosity and storage modulus. The addition of these materials also enhanced the mechanical strength of the WWC but had little effect on transmittance. Glossiness, hardness, abrasion resistance and adhesion strength were evaluated, and the DES-CNCs provided the greatest improvements at a low concentration. A plausible reinforcement mechanism was presented. This work provided an efficient cellulose extraction method and detailed structure elucidation of the nanocellulose together with suggestions for value-added applications of cellulosic nanofillers for reinforcing WWC.

Controlling the critical parameters of ultrasonication to affect the dispersion state, isolation, and chiral nematic assembly of cellulose nanocrystals

Cellulose nanocrystals (CNCs) are typically extracted from plants and present a range of opto-mechanical properties that warrant their use for the fabrication of sustainable materials. While their commercialization is ongoing, their sustainable extraction at large scale is still being optimized. Ultrasonication is a well-established and routinely used technology for (re-) dispersing and/or isolating plant-based CNCs without the need for additional reagents or chemical processes. Several critical ultrasonication parameters, such as time, amplitude, and energy input, play dominant roles in reducing the particle size and altering the morphology of CNCs. Interestingly, this technology can be coupled with other methods to generate moderate and high yields of CNCs. Besides, the ultrasonics treatment also has a significant impact on the dispersion state and the surface chemistry of CNCs. Accordingly, their ability to self-assemble into liquid crystals and subsequent superstructures can, for example, imbue materials with finely tuned structural colors. This article gives an overview of the primary functions arising from the ultrasonication parameters for stabilizing CNCs, producing CNCs in combination with other promising methods, and highlighting examples where the design of photonic materials using nanocrystal-based celluloses is substantially impacted.

Polysaccharide-based biosorbents for cholesterol and bile salts in gastric-intestinal passage: Advances and future trends

Cholesterol is one of the hazard elements for many cardiovascular diseases, but many cholesterol-lowering drugs are expensive and unhealthy. Therefore, it is necessary to develop edible and safe biosorbents to reduce excess cholesterol and bile salts in the gastric-intestinal passage. Polysaccharide-based biosorbents offer a feasible strategy for decreasing them. This review summarized polysaccharide-based biosorbents that have been developed for adsorbing cholesterol and bile salts from the gastric-intestinal passage and analyzed common modification methods for these adsorbents. Finally, the adsorption models were also elucidated. Polysaccharides, including β-cyclodextrin, pectin, chitin/chitosan, dietary fiber extract, and cellulose, have been proposed for adsorbing cholesterol and bile salts in the gastric-intestinal passage as biosorbents. This is mainly due to the retention of pores, the capture of the viscosity network, and the help of hydrophobic interactions. In spite of this, the adsorption capacity of polysaccharides is still limited. Therefore, the modifications for them became the most popular areas in the recent studies of in vitro cholesterol adsorption. Chemical approaches namely grafting, (1) acetylation, (2) hydroxypropylation, (3) carboxymethylation, and (4) amination are considered to modify the polysaccharides for higher adsorption ability. Moreover, ultrasonic/microwave/pressure treatment and micron technology (microfluidization, micronization, and ball milling) are effective physical modification methods, while the biological approach mainly refers to enzymatic hydrolysis and microbial fermentation. The adsorption models are generally explained by two adsorption isotherms and two adsorption kinetics. In sum, it is reckoned that further food applications will follow soon.

Cellulose Isolation from Tomato Pomace: Part II-Integrating High-Pressure Homogenization in a Cascade Hydrolysis Process for the Recovery of Nanostructured Cellulose and Bioactive Molecules

This work proposes a biorefinery approach for utilizing tomato pomace (TP) through a top-down deconstructing strategy, combining mild chemical hydrolysis with high-pressure homogenization (HPH). The objective of the study is to isolate cellulose pulp using different combinations of chemical and physical processes: (i) direct HPH treatment of the raw material, (ii) HPH treatment following acid hydrolysis, and (iii) HPH treatment following alkaline hydrolysis. The results demonstrate that these isolation routes enable the production of cellulose with tailored morphological properties from TP with higher yields (up to +21% when HPH was applied before hydrolysis and approximately +6% when applied after acid or after alkaline hydrolysis). Additionally, the side streams generated by this cascade process show a four-fold increase in phenolic compounds when HPH is integrated after acid hydrolysis compared to untreated sample, and they also contain nanoparticles composed of hemicellulose and lignin, as shown by FT-IR and SEM. Notably, the further application of HPH treatment enables the production of nanostructured cellulose from cellulose pulp derived from TP, offering tunable properties. This approach presents a sustainable pathway for the extraction of cellulose and nanocellulose, as well as the valorization of value-added compounds found in residual biomass in the form of side streams.

Assessing the Genotoxicity of Cellulose Nanomaterials in a Co-Culture of Human Lung Epithelial Cells and Monocyte-Derived Macrophages

Cellulose micro/nanomaterials (CMNMs) are innovative materials with a wide spectrum of industrial and biomedical applications. Although cellulose has been recognized as a safe material, the unique properties of its nanosized forms have raised concerns about their safety for human health. Genotoxicity is an endpoint that must be assessed to ensure that no carcinogenic risks are associated with exposure to nanomaterials. In this study, we evaluated the genotoxicity of two types of cellulose micro/nanofibrils (CMF and CNF) and one sample of cellulose nanocrystals (CNC), obtained from industrial bleached Eucalyptus globulus kraft pulp. For that, we exposed co-cultures of human alveolar epithelial A549 cells and THP-1 monocyte-derived macrophages to a concentration range of each CMNM and used the micronucleus (MN) and comet assays. Our results showed that only the lowest concentrations of the CMF sample were able to induce DNA strand breaks (FPG-comet assay). However, none of the three CMNMs produced significant chromosomal alterations (MN assay). These findings, together with results from previous in vitro studies using monocultures of A549 cells, indicate that the tested CNF and CNC are not genotoxic under the conditions tested, while the CMF display a low genotoxic potential.

Design of Bifunctional Nanocatalysts Based on Zeolites for Biomass Processing

Bifunctional catalysts consisting of metal-containing nanoparticles (NPs) and zeolite supports have received considerable attention due to their excellent catalytic properties in numerous reactions, including direct (biomass is a substrate) and indirect (platform chemical is a substrate) biomass processing. In this short review, we discuss major approaches to the preparation of NPs in zeolites, concentrating on methods that allow for the best interplay (synergy) between metal and acid sites, which is normally achieved for small NPs well-distributed through zeolite. We focus on the modification of zeolites to provide structural integrity and controlled acidity, which can be accomplished by the incorporation of certain metal ions or elements. The other modification avenue is the adjustment of zeolite morphology, including the creation of numerous defects for the NP entrapment and designed hierarchical porosity for improved mass transfer. In this review, we also provide examples of synergy between metal and acid sites and emphasize that without density functional theory calculations, many assumptions about the interactions between active sites remain unvalidated. Finally, we describe the most interesting examples of direct and indirect biomass (waste) processing for the last five years.

Current and Potential Applications of Green Membranes with Nanocellulose

Large-scale applications of nanotechnology have been extensively studied within the last decade. By exploiting certain advantageous properties of nanomaterials, multifunctional products can be manufactured that can contribute to the improvement of everyday life. In recent years, one such material has been nanocellulose. Nanocellulose (NC) is a naturally occurring nanomaterial and a high-performance additive extracted from plant fibers. This sustainable material is characterized by a unique combination of exceptional properties, including high tensile strength, biocompatibility, and electrical conductivity. In recent studies, these unique properties of nanocellulose have been analyzed and applied to processes related to membrane technology. This article provides a review of recent synthesis methods and characterization of nanocellulose-based membranes, followed by a study of their applications on a larger scale. The article reviews successful case studies of the incorporation of nanocellulose in different types of membrane materials, as well as their utilization in water purification, desalination, gas separations/gas barriers, and antimicrobial applications, in an effort to provide an enhanced comprehension of their capabilities in commercial products.

Improving electrochemical performance of hybrid electrode materials by a composite of nanocellulose, reduced oxide graphene and polyaniline

Novel ternary composites of polyaniline (PANI), reduced graphene oxide (RGO), and cellulose nanofibers (CNFs) are prepared by a chemical method for hybrid supercapacitors. CNFs were extracted from sugarcane bagasse waste in sugar production, by physicochemical processes. The composites were investigated as electrode-active materials for hybrid supercapacitors. The obtained results revealed that the presence of RGO and CNFs in the composites led to enhanced electrochemical performances, such as capacitance, rate capability, and long-term cyclability of the composite. The optimal composite of CNFs/RGO/PANI with a weight ratio of 4/16/80 can deliver the highest specific capacitance at 566.2 F g^-1 under an applied current of 1 A g^-1. After 1000 cycles of repetitive charge and discharge, the optimal composite retains 85.4% of its initial capacitance, whereas the PANI electrode obtained only 36.7% under the same conditions. Moreover, the supercapacitive performance is also strongly dependent on the component of the ternary composites. Overall, the composite is a promising material for hybrid supercapacitors; and the CNF component is a renewable material and a product of waste materials.

Production and Characterization of Cellulose Nanocrystals from Eucalyptus Dissolving Pulp Using Endoglucanases from Myceliophthora thermophila

Endoglucanase (EG) is a key enzyme during enzymatic preparation of cellulose nanocrystals (CNCs). Myceliophthora thermophila is a thermophilic fungus that has thermal properties and a high secretion of endoglucanases (EGs), and could serve as potential sources of EGs for the preparation of CNCs. In this work, four different GH families (GH5, GH7, GH12, and GH45) of EGs from M. thermophila were expressed and purified, and their enzymatic characteristics and feasibility of application in CNC preparation were investigated. It was shown that the MtEG5A from M. thermophila has good potential in the enzymatic preparation of CNCs using eucalyptus dissolving pulp as feedstock. It was also observed that there was a synergistic effect between the MtEG5A and other MtEGs in the preparation of CNCs, which improved the yield and properties of CNCs obtained by enzymatic hydrolysis. This study provides a reference for understanding the enzymatic characteristics of different families of EGs from M. thermophile and their potential application in nanocellulose production.

Integrated Biobased Processes for Nanocellulose Preparation from Rice Straw Cellulose

High-potential nanomaterials were derived from rice straw using the integrated biobased processes of enzymatic hydrolysis with green organic acid hydrolysis assisted with ultrasonication pretreatment. The optimization condition of nanocellulose preparation by enzymatic hydrolysis via central composite design (CCD) achieved a maximum nanocellulose content of 32.37 ± 0.47% using a cellulase concentration of 107.06 U/mL and 0.13% (w/w) of rice straw cellulose. The ultrasonication-assisted pretreatment prior to enzymatic hydrolysis improved nanocellulose preparation to 52.28 ± 1.55%. Integration with oxalic acid hydrolysis increased the nanocellulose content to 64.99 ± 0.16%. Granular nanocellulose was obtained and consisted of a 105–825 nm nanosize with a zeta potential value of −34.5 mV, and nanocellulose suspension showed high stability without aggregation. In addition, the remaining rice straw cellulose after oxalic acid was microcrystalline nanocellulose. All prepared nanocellulose represented a functional group as original cellulose but had a low crystallinity index (CrI) of 15.68% that could be classified as amorphous nanocellulose. Based on their characteristics, all nanocellose could be further applied in food, cosmetics, and pharmaceuticals. Moreover, the results indicated that the rice straw could be an alternative non-edible cellulose source for preparing potential nanocellulose via a controlled hydrolysis process.

Wheat thermoplastic starch composite films reinforced with nanocellulose

The rising costs of non-renewable plastic and environmental concerns with their industrial usage have encouraged the study and development of renewable products. As an alternative, biological-based materials create a huge opportunity for a healthy and safe environment by replacing non-renewable plastic in a variety of applications. Wheat is one of the world’s most widely cultivated crops. Due to its mechanical and physical properties, wheat starch is vital in the biopolymer industry. Wheat thermoplastic starch exhibits useable properties when plasticizers, elevated temperatures and shear are present. Thus, make it very suitable to be used as packaging material. However, this material suffers from low mechanical properties, which limit its applications. Several studies looked at the feasibility of using plant components which is nanocellulose as a reinforcing agent in wheat starch thermoplastic composites. Overall, the addition of nanocellulose can improve the performance of wheat thermoplastic starch, especially for its mechanical properties. It can potentially be used in several areas of packaging and biomedical. The objective of this review is to discuss several achievements regarding wheat starch/nanocellulose-based composites. Several important aspects of the mechanical performance and the thermal properties of the composites were evaluated. The discussion on wheat starch and nanocellulose was also tackled in this review.

Horse manure as resource for biogas and nanolignocellulosic fibres

Nanofibrillated cellulose (NFC) has key applications in composites, water filters and as emulsifiers. The affinity of NFC to water is a challenge, as it negatively influences its integrity. Lignin, a major component of plant biomass, is a natural hydrophobiser. Anaerobic digestion (AD) of biomass to produce biomethane allows to up-concentrate lignin in the fermentation residue containing lignocellulosic fibres. Horse manure was used as substrate for biogas production from which nanolignocellulose fibres (LCNF) were extracted. A biogas yield of 207 L_N kg_VS^-1 with a methane concentration of 65 % was achieved. From the fermentation residue LCNFs, in yields of up to 41 %, with lignin contents between 23 and 29 wt% depending on fermentation time were obtained. Nanopapers produced from LCNFs possessed tensile strengths and moduli of 45 to 91 MPa and 7 to 8 GPa, respectively. The increased lignin content was responsible for decreased water absorption capacity of nanopapers.

Nanocellulosics in Transient Technology

Envisage a world where discarded electrical/electronic devices and single-use consumables can dematerialize and lapse into the environment after the end-of-useful life without constituting health and environmental burdens. As available resources are consumed and human activities build up wastes, there is an urgency for the consolidation of efforts and strategies in meeting current materials needs while assuaging the concomitant negative impacts of conventional materials exploration, usage, and disposal. Hence, the emerging field of transient technology (Green Technology), rooted in eco-design and closing the material loop toward a friendlier and sustainable materials system, holds enormous possibilities for assuaging current challenges in materials usage and disposability. The core requirements for transient materials are anchored on meeting multicomponent functionality, low-cost production, simplicity in disposability, flexibility in materials fabrication and design, biodegradability, biocompatibility, and environmental benignity. In this regard, biorenewables such as cellulose-based materials have demonstrated capacity as promising platforms to fabricate scalable, renewable, greener, and efficient materials and devices such as membranes, sensors, display units (for example, OLEDs), and so on. This work critically reviews the recent progress of nanocellulosic materials in transient technologies toward mitigating current environmental challenges resulting from traditional material exploration, usage, and disposal. While spotlighting important fundamental properties and functions in the material selection toward practicability and identifying current difficulties, we propose crucial research directions in advancing transient technology and cellulose-based materials in closing the loop for conventional materials and sustainability.

Fabrication of Cellulose Nanocrystal (CNCs) Based Biosorbent From Oil Palm Trunks Through Acid Hydrolysis With Sonication Assisted and Adsorption Kinetic Study

Developing cellulose nanocrystal (CNCs) preparation techniques is a challenge confronted by many researchers. The advantages of property remain the reason for research to be developed. To deal with this issue, it is essential to conduct research related to process optimization, particularly in the hydrolysis process, which is the primary step in forming CNCs. In this study, the effect of sonication-assisted hydrolysis time was investigated. XRD characterization showed that the CNCs formed where the first group with specific peaks indicated. The crystallinity of CNCs decreased with increasing sonication duration, indicating that sonication-assisted hydrolysis was nonselective. The crystallinity of CNCs obtained for 15, 30, and 45 min was 61.6, 55.0, and 48.4 %, respectively. For sonication duration variations of 15, 30, and 45 min, the hydration diameter of CNCs was nearly identical at 42.35 ± 27.10, 42.99 ± 29.46, and 42.63 ± 29.49 nm, respectively. Similarly, the removal of methylene blue can be achieved using CNCs bio-adsorbent. The results of percent removal of methylene blue under sonication treatment of 15, 30, and 45 min of sonication were 73.34; 73.62; 72.86 %, respectively. The adsorption rate of CNCs follows the pseudo-second-order kinetic model, with the adsorption values under sonication treatment of 15, 30, and 45 min were 0.075 ± 0.008; 0.166 ± 0.013; 0.078 ± 0.005 g mg-1 min-1, respectively.

Cellulose and protein nanofibrils: Singular biobased nanostructures for the design of sustainable advanced materials

Polysaccharides and proteins are extensively used for the design of advanced sustainable materials. Owing to the high aspect ratio and specific surface area, ease of modification, high mechanical strength and thermal stability, renewability, and biodegradability, biopolymeric nanofibrils are gaining growing popularity amongst the catalog of nanostructures exploited in a panoply of fields. These include the nanocomposites, paper and packaging, environmental remediation, electronics, energy, and biomedical applications. In this review, recent trends on the use of cellulose and protein nanofibrils as versatile substrates for the design of high-performance nanomaterials are assessed. A concise description of the preparation methodologies and characteristics of cellulosic nanofibrils, namely nanofibrillated cellulose (NFC), bacterial nanocellulose (BNC), and protein nanofibrils is presented. Furthermore, the use of these nanofibrils in the production of sustainable materials, such as membranes, films, and patches, amongst others, as well as their major domains of application, are briefly described, with focus on the works carried out at the BioPol4Fun Research Group (Innovation in BioPolymer based Functional Materials and Bioactive Compounds) from the Portuguese associate laboratory CICECO-Aveiro Institute of Materials (University of Aveiro). The potential for partnership between both types of nanofibrils in advanced material development is also reviewed. Finally, the critical challenges and opportunities for these biobased nanostructures for the development of functional materials are addressed.

Different Preparation Method of Nanocellulose from Macaranga gigantea and Its Preliminary Study on Packaging Film Potential

Nanocellulose is a versatile cellulosic nanomaterial that can be used in many application areas. Applying different preparation strategies leads to different types of nanocellulose. In this study, nanocrystalline cellulose (NCC) and nanofibrillated cellulose (NFC) were prepared from lesser known wood species, viz., Macaranga gigantea, using sulfuric acid hydrolysis and enzymatic pretreatment with ultrafine grinding approaches, respectively. The respective nanocellulose was characterized by means of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), atomic force microscopy (AFM). It was then converted into a thin film to assess its performance which includes tensile test, transparency, air permeance, water vapor transmission rate (WVTR), and water vapor permeability (WVP) properties. NCC and NFC produced from the raw material of Macaranga had average widths of 6.38 ± 3.92 nm and 13.17 ± 12.71 nm, respectively. Peaks in FTIR spectra showed the conversion of Macaranga wood to nanocellulose by the presence of cellulose fingerprint as well as absence of lignin and hemicellulose after alkaline treatment. The successful conversion was also supported by XRD analysis which displayed the increased crystallinity value from 54% to 70%. TGA decomposition pattern at 200-490 °C revealed the thermal stability of the samples. The thin film produced from nanocelluloses had WVTR values of 4.58 and 12.14 g/(day·m²) for NFC and NCC, respectively, comparable to those of films from polyester and oriented polypropylene. Nanocellulose-based thin film has the potential to be used as sustainable and biodegradable packaging.

High-efficiency recovery and regeneration of choline-polyol deep eutectic solvent for biorefinery via bipolar membrane electrodialysis and ultrafiltration

Deep eutectic solvents (DES) have been widely studied for interesting solvent properties in resources utilization and green conversion of energy. Complex composition of DES and lack of recovery techniques restricts their further scale-up application. Exploring efficient recovery and regeneration methodology of DES in biorefinery could be beneficial for low-carbon circular bioeconomy. Recovery and regeneration of choline-polyol DES (choline chloride-ethylene glycol, ChCl-EG) after biomass pretreatment was studied using bipolar membrane electrodialysis (BMED) with ultrafiltration (UF). UF-BMED treatment worked based on the interception of macromolecular degradation products in pretreatment liquor and regional recovery of Ch⁺, Cl^- with EG. Influence of major parameters on DES recovery performance was studied with emphasis. Maximum recovery ratio of DES reached 97.4% and minimum specific energy consumption of DES recovery approached 6.0 kW·h/kg. Cognition gained from this research revealed an efficient technique for DES recycling after biorefinery.

Emerging Food Packaging Applications of Cellulose Nanocomposites: A Review

Cellulose is the most abundant biopolymer on Earth, which is synthesized by plants, bacteria, and animals, with source-dependent properties. Cellulose containing β-1,4-linked D-glucoses further assembles into hierarchical structures in microfibrils, which can be processed to nanocellulose with length or width in the nanoscale after a variety of pretreatments including enzymatic hydrolysis, TEMPO-oxidation, and carboxymethylation. Nanocellulose can be mainly categorized into cellulose nanocrystal (CNC) produced by acid hydrolysis, cellulose nanofibrils (CNF) prepared by refining, homogenization, microfluidization, sonification, ball milling, and the aqueous counter collision (ACC) method, and bacterial cellulose (BC) biosynthesized by the Acetobacter species. Due to nontoxicity, good biodegradability and biocompatibility, high aspect ratio, low thermal expansion coefficient, excellent mechanical strength, and unique optical properties, nanocellulose is utilized to develop various cellulose nanocomposites through solution casting, Layer-by-Layer (LBL) assembly, extrusion, coating, gel-forming, spray drying, electrostatic spinning, adsorption, nanoemulsion, and other techniques, and has been widely used as food packaging material with excellent barrier and mechanical properties, antibacterial activity, and stimuli-responsive performance to improve the food quality and shelf life. Under the driving force of the increasing green food packaging market, nanocellulose production has gradually developed from lab-scale to pilot- or even industrial-scale, mainly in Europe, Africa, and Asia, though developing cost-effective preparation techniques and precisely tuning the physicochemical properties are key to the commercialization. We expect this review to summarise the recent literature in the nanocellulose-based food packaging field and provide the readers with the state-of-the-art of this research area.

Cellulose nanocrystals based delivery vehicles for anticancer agent curcumin

Cancer is a complex disease that starts with genetic alterations and mutations in healthy cells. The past decade has witnessed a huge demand for new biocompatibility and high-performance intelligent drug delivery systems. Curcumin (CUR) is a bioactive stimulant with numerous medical benefits. However, because of its hydrophobic nature, it has low bioavailability. The utilization of many biobased materials has been found to improve the loading of hydrophobic drugs. Cellulose nanocrystals (CNCs) with exceptional qualities and a wide range of applications, feature strong hydrophilicity and lipophilicity, great emulsification stability, high crystallinity and outstanding mechanical attributes. In this review, numerous CNCs-based composites have been evaluated for involvement in the controlled release of CUR. The first part of the review deals with recent advancements in the extraction of CNCs from lignocellulose biomass. The second elaborates some recent developments in the post-processing of CNCs in conjunction with other materials like natural polymers, synthetic polymers, β-CD, and surfactants for CUR loading/encapsulation and controlled release. Furthermore, numerous CUR drug delivery systems, challenges, and techniques for effective loading/encapsulation of CUR on CNCs-based composites have been presented. Finally, conclusions and future outlooks are also explored.

Poly(3-hydroxybutyrate) Nanocomposites with Cellulose Nanocrystals

Poly(3-hydroxybutyrate) (PHB) is one of the most promising substitutes for the petroleum-based polymers used in the packaging and biomedical fields due to its biodegradability, biocompatibility, good stiffness, and strength, along with its good gas-barrier properties. One route to overcome some of the PHB’s weaknesses, such as its slow crystallization, brittleness, modest thermal stability, and low melt strength is the addition of cellulose nanocrystals (CNCs) and the production of PHB/CNCs nanocomposites. Choosing the adequate processing technology for the fabrication of the PHB/CNCs nanocomposites and a suitable surface treatment for the CNCs are key factors in obtaining a good interfacial adhesion, superior thermal stability, and mechanical performances for the resulting nanocomposites. The information provided in this review related to the preparation routes, thermal, mechanical, and barrier properties of the PHB/CNCs nanocomposites may represent a starting point in finding new strategies to reduce the manufacturing costs or to design better technological solutions for the production of these materials at industrial scale. It is outlined in this review that the use of low-value biomass resources in the obtaining of both PHB and CNCs might be a safe track for a circular and bio-based economy. Undoubtedly, the PHB/CNCs nanocomposites will be an important part of a greener future in terms of successful replacement of the conventional plastic materials in many engineering and biomedical applications.