Hydrophobization of surfaces on cellulose nanofibers by enzymatic grafting of partially 2-deoxygenated amylose.

Recently, attention has been paid to cellulose nanofibers, such as 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized cellulose nanofibers (TOCN), as new bio-based materials. In addition, hydrophobized surface on TOCNs can be expected to provide new applications. Based on our previous finding that partially 2-deoxygenated (P2D)-amylose, which was synthesized by GP-catalyzed enzymatic copolymerization of D-glucal with α-d-glucose 1-phosphate (Glc-1-P) as comonomers, was hydrophobic, in this study, hydrophobization of surfaces on TOCNs was investigated by the GP-catalyzed enzymatic grafting of P2D-amylose chains on TOCNs. After maltooligosaccharide primers were modified on TOCNs, the GP-catalyzed enzymatic copolymerization of D-glucal with Glc-1-P was performed for grafting of P2D-amylose chains. 1H NMR spectroscopic analysis confirmed the production of P2D-amylose-grafted TOCNs with different 2-deoxyglucose/Glc unit ratios. The powder X-ray diffraction profiles of the products indicated that the entire crystalline structures were strongly affected by the unit ratios and chain lengths of the grafted polysaccharides. The SEM images observed differences in nanofiber diameter in the reaction solutions and surface morphology after film formation, due to grafting of P2D-amylose chains from TOCNs. The water contact angle measurement of a cast film prepared from the product indicated its hydrophobicity.

Catalytic activity of Cu2O nanoparticles supported on cellulose beads prepared by emulsion-gelation using cellulose/LiBr solution and vegetable oil.

Nanocatalysts tend to aggregate and are difficult to recycle, limiting their practical applications. In this study, an environmentally friendly method was developed to produce cellulose beads for use as supporting materials for Cu-based nanocatalysts. Cellulose beads were synthesized from a water-in-oil emulsion using cellulose dissolved in an LiBr solution as the water phase and vegetable oil as the oil phase. Upon cooling, the gelation of the cellulose solution produced spherical cellulose beads, which were then oxidized to introduce surface carboxyl groups. These beads (diameter: 95-105 µm; specific surface area: 165-225 m2 g-1) have a three-dimensional network of nanofibers (width: 20-30 nm). Furthermore, the Cu2O nanoparticles were loaded onto oxidized cellulose beads before testing their catalytic activity in the reduction of 4-nitrophenol using NaBH4. The apparent reaction rate constant increased with increasing loading of Cu2O nanoparticles and the conversion efficiency was >90 %. The turnover frequency was 376.2 h-1 for the oxidized cellulose beads with the lowest Cu2O loading, indicating a higher catalytic activity compared to those of other Cu-based nanoparticle-loaded materials. In addition to their high catalytic activity, the cellulose beads are reusable and exhibit excellent stability.

Influence of chitosan and hydroxyethyl cellulose modifications towards the design of cross-linked double networks hydrogel for diabetic wound healing.

The wound dressings' lack of antioxidant and antibacterial properties, and delayed wound healing limit their use in wound treatment and management. Recent advances in dressing materials are aimed at improving the limitations discussed above. Therefore, the aim of this study includes the preparation and characterization of oxidized hydroxyethyl cellulose (OHEC) and ferulic acid-grafted chitosan (CS-FA) hydrogel loaded with green synthesized selenium nanoparticles (Se NPs) (OHEC-CS-FA-Se NPs named as nanohydrogel) for diabetic wound healing. The structure and properties of the hydrogel was characterized by FTIR, FE-SEM, HR-TEM, EDAX, UV-Vis spectrophotometry, XRD, DLS, zeta potential and rheological studies. The findings of these experiments demonstrate that nanohydrogel possesses a variety of outstanding qualities, including an optimal gel time, good swelling characteristics, a fair water retention rate, a good degradation rate, and strong mechanical stability. Nanohydrogel has been shown to have a synergistic impact by significantly increasing antioxidant activity by scavenging ABTS and DPPH radicals. The nanohydrogel's strong biocompatibility was confirmed by cytocompatibility testing using L929 mouse fibroblast cells. In addition, the wound healing potential of nanohydrogel was tested on L929 cells by an in vitro scratch assay and the nanohydrogel showed a wound closure rate of 100 % after 12 h. In addition to this study, nanohydrogel has demonstrated significant antimicrobial properties against human and wound infection causing pathogens such as Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Pseudomonas aeruginosa. In the animal model, almost complete diabetic wound healing was achieved on day 14 after application of the nanohydrogel. The results obtained indicate that the multifunctional bioactive nature of OHEC-CS-FA-Se NPs showed exceptional antioxidant and antibacterial potential for the treatment of infected and chronic wounds.

Preparation and assessment of agar/TEMPO-oxidized bacterial cellulose cryogels for hemostatic applications.

In this work, we have demonstrated agar and oxidized bacterial cellulose cryogels as a potential hemostatic dressing material. TEMPO-oxidized bacterial cellulose (OBC) was incorporated into the agar matrix, improving its mechanical and hemostatic properties. The oxidation of bacterial cellulose (BC) was evidenced by chemical characterization studies, confirming the presence of carboxyl groups. The in vitro blood clotting test conducted on agar/OBC composite cryogels demonstrated complete blood clotting within 90 seconds, indicating their excellent hemostatic efficacy. The cryogels exhibited superabsorbent properties with a swelling degree of 4200%, enabling them to absorb large amounts of blood. Moreover, the compressive strength of the composite cryogels was appreciably improved compared to pure agar, resulting in a more stable physical structure. The platelet adhesion test proved the significant ability of the composite cryogels to adhere to and aggregate platelets. Hemocompatibility and cytocompatibility tests have verified the safety of these cryogels for hemostatic applications. Finally, the material exhibited remarkable in vivo hemostatic performance, achieving clotting times of 64 seconds and 35 seconds when tested in the rat tail amputation model and the liver puncture model, respectively. The experiment results were compared with those of commercial hemostat, Axiostat, and Surgispon, affirming the potential of agar/OBC composite cryogel as a hemostatic dressing material.

Nanocellulose-mediated conductive hydrogels with NIR photoresponse and fatigue resistance for multifunctional wearable sensors.

The rapid development of hydrogels has garnered significant attention in health monitoring and human motion sensing. However, the synthesis of multifunctional conductive hydrogels with excellent strain/pressure sensing and photoresponsiveness remains a challenge. Herein, the conductive hydrogels (BPTP) with excellent mechanical properties, fatigue resistance and photoresponsive behavior composed of polyacrylamide (PAM) matrix, 2,2,6,6-tetramethylpiperidin-1-yloxy-oxidized cellulose nanofibers (TOCNs) reinforcement and polydopamine-modified black phosphorus (BP@PDA) photosensitizer are prepared through a facile free-radical polymerization approach. The PDA adhered to the BP surface by π-π stacking promotes the optical properties of BP while also preventing BP oxidation from water. Through hydrogen bonding interactions, TOCNs improve the homogeneous dispersion of BP@PDA nanosheets and the mechanical toughness of BPTP. Benefiting from the synergistic effect of PDA and TOCNs, the conductive BPTP integrates superior mechanical performances, excellent photoelectric response and photothermal conversion capability. The BPTP-based sensor with high cycling stability demonstrates superior strain sensitivity (GF = 6.0) and pressure sensing capability (S = 0.13 kPa-1) to monitor various human activities. Therefore, this work delivers an alternative construction strategy for generating high-performance conductive hydrogels as multifunctional wearable sensors.

Oxidized cellulose-filled double thermo/pH-sensitive hydrogel for local chemo-photothermal therapy in breast cancer.

Lumpectomy plus radiation is a treatment option offering better survival than conventional mastectomy for patients with early-stage breast cancer. However, successive radioactive therapy remains tedious and unsafe with severe adverse reactions and secondary injury. Herein, a composite hydrogel with pH- and photothermal double-sensitive activity is developed via physical crosslinking. The composite hydrogel incorporated with tempo-oxidized cellulose nanofiber (TOCN), polyvinyl alcohol (PVA) and a polydopamine (PDA) coating for photothermal therapy (PTT) triggered in situ release of doxorubicin (DOX) drug was utilized to optimize postoperative strategies of malignant tumors inhibition. The incorporation of TOCN significantly affects the performance of composite hydrogels. The best-performing TOCN/PVA7 was selected for drug loading and polydopamine coating by rational design. In vitro studies have demonstrated that the composite hydrogel exhibited high NIR photothermal conversion efficiency, benign cytotoxicity to L929 cells, pH-dependent release profiles, and strong MCF-7 cell inhibitory effects. Then the TOCN/PVA7-PDA@DOX hydrogel is implanted into the tumor resection cavity for local in vivo chemo-photothermal synergistical therapy to ablate residue tumor tissues. Overall, this work suggests that such a chemo-photothermal hydrogel delivery system has great potential as a promising tool for the postsurgical management of breast cancer.

Silver-infused lysine crosslinked hydrogel with oxidized regenerated cellulose for prospective advanced wound dressings.

The study aimed to develop a multifunctional wound dressing with enhanced antibacterial properties and wound healing promotion. The synthesis process involved preparing oxidized regenerated cellulose (ORC) following a modified procedure, synthesizing chitosan/silver nanoparticles (CS/Ag NPs) via an in-situ reduction method, and subsequently preparing ORC/CS/Lys@Ag NPs hydrogels. Characterization techniques including FTIR, XRD, SEM, and EDS were employed to analyze functional groups, lattice structure, morphology, and elemental composition. Gelation time, swelling behavior, water retention, mechanical properties, viscosity, self-healing capacity, rheological behavior, oxygen permeability, in vitro degradation, release of Ag+, and antibacterial properties were evaluated using various experimental methods. Results indicated that the novel wound dressing has the capability to evenly distribute Ag NPs to effectively counteract bacteria. It can maintain moist conditions for 86 h, resist a sturdy mechanical pressure of 11.3 KPa, and degrade by 11.045 % ± 0.429 within 8 h. Combining its efficient gas exchange abilities, self-repairing function, and biocompatibility, almost full recovery was observed in injured mouse skin within 13 days, highlighting its promising clinical utility.

Preparation of tannic acid-reinforced cellulose nanofiber composites for all-water-based high-performance wood adhesives.

Traditional adhesives easily release toxic gases during the preparation process or apply to wood composite products, which have adverse effects on the human body and the environment. Herein, an all-water-based high-performance wood adhesive is prepared using TEMPO-oxidized cellulose nanofiber (TOCNF), acrylamide (AM), and tannic acid (TA) through free radical polymerization. Different characteristics of the prepared composites, including morphology, injectability, and adhesion properties, have been investigated. Results showed that the TA/TOCNF/PAM composite has excellent injectability. The addition of TA can enhance the lap shear strength of the TA/TOCNF/PAM composites and with the increment of TA content, the lap shear strength gradually decreases. The formation of effective hydrogen bonds and Van der Waals interaction among the rich functional groups in the composite, lead to strong lap shear strength on different substrates. The composite with 5.0 g of AM, 5.0 g of the TOCNF suspension and 0.1 g TA possesses a high lap shear strength of 10.5 MPa on wood and 1.5 MPa on aluminium. Based on strong adhesion properties and excellent injectability, the TA/TOCNF/PAM composites have great potential in the furniture construction and building industries.

Green, recyclable and high latent heat form-stable phase change composites supported by cellulose nanofibers for thermal energy management.

Efficiently addressing the challenge of leakage is crucial in the advancement of solid-liquid phase change thermal storage composite materials; however, numerous existing preparation methods often entail complexity and high energy consumption. Herein, a straightforward blending approach was adopted to fabricate stable phase change nanocomposites capitalizing on the interaction between TEMPO-oxidized cellulose nanofibers (TOCNF) and polyethylene glycol (PEG) molecules. By adjusting the ratio of TOCNF to PEG and the molecular weights of PEG, TOCNF/PEG phase change composites (TPCC) with customizable phase transition temperature (40.3-59.1 °C) and high phase transition latent heat (126.3-172.1 J/g) were obtained. The TPCC of high-loaded PEG (80-95 wt%) ensured a leakage rate of less than 1.7 wt% after 100 heating-cooling cycles. Moreover, TPCC exhibits excellent optical properties with a transmittance of over 90 % at room temperature and up to 96 % after heating. The thermal response analysis of TPCC demonstrates exceptional thermal-induced flexibility and good thermal stability, as well as recyclability and reshaping ability. This study may inspire others to design bio-based phase change composites with potential applications in thermal energy storage and management of smart-energy buildings, photothermal response devices, and waste heat-generating electronics.

Preparation of sustainable oxidized nanocellulose films with high UV shielding effect, high transparency and high strength.

UV protection has become crucial as increasing environmental pollution has led to the destruction of the ozone layer, which has a weakened ability to block UV rays. In this paper, we successfully prepared cellulose-based biomass films with high UV shielding effect, high transparency and high tensile strength by graft-modifying oxidized cellulose nanocellulose (TOCN) with folic acid (FA) and borrowing vacuum-assisted filtration. The films had tunable UV shielding properties depending on the amount of FA added. When the FA addition was 20 % (V/V), the film showed 0 % transmittance in the UV region (200-400 nm) and 90.61 % transmittance in the visible region (600 nm), while the tensile strength was up to 150.04 MPa. This study provides a new integrated process for the value-added utilization of nanocellulose and a new route for the production of functional biomass packaging materials. The film is expected to be applied in the field of food packaging with UV shielding.

An agarose-based TOCN-ECM bilayer lyophilized-hydrogel with hemostatic and regenerative properties for post-operative adhesion management.

This study used a unique approach by developing a bilayer system that can simultaneously accomplish non-adhesion, hemostatic, and tissue regenerative properties. In this system, agarose was used as a carrier material, with an agarose-TEMPO-oxidized cellulose nanofiber (TOCN), (AT) layer acting as a non-adhesion layer and an Agarose-Extracellular matrix, (AE) layer acting as a tissue regenerative layer. Thrombin was loaded on the AE layer as an initiator of the healing process, by hemostasis. AT 1:4 showed 79.3 % and AE 1:4 showed 84.66 % cell viability initially confirming the biocompatible nature of the layers. The AE layer showed cell attachment and proliferation on its surface whereas on the AT layer, cells are visible but no attachment was observed. Furthermore, in vivo analysis was conducted. The non-adhesive layer was grafted between the cecum and peritoneal wall which showed that (AT 1:4) displayed remarkable non-adhesion properties as compared to a commercial product and the non-treated group. Hemostasis and tissue regeneration ability were evaluated using rat liver models. The bleeding time of AE 1:4TH was recorded as 160 s and the blood loss was 5.6 g. The results showed that (AE 1:4) displayed effective regeneration ability in the liver model after two weeks.

Pickering emulsions of thyme oil in water using oxidized cellulose nanofibers: Towards bio-based active packaging.

The antioxidant and antimicrobial properties of thyme essential oil (TEO) are useful for active food packaging, but its poor aqueous solubility restricts its applications. This work involves anionic cellulose nanofibers (CNFs) as the sole stabilizing agent for TEO-in-water emulsions, with oil concentrations ranging from 10 mL/L to 300 mL/L. A double mechanism was proposed: the adsorption of CNFs at oil/water interfaces restricted coalescence to a limited extent, while thickening (rheological stabilization) was required to avoid the buoyance of large droplets (>10 µm). Thickening effects comprised both higher viscosity (over 0.1 Pa·s at 10 s-1) and yield stress (approximately 0.9 Pa). Dilute emulsions had good film-forming capabilities, whereas concentrated emulsions were suitable for paper coating. Regarding antimicrobial activity, CNF-stabilized TEO-in-water emulsions successfully inhibited the growth of both Gram-negative (E. coli, S. typhimurium) and Gram-positive bacteria (L. monocytogenes). As for the antioxidant properties, approximately 50 mg of paper or 3-5 mg of film per mL of food simulant D1 were required to attain 50 % inhibition in radical scavenging tests. Nonetheless, despite the stability and the active properties of these bio-based hydrocolloids, providing this antioxidant and antimicrobial activity was incompatible with maintaining the organoleptic properties of the foodstuff unaltered.

Biocompatibility of intraperitoneally implanted TEMPO-oxidized cellulose nanofiber hydrogels for antigen delivery in Atlantic salmon (Salmo salar L.) vaccines.

Disease outbreaks are a major impediment to aquaculture production, and vaccines are integral for disease management. Vaccines can be expensive, vary in effectiveness, and come with adjuvant-induced adverse effects, causing fish welfare issues and negative economic impacts. Three-dimensional biopolymer hydrogels are an appealing new technology for vaccine delivery in aquaculture, with the potential for controlled release of multiple immunomodulators and antigens simultaneously, action as local depots, and tunable surface properties. This research examined the intraperitoneal implantation of a cross-linked TEMPO cellulose nanofiber (TOCNF) hydrogel formulated with a Vibrio anguillarum bacterin in Atlantic salmon with macroscopic and microscopic monitoring to 600-degree days post-implantation. Results demonstrated a modified passive integrated transponder tagging (PITT) device allowed for implantation of the hydrogel. However, the Atlantic salmon implanted with TOCNF hydrogels exhibited a significant foreign body response (FBR) compared to sham-injected negative controls. The FBR was characterized by gross and microscopic external and visceral proliferative lesions, granulomas, adhesions, and fibrosis surrounding the hydrogel using Speilberg scoring of the peritoneum and histopathology of the body wall and coelom. Acutely, gross monitoring displayed rapid coagulation of blood in response to the implantation wound with development of fibrinous adhesions surrounding the hydrogel by 72 h post-implantation consistent with early stage FBR. While these results were undesirable for aquaculture vaccines, this work informs on the innate immune response to an implanted biopolymer hydrogel in Atlantic salmon and directs future research using cellulose nanomaterial formulations in Atlantic salmon for a new generation of aquaculture vaccine technology.

Effect of TEMPO-oxidized bacterial cellulose nanofibers stabilized Pickering emulsion of cinnamon essential oil on structure and properties of gelatin composite films.

Pure gelatin film often exhibits high hydrophilicity and a lack of antibacterial activity, hindering its practical application in the field of food preservation. To address these issues, we incorporated 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized bacterial cellulose (TOBC) nanofibers stabilized cinnamon essential oil (CEO) Pickering emulsions into the gelatin matrix to develop active food packaging films. The study revealed that the good distribution of emulsion droplets in the film matrix. While with increasing Pickering emulsion proportion, the microstructures of composite films were more heterogeneous, showing some pores or cavities. In addition, the insertion of TOBC-stabilized CEO emulsions could improve the elongation at break (EAB), water-resistance, UV blocking ability, and antibacterial activity of film, but reduced its tensile strength (TS) and water vapor barrier properties (WVP). Notably, the film prepared with 4 % TOBC-stabilized CEO Pickering emulsion demonstrated enhanced preservation of strawberries. Overall, the as-prepared gelatin-based active composite films have considerable potential for food packaging.

Transparent biodegradable composite plastic packaging film from TEMPO-oxidized cellulose nanofibers.

In this research, we develop a method to create biodegradable food packaging films. Initially, TEMPO-oxidized cellulose nanofiber (TOCNF) undergoes sonication to produce well-dispersed single-strain nanofibers. These nanofibers are then blended with waterborne polyurethane (WPU) to enhance their extensibility. To further enhance compatibility between these two components, a non-ionic surfactant, Tween 80, is introduced into the TOCNF/WPU mixture to improve the dispersion of the WPU within the blend. The addition of Tween 80 significantly increases the transparency of the resulting film (Transmittance: 89.4 %, Haze: 2.2 %). Furthermore, the incorporation of the surfactant effectively reduces the formation of wrinkles and cracks during the film drying process, preventing adverse impacts on the film's barrier properties. The thin film further undergoes esterification crosslinking with citric acid to remove its hydrophilic groups for better water vapor barrier properties. The resulting bio-based packaging film exhibits remarkable transparency, strong biodegradability, and superior gas-barrier properties (water vapor and oxygen) compared to commonly used food packaging.

Quaternized chitosan/oxidized bacterial cellulose cryogels with shape recovery for noncompressible hemorrhage and wound healing.

Management of noncompressible torso hemorrhage is an urgent clinical requirement, desiring biomaterials with rapid hemostasis, anti-infection and excellent resilient properties. In this research, we have prepared a highly resilient cryogel with both hemostatic and antibacterial effects by chemical crosslinking and electrostatic interaction. The network structure crosslinked by quaternized chitosan and genipin was interspersed with oxidized bacterial cellulose after lyophilization. The as-prepared cryogel can quickly return to the original volume when soaking in water or blood. The appropriately sized pores in the cryogel help to absorb blood cells and further activate coagulation, while the quaternary ammonium salt groups on quaternized chitosan inhibit bacterial infections. Both cell and animal experiments showed that the cryogel was hypotoxic and could promote the regeneration of wound tissue. This research provides a new pathway for the preparation of double crosslinking cryogels and offers effective and safe biomaterials for the emergent bleeding management of incompressible wounds.

Mechanically strong, hydrostable, and biodegradable all-biobased transparent wood films with UV-blocking performance.

Petroleum-based plastics are useful but they pose a great threat to the environment and human health. It is highly desirable yet challenging to develop sustainable structural materials with excellent mechanical and optical properties for plastic replacement. Here, we report a simple and efficient method to manufacture high-performance all-biobased structural materials from cellulosic wood skeleton (WS) and gelatin via oxidation and densification. Specifically, gelatin was grafted to the oxidized cellulose wood skeletons (DAWS) and then physically crosslinked via Tannic acid (TA), resulting in a significant enhancement of the material properties. Notably, only a mild pressure was applied during the drying process to form a densified TA/Gelatin/transparent wood film(TWF). The developed TA/Gelatin/TWF (thickness:100 ± 12 µm) exhibited a desirable combination of high strength (∼154.59 MPa), light transmittance (86.2 % at 600 nm), low haze (16.7 %), high water stability (wet strength: ∼130.13 MPa) and ultraviolet blocking efficacy which surpass most of the petroleum-based plastics. In addition, due to the all bio-based origins (wood and gelatin), TA/Gelatin/TWF are easily biodegradable under natural conditions, leading to less impact on the environment. These findings would hold promises for exploring high-quality all bio-based wood composites as eco-friendly alternatives to substitute plastics with wide applications, e.g. anti-counterfeiting, UV protection, and flexible electricals.

Construction of metal-organic framework/cellulose nanofibers-based hybrid membranes and their ion transport property for efficient osmotic energy conversion.

The development of advanced nanofluidic membranes with better ion selectivity, efficient energy conversion and high output power density remains challenging. Herein, we prepared nanofluidic hybrid membranes based on TEMPO oxidized cellulose nanofibers (T-CNF) and manganese-based metal organic framework (MOF) using a simple in situ synthesis method. Incorporated T-CNF endows the MOF/T-CNF hybrid membrane with a high cation selectivity up to 0.93. Nanoporous MOF in three-dimensional interconnected nanochannels provides massive ion transport pathways. High transmembrane ion flux and low ion permeation energy barrier are correlated with a superior energy conversion efficiency (36 %) in MOF/T-CNF hybrid membrane. When operating under 50-fold salinity gradient by mixing simulated seawater and river water, the MOF/T-CNF hybrid membrane achieves a maximum power density value of 1.87 W m-2. About 5-fold increase in output power density was achieved compared to pure T-CNF membrane. The integration of natural nanofibers with high charge density and nanoporous MOF materials is demonstrated an effective and novel strategy for the enhancement of output power density of nanofluidic membranes, showing the great potential of MOF/T-CNF hybrid membranes as efficient nanofluidic osmotic energy generators.

Characterization and comparison of carboxymethylation and TEMPO-mediated oxidation for polysaccharides modification.

In this study, carboxymethylation and TEMPO-mediated oxidation were compared for their ability to introduce carboxyl groups to polysaccharides, using cellulose and chitin as model polysaccharides. The carboxyl group contents and changes in the molecular weight of carboxymethylated and TEMPO-oxidized cellulose/chitin were measured. The results revealed that carboxymethylation achieved higher carboxyl group contents, with values of 4.99 mmol/g for cellulose and 4.46 mmol/g for chitin, whereas for TEMPO-oxidized cellulose and chitin, the values were 1.64 mmol/g and 1.12 mmol/g, respectively. As a consequence of TEMPO-mediated oxidation, polysaccharides underwent degradation, leading to a decrease in the molecular weight of 42.46 % for oxidized cellulose and 64.5 % for oxidized chitin. Additionally, the crystallinity of carboxymethylated polysaccharides decreased with an increase in the carboxyl group contents, whereas that of TEMPO-oxidized polysaccharides remained unchanged. Furthermore, TEMPO-mediated oxidation selectively oxidized C6 primary hydroxyls, while carboxylmethylation converted all the hydroxyl groups on the polysaccharides.

Synthesis of oxidized carboxymethyl cellulose-chitosan and its composite films with SiC and SiC@SiO2 nanoparticles for methylene blue dye adsorption.

The cationic methylene blue (MB) dye sequestration was studied by using oxidized carboxymethyl cellulose-chitosan (OCMC-CS) and its composite films with silicon carbide (OCMC-CS-SiC), and silica-coated SiC nanoparticles (OCMC-CS-SiC@SiO2). The resulting composite films were characterized through various analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDS). The dye adsorption properties of the synthesized composite films were comprehensively investigated in batch experiments and the effect of parameters such as contact time, initial dye concentration, catalyst dosages, temperature, and pH were systematically evaluated. The results indicated that the film's adsorption efficiency was increased by increasing the contact time, catalyst amount, and temperature, and with a decreased initial concentration of dye solution. The adsorption efficiency was highest at neutral pH. The experimental results demonstrated that OCMC-CS films have high dye adsorption capabilities as compared to OCMC-CS-SiC, and OCMC-CS-SiC@SiO2. Additionally, the desorption investigation suggested that the adsorbents are successfully regenerated. Overall, this study contributes to the development of sustainable and effective adsorbent materials for dye removal applications. These films present a promising and environmentally friendly approach to mitigate dye pollution from aqueous systems.