Cellulose Nanofibers Research Articles

Effect of cellulose nanofibers and recycled glass powder on the geotechnical and microstructural parameters of dispersive soil

Effect of cellulose nanofibers and recycled glass powder on the geotechnical and microstructural parameters of dispersive soil

Utilizing cellulose nanofibers to enhance spent engine oil performance: A sustainable environmental solution

Spent engine oil is a major source of environmental pollution that affects the aquatic ecosystem and human health. Cellulose nanofibers (CNF) are natural nanomaterials that can be used as additives in spent engine oil to enhance its performance, especially at high temperatures and pressures. Utilizing sulfur-based unbleached rice straw pulping technique, the rice straw was grinded in a solution with 10 % sodium sulfite and 2 % sodium carbonate, that heated to 160 °C for 2 h. This produces unbleached sulfur pulp, which is then analyzed for ash, cellulose, and lignin content. A subsequent bleaching step at 80 °C with a sodium chlorite/acetic acid mix completes the process. This technique was adopted to produce CNF. In this study, preparation and characteriztion of CNF-additives to spent engine oil was performed using different techniquessuch as; IR spectra analysis, kinematic viscosity, and wear scar width. It was also evaluated on the oil adsorption, vibration, and noise reduction properties of the resulted additive oil. The results showed that CNF improved viscosity, lubrication, and anti-wear properties of the oil, and decreased its friction, vibration, and noise. The optimal concentration of CNF was 2.0 wt%, which increased the kinematic viscosity by 14.5 % and reduced the wear scar width by 31 % compared to the spent oil sample. Moreovere, CNF reduced the environmental impact of oil disposal and recycling. Overall, CNF are promising nanofillers for improving the performance of spent engine oil and lowering its environmental impact.

Hexagonal boron nitride nanosheets/graphene nanoplatelets/cellulose nanofibers-based multifunctional thermal interface materials enabling electromagnetic interference shielding and electrical insulation

Thermal interface materials (TIMs) that block electromagnetic interference (EMI) and current leakage are essential for high-density, high-power devices and compact form factors of electronic and mobility platforms. However, their coupled thermal-electrical-electromagnetic characteristics involve mismatches in thermal conductivity, electrical insulation, and EMI shielding, limiting the multifunctionality. Herein, a sandwich-like structural design that rationally combines graphene nanoplatelets (GNPs), hexagonal boron nitride nanosheets (BNNSs) and cellulose nanofibers (CNFs) is presented toward multifunctional trilayer TIMs enabling high thermal conductivity, EMI shielding, electrical insulation, mechanical compatibility and flame retardancy. The top and bottom BNNSs serve as electrically insulating yet thermally conductive layers while the GNPs in the central layer mitigate EMI and the CNFs as a binder complete the mechanical properties for the lamella-like trilayers. The resulting TIM exhibits a high in-plane thermal conductivity (25.5 W/m·K), and the LED cooling system using the TIM demonstrates the capability of reducing the operating temperature. Furthermore, it shows a high-volume resistivity (4.12 × 1013 Ω cm) and EMI shielding effectiveness (29.0 dB) at X-band frequencies. Its mechanical robustness is confirmed with tensile strength and elongation of 65.0 MPa and 2.36 %, and the high flame retardancy is validated. The outcomes will inspire tailoring multifunctional TIMs using lamellar structures that optimally combine micro/nanomaterials.

High strength and transparent polyvinyl alcohol/nanocellulose film with encoding fluorescence properties

Fluorescent anti-counterfeiting films have garnered significant attention due to their advantages of tunable emission, strong concealment, high difficulty of imitation, and good processability. In this work, two zinc sulfide quantum dots (ZnS QDs) with different fluorescence wavelengths were loaded to construct polyvinyl alcohol (PVA)/cellulose nanofiber (CNF) composite films with encoding anti-counterfeiting fluorescence properties. By controlling the loading ratio of the two ZnS QDs, coded signals with different fluorescence intensity ratios at emission wavelengths of 400 nm and 600 nm were achieved. The fluorescence intensity ratio of the film can be adjusted between 1.3 × 105 and 1 × 10−4, resulting in a wide range of blue to orange color changes under ultraviolet light. The fluorescence intensity ratio corresponds to the color change of the film, which can be used for fluorescence coding design. By fine-tuning the addition ratio of the two types of QDs, the fluorescence intensity ratio and the color of the film can be precisely controlled, enhancing the anti-counterfeiting performance of the film. PVA is employed as a carrier to maintain high transmittance (> 80 %). The strength of the film was elevated up to 90 MPa due to the reinforcing effect of CNF, and the hydrophobic property was significantly improved with a contact angle higher than 113° through modification with diphenyl diisocyanate (MDI). This type of fluorescent PVA/CNF composite film, with its high mechanical strength and transparency, holds great potential in the field of anti-counterfeiting.

A 28-Day Repeated Oral Administration Study of Mechanically Fibrillated Cellulose Nanofibers According to OECD TG407.

The impact of oral administration of mechanically fibrillated cellulose nanofibers (fib-CNF), a commonly used nanofiber, on toxicity and health remains unclear, despite reports of the safety and beneficial effects of chitin-based nanofibers. Thus, evaluating the oral toxicity of fib-CNF in accordance with OECD Test Guideline 407 (TG407) is essential. This study aimed to assess the safety of orally administered fib-CNF through an acute toxicity study in rats, following the OECD TG407 guidelines for 4 weeks. CNF "BiNFi-s" FMa-10005, derived from mechanically fibrillated pulp cellulose, was administered via gavage to male and female Crl:CD(SD) rats at doses of 50, 150, 500, and 1000 mg/kg/day for 28 days, with a control group receiving water for injection. The study evaluated the toxic effects of repeated administration, and the rats were monitored for an additional 14 days post-administration to assess recovery from any toxic effects. The results showed no mortality in either sex during the administration period, and no toxicological effects related to the test substance were observed in various assessments, including general condition and behavioral function observations, urinalysis, hematological examination, blood biochemical examination, necropsy findings, organ weights, and histopathological examination. Notably, only female rats treated with 1000 mg/kg/day of CNF exhibited a consistent reduction in body weight during the 14-day recovery period after the end of treatment. They also showed a slight decrease in pituitary and liver weights. However, hematological and blood biochemical tests did not reveal significant differences, suggesting a potential weight-suppressive effect of CNF ingestion.

Synergistic enhancement of foam stability by nanocellulose and hydrocarbon surfactants

Synergistic effects and stability mechanism of carboxylated cellulose nanofiber (CCNF) and hydrocarbon surfactants on the environmentally friendly foam are investigated in this work. Higher concentrations of CCNF decelerate the bubble coarsening and liquid drainage processes, consequently enhancing foam stability. Increasing viscosity is the primary cause of foam stability enhancement for all surfactant solutions. However, the generation of aggregates is still another reason for the enhanced stability of CTAB/CCNF foam. In addition, CCNF diminishes the foaming ability of all surfactants. Furthermore, as CCNF exceeds 0.8 wt.%, the foaming ability of all surfactants diminishes noticeably, with CTAB solution experiencing a more pronounced reduction. In SDS solutions, the foaming ability is governed by viscosity, whereas in CTAB solutions, it is influenced by adsorption kinetics and viscosity.

Biodegradable hydrogel with excellent portability, stability and anti-pollution performance in solar-driven seawater desalination

Solar-driven interfacial evaporation technology holds great potential for efficiently utilizing solar energy to convert untapped water sources into clean water. This study developed a cellulose nanofiber (CNF)/polyvinyl alcohol (PVA)/multi-walled carbon nanotubes (MWCNTs) hydrogel-based evaporator (PCC) using low-cost wood pulp cellulose as the raw material. The experimental results revealed that the PCC hydrogel evaporator achieved a water evaporation rate of 1.61 kg·m−2·h−1 under 1 sun irradiation (solar intensity of 1 kW·m−2). Assisted by the three-dimensional interconnected hydrophilic network, the hydrogel exhibited excellent water supply capabilities, with water transport dominating within the hydrogel, enabling continuous steam generation from seawater. And the water layer formed by the super-hydrophilic pore wall structure was also beneficial to activating water, promoting the diffusion of high-concentration salt water, and enhancing the underwater oil repellent ability. After multiple compression-recovery performance tests, the PCC maintained stable evaporation performance, which greatly enhanced portability during use. In addition, the application of PCC evaporators in the fields of seawater desalination, wastewater treatment, and agricultural irrigation had shown excellent results, confirming the potential application value of this evaporator. Combined with its environmental friendliness, cost-effectiveness, and other advantages, it had broad development prospects.

Preparation of Molecularly Imprinted Bacterial Cellulose Nanofiber Nonwovens for Selectively Removing Dye Molecule from Aqueous Solution

Preparation of Molecularly Imprinted Bacterial Cellulose Nanofiber Nonwovens for Selectively Removing Dye Molecule from Aqueous Solution

Mussel-adhesive chemistry inspired conductive hydrogel with self-adhesion, biocompatibility, self-recovery and fatigue-resistance performances as flexible sensing electronics

Conductive hydrogels are ideal candidates for wearable strain sensors due to their intrinsic stretchability and conductivity. However, it’s still a challenge to fabricate a conductive hydrogel with a combination performance of high mechanical strength, self-adhesion, sensitivity, self-recovery capability, fatigue-resistant ability and biocompatibility. Herein, a dual-network hydrogel (TG/P-LP) composed of 2,2,6,6-tetra-methylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCNs) supported graphene (GN), Laponite-oxidized polydopamine (LP) and polyacrylic acid-co-poly acrylamide (P) hydrogel matrix was synthesized via a facile in-situ radical polymerization process. The optimized biocompatible TG/P-LP hydrogel exhibits a high mechanical strength, self-adhesive performance, intrinsic self-recovery capability (95.7 % in 60 min) and anti-fatigue property. The hydrogel-based strain sensor exhibits a wide strain range (0 ∼ 600 %) and a high sensitivity (GF = 12). This work designs a novel hydrogel-based sensor with excellent mechanical properties, long-term fatigue resistance, high strain sensitivity and wearability, demonstrating enormous potential in the applications of human motion detection and human–machine interaction.

Enhancing Solar Steam Generation of Hydrogels via Silver Nanoparticle-Doped Cellulose Nanofibers.

Solar steam generation (SSG) is regarded as an efficient approach for harnessing solar energy to purify polluted or saline water. Herein, we demonstrate a hydrogel composed of cellulose nanofibers (CNFs), polyethylenimine (PEI), and reduced graphene oxide (rGO) that functions as an independent solar steam generator, which shows enhanced solar water evaporation efficiency by incorporating silver nanoparticles (AgNPs). It presented that the presence of AgNPs increases the photothermal conversion efficiency and thermal conductivity of the evaporator and reduces the enthalpy of evaporation. As a result, an outstanding water evaporation rate of 3.62 kg m-2 h-1 and a photothermal conversion efficiency of 96.25% are successfully obtained under one sun illumination. Also, the resulting hydrogel exhibits exceptional mechanical properties, as well as outstanding desalination and salt-resistant abilities during prolonged seawater desalination. In oil/water mixtures, the evaporation of the hydrogel decreases to 2.94 kg m-2 h-1, owing to the oil layer barrier. This work paves a reference approach to produce easily addressed cellulose nanofiber (CNF)-based hydrogel evaporators with significantly enhanced evaporation rates.

Dried nanocellulose/xanthan as reinforcing fillers in thermoplastic starch

Nanocellulose fibres are known to enhance the mechanical properties of biopolymers when added as a filler. Nanocellulose irreversibly agglomerates upon drying and is therefore sold as an aqueous gel or suspension, increasing shipping cost and limiting application. This work studied the utility of xanthan gum as a dispersant aid for dried nanocellulose fibres. At levels as low as 15% xanthan gum addition, based on the mass of nanocellulose, prior to drying, agglomeration was significantly decreased. Mild shear rates could disperse the dried nanocellulose to a similar degree as ultrasonication when xanthan gum was present. Several complementary techniques, such as rheology, turbidimetry, and SEM- and TEM-imaging, proved that the native nanocellulose properties could be recovered after drying. Xanthan gum and nanocellulose, when incorporated into thermoplastic starch, showed a synergistic effect regarding the increase in tensile strength of the resultant biopolymer film. The addition of previously dried nanocellulose/xanthan, in a 4:1 ratio, to thermoplastic starch at a starch-cellulose ratio of 20:1, increased the tensile strength from 5.4 to 23.0 MPa. The ability to produce a dispersible and dry nanocellulose product that retains its properties has clear commercial benefits.

Variation of Nanocellulose Reinforced Recycled Paper: Effect on Tensile Strength

The idea of paper recycling was done due to environmental issue. However, the properties of recycled paper like tensile will decrease each time it is recycled. Addition of reinforcing filler may increase the properties of recycled paper. Thus, in this research, nanocellulose was used as reinforcing filler in recycled paper. The objectives of this research are to fabricate papers from recycled paper and to investigate the effect of different nanocellulose and pressure of compression molding in paper fabrication towards tensile strength of recycled paper. Two types of nanocellulose used were commercialized cellulose nanofiber (CNF) and cellulose nanocrystals (CNC). CNC from filter paper and empty fruit bunches (EFB) were isolated via acid hydrolysis. The recycled paper was fabricated using traditional me. thods (net) and further processed with compression molding. All samples with nanocellulose increase in tensile strength. The tensile strength recorded 114% improvement at 15.28 N/mm2 with 5wt% of CNF.

Rice straw-based cellulose nanofiber reinforcing polyvinyl alcohol antibacterial film through electrospinning

TEMPO-cellulose nanofibers (T-CNF) were prepared from rice straw through 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation method. Subsequently, T-CNF reinforced polyvinyl alcohol fiber films (T-CNF/PVA) were fabricated by electrospinning. SEM images revealed that the introduction of T-CNF into PVA resulted in a slight decrease in fiber diameter within the T-CNF/PVA films. The tensile strength and elastic modulus of the T-CNF/PVA-2 fiber film were 44.59 MPa and 20.75 MPa, respectively, with T-CNF content of 1.64 wt%. The tensile strength of T-CNF/PVA-2 being approximately 9 times greater than that of pure PVA fiber film. Molecular dynamics (MD) simulation showed that the intermolecular forces between T-CNF and PVA were stronger than those within pure PVA. Additionally, the T-CNF/PVA-2 fiber film exhibited excellent antibacterial properties, achieving an inhibition rate of 99.99 % against S. aureus.

Soil flushing coupled with aminated-nanocellulose/MOF hydrogel nanocomposites adsorbents: A novel sustainable remediation strategy for Cr(VI)-contaminated agricultural soils

Soil flushing and adsorption-based soil remediation are promising options for removing heavy metals in agricultural soil. However, they encounter limitations in low removal efficiency, secondary pollution potential, or the need for a purification/recovery process. Optimizing flushing solutions or the functional properties of adsorbents could fundamentally eliminate the drawbacks of these methods. Yet, their practical application remains a formidable challenge. Herein, a new combined remediation strategy of multiple-pulse water soil flushing (MF) with novel aminated cellulose nanofibers (A-NFCs)/AEM/AM@MIL-100(Fe) nanocomposite hydrogel adsorbent (ANCMH) was adopted to remove Cr(VI) from agricultural soil. The characteristic analyses approved Cr(VI) adsorption-coupled reduction/swelling-based mechanisms on ANCMH with the maximum theoretical adsorption capacity of 338.24 mg g−1 at pH 6.8 governed by pseudo-second-order and Freundlich models. Instead of conventional MF application using environmentally problematic extractant fluids, a 5-day soil column simulation trial of MF coupled with ANCMH adsorbent layers (MF@ANCMH) was applied in medium-to-highly Cr(VI)-contaminated soil followed by easy ANCMHs separation, preventing secondary pollution. Innovatively, the water flushing-stop flux events favorably decreased the pH of neutral soil by 0.83 folds and allowed Cr(VI) release from the soil matrix to be adsorbed by ANCMHs, achieving a high Cr(VI) removal efficiency of 98.9 %. Compared to the soil treated with ANCMH individually and soil flushed with water or Na2EDTA, the MF@ANCMH-treated soil reached the corresponding regulation of permissible levels for Cr(VI) residential scenarios in agricultural soil of 5.6 ppm with 3-cycles of ANCMH reuse. The residual Cr in MF@ANCMH-remediated soil displayed minimal bioavailability at root-zoon soil of ≤4.2 ppm and a 97.66 % reduction in its exchangeable-carbonate fraction compared to untreated soil, corresponding to a risk assessment code score below 1 %. Also, the application of MF@ANCMH resulted in Cr bioaccumulation below 0.1 ppm in cultivated wheat plants, prevented the physiological phytotoxicity symptoms, and elevated their antioxidant enzyme activity, photosynthesis, growth, and yielding indicators compared to that grown in untreated soil. Furthermore, it improved soil organic matter, microbial community, diversity, and microecological functions. This study provides a promising alternative remediation strategy for neutral soil that can maintain soil/crop quality and soil health with high chemical/environmental stability of pollutants after remediation, demonstrating its sustainability and feasibility in agricultural soil.

In vitro evaluation of ethyl cellulose and polyvinyl pyrrolidone composite nanofibers for transdermal delivery of diclofenac diethylamine

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most prominent painkiller and anti-inflammatory drugs with gastrointestinal (GI) adverse effects. Transdermal drug delivery systems (TDDS) could overcome GI adverse effects associated with oral ingestion of NSAIDs as well as maintaining a prolonged release of the drug. The main aim of this study was to prepare and investigate diclofenac diethylamine (DDA) loaded nanofibers made of ethyl cellulose (EC) and polyvinyl pyrrolidone K90 (PVP) using electrospinning. The impact of penetration enhancers such as nerolidol and farnesol on release profiles through cellophane membranes and other characteristics of nanofibers were also investigated. Based on release studies, some formulations were selected for release examination through rate skin using Franz diffusion cells. To gain insight about potential interactions between drug and polymers FTIR, DSC, and XRD analyses were performed. Morphology examination was also conducted using scanning electron microscopy (SEM). Morphology studies showed that nanofibers made of EC only are greater in the mean diameter than other nanofibers while other formulations were not significantly different from each other regardless of the presence of penetration enhancers. EC nanofibers had the lowest elastic modulus and tensile strength and most elongation at break which makes them the least tough and most flexible nanofibers among all the formulations. The addition of PVP increased the toughness and decreased the flexibility of nanofibers. The addition of nerolidol did not alter the mechanical properties of nanofibers significantly, while the addition of farnesol increased elastic modulus, tensile strength, and elongation at break significantly in a concentration-dependent manner. EC nanofibers had the lowest release rate and lowest total cumulative release content while the addition of PVP significantly improved both of these features. In release studies through cellophane membrane, the addition of 5 % of penetration enhancer slightly increased the release rate while did not significantly alter cumulative release while the addition of 10 % farnesol notably increased the release rate and total cumulative released content. Release studies through rat skin were in accordance with cellophane membrane studies and the formulation with 10 % farnesol had the most release rate and total cumulative release and these findings confirm the positive effect of penetration enhancers. DSC thermogram showed an amorphous state of the drug in fibres and this was supported by XRD results. The FTIR results confirmed that no chemical interaction between the drug and other formulation components has occurred and no new compounds have been formed. Based on these results, the utilization of DDA-loaded PVP and EC nanofibers in conjunction with a penetration enhancer showed significant potential for application in transdermal patches.

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.

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

AbstractPolyethylene 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.

Anisotropic ZrO2 porous ceramic constructed using bacterial cellulose nanofiber framework for extreme insulation environment

Zirconium oxide (ZrO2) porous ceramic shows promising application in construction and industry due to its remarkable chemical stability, corrosion resistance, oxidation resistance, and thermal resistance. While the construction of stable anisotropic ZrO2 porous ceramic is still a challenge. In this study, we report an anisotropic ZrO2 porous ceramic using bacterial cellulose nanofiber (BCNF) as a framework and zirconium oxychloride octahydrate as the zirconium source. ZrO2 porous ceramic was achieved through directional freezing, vacuum freeze-drying, and calcination processes. ZrO2 arrangement relies on the BCNF framework and retains the three-dimensional (3D) structure after the calcination of BCNF. Results reveal that the resulting ZrO2 porous ceramic possesses a well-ordered anisotropic network structure, exhibiting excellent stability at 1100 °C in air. Benefiting from the anisotropic structure, ZrO2 porous ceramic exhibits high load-bearing capacity in the longitudinal direction, and thermal insulation with a significant temperature difference of approximately 50 °C between transverse and longitudinal heat transfer. It also keeps stable in extreme conditions including low temperature and acid solution. These unique properties make it an ideal insulation material in extreme environments where the protection of structures with complex shapes and variable dimensions is critical.

3D hierarchical graphene-based composite for ultra-high heat-conducting film

In order to pursue lightness and portability, modern electronic devices usually use a compact layout to place various components, but this highly integrated design increases the heat density of the device and causes heat accumulation. Excessive heat accumulation will reduce the reliability of the device and even cause thermal failure. The advantages of light weight, easy processing and low cost of polymer-based thermally conductive composites have become main concerns of modern thermal management materials, but the low thermal conductivity (TC) has seriously limited their application. Here, 3D hierarchical anisotropic oriented graphene-based composites with high TC are fabricated by layer-by-layer self-assembling of one-dimensional carboxylated cellulose nanofibers (CNF–C) and poly dopamine modified nickel particle-coated two-dimensional graphene nanosheets (PDA-Ni@GNS). Owing to the well-defined flaky packing layers and the hydrogen bonding, the composite exhibits not only sufficiently high in-plane TC of 28.8 W m−1 K−1 and tensile strength of 124 MPa, but also exhibits hydrophobic property. A generalized four-parameter model (FPM) is found to reasonably predict the entire CPU temperature evolution versus time. This work presents a facile strategy for constructing 3D hierarchical interfacial structure to obtain excellent versatility of anisotropic thermal management composites.

Aluminum-Crosslinked Nanocellulose Scaffolds for Fluoride Removal.

Anionic carboxylated cellulose nanofibers (CNF) are effective media to remove cationic contaminants from water. In this study, sustainable cationic CNF-based adsorbents capable of removing anionic contaminants were demonstrated using a simple approach. Specifically, the zero-waste nitro-oxidization process was used to produce carboxylated CNF (NOCNF), which was subsequently converted into a cationic scaffold by crosslinking with aluminum ions. The system, termed Al-CNF, is found to be effective for the removal of fluoride ions from water. Using the Langmuir isotherm model, the fluoride adsorption study indicates that Al-CNF has a maximum adsorption capacity of 43.3 mg/g, which is significantly higher than that of alumina-based adsorbents such as activated alumina (16.3 mg/g). The selectivity of fluoride adsorption in the presence of other anionic species (nitrate or sulfate) by Al-CNF at different pH values was also evaluated. The results indicate that Al-CNF can maintain a relatively high selectivity towards the adsorption of fluoride. Finally, the sequential applicability of using spent Al-CNF after the fluoride adsorption to further remove cationic contaminant such as Basic Red 2 dye was demonstrated. The low cost and relatively high adsorption capacity of Al-CNF make it suitable for practical applications in fluoride removal from water.