Cellulose最新文献

In this study, we explored the overall enhancement of cellulose acetate (CA) UF performance (i.e., permeation, antifouling, antibacterial, and dye rejection properties) through incorporation of AgFeO₂ nanoparticles (NPs) in the membrane matrix. The prepared nanocomposite membranes featured an asymmetric, sponge-like structure with random distribution of AgFeO₂ NPs. This developed morphology altered the intrinsic characteristics compared with the neat CA membrane. For instance, the nanocomposite membrane (M5) containing 8 wt% (of AgFeO₂ NPs possessed the lowest contact angle (42.68°), and the highest negative zeta potential of -24.9 mV. This was reflected on the pure water permeability (PWP) and bovine serum albumin (BSA) permeability (4.813 LMH·bar⁻¹and 4.37 LMH·bar⁻¹, respectively). In experiments for BSA, MB, and CV dye rejection, the same membrane achieved rejection rates of 51.1%, 64.4%, and 93.7%, respectively. In addition, this membrane showed excellent reusability, as indicated by a high flux recovery ratio (FRR) of 94.12% after three cycles and a low total fouling ratio, with a significant portion being reversible fouling and reduced hydraulic resistance. Strong antibacterial performance and filtration efficiency against S. aureus and E. coli is another additional asset of this membrane. In summary, AgFeO₂ NPs served as effective modifier for CA UF membrane, enhancing its permeation, antifouling, antibacterial, and dye removal capabilities without compromising the rejection performance.

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Natural polymer hydrogels that mimic the extracellular matrix have garnered increasing interest for bone regeneration. However, simply promoting cell adhesion in the hydrogel is insufficient for optimal bone regeneration; modulating macrophage immune polarization is also critical for accelerating healing. Herein, sugarcane bagasse xylan has been used to modify sericin/gelatin composite hydrogel to develop a modified composite hydrogel, which aims to mimic the composition of the native bone tissue. The physicochemical properties of the composite hydrogels were characterized, and the inflammation regulation and osteogenic ability of the hydrogels in vitro were investigated. The results show that the carboxymethylated bagasse xylan can significantly change the physicochemical properties of the composite hydrogel. The morphology and chemical analysis revealed that the inter- and intra-molecular covalent bonding interactions were formed within the hydrogels, leading to a remarkably enhanced thermal stability and swell ratio of the hydrogel. Cellular experiments have demonstrated that the composite hydrogels promote cell proliferation and activity, exhibiting excellent cytocompatibility. They also facilitate the polarization of macrophages towards the M2 phenotype and significantly enhance the osteogenic differentiation of mesenchymal stem cells, thereby manifesting superior osteogenic capacity. This study provides a novel perspective on the application of sugarcane bagasse xylan in bone repair.

Indoor humidity regulation is critical for human health, yet conventional electrical systems remain energy-intensive. While wood’s natural hygroscopicity offers passive humidity control, its limited adsorption capacity restricts practical applications. This study presents a passive humidity-regulating wood composite synergizing metal–organic frameworks (MOFs) with laser-drilled wood substrates to overcome these limitations. Through systematic screening of MOFs (HKUST-1, MIL-100(Fe), MIL-101(Cr)), MIL-101(Cr) was selected due to its hierarchical porosity and S-shaped isotherms in the critical 40–60% relative humidity (R.H.) range. The MIL-101(Cr)@wood composite exhibited a 287% enhancement moisture adsorption versus native wood at 50% R.H. Crucially, the composite suppressed bacterial proliferation after 480 min of exposure to 95% R.H., mitigating bacterial risks inherent to extreme high humidity indoor environment (using E. coli as a model microorganism). This work advances sustainable building technologies, positioning wood-based composites as promising candidates for innovative ventilation system designs that promote healthier indoor environments.

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Pretreating natural cellulose materials, such as raw cotton fibers, is often challenging due to dissolution difficulties caused by their complex structure. Here, we efficiently dissolved raw cotton fibers, regenerated them into cellulose nanofibers (CNFs), and successfully used these CNFs to prepare 3D porous air-filtering media. Raw cotton fibers were dissolved in a green deep eutectic solvent (DES) based on aluminum and zinc chloride by microwave-heating method. Response surface methodology was utilized to optimize the key dissolution parameters. Thereby, temperature was found to be the most significant factor affecting solubility performance. The optimal dissolution parameters were determined by the desirability function approach, and the verified experimental results realized a solubility of 96.05%. Additionally, the dissolution mechanism of the cellulose model in DES was analyzed from an energy perspective using theoretical calculations. Based on the optimized cellulose solution, CNFs were successfully prepared by shear-induced regeneration. By integrating CNFs with basalt fibers, porous filtration media were prepared with optimized fiber ratios. The materials demonstrated outstanding comprehensive performance, with PM_0.3 filtration efficiency of over 98.00%, highlighting their potential practical value. Overall, this study presents a feasible strategy for the employment and application of raw cotton fibers featuring a complex biopolymeric network.

Cellulose microspheres with high specific surface area have considerable application prospects in drug delivery. The traditional methods for preparation of microspheres with diameter of less than 10 µm and controllable particle size are highly challenging. Herein, regenerated nanoporous cellulose microspheres (NCMs) with a high specific surface area up to 137 m²/g and a diameter sub-5 μm were prepared by membrane emulsification method. By optimizing the membrane pore size, cellulose concentration, and applied pressure, cellulose microspheres with control size and nanopores (10–50 nm) were prepared. Unlike conventional methods requiring chemical crosslinking, freeze-drying for physical solidification was applied to ensure biocompatibility and sustainability. The XRD results confirmed the transformation of cellulose crystalline structure from type I to type II, accompanied by reduced crystallinity. The NCMs demonstrated exceptional folic acid (FA) loading performance, achieving a maximum capacity of 35.21% and significantly improved storage stability, 70.04% retention after 30 h at 70 °C, compared to 50.38% for pure FA. Furthermore, in the simulated in vitro digestion experiments, the FCM exhibited a control release of FA in the gastrointestinal fluid. These results highlight the potential of NCMs as versatile carriers for drug delivery systems, offering advantages in controlled release, stability enhancement, and scalability for biomedical applications.

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Bamboo scrimber, as a sustainable engineered composite material, faces challenges in interfacial adhesion and mildew resistance due to the hydrophobic surface of bamboo bark/inner skin and its nutrient-rich composition (e.g., starch and other saccharides). Atmospheric plasma, through high-energy particles, can activate the bamboo surface by grafting oxygen-containing functional groups and inducing micro-roughness. This study proposes a novel strategy combining atmospheric plasma treatment with in situ zinc oxide nanoparticle deposition to simultaneously enhance interfacial bonding and anti-mold performance. The plasma-driven pyrolysis of zinc acetate precursor generates zinc oxide nanoparticles in situ, imparting mildew resistance to the material. Concurrently, this modification promotes deep penetration and uniform spreading of phenolic resin, forming a continuous bonding layer and mechanically interlocked "glue nail" structure at the bamboo-resin interface. The optimized composite exhibited a 13.7% increase in modulus of rupture (MOR), a 24.9% increase in modulus of elasticity (MOE), and a 107% increase in surface free energy. The inhibition rates against Aspergillus niger and Penicillium purpurogenum exceeded 90%, while the inhibition rate against Trichoderma viride reached 75%. This green and efficient one-step approach fully utilizes bamboo bark, significantly improving interfacial strength and mildew resistance, offering new insights for the interface engineering of natural fiber composites.

As interest in sustainable materials grows, paper is being reimagined as a multifunctional substrate with significant potential for future technologies for innovative, environmentally friendly solutions. This study investigates the swelling behavior and environmental responsiveness of a copolymer, poly(N,N-dimethylacrylamide-co-4-methacryloyloxybenzophenone) [P(DMAA-co-MABP)], when applied to cellulosic paper for use in humidity-sensitive actuators. The copolymer’s swelling behavior was characterized using dynamic vapor sorption (DVS) and in-situ atomic force microscopy (AFM). DVS measurements demonstrated that the polymer coating significantly enhances the hygroscopic properties of the paper, while AFM revealed the polymer’s fast response to relative humidity (RH) changes, shown by immediate height adjustments, increased adhesion, and decreased stiffness at higher RH levels. Studies on polymer-modified paper-based bilayer actuators demonstrate that incorporating the hydrophilic P(DMAA-co-MABP) results in actuation in response to relative humidity variations between 10 and 90% RH. From these findings, two models were proposed to assess key mechanisms in the swelling behavior: the correlation between the heterogeneity in crosslinking and the polymer swelling behavior, and the correlation between polymer-paper interactions and the hygro-responsive bending behavior. Additionally, thermal analysis was performed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), providing a comprehensive profile of the copolymer’s behavior.

Bacterial cellulose (BC) is an emerging, sustainable biomaterial that distinguishes itself from plant-derived cellulose by being free from lignin and hemicellulose and its ability to be synthesized from various organic waste sources. The eco-friendly production and high design flexibility make BC a promising material for advanced membrane technologies. Through careful control of its production conditions and physical or chemical modifications, BC's structural and functional properties can be tailored for diverse applications. Current limitations of bacterial cellulose applications include its high production costs, limited mechanical strength for some particular applications and susceptibility to microbial contamination. This review provides a comprehensive overview of BC as a next-generation membrane material for selective transport, covering its synthesis, modification strategies, and application-specific design. Emphasis is placed on BC’s role in fields where controlled mass transfer is critical, such as drug delivery, food packaging, wastewater treatment, and filtration systems. For each domain, the mechanisms of transport across the BC membrane are discussed, focusing on the types of phases involved (gas, liquid, or solid) and the nature of the components being selectively transferred. The review classifies BC membranes according to application sectors and highlights their performance in facilitating selective transport through mechanisms such as adsorption, permeability, and diffusion. By examining recent research trends and innovations, this study emphasizes the versatility and adaptability of bacterial cellulose in both conventional and emerging membrane technologies, contributing to its broader integration into sustainable and functional material systems.

The photoelectrochemical (PEC) conversion of carbon dioxide (CO₂) into valuable chemicals and fuels offers a promising strategy to address global challenges such as climate change and glacier retreat. However, developing high-performance photocathodes for the CO₂ reduction reaction (CO₂RR) is challenging, particularly in optimizing the surface morphology and active site distribution of the electrodes. In this study, we propose a CuBi₂O₄ (CBO)-based photocathode capable of gas-phase CO₂RR through hybridization with cellulose nanofiber (CNF). Our results reveal that the CBO-CNF membrane exhibits inherent hydrophilicity and significantly larger active sites compared to a CBO film prepared with a Nafion binder, leading to reduced charge transfer resistance on the photocathode surface. Moreover, the simultaneous hydrothermal synthesis of the CBO-CNF composite precursor solution effectively inhibits the formation of undesirable CuO nanoparticles on the surface, which would otherwise increase charge transport resistance within the photocathode bulk. Consequently, the CBO-CNF membrane demonstrates superior PEC activities for CO₂RR, achieving a photocurrent density of − 5.69 mA/cm² at − 0.4 V_RHE and an onset potential of 0.015 V_RHE. Furthermore, the incorporation of CNF improves the long-term PEC stability of the photocathode by promoting charge carrier participation in CO₂RR rather than undesired self-reduction reaction. This enhanced stability, coupled with the improved PEC performance, highlights the potential of CNF to replace existing polymer binder materials. These results suggest the feasibility of developing a new type of CBO photocathode with a porous membrane structure suitable for gas-phase PEC cells, marking a significant step forward in PEC technology for CO₂ conversion.

Kombucha is a fermented tea beverage obtained through the metabolic activity of a symbiotic culture of acetic acid bacteria and yeasts (SCOBY). During fermentation, specific bacterial strains, particularly Komagataeibacter xylinus, synthesize bacterial cellulose (BC), an extracellular biopolymer with high purity, crystallinity, and biocompatibility. This study aimed to optimize the fermentation parameters to enhance BC yield and improve its physicochemical, mechanical, and structural properties. A central composite design based on response surface methodology was applied to evaluate the effects of starter tea volume (18–54 mL), glucose concentration (18–36 g), and fermentation temperature (25–35 °C) on key response variables. The production yields of SCOBY (wet basis) and purified BC (dry basis) were assessed, along with swelling capacity, water dispersion, water vapor permeability, tensile strength, percent elongation, and crystallinity. Individual and simultaneous optimizations were performed. The best individual condition yielded 65.14 g/L of SCOBY and 2.70 g/L of BC, using 5.72 mL of starter tea and 29.04 g of glucose. Simultaneous optimization resulted in 70 g/L of SCOBY and 2.94 g/L of BC with 66.27 mL of starter tea, 22.37 g of glucose, and 38.4 °C. The optimized BC exhibited favorable properties: tensile strength (4 MPa), elongation (3.8%), swelling capacity (400%), water vapor permeability (27 g·s⁻¹·m⁻¹·MPa⁻¹), and crystallinity (59.89%). These findings demonstrate the feasibility of tailoring kombucha fermentation to obtain BC with promising functional characteristics for applications in agriculture, cosmetics, and biomaterials.