ABSTRACT
Nano zero-valent iron (nZVI) is widely used in soil remediation due to its high reactivity. However, the easy agglomeration, poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its application scale in Cr-contaminated soil remediation, especially in high concentration of Cr-contaminated soil. Herein, we found that the carboxymethyl cellulose on nZVI particles could increase the zeta potential value of soil and change the phase of nZVI. Along with the presence of biochar, 97.0% and 96.6% Cr immobilization efficiency through CMC-nZVI/BC were respectively achieved in high and low concentrations of Cr-contaminated soils after 90-days remediation. In addition, the immobilization efficiency of Cr(VI) only decreased by 5.1% through CMC-nZVI/BC treatment after 10 weeks aging in air, attributing to the strong antioxidation ability. As for the surrounding Cr-contaminated groundwater, the Cr(VI) removal capacity of CMC-nZVI/BC was evaluated under different reaction conditions through column experiments and COMSOL Multiphysics. CMC-nZVI/BC could efficiently remove 85% of Cr(VI) in about 400 hr when the initial Cr(VI) concentration was 40 mg/L and the flow rate was 0.5 mL/min. This study demonstrates that uniformly dispersed CMC-nZVI/BC has an excellent remediation effect on different concentrations of Cr-contaminated soils.
Subject(s)
Carboxymethylcellulose Sodium , Charcoal , Chromium , Environmental Restoration and Remediation , Iron , Soil Pollutants , Soil Pollutants/chemistry , Charcoal/chemistry , Environmental Restoration and Remediation/methods , Iron/chemistry , Chromium/chemistry , Carboxymethylcellulose Sodium/chemistry , Soil/chemistry , Metal Nanoparticles/chemistryABSTRACT
Hydroxyl groups on the surface of cellulose nanocrystals (CNC) are modified by chemical methods, CNC and the modified CNC are used as fillers to prepare PHB/cellulose nanocomposites. The absorption peak of carbonyl group of the modified CNC (CNC-CL and CNC-LA) appears in the FT-IR spectra, which proves that the modifications are successful. Thermal stability of CNC-CL and CNC-LA is better than that of pure CNC. Pure CNC is beneficial to the nucleation of PHB, while CNC-CL and CNC-LA inhibit the nucleation of PHB. The spherulite size of PHB and its nanocomposites increases linearly over time, and the maximum growth rate of PHB spherulite exists at 90 °C. Rheological analysis shows that viscous deformation plays the dominant role in PHB, PHBC and PHBC-CL samples, while the elastic deformation is dominant in PHBC-LA. According to the rheological data, the dispersion of CNC-CL and CNC-LA in PHB is better than that of CNC. This work demonstrates the impact of modified CNC on the crystallization and viscoelastic properties of PHB. Moreover, the interface enhancement effect of modified CNC on PHB/CNC nanomaterials is revealed from the crystallization and rheology perspectives.
ABSTRACT
Fiber-shaped Zn-ion capacitors (FSZICs) have shown great potential in wearable electronics due to their long cycle life, high energy density, and good flexibility. Nevertheless, it is still a critical challenge to develop a conductive fiber with long size and high mechanical properties as the FSZIC cathode using sustainable and low-cost materials. Herein, regenerated cellulose (RC) -based conductive microfibers are prepared by a simple, continuous, and scalable wet spinning process. The 3D nanoporous networks of RC caused by physical self-cross-linking allow MXene and MnO2 to be uniformly and firmly embedded. The rapid extrusion and limited drying result in the highly aligned structure of the fibers, endowing the hybrid fiber with an ultra-high tensile strength (145.83 Mpa) and Young's modulus (1672.11 Mpa). MXene/MnO2-RC-based FSZIC demonstrates a high specific capacitance of 110.01 mF cm-3, an energy density of 22.0 mWh cm-3 at 0.57 A cm-3 and excellent cycling stability with 90.5 % capacity retention after 5000 cycles. This work would lead to a great potential of cellulose for application in next-generation green and wearable electronics.
ABSTRACT
Passive daytime radiative cooling is a zero-energy consumption cooling technology, which can dissipate heat to outer space via infrared radiation. Recently, coupling radiative cooling technology and thermoelectric devices to generate electricity has attracted much attention. However, existing radiative cooling integrated thermoelectric devices still suffer from low-temperature gradient and output voltage. Here, based on the Mie scattering and internal reflection enhancing principle, an impact-inducing geometry reconstruction approach was proposed to fabricate hierarchical nanostructured cellulosic coatings with good daytime cooling performance to achieve stable electricity generation function, which can be realized by using a scalable and facile wet ball milling technology. Guided by the theoretical simulations of the finite difference time domain method (FDTD), the cellulose and TiO2 nanoparticles can assemble into spherical envelope structured coatings drying by the shear, impact, and friction interaction in the ball milling process, dramatically enhancing the Mie scattering and internal reflection of coatings. The cellulosic coatings exhibit sunlight reflectivity of 0.962 and infrared emissivity of 0.94, resulting in a daytime radiative cooling efficiency of 5.9 °C under direct sunlight. Energy Plus stimulation demonstrated 35 % cooling energy and 468.9 kWh of cooling energy can be saved annually in China. Meanwhile, this cellulosic coating-based thermoelectric device can deliver a high voltage output of 150 mV under 1 Sun due to the strong bonding and high-temperature gradient formation (30 °C), which is higher than previous reports. This study will facilitate the development of sustainable power generation device for the goal of green future.
ABSTRACT
Traditional vinegars are naturally produced from sugar- or starch-containing raw materials, through alcoholic fermentation followed by acetic fermentation. Fermentation is a spontaneous and complex process involving interactions between various microorganisms. In this study, we produced vinegar using traditional methods from six fruits: rosehip, pear, fig, wild pear, apple, and plum. Bacteria that produce bacterial cellulose (BC) were isolated from these vinegars and identified. In addition, we investigated the properties of BC produced from these bacteria. The strains isolated from vinegars were identified as Gluconobacter oxydans strain MG2022, Acetobacter tropicalis strain MG2022, Acetobacter fabarum strain MG2022, Komagataeibacter saccharivorans strain MG2022, K. saccharivorans strain EG2022, and Acetobacter lovaniensis strain OD2022. In total, 0.83-2.04â¯g/Lâ¯BC was produced and the bacterial strain isolated from pear vinegar yielded the most BC. BC produced by the bacterial strain isolated from wild pear vinegar had the highest thermal stability and crystallinity (87.44â¯%). Overall, this study shows that different fruits contain different BC-producing bacteria in their natural flora and vinegars obtained from fruits can be used in BC production. Also, different BC-producing bacteria can be isolated from different vinegars, and BC produced by these bacteria might have different properties.
ABSTRACT
Regenerated cellulose (RC) films are considered a sustainable packaging material that can replace non-degradable petroleum-based plastics. However, their susceptibility to water vapor and oxygen can limit their effectiveness in protecting products. This study introduces a novel approach for enhancing RC films to create durable, flexible, hydrophobic, high-barrier, and biodegradable packaging materials. By exploring the impact of ascorbic acid coagulation bath treatment and plasma-enhanced chemical vapor deposition (PECVD) on the properties of RC films, we found that the coagulation bath treatment facilitated the organized reconfiguration of cellulose chains, while PECVD applied a dense SiOx coating on the film surface. The results demonstrated a significant enhancement in water vapor and oxygen barrier properties of the composite film, almost reaching the level of commercial barrier films. Moreover, the composite film displayed exceptional biodegradability, fully degrading in soil within 35 days. Additionally, it showcased impressive mechanical strength, hydrophobic characteristics, and freshness preservation, positioning it as a valuable option for bio-based high-barrier packaging applications.
ABSTRACT
Exploring efficient and comprehensive utilization of agricultural waste to produce high value-added products has been global research hotspot. In this study, a novel process for integrated production of xylose and docosahexaenoic acid (DHA) from hemicellulose and cellulose in corncob was developed. Corncob was treated with dilute H2SO4 at 121 °C for 1 h and xylose was readily produced with a recovery yield of 79.35 %. The corncob residue was then subject to alkali pretreatment under optimized conditions of 0.1 g NaOH/g dry solid, 60 °C for 2 h, and the contents of cellulose, hemicellulose, and lignin in the resulting residue were 87.49 %, 7.58 % and 2.31 %, respectively. The cellulose in the residue was easily hydrolyzed by cellulase, yielding 74.87 g/L glucose with hydrolysis efficiency of 77.02 %. Remarkably, the corncob residue hydrolysate supported cell growth and DHA production in Schizochytrium sp. ATCC 20888 well, and the maximum biomass of 32.71 g/L and DHA yield of 4.63 g/L were obtained, with DHA percentage in total fatty acids of 36.89 %. This study demonstrates that the corncob residue generated during xylose production, rich in cellulose, can be effectively utilized for DHA production by Schizochytrium sp., offering a cost-effective and sustainable alternative to pure glucose.
ABSTRACT
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.
ABSTRACT
Introduction: Patients who need to be readmitted to the hospital because of complications from infections or require long-term care and rehabilitation face substantial financial hardships. To ensure the safety of patients undergoing surgery, it is crucial to implement measures that prevent wound infections before and after the procedure. Antibacterial wound dressings are essential to prevent infections during surgical procedures. There are various types of antibacterial wound dressings available on the market, such as silver-based dressings, hydrocolloid dressings, polyhexamethylene biguanide, alginate dressings, collagen-based dressings, and iodine-based dressings. Methods: We used each type (standard, knit, fibril, and non-woven) of a commercial brand of oxidized regenerated cellulose (ORC) called Regecel to test bacterial growth. The choice of antibacterial wound dressing depends on the type of wound being treated. Different bacterial strains require specific culture conditions to thrive and grow in laboratory settings. To obtain accurate and reliable results, it is vital to follow the precise culture conditions required for each bacterial strain. Results: The evaluation of ORC highlighted its potential to inhibit bacterial growth, showing promising results against various bacterial strains and Candida albicans. Different variants of ORC, such as Regecel, have demonstrated impressive capacity to hinder the growth of 32 distinct bacterial strains, with inhibition rates ranging from 40-100%. These bacteria include methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and penicillin-resistant Streptococcus pneumoniae. Conclusion: This study supports the usage and development of ORC (Regecel) as an innovative approach to treating bacterial infections.
ABSTRACT
Fertilization relies on pollen mother cells able to transit from mitosis to meiosis to supply gametes. This process involves remarkable changes at the molecular, cellular and physiological levels including (but not limited to) remodelling of the cell wall. During the meiosis onset, cellulose content at the pollen mother cell walls gradually declines with the concurrent deposition of the polysaccharide callose in anther locules. We aim to understand the biological significance of cellulose-to-callose turnover in pollen mother cells walls using electron microscopic analyses of rice flowers. Our observations indicate that in wild type rice anthers, the mitosis-to-meiosis transition coincides with a gradual reduction in the number of cytoplasmic connections called plasmodesmata. A mutant in the Oryza sativa callose synthase GSL5 (Osgsl5-3), impaired in callose accumulation in premeiotic and meiotic anthers, displayed a greater reduction in plasmodesmata frequency among pollen mother cells and tapetal cells suggesting a role for callose in plasmodesmata maintenance. In addition, a significant increase in extracellular distance between pollen mother cells and impaired premeiotic cell shaping was observed in the Osgsl5-3 mutant. The results suggest that callose-to-cellulose turnover during mitosis-meiosis transition is necessary to maintain cell-to-cell connections and optimal extracellular distance among the central anther locular cells. Findings of this study contribute to our understanding of the regulatory influence of callose metabolism during meiosis initiation in flowering plants.
ABSTRACT
Nanostructured materials represent promising substrates for biocatalysts immobilization and activation. Cellulose nanocrystals (CNCs), accessible from waste and/or renewable sources, are sustainable and biodegradable, show high specific surface area for anchoring a high number of enzymatic units, and high thermal and mechanical stability. In this work, we present a holistic enzyme-based approach to functional antibacterial materials by bioconjugation between the lysozyme from chicken egg white and enzymatic cellulose nanocrystals. The neutral CNCs were prepared by endoglucanase hydrolysis from Avicel. We explore the covalent immobilization of lysozyme on the enzymatic CNCs and on their TEMPO oxidized derivatives (TO-CNCs), comparing immobilization yields, materials properties, and enzymatic activities. The materials were characterized by X-ray diffractometry (XRD), attenuated total reflectance Fourier Transform infrared spectroscopy (ATR-FTIR), bicinchoninic acid (BCA) assay, field-emission scanning electron microscopy (FE-SEM) and dynamic light scattering (DLS). We demonstrate the higher overall efficiency of the immobilization process carried out on TO-CNCs, based on the success of covalent bonding and on the stability of the isolated biocojugates.
ABSTRACT
This study evaluates the feasibility of using enzymatic technology to produce novel nanostructures of cellulose nanomaterials, specifically cellulose nanospheres (CNS), through enzymatic hydrolysis with endoglucanase and xylanase of pre-treated cellulose fibers. A statistical experimental design facilitated a comprehensive understanding of the process parameters, which enabled high yields of up to 82.7 %, while maintaining a uniform diameter of 54 nm and slightly improved crystallinity and thermal stability. Atomic force microscopy analyses revealed a distinct CNS formation mechanism, where initial fragmentation of rod-like nanoparticles and subsequent self-assembly of shorter rod-shaped nanoparticles led to CNS formation. Additionally, adjustments in process parameters allowed precise control over the CNS diameter, ranging from 20 to 100 nm, highlighting the potential for customization in high-performance applications. Furthermore, this study demonstrates how the process framework, originally developed for cellulose nanocrystals (CNC) production, was successfully adapted and optimized for CNS production, ensuring scalability and efficiency. In conclusion, this study emphasizes the versatility and efficiency of the enzyme-based platform for producing high-quality CNS, providing valuable insights into energy consumption for large-scale economic and environmental assessments.
ABSTRACT
Chiral architectures, one of the key structural features of natural systems ranging from the nanoscale to macroscale, are an infinite source of inspiration for functional materials. Researchers have been, and still are, strongly pursuing the goal of constructing such structures with renewable and sustainable building blocks via simple and efficient strategies. With the merits of high sustainability, renewability, and the ability to self-assemble into chiral nematic structures in aqueous suspensions that can be preserved in the solid state, polysaccharide nanocrystals (PNs) including cellulose nanocrystals (CNCs) and chitin nanocrystals (ChNCs) offer opportunities to reach the target. We herein provide a comprehensive review that focuses on the development of CNCs and ChNCs for the use in advanced functional materials. First, the introduction of CNCs and ChNCs, and cellulose- and chitin-formed chiral nematic organizations in the natural world, are given. Then, the self-assembly process of such PNs and the factors influencing this process are comprehensively discussed. After that, we showcased the emerging applications of the self-assembled chiral nematic structures of CNCs and ChNCs. Finally, this review concludes with perspectives on the challenges and opportunities in this field.
ABSTRACT
Anisotropic cellulose nanofiber (CNF) foams represent the state-of-the-art in renewable insulation. These foams consist of large (diameter >10 µm) uniaxially aligned macropores with mesoporous pore-walls and aligned CNF. The foams show anisotropic thermal conduction, where heat transports more efficiently in the axial direction (along the aligned CNF and macropores) than in the radial direction (perpendicular to the aligned CNF and macropores). Here we explore the impact on axial and radial thermal conductivity upon depositing a thin film of reduced graphene oxide (rGO) on the macropore walls in anisotropic CNF foams. To obtain rGO films on the foam walls we developed liquid-phase self-assembly to deposit rGO in a layer-by-layer fashion. Using electron and ion microscopy, we thoroughly characterized the resulting rGO-CNF foams and confirmed the successful deposition of rGO. These hierarchical rGO-CNF foams show lower radial thermal conductivity (λr) across a wide range of relative humidity compared to CNF control foams. Our work therefore demonstrates a potential method for improved thermal insulation in anisotropic CNF foams and introduces versatile self-assembly for postmodification of such foams.
ABSTRACT
Accurately identifying and quantifying toxicants is crucial for medico-legal investigations in forensic toxicology; however, low analyte concentrations and the complex samples matrix make this work difficult. Therefore, a simplified sample preparation procedure is crucial to streamline the analysis to minimize sample handling errors, reduce cost and improve the overall efficiency of analysis of toxicants. To address these challenges, an innovative disposable in-tip cellulose paper (DICP) device has been developed for the extraction of three pesticides viz. Chlorpyrifos, Quinalphos and Carbofuran from postmortem blood samples. The DICP device leverages cellulose paper strips housed within a pipette tip to streamline the extraction process, significantly reducing solvent usage, time, and labor while maintaining high analytical accuracy. The extraction of pesticides from postmortem blood using the DICP device involves a streamlined process characterized by adsorption and desorption. The diluted blood samples were processed through the DICP device via repeated aspirating and dispensing calyces to adsorb the pesticides onto the cellulose paper. The adsorbed pesticides are then eluted using acetone, which is collected for GC-MS analysis. The method was meticulously optimized, achieving a limit of quantification in the range of 0.009-0.01 µg mL-1. The intra-day and inter-day precisions were consistently less than 5 % and 10 %, respectively, with accuracy ranging from 94-106 %. Relative recoveries for the analytes were observed to be between 60 % and 93.3 %, and matrix effects were determined to be less than 10 %. The method's sustainability was validated with a whiteness score of 98.8, an AGREE score of 0.64, a BAGI score of 70 and ComplexMoGAPI score of 77. Applicability was demonstrated through successful analysis of real postmortem blood samples and proficiency testing samples, highlighting its potential utility in forensic toxicology.
ABSTRACT
Intelligent indicator films with colorimetric pH indicator properties were developed, incorporating black soybean seed coat anthocyanin (BA), cellulose nanocrystals (CNC), and sodium alginate (SA) to monitor meat freshness. The effect of different CNC additions on the microstructure, water barrier properties of the films, and BA release kinetics were comprehensively investigated. The results showed that with the increasement of CNC addition, the mechanical properties of SA/BA/CNC films were improved, the water contact angle significantly increased from 51.6° to 69°. Moreover, water solubility, vapor adsorption, and permeability significantly decreased, indicating enhanced water barrier properties. The release kinetic results showed that BA was released rapidly within 72â¯h and slowly thereafter, and its release process was described by Fick's model. Films with 7â¯% and 10â¯% CNC had lower BA diffusion coefficients. Their diffusions were formulated as linear regression equations (yâ¯=â¯nxâ¯+â¯a), where R2 was >0.80 and n was <0.50. Structural characterization showed that CNC immobilized BA mainly through hydrogen bonding, forming compact network microstructures with SA and BA. Meat freshness monitoring results showed that the film containing 7â¯% CNC showed visible color changes with increasing total volatile basic nitrogen and pH, along with low BA release, high water barrier and mechanical properties. Therefore, CNC has great potential for improving the physicochemical properties of indicator films, and the intelligent colorimetric indicator film could be applied to various food product.
ABSTRACT
Polyurethane (PU) has a diverse array of customized physical, chemical, mechanical, and structural characteristics, rendering it a superb option for biomedical applications. The current study involves modifying the polyurethane surface by the process of aminolysis (aminolyzed polyurethane; PU-A), followed by covalently immobilizing Carboxymethyl cellulose (CMC) polymer utilizing Schiff base chemistry. Oxidation of CMC periodically leads to the creation of dialdehyde groups along the CMC chain. When the aldehyde groups on the OCMC contact the amine group on a modified PU surface, they form an imine bond. Scanning electron microscopy (SEM), contact angle, and X-ray photoelectron spectroscopy (XPS) techniques are employed to analyze and confirm the immobilization of OCMC on aminolyzed PU film (PU-O). The OCMC gel incorporates Nitrofurantoin (NF) and immobilizes it on the PU surface (PU-ON), creating an antibacterial PU surface. The confirmation of medication incorporation is achieved using EDX analysis. The varying doses of NF have demonstrated concentration-dependent bacteriostatic and bactericidal effects on both Gram-positive and Gram-negative bacteria, in addition to sustained release. The proposed polyurethane (PU-ON) surface exhibited excellent infection resistance in in vivo testing. The material exhibited biocompatibility and is well-suited for biomedical applications.
ABSTRACT
INTRODUCTION: The pharmaceutical industry is gradually changing batch-wise manufacturing processes to continuous manufacturing processes, due to the advantages it has to offer. The final product quality and process efficiency of continuous manufacturing processes is among others impacted by the properties of the raw materials. Existing knowledge on the role of raw material properties in batch processing is however not directly transferable to continuous processes, due to the inherent differences between batch and continuous processes. AREAS COVERED: A review is performed to evaluate the role of excipient properties for different unit operations used in continuous manufacturing processes. Unit operations that will be discussed include feeding, blending, granulation, final blending, and compression. EXPERT OPINION: Although the potency of continuous manufacturing is widely recognized, full utilization still requires a number of challenges to be addressed effectively. An expert opinion will be provided that discusses those challenges and potential solutions to overcome those challenges. The provided overview can serve as a framework for the pharmaceutical industry to push ahead process optimization and formulation development for continuous manufacturing processes.
ABSTRACT
Fractionated corn bran was processed to maximize ethanol production from starch, cellulose, and xylan. After various bench-scale experiments, an optimized process with dilute acid pretreatment (1.5 % w/w H2SO4) at 90 °C for 60 min was utilized followed by enzymatic hydrolysis using cellulase and hemicellulase for 48 hr. After simultaneous saccharification (regarding starch) and fermentation at 150 L using an engineered yeast, which consumes both glucose and xylose to make ethanol, the 86 % total sugar conversion yield was achieved, including conversions of 95 % for starch, 77 % for cellulose and 77 % for xylan. Also, an accurate mass balance was formulated for ethanol-producing carbohydrates including starch, cellulose, and xylan from feedstock to final ethanol. A highly efficient process of converting corn fiber to ethanol was successfully scaled up to 150 L.
ABSTRACT
Based on the basic idea of expanding the interlayer spacing of MXene, utilizing the effect of gallic acid-modified cellulose nanofibers for rapid moisture separation, the flexible sensing and driving composite film with a perfect balance among humidity signal response and mechanical properties was prepared. Inspired by the stacking of autumn fallen leaves, the cellulose nanofibers-based composite films were formed by self-assembly under vacuum filtration of blending gallic acid-modified cellulose nanofibers with MXene. The enhanced mechanical properties (tensile strength 131.1 MPa, puncture load 0.88 N, tearing strength 165.55 N/mm, and elongation at break 16.14 %), humidity sensing (the stable induced voltage 63.7 mV and response/recovery time 3.2/5.1 s), and humidity driving (154.7° bending angle) properties were observed. The synergistic effect of hydrogen bonds, the "pinning effect" arising from the side chains, and the hierarchical layered microstructure contributed to the enhanced performance. This work exemplifies the application of green natural product for preparing intelligent sensing, wearable devices, and biomimetic robots.