Cross-linked Cellulose Research Articles

A novel bio-aerogel based on agroforestry waste chestnut shell for enhanced oil-water separation performance

Bio-based aerogels have attracted much attention due to their biodegradability and excellent oil-water separation properties. However, the preparation of inexpensive green aerogels with high separation efficiency is still a great challenge. In this paper, low-density, high-adsorption capacity and superhydrophobic chestnut shell-based bio-aerogels were prepared by chemical cross-linking and chemical vapor deposition using agricultural and forestry waste chestnut shells as the precursor of aerogels to achieve high efficiency of oil-water separation and to achieve the goal of “treating waste with waste”. The covalent cross-linking of chestnut shell cellulose and cross-linking agent to form silicone-containing functional groups improved the pore structure, hydrophobicity and mechanical properties of chestnut shell cellulose, and under the action of capillary force, the oil was retained in the pores of the bio-aerogels, which achieved the selective adsorption of oil and organic solvents in the oil-water mixture, with a separation efficiency of more than 98%. After 10 cycles, the bio-aerogel still has good reusability. This eco-friendly and low-cost aerogel provides a practical method for resource conversion and recycling, as well as a green and innovative way for the treatment of oily wastewater.

DNP enhanced solid-state NMR – A powerful tool to address the surface functionalization of cellulose/paper derived materials

This concept summarizes recent advances in development and application of DNP enhanced multinuclear solid-state NMR to study the molecular structure and surface functionalization of cellulose and paper-based materials. Moreover, a novel application is presented where DNP enhanced 13C and 15N solid-state NMR is used to identify structure moieties formed by cross-linking of hydroxypropyl cellulose. Given these two aspects of this concept-type of article, we thus combine both, a review on recent findings already published and unpublished recent data that complement the existing knowledge in the field of characterization of functional lignocellulosic materials by DNP enhanced solid-state NMR.

A mechanistic study on the alleged cellulose cross-linking system: Maleic acid/sodium hypophosphite

A combination of maleic acid and sodium hypophosphite as a durable press finishing agent has been reported as a safer but equally effective alternative to conventional formaldehyde-based cross-linking agents for applications in cellulose-based fiber and textile finishing. However, the mechanistic details of this system have not yet been fully elucidated to allow optimization of the conditions. Effective cross-linking treatment requires high curing temperatures of ≥160 °C, which enhances oxidative and thermal degradation of cellulose. In this work, the sequential steps of the cross-linking mechanism were investigated both with model compounds and cellulosic substrates. Extensive NMR studies on model compounds revealed several side reactions alongside the synthesis of the targeted cross-linkable moiety. As an alternative, to circumvent side reactions, a two-step procedure was used by synthesizing the cross-linker sodium 2-[(1,2-dicarboxyethyl)phosphinate]succinic acid in a well-defined pre-condensation reaction before application onto the cellulosic substrate. Further, the effect of the cross-linking treatment on the molecular weight distribution of cellulose was studied by gel permeation chromatography, which showed degradation due to maleic acid/sodium hypophosphite treatment. By using sodium 2-[(1,2-dicarboxyethyl)phosphinate]succinic acid and sodium hypophosphite, this degradation could be significantly limited.

Foaming and cross-linking of cellulose fibers using phytic acid

Bio-based compounds have become the focus in the development of next-generation materials. The polyphosphated structure and availability of phytic acid has sparked an interest to understand its properties and apply it to making fire-retardant fabrics. However, its degradative effect on natural fibers sets limitations to its potential uses. In this study, we unveiled a new dimension to explore with phytic acid: cellulose fiber foams. Phytic acid enabled synergistic foaming with carboxymethyl cellulose albeit causing issues in long-term wet foam stability. Adding cellulose fibers to this mixture and drying at 160 °C produced solid foams with increased compressive strength and stiffness; comparable to foams cross-linked with the commonly used citric acid. The reduced contact area in low-density fiber networks allowed the cross-linking between phytic acid and the fiber network to mitigate structural weakening due to fiber degradation. Imaging also revealed the formation of a film encompassing fiber bonds; attributed to the strong interaction between phytic acid and carboxymethyl cellulose. Furthermore, phytic acid imparted self-extinguishing fire-retardant properties to the cellulose fiber foams measured using thermogravimetric analysis and cone calorimetry. This work showcases a simple new application for phytic acid without the use of catalysts or solvents. It serves to encourage further development of green practices to continuously challenge the industrial landscape.

Intelligent and biocompatible cellulose aerogels featured with high-elastic and fast-hemostatic for epistaxis and wound healing

Nasal tamponade is a commonly employed and highly effective treatment method for preventing nasal bleeding. However, the current nasal packing hemostatic materials exhibit some limitations, such as low hemostatic efficiency, the potential for causing secondary injury when removed from the nasal cavity, limited intelligence in their design, and an inability to promote the healing of nasal mucosa wounds. Herein, we report the fabrication of a smart cellulose aerogel through the covalent cross-linking of carboxymethyl cellulose (CMC) macromolecules, while incorporating one-dimensional cellulose nanofibers (CNF) and two-dimensional MXene as reinforcing network scaffolds and conductive fillers. The abundant hydrogen and ether bonds in aerogels make them possess high elasticity in both dry and wet states, which can be compressed 100 times at 90 % deformation with a stress loss of <10 % under water. The highly elastic aerogels can be filled into the narrow nasal passages, pressuring the capillaries and reducing the amount of bleeding. Moreover, the strong interface between aerogels and blood can promote red blood cell aggregation, platelet adhesion and activation, activate intrinsic coagulation pathway and accelerate blood coagulation, resulting in excellent hemostatic ability. Furthermore, the aerogels exhibit excellent hemocompatibility and cytocompatibility, making them suitable for wound healing and capable of fully healing wounds within 15 days. Notably, the presence of MXene causes the aerogels to form a conductive network when exposed to blood, enabling them to perform real-time hemostatic monitoring without removing the dressing. This innovative biomedical aerogel, prepared from natural materials, shows excellent potential for applications in rapid nasal hemostasis.

INFLUENCES OF CROSSLINKER AND MOLECULAR WEIGHT OF CHITOSAN ON PHYSICO-CHEMICAL PROPERTIES OF ANTIBACTERIAL TREATED COTTON FABRICS

This study investigated the influences of crosslinking agent and molecular weight on the surface and comfort properties of cotton fabrics treated by chitosan. Two types of chitosan, with molecular weight (2.6 kDa and 187 kDa), with deacetylation degree (DD) of 75%, were used, along with two types of crosslinking agents: citric acid (CA) and dimethylol dihydroxyethyleneurea (DMDHEU). These agents were applied to cotton fabrics for antibacterial treatments. The treated cotton fabrics were evaluated using several quality indicators related to physico-chemical properties, including whiteness (according to ISO 105 J02), breathability (according to ASTM D737:2004), moisture (according to ASTM D 2495-87), and thermal and moisture resistance under steady-state conditions (according to ISO 11092). Moreover, surface features of treated samples were observed through SEM images. The results showed that the antibacterial treatment of fabrics with lower molecular weight (Mw) chitosan was more favorable for the finishing processes, although the whiteness of the treated samples was quite low. Additionally, cotton fabrics treated with the CA agent exhibited better hygroscopicity and vapor transmission, but tended to have more pronounced yellow color, compared to those treated with the DMDHEU agent. These physico-chemical findings clarified the bonding mechanism of cellulose–crosslinker–chitosan in antibacterial treated cotton fabrics.

Cross-Linked Cellulose Nanocrystal Membranes with Cholesteric Assembly.

Forming membranes by tangential flow deposition of cellulose nanocrystal (CNC) suspensions is an attractive new approach to bottom-up membrane fabrication, providing control of separation performance using shear rate and ionic strength. Previously, the stabilization of these membranes was achieved by irreversibly coagulating the deposited layer upon the permeation of a high-ionic-strength salt solution. Here, we demonstrate for the first time the chemical cross-linking of carboxyl-containing TEMPO-oxidized CNCs by Ag(I)-catalyzed oxidative decarboxylation and the stabilization of CNC membranes using this post-treatment. Cross-linking of TEMPO-CNCs was first demonstrated in suspension via turbidity, dynamic light scattering, and storage (G') and loss (G″) moduli measurements. Membranes were formed by filtering a 0.15 wt % TEMPO-CNC suspension onto a porous support, followed by permeation of the cross-linking solution containing AgNO3 and KPS through the deposited layer. Rejection for Blue Dextran with a 5 kDa molecular weight was 95.3 ± 1.9%, 90.6 ± 3.7%, and 95.9 ± 1.0% for membranes made from suspensions of TEMPO-CNC, desulfated TEMPO-CNC. and TEMPO-CNC with 100 mM NaCl, respectively. Suspensions with added NaCl led to membranes with improved stability and cholesteric self-assembly in the membrane layer. Membranes subjected to cross-linking post-treatment remained intact upon drying, while those stabilized physically using 200 mM AlCl3 solution were cracked, demonstrating the advantage of the cross-linking approach for scale-up, which requires drying of the membranes for module preparation and storage.

Cellulose hydrogels with high response sensitivity and mechanical adaptability for flexible strain sensor and triboelectric nanogenerator

Cellulose hydrogels are widely regarded as green and environmentally friendly flexible electronic materials. Herein, a novel multiple cross-linked cellulose hydrogel (MCC/SA20/MCC-g-P(AA-co-AM-AMPS)) with high sensitivity (gauge factor = 440, 670 %, 60 ms) and good mechanical adaptability was designed and prepared. The prepolymer (MCC-g-P(AA-co-AM-AMPS)) was introduced into the microcrystalline cellulose/sodium alginate (MCC/SA) hydrogel network to form a multiple cross-linked network structure, which effectively enhanced the tension and elasticity of the cross-linked network, and improved the mechanical adaptability and sensitivity of the hydrogel. Additionally, it was assembled as a strain sensor that can accurately identify and monitor various motion states of the human body. It was also assembled as a friction nanogenerator (TENG) that continuously generates a stable open circuit voltage (7.2 V) for self-powering small electronic devices. This study provides an effective and feasible strategy for cellulose hydrogels in flexible sensors for sports health monitoring, sustainable green energy harvesting, and self-powering applications for small electronic devices.

Creating value added nano silicon anodes from end-of-life photovoltaic modules: recovery, nano structuring, and the impact of ball milling and binder on its electrochemical performance

Recovery of silicon from end-of-life photovoltaic (PV) modules, purification, conversion to nano silicon (nano-Si), and subsequent application as an anode in lithium-ion batteries is challenging but can significantly influence the circular economy. Currently, a complete technology consisting of cross-contamination-free recovery of silicon wafers from end-of-life PV modules, a low-cost environmentally friendly purification process of the recovered PV silicon, a high yield conversion process of the recovered PV silicon into nano-Si, and its subsequent application in lithium-ion batteries is unavailable. This study provides a complete package including cross-contamination-free recovery, economical purification, reliable conversion to nano-Si, and efficient application of the end-of-life PV nano-Si in lithium-ion batteries. Hydrofluoric acid-free recovery and purification processes are demonstrated which can deliver large quantities of high-purity (≥ 99) silicon. In addition, the subsequent ball milling process produces very distinct nano-Si with different shapes and sizes. This study also creates a very effective nano-Si anode through in-situ crosslinking of water-soluble carboxymethyl cellulose and poly (acrylic acid) precursors. The integration of distinct PV nano-Si and water-soluble carboxymethyl cellulose-poly (acrylic acid) crosslink binder opens distinct possibilities to develop silicon-based practical anode for next generation low-cost lithium-ion batteries to power cell phones to electric vehicles.

Modeling and simulation of anisotropic cross-linked cellulose fiber networks with an out-of-plane topography

Non-woven cellulose fiber networks of low areal density are widely used in many industrial applications and consumer products. A discrete element method (DEM) modeling framework is advanced to simulate the formation of strongly anisotropic cellulose fiber network sheets in the dilute limit with simplified hydrodynamic and hydroelastic interactions. Our modeling accounts for in-plane fiber orientation and viscous drag indirectly by using theories developed by Niskanen (2018 Fundamentals of Papermaking, Trans. 9th Pulp and Paper Fundamental Research Symp. Cambridge, 1989 (FRC) pp 275–308) and Cox (1970 J. Fluid Mech. 44 791–810) respectively. Networks formed on a patterned and flat substrate are simulated for different fiber types, and their tensile response is used to assess the influence of the out-of-plane topographical pattern, specifically, on their stiffness and strength. Sheets with the same grammage and thickness, but composed with a higher fraction of softwood fiber (longer fibers with large diameter), have higher strength and higher strain to failure compared to sheets made from hardwood fibers (short fibers with small diameter). However, varying the fiber fraction produces only an insignificant variation in the initial sheet stiffness. The above simulation predictions are confirmed experimentally for sheets comprised of fibers with different ratios of Eucalyptus kraft and Northern Bleached Softwood Kraft fibers. Sheets with out-of-plane topography show an unsymmetric mass distribution, lower tensile stiffness, and lower tensile strength compared to those formed on a flat substrate. The additional fiber deformation modes activated by the out-of-plane topography, such as bending and twisting, explain these differences in the sheet mechanical characteristics.

A tough, reversible and highly sensitive humidity actuator based on cellulose nanofiber films by intercalation modulated plasticization

Cellulose nanofiber was an ideal candidate for humidity actuators based on its wide availability, biocompatibility and excellent hydrophilicity. However, conventional cellulose nanofiber-based actuators faced challenges like poor water resistance, flexibility, and sensitivity. Herein, water-resistant, flexible, and highly sensitive cross-linked cellulose nanofibers (CCNF) single-layer humidity actuators with remarkable reversible humidity responsiveness were prepared by combining the green click chemistry modification and intercalation modulated plasticization (IMP). The incorporation of phenyl ring and the crosslinked network structure in CCNF films contributed to its improved water resistance and mechanical properties (with a stress increased from 85.9 ± 3.1 MPa to 141.2 ± 21.5 MPa). SEM analysis confirmed enhanced interlaminar sliding properties facilitated by IMP. This resulted in increased flexibility and toughness of CCNF films, with a strain of 11.5 % and toughness of 9.9 MJ/m3. These improvements efficiently enhanced humidity sensitivity for cellulose nanofiber, with a 4.8-fold increase in bending curvature and a response time of only 3.4 ± 0.1 s. Finally, the good humidity sensitivity of modified CNF can be easily imparted to carbon nanotubes (CNTs) via simple self-assembly method, thus leading to a high-performance humidity-responsive actuator. The click chemistry modification and IMP offer a new avenue to fabricate tough, reversible and highly sensitive humidity actuator based on cellulose nanofiber.

Preparation of strong, UV-blocking and sustainable glucose-cross-linked cellulose plastics via hydroxyl-yne click reaction

The construction of functional cellulose plastics possessing strong UV-blocking, hydrophilicity, and biodegradability is challenging. Therefore, we provide a novel strategy to successfully prepare sustainable and hydrophilic glucose-cross-linked cellulose (GC) plastics showing effective UV-blocking and excellent mechanical properties via hydroxyl-yne click reaction at room temperature. The results demonstrated that hydroxyl-yne click chemistry enabled efficient crosslinking of cellulose with glucose using 4-dimethylamino pyridine (DMAP) as a catalyst. Moreover, the DMAP residue imparted good UV-shielding properties to GC films exhibiting nearly 100 % UVC (200–275 nm) and 100 % UVB (320–275 nm) shielding ratios. The introduction of glucose imparted superior hydrophilicity (water contact angle of 40.3–43.2°) and improved water adsorption. Additionally, the mechanical properties of the GC films increased with the increasing crosslinking density, and the highest tensile stress was 94 MPa. The water-induced breaking and hydrogen bond reforming strategy led to a stress of 127 MPa and a strain of 25.6 % for the final GC2 film, which were excellent compared to those of the most reported cellulose films. Additionally, GC films were biosafe, exhibited improved oxygen barrier, and good biodegradability. Hence, this study provides a promising and efficient approach for preparing high-performance cellulose plastics.

Controlling N-Doping Nature at Carbon Aerogels from Biomass for Enhanced Oxygen Reduction in Seawater Batteries.

Pyridinic N-type doped at carbon has been known to have better electrocatalytic activity toward the oxygen reduction reaction (ORR) than the others. Herein, we proposed to prepare pyridinic N doped at carbon aerogels (CaA) derived from biomass, i.e., coir fiber (CF) and palm empty fruit bunches (PEFBs), by adjusting the pyrolysis temperature during carbonization of the biomass-based-cellulose aerogels. The cellulose aerogels were prepared by the ammonia-urea system as the cellulose solvent, in which ammonia also acted as a N source for doping and urea as the cellulose cross-linker. The as-prepared cellulose aerogels were directly pyrolyzed to produce N-doped CaA. It was found that the type of N doping is dominated by pyrrolic N at pyrolysis temperature of 600 °C, pyridinic N at 700 °C, and graphitic N at 800 °C. The pyridinic N exhibited better performance as an electrocatalyst for the ORR than pyrrolic N and graphitic N. The ORR using pyridinic N follows the four-electron pathway, which quantitatively implies a more electrochemically stable process. When used as a cathode for the Mg-air battery using a 3.5% NaCl electrolyte, the pyridinic N CaA exhibited excellent performance by giving a cell voltage of approximately 1.1 V and delivered a high discharge capacity of 411.64 mA h g-1 for CF and 492.64 mA h g-1 for PEFB corresponding to an energy density of 464.23 and 529.49 mW h g-1, respectively.

Novel ROS-scavenging hydrogel produced in situ crosslinking between cyclodextrin and cellulose for promoting diabetic wound healing

Diabetic wounds are usually difficult to heal due to the high content of blood sugar, excessive ROS, impaired immune response, and delayed angiogenesis. In this study, we developed the multiple bonds crosslinked hydrogel with the properties of drug release regulatory, antibacterial, angiogenic, and scavenging ROS for promote diabetic wound healing effectively. The hydrogel was fabricated by one-pot crosslinking of bamboo parenchymal cellulose and modified β-cyclodextrin via multiple connections formed including hydrogen- and ester-bond. Results indicated that the composited hydrogel has a significantly large pore structure, which can absorb wound exudate effectively as dressing. Owing to the special network, the release of internal drugs from hydrogels was regulated by different response to the pH of physiological environment. Additionally, the cavity structure of cyclodextrin enables the drug to be released continuously for 96 h. According to the synergistic combination of the structures of pores and cavities, the composited hydrogel exhibited excellent capacities of drug loading and releasing. In vitro bacteriostasis experiments also affirmed that wound dressing (BPCAH-C) had a remarkable bacteriostasis effect against E. coli and S. aureus (bacteriostasis area up to 230 %). The prepared wound dressing can achieve a healing rate of 90 % within 14 days, meanwhile, the free radical clearance rate was reached 75 %. This kind of hydrogel dressing can accommodate and improve the change of microenvironment, has a broad application prospect in the clinical healing of diabetic wound.

Electrochemical performance enhanced by solvent infiltration strategy to increase micro-mesopores within wood tracheid walls

The utilization of wood-derived carbon thick electrodes has demonstrated remarkable structural advantages in the realm of electrochemical energy storage and catalysis. Its exceptional structural stability, mechanical strength, and well-organized pore structure position it as a promising material for self-supporting electrodes. The multi-scale cross-linking of lignin, cellulose, and hemicellulose within the wood tracheid wall establishes a convenient prerequisite for structural modification. However, the significance of dynamic nanopores on wood tracheid walls in enhancing the microporous/mesoporous structure of wood-derived carbon electrodes has been overlooked due to the focus on operability of microscale array pores and wood decomposition processes. Here, we employ a straightforward, highly efficient, and environmentally sustainable solvent infiltration strategy to enhance the nanopore content within the wood tracheid wall, ultimately resulting in a significant enhancement of the microporous/mesoporous composition within the wood-derived electrode. The charge storage capacity of wood-derived carbon electrode is doubled through the implementation of a solvent permeation modification strategy, while its abundant micro/mesoporous structure also endows it with significant potential in the field of electrocatalysis. Therefore, this thermal and solvent permeation modification strategy is anticipated to supplant the conventional acid-base etching method and offer a novel research concept for the advancement of wood-based carbon electrodes with abundant pore structure and exceptional electrochemical properties.

A Sustainable Dual Cross-Linked Cellulose Hydrogel Electrolyte for High-Performance Zinc-Metal Batteries

HighlightsA sustainable dual cross-linked cellulose hydrogel with excellent mechanical strength was fabricated from aqueous alkali hydroxide/urea solution using a sequential chemical and physical cross-linking strategy.The hydrogel electrolyte effectively suppresses dendrites growth and side reactions to achieve a stable Zn anode (over 2000 h for Zn||Zn cell), which are proved by a multi-perspective and in-depth mechanism investigation.The hydrogel electrolyte is easily accessible and biodegradable, making the zinc batteries attractive in terms of scalability and sustainability.

Self-Healing Composite Coating Fabricated with a Cystamine Cross-Linked Cellulose Nanocrystal-Stabilized Pickering Emulsion.

A gelled Pickering emulsion system was fabricated by first stabilizing linseed oil droplets in water with dialdehyde cellulose nanocrystals (DACNCs) and then cross-linking with cystamine. Cross-linking of the DACNCs was shown to occur by a reaction between the amine groups on cystamine and the aldehyde groups on the CNCs, causing gelation of the nanocellulose suspension. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to characterize the cystamine-cross-linked CNCs (cysCNCs), demonstrating their presence. Transmission electron microscopy images evidenced that cross-linking between cysCNCs took place. This cross-linking was utilized in a linseed oil-in-water Pickering emulsion system, creating a novel gelled Pickering emulsion system. The rheological properties of both DACNC suspensions and nanocellulose-stabilized Pickering emulsions were monitored during the cross-linking reaction. Dynamic light scattering and confocal laser scanning microscopy (CLSM) of the Pickering emulsion before gelling imaged CNC-stabilized oil droplets along with isolated CNC rods and CNC clusters, which had not been adsorbed to the oil droplet surfaces. Atomic force microscopy imaging of the air-dried gelled Pickering emulsion also demonstrated the presence of free CNCs alongside the oil droplets and the cross-linked CNC network directly at the oil-water interface on the oil droplet surfaces. Finally, these gelled Pickering emulsions were mixed with poly(vinyl alcohol) solutions and fabricated into self-healing composite coating systems. These self-healing composite coatings were then scratched and viewed under both an optical microscope and a scanning electron microscope before and after self-healing. The linseed oil was demonstrated to leak into the scratches, healing the gap automatically and giving a practical approach for a variety of potential applications.

Hierarchically core-shell structured nanocellulose/carbon nanotube hybrid aerogels for patternable, self-healing and flexible supercapacitors

The flexible and self-healing supercapacitors (SCs) are considered to be promising smart energy storage devices. Nevertheless, the SCs integrated with flexibility, lightweight, pattern editability, self-healing capabilities and desirable electrochemical properties remain a challenge. Herein, an all-in-one self-healing SC fabricated with the free-standing hybrid film (TCMP) composed of the 2,2,6,6-tetramethylpiperidin-1-yloxy-oxidized cellulose nanofibers (TOCNs) carried carbon nanotubes (CNTs), manganese dioxide (MnO2) and polyaniline (PANI) as the electrode, polyvinyl alcohol/sulfuric acid (PVA/H2SO4) gel as the electrolyte and dynamically cross-linked cellulose nanofibers/PVA/sodium tetraborate decahydrate (CNF/PB) hydrogel as the self-healing electrode matrix is developed. The TCMP film electrodes are fabricated through a facile in-situ polymerization of MnO2 and PANI in TOCNs-dispersed CNTs composite networks, exhibiting lightweight, high electrical conductivity, flexibility, pattern editability and excellent electrochemical properties. Benefited from the hierarchically porous structure and high mechanical properties of TOCNs, excellent electrical conductivity of CNTs and the desirable synergistic effect of pseudocapacitance induced by MnO2 and PANI, the assembled SC with an interdigital structure demonstrated a high areal capacitance of 1108 mF cm−2 at 2 mA cm−2, large areal energy density of 153.7 μWh cm−2 at 1101.7 μW cm−2. A satisfactory bending cycle performance (capacitance retention up to 95 % after 200 bending deformations) and self-healing characteristics (∼90 % capacitance retention after 10 cut/repair cycles) are demonstrated for the TCMP-based symmetric SC, delivering a feasible strategy for electrochemical energy storage devices with excellent performance, designable patterns and desirable safe lifespan.

Towards sustainable building solutions: Development of hemp shiv-based green insulation material

There is currently a growing need for sustainable and environmentally friendly materials. One promising candidate is hemp shiv, which is considered waste material. hemp shiv exhibits lightweight properties and high insulation capabilities. This study focuses on the development of a material based in hemp shiv, recycled cardboard fibers is used as binder material, with the addition of a vegetable coating (colophony and arabic gum) for moisture protection and citric acid to enhance cellulose crosslinking. Thermal insulation properties were assessed measuring the heat transfer through the material. Acoustic insulation properties were evaluated using a Kundt tube within a frequency range of 100–6500 Hz. Mechanical tests, including compression, shear, and bending, were performed to assess the material’s strength. Additionally, moisture and fire resistance properties, as well as microstructure analysis, were examined. The influence of citric acid in the cellulose crosslinking was verified using FTIR-ATR spectroscopy. Results demonstrated that a higher percentage of hemp shiv content led to improved insulation performance, achieving attenuation values greater than 0.85–0.95 dB/dB and a thermal conductivity of 0.02–0.03 W/m K. These findings indicate a great performance compared to commercial materials. The coating shields the material from external factors. It was observed that the citric acid does not react with hemp shiv.

Efficient defluoridation of water by employing hybrid nanosized cerium oxides embedded within cross-linked cellulose foam

Efficient defluoridation utilizing current hybrid nano-oxides remains a great challenge because of low loading capacity and hindered nucleation during immobilization. In this study, a new adsorbent for defluoridation was developed by encapsulating nanosized cerium oxides within a cross-linked network of cellulose foam using an embedding method. The controllable structure, uniform dispersion, and high content of NCO endowed the composite with high efficiency for fluoride removal. The batch adsorption experiments exhibited a broad pH range (2.0–6.0) for optimal fluoride adsorption and confirmed that NCO@CF had a maximum adsorption capacity of 109.88 mg·g−1 at pH 4.0, which was much higher than that of other materials. Exceptional adsorption selectivity was also observed, indicating strong attraction between NCO@CF and fluoride ions, even at high concentrations of competing ions. X-ray photoelectron spectrogram and the Fourier transform infrared spectra analyses suggested that the defluoridation mechanism involved ligand exchange and inner-sphere complexation between NCO@CF and fluoride. Batch adsorption–regeneration cycles demonstrated that NCO@CF could be effectively and consistently regenerated using an alkaline solution. In fixed-bed adsorption experiments, remarkable working capacities of 1782 and 480 bed volume were observed for NCO@CF at pH 4.0 and 6.0, respectively. The findings of this study provide insights into the practical application of hybrid NCO in efficient defluoridation from water.