Polysaccharides, Volume 6, Issue 1 (March 2025) – 23 articles

Rejections of commercial bone implants have driven research in the biomaterials field to develop more biocompatible and less cytotoxic alternatives. This study aims to create composites based on oxidized bacterial cellulose (OBC) and strontium apatite (SrAp). These composites were produced through a biomimetic method using a simulated body fluid modified with strontium ions to enhance bioactivity and stabilize apatite within the biomaterial. The incorporation of SrAp into OBC membranes was confirmed by infrared spectroscopy and indicated by the appearance of a peak corresponding to phosphate group elongation (850 cm⁻¹). Quantification of strontium content by atomic absorption spectrometry revealed a concentration of 3359 ± 727 mg·g⁻¹ of Sr adsorbed onto the material surface after 7 days, beyond which no significant increase was observed. Scanning electron microscopy verified biomineralization through structural modifications, and X-ray diffraction showed that despite new peak appearances, the biomineralized membranes retained crystallinity similar to pure samples. The composite also demonstrated high cell viability for mouse osteoblasts and fibroblasts and a low mortality rate in brine shrimp Artemia (approximately 12.94 ± 4.77%). These findings suggest that these membranes have great potential for application in bone tissue engineering. Full article

This study is a comparative investigation of the activity of unloaded and curcumin-loaded oil-in-water emulsion or chitosan-based capsules on rabbit retinal cells (RRC), coronavirus HCoV-OC43, and virus HSV-1 virus in relation to their potential ophthalmologic applications. The carriers are developed by using well-established experimental procedures. The characterization of their surface properties and stability in simulated ocular fluids (tear fluid, aqueous humor, and vitreous humor) is performed using the dynamic light scattering method and UV–vis spectrophotometry. In vitro tests are performed to determine the cytotoxicity and phototoxicity of pure curcumin (CR) and selected CR-containing carriers on RRC. The effect of the unloaded and CR-loaded carriers on the antiviral activity, the behavior of the extracellular virions, and the influence on viral adsorption is evaluated against coronavirus HCoV-OC43 and HSV-1 virus by using suitable microbiological assays. In accordance with the obtained experimental results, the toxicity of carriers containing CR is significantly reduced compared to pure compound and unloaded carriers. Moreover, the activity of the unloaded carriers can be increased several times by incorporating CR. The experimental results demonstrate that the variation in the properties of even one component of the structural composition can provoke the different activity of the carriers. Full article

Introduction. The rise of multidrug resistance in Gram-negative ESKAPE pathogens is a critical challenge for modern healthcare. Colistin (CT), a peptide antibiotic, remains a last-resort treatment for infections caused by these superbugs due to its potent activity against Gram-negative bacteria and the rarity of resistance. However, its clinical use is severely limited by high nephro- and neurotoxicity, low oral bioavailability, and other adverse effects. A promising strategy to improve the biopharmaceutical properties and safety profile of antibiotics is the development of biopolymer-based delivery systems, also known as nanoantibiotics. Objective. The aim of this study was to develop polyelectrolyte complexes (PECs) for the oral delivery of CT to overcome its major limitations, such as poor bioavailability and toxicity. Methods. PECs were formulated using chondroitin sulfate (CHS) and a cyanocobalamin–chitosan conjugate (CSB12). Vitamin B12 was incorporated as a targeting ligand to enhance intestinal permeability through receptor-mediated transport. The resulting complexes (CHS-CT-CSB12) were characterized for particle size, ζ-potential, encapsulation efficiency, and drug release profile under simulated gastrointestinal conditions (pH 1.6, 6.5, and 7.4). The antimicrobial activity of the encapsulated CT was evaluated in vitro against Pseudomonas aeruginosa. Results. The CHS-CT-CSB12 PECs exhibited a hydrodynamic diameter of 446 nm and a ζ-potential of +28.2 mV. The encapsulation efficiency of CT reached 100% at a drug loading of 200 µg/mg. In vitro release studies showed that approximately 70% of the drug was released within 1 h at pH 1.6 (simulating gastric conditions), while a cumulative CT release of 80% over 6 h was observed at pH 6.5 and 7.4 (simulating intestinal conditions). This release profile suggests the potential use of enteric-coated capsules or specific administration guidelines, such as taking the drug on an empty stomach with plenty of water. The antimicrobial activity of encapsulated CT against P. aeruginosa was comparable to that of the free drug, with a minimum inhibitory concentration of 1 µg/mL for both. The inclusion of vitamin B12 in the PECs significantly improved intestinal permeability, as evidenced by an apparent permeability coefficient (P_app) of 1.1 × 10⁻⁶ cm/s for CT. Discussion. The developed PECs offer several advantages over conventional CT formulations. The use of vitamin B12 as a targeting ligand enhances drug absorption across the intestinal barrier, potentially increasing oral bioavailability. In addition, the controlled release of CT in the intestinal environment reduces the risk of systemic toxicity, particularly nephro- and neurotoxicity. These findings highlight the potential of CHS-CT-CSB12 PECs as a nanotechnology-based platform for improving the delivery of CT and other challenging antibiotics. Conclusions. This study demonstrates the promising potential of CHS-CT-CSB12 PECs as an innovative oral delivery system for CT that addresses its major limitations and improves its therapeutic efficacy. Future work will focus on in vivo evaluation of the safety and efficacy of the system, as well as exploring its applicability for delivery of other antibiotics with similar challenges. Full article

The impact of a glycerol–silicate (GS) plasticizer on the mechanical, thermal and hydrophobic properties pertaining to sodium alginate (NaAlg) and calcium alginate (CaAlg) films were investigated. Spectroscopic and physio-chemical analysis were conducted to evaluate the effects of the GS incorporation. The results determine that both NaAlg and CaAlg films exhibited poor mechanical properties which only improved by increasing the GS loading (up to 25 wt%), after which it declined. CaAlg exhibited the highest tensile strength after 25 wt% GS loading was incorporated. The elongation at break varied, with NaAlg films showing a ~10-fold increase, while the CaAlg films remained relatively unchanged. Thermal gravimetric analysis (TGA) revealed that GS reduced the onset decomposition temperature of NaAlg films, whereas CaAlg films maintained a greater onset decomposition temperature. The advancing contact angle measurements indicated a nearly linear decrease (from 54° to 39°) in hydrophobicity for the NaAlg films while the hydrophobicity for CaAlg films initially increased from 65° to 74°, and then became more hydrophilic with greater GS loading. These findings highlight the potential of GS plasticization to enhance and tailor alginate film properties, providing insights into the development of sustainable bioplastics with improved mechanical properties. Full article

Chitosan is an attractive material for developing inks for extrusion-based bioprinting of 3D structures owing to its excellent properties, including its mechanical properties and antimicrobial activity when used in wound dressings. A key challenge in formulating chitosan-based inks is to improve its gelation property to ensure reliable printing and the mechanical stability of the printed structures. To address these challenges, this article presents a novel chitosan/oxidized glucomannan composite hydrogel obtained through the combination of Schiff base and phenol crosslinking reactions. The proposed biomaterial forms soft hydrogels through Schiff base crosslinking, which can be further stabilized via visible light-induced phenol crosslinking. This dual-crosslinking approach enhances the printability and robustness of chitosan-based ink materials. The proposed chitosan/oxidized glucomannan hydrogel exhibits excellent extrudability and improved shape retention after extrusion, along with antimicrobial properties against Escherichia coli. Moreover, good cytocompatibility was confirmed in animal cell studies using mouse fibroblast 10T1/2 cells. These favorable features make this hydrogel highly promising for the extrusion-based bioprinting of complex 3D structures, such as tubes and nose-like structures, at a low crosslinker concentration and can expand the prospects of chitosan in bioprinting, providing a safer and more efficient alternative for tissue engineering and other biomedical applications. Full article

Medicinal plants are widely used in Bolivian folk medicine for the treatment of infectious diseases. We have selected one, Clinopodium bolivianum (Benth.) Kuntze, known as “Khoa”, to investigate its potential anti-HIV activity since, traditionally, it has been used to treat other viral infectious diseases. We have carried out an antiviral bioassay-guided fractionation of different extracts of the aerial parts of C. bolivianum. An antiviral crude polysaccharide was obtained, (SBA_S), which is rich in glucose, galactose, mannose, arabinose, xylose, and rhamnose and only has traces of galacturonic acid. SBA_S exhibited antiviral activity with a mechanism of action unrelated to the mannose–lectin DC-SIGN receptors but with a strong viral neutralization activity. In summary, a purified polysaccharide from C. bolivianum has been identified as the main compound responsible for its antiviral activity. SBAs proved to be a neutralizing agent with high antiviral capacity in vitro, so they could be part of new microbicide formulations to prevent HIV transmission. Full article

We developed bio-based chitosan–gelatin films, CHG-LO films, incorporating lavender essential oil (15–26 wt% LO) and oleic acid (33–47 wt% OA) with smooth surfaces and thicknesses of 0.42–0.99 mm. For their manufacture, the nanoemulsions were prepared to possess uniform dispersion and colloidal stability with average droplet sizes of 475–854 nm, polydispersity indices (PDI) of 0.095–0.235, and zeta potentials of 23.7–56.9 mV at 40 °C, where OA served as surfactant and phase change material. The opacities of the CHG-LO films increased by 1.8 to 5.5 times compared to the control group, and their UV-visible light-blocking properties improved. These films demonstrated cyclic thermal buffering character, with heat storage capacities ranging from 14.0 to 36.0 J·g⁻¹ between −26 °C and 20 °C compatible with that of OA. Additionally, they showed reduced water vapor transmission rates and swelling degrees in acidic and neutral environments. The total phenolic contents of the CHG-LO films increased 1.5–4.2 times compared to the control associated with the presence of LO phenolic groups in the structure. DPPH (2,2-diphenyl-1 picrylhydrazyl) and ABTS (2,2′–azino–bis(3–ethylbenzothiazoline–6–sulphonic acid)) scavenging activity test results show that the antioxidant properties of these films improved with increasing LO-OA content up to 2.2 and 1.3 times the control, respectively, and also showed antimicrobial properties. The multifunctional CHG-LO films of this study are promising candidates for temperature-sensitive active packaging in food as well as in pharmaceutical and cosmetic industries. Full article

Mexican yuca (Yucca decipiens Trel.) is native to the semi-desert region of north-central Mexico. Based on its medicinal uses, the flour produced from its leaves and stems was evaluated to determine new food uses. The flour was characterized based on granulometry, rheology, texture and functional properties, which were analyzed with the RStudio software. The results indicate that the Water Absorption Index (WAI) of yuca flour (0.11 mL g−¹) is similar to that of wheat flour (0.56 mL g−¹). However, the Fat Absorption Index (FAI) of yuca flour (0.40 mL g−¹) is significantly lower than that of Saltillo Pinto bean flour (1.55 mL g−¹). This suggests that yuca exhibits hydrophilic behavior comparable to that of wheat flour and requires less oil in potential formulations. The expansion capacity of yuca flour is similar to that of wheat flour, demonstrating a gluten-like behavior ideal for food applications that require this structural component. The flour also exhibited notable foaming properties, high stability and low fat content, highlighting its food potential. Fermentation matched the parameters of the Cereal & Grains Association’s physicochemical test methods 56–60; consequently, yuca flours are classified as the same as those produced from soft, weak wheat, supporting their use for fermentation processes. Internal friction values (0.85–0.92) suggest limited flow; however, its high density shows fine granulometry that facilitates the bagging, handling and storage of the flour, complying with the Mexican standards. Full article

Owing to its natural degradability and excellent film-forming characteristics, sodium alginate (SA) is gaining growing popularity in the field of food packaging. However, the insufficient antioxidant and antibacterial properties hinder its application. In the current research, protocatechuic acid (PCA) and Fe³⁺ were utilized to fabricate a metal polyphenol network structure. Subsequently, geranium essential oil emulsion (GEOE) was incorporated into the SA matrix, and SA-based films were prepared through the flat-sheet casting method. The impacts of PCA/Fe and various concentrations of GEOE on the physical, structural, as well as functional characteristics of SA-based films were comprehensively examined. The thickness of the prepared SA-based films was between 30 and 50 μm. The results showed that PCA/Fe, GEOE, and SA exhibited good biocompatibility, and the formed films were uniform. The incorporation of PCA/Fe and GEOE significantly improved the UV blocking ability, thermal stability, and antibacterial activity of SA-based films. In addition, PCA/Fe and GEOE enhanced the total antioxidant capacity of SA-based films from 3.5% to 88%. This research could provide some theoretical basis for the utilization of metal polyphenol networks and natural essential oils within the realm of food active packaging films. Full article

Pickering emulsions (PEs) can be utilized as inks for 3D food printing owing to their extensive stability and appropriate viscoelastic properties. This research explores food-grade PEs stabilized with nanoparticles (NPs) based on modified pea protein (PP) isolate and k-carrageenan (KC). NPs are fabricated from solutions with different concentrations of protein and polysaccharide and characterized in terms of size, zeta potential, and wetting properties. The composition of the emulsion is 60% sunflower oil and 40% aqueous phase. Nine emulsion formulations with varying PP and KC concentrations are investigated. The formation of hollow NPs with a hydrodynamic diameter of 120–250 nm is observed. Microscope imaging shows oil droplets surrounded by a continuous aqueous phase, forming homogenous PEs in all formulations that are stable for over 30 days. Further, the oil droplet size decreases with increasing NP concentration while the viscosity increases. Rheologic experiments portray elastic emulsion gels with thixotropic qualities ascribed to the presence of the polysaccharide. The emulsions are subjected to centrifugation in order to compare the original emulsions to concentrated PEs that possess improved capabilities. These emulsions may serve as sustainable and printable saturated fat alternatives due to their composition, texture, stability, and rheological properties. Lastly, PEs are printed smoothly and precisely while maintaining a self-supported structure. Full article

This study presents the synthesis of allyl-functionalized polysaccharide carbamates (AFCs) with tailored water solubility designed for use in responsive hydrogels and 3D printing applications. A modular one-pot approach was employed to produce cellulose- and xylan-based AFCs, utilizing polysaccharide phenyl carbonates as activated compounds. By fine-tuning the degree of substitution (DS) of functional groups, the water solubility and shear-thinning properties of AFCs were controlled to enhance the gelation and printability. AFC-based hydrogels could be obtained by rapid gelation induced without harmful catalysts through UV irradiation at 365 nm. The materials displayed highly porous and interconnected microstructures, as well as mechanical resilience and high swelling ratios. The hydrogel formation was characterized, and its crosslinking degree was calculated using HR-MAS NMR. The study demonstrated that gelation behavior was sensitive to the pH value, with optimal results under neutral or acidic conditions. Initial 3D printing trials confirmed the material’s rapid shaping capabilities, which is beneficial for biomedical applications and advanced manufacturing of stimuli-responsive materials. Full article

This study investigates the environmental issue of air pollution (PM 2.5) from agricultural waste in Thailand and promotes the utilization of agricultural wastes by using their chemical compositions, especially cellulose content. The fourth readily available varieties of agricultural waste, such as rice straw, corn husk, hemp shive, and durian rind, were selected to evaluate their fiber morphology and chemical properties. Subsequently, dialdehyde carboxymethyl cellulose (DCMC) was produced from four kinds of agricultural wastes under synthesis conditions involving a pH value of 3.0, a reaction temperature of 35 °C, a mass ratio of NaIO₄ and carboxymethyl cellulose (CMC) of 1:3, and a reaction time of 4 h. The formation of aldehyde substitution was confirmed by the degree of oxidation (DO) and aldehyde content. To characterize the DCMC properties determined, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), gel permeation chromatography (GPC), and scanning electron microscopy (SEM) were used. The results revealed that rice straw, corn husk, hemp shives, and durian rinds presented high DO and aldehyde content; the aldehyde contents were more significant than 30% and 50%, respectively. The highest DO and aldehyde contents were 38.63 and 77.23%, respectively, for the hemp shives. The characterized data in recent research illustrated that the added value of agricultural wastes could be increased by DCMC production, which can be applied as a crosslinking reagent for future novel biopolymer film applications. Full article

Chitosan remains one of the most widely used biopolymers in biomedicine due to its non-toxicity and biodegradability. It is easily chemically modified, allowing its properties to be effectively altered to improve its performance as a gene and drug carrier. The introduction of hydrophobic moieties into chitosan can significantly enhance its interaction with cancer cells, improving its potential for targeted delivery. The hydrophobic moiety plays a crucial role in the interaction of the particle with the cell membrane during internalization by endocytosis. The type of hydrophobic moiety, its degree of substitution, and its placement along the chitosan backbone all influence the physicochemical properties and biological performance of the resulting polymer. Hydrophobic modification can also affect the self-assembly behavior of chitosan, influencing the size, shape, and stability of the resulting particles. These factors impact the loading efficiency of therapeutic agents and the release kinetics of the encapsulated cargo. While hydrophobic modification can enhance the therapeutic efficacy of chitosan, it is important to consider potential toxic effects. In summary, the hydrophobic modification of chitosan is a powerful strategy to improve its efficiency as a gene and drug carrier. By understanding the role of the hydrophobic moiety in cellular uptake, endosomal escape, self-assembly, and toxicity, researchers can design and develop optimized chitosan-based delivery systems for targeted cancer therapy. Full article

Polymer matrices can be reinforced with cellulose fillers in a variety of geometric shapes. Depending on the morphology of the particles, the volume fraction of the composite additive may decrease, while the values of the elastic modulus may increase. Increasing the length while decreasing the width of the cellulose filler is an intriguing path in the development of composite additives and materials based on it. It is difficult to form thin continuous cellulose fibers, but this can be accomplished via the sea-island composite fiber manufacturing process. The creation of cellulose fibrils in polyacrylonitrile (PAN)/cellulose based systems happens during the spinning of the mixed solution. A selective solvent facilitates the isolation of cellulose fibrils. The structure of the isolated microfibers was investigated using X-ray diffraction, IR spectroscopy, SEM, and AFM. The structure of the resulting cellulose microfibers was compared to bacterial cellulose. It has been shown that composite fibers have a superposition pattern, while cellulose fibrils have a structure different from native cellulose and similar to Lyocell fibers (polymorph II). The crystallite sizes and crystallinity of regenerated cellulose were determined. The identified structural parameters for cellulose fibrils provide strength at the level of industrial hydrated cellulose fibers. Full article

Xylans, polysaccharides abundantly derived from agricultural byproducts, have shown potential pharmacological properties, making them a subject of increasing research interest. This study aimed to expand the understanding of xylans’ pharmacological properties and relate them to their composition. A method combining ultrasound and alkaline media for xylan extraction from corn cobs (ERX) was used, resulting in a significant increase in final yield compared to other methodologies. The physicochemical characterization of ERX was carried out, and its antioxidant, cytotoxic, anticoagulant, and immunomodulatory properties were evaluated. ERX demonstrated significant antioxidant activity with metal-chelating properties and induced apoptosis in HeLa tumor cells (p < 0.0001). It also reduced nitric oxide (NO) production by activated macrophages and extended the blood coagulation time, as assessed by the APTT assay (p < 0.0001). Further fractionation of ERX using various organic solvents resulted in multiple xylan subfractions. Among them, the ethanol-derived subfraction E1.4 exhibited remarkable pharmacological activities, including metal-chelation, cytotoxicity against HeLa cells via apoptosis, reduced NO production (p < 0.0001), and prolonged coagulation times (p < 0.0001). E1.4 is heteroxylan with a molecular weight of approximately 100 kDa. These findings suggest that corn cobs could be a promising source of pharmacologically significant molecules, particularly the heteroxylan E1.4. Future studies should focus on the structural characterization of this xylan to understand the relationship between structure and biological activity and explore the therapeutic potential of E1.4 in vivo models. Full article

The printing and dyeing industries generate wastewater containing toxic, hard-to-degrade organic dyes like methylene blue (MB). Recent research focuses on biodegradable, renewable materials such as cellulose-based absorbents to address this issue. This study investigates bacterial cellulose (BC) functionalized with citric acid as a sustainable adsorbent for MB removal. BC, a by-product of kombucha fermentation, is functionalized with citric acid, and its adsorption capacity is analyzed. BC production reaches 3.65 ± 0.16 g L⁻¹ by day 12. Using 0.05 g of functionalized BC (FBC) at pH 7, a maximum adsorption capacity of 13.22 ± 1.27 mg g⁻¹ is achieved for MB at 600 mg L⁻¹ over 60 min. The adsorption mechanism is complex, with both pseudo-first- and pseudo-second-order models fitting well at 20 °C, 40 °C, and 70 °C. The carboxyl groups of citric acid bind to the hydroxyl groups of cellulose fibers via esterification, altering the material’s charge, reactivity, thermal, and crystallinity properties. This functionalization enhances BC’s adsorption capacity, making it a promising material for bioremediation in circular systems. Full article

Pullulan is a natural polysaccharide used in many health products, including dry powders for oral and pulmonary administration. In these cases, the control of the shape and dimensions of particles is crucial for obtaining the desired functionality. Different from other polysaccharides, pullulan cannot be easily shaped without chemical modifications or adjuvants’ addition. This work aims to systematically investigate the impact of the solvent composition and polymer concentration on the possibility of tuning the pullulan particle shape by spray drying. The results revealed that the microparticle-to-fiber transition can be induced using a hydro-alcoholic solution since ethanol increased the relaxation time and reduced the evaporation rate. Furthermore, a high Péclet number during drying favors the formation of wrinkled surfaces at all feed compositions. Overall, these data evidenced the possibility of tuning the spray-dried product morphology without any processing aids, paving the way for new applications of pullulan, especially in the pharmaceutical field. Full article

The nasal cavity has become a focal point for drug delivery research. Beyond its use in treating local diseases, the nasal route is appealing due its ability to deliver systemically potent drugs with low oral bioavailability. Recent interest in nasal vaccination has driven significant pre-clinical and clinical advancements. Further R&D holds promise for expanding nasal medications, offering innovative healthcare solutions. This review explores strategies using polysaccharides to enhance nasal delivery of hydrophilic drugs, peptides, proteins, genes, and other active compounds that typically struggle to permeate the nasal epithelium. Polysaccharides are attractive excipients due to their potential to enhance nasal absorption, regulate drug release, and extend residence time in the nasal cavity through bioadhesive properties. Studies on their mechanisms affecting drug absorption, potential toxicities, and applications will also be reviewed considering the particularities of nasal epithelium anatomy and physiology. Most products with these excipients are in pre-clinical and clinical evaluation, but PecFent, a pectin-based formulation, is approved for nasal administration of opioids for breakthrough cancer pain, offering faster pain relief and a better benefit–risk ratio due to pectin. Other polysaccharides like chitosan, cyclodextrins, hyaluronic acid, and alginate have shown potential in enhancing nasal drug absorption. This approach also holds promise for enhancing drug transport from the nasal cavity to the CNS (nose-to-brain), potentially advancing treatments for neurodegenerative diseases. Full article

Polysaccharides offer a perfect option as raw materials for the development of a new generation of sustainable batteries and supercapacitors. This is due to their abundance and inherent structural characteristics. Polysaccharides can be chemically functionalized and engineered, offering a wide range of possibilities as electrode materials (as precursors of porous nanocarbons), binders and separators. Their hierarchical morphology also enables their exploitation as aerogel and hydrogel structures for quasi-solid and solid polymer electrolytes with high conductivity and wide voltage stability windows. In this review, we discuss how different polysaccharides, such as lignocellulosic biomass, starch, chitosan, natural gums, sugars and marine polysaccharides, can be applied in different components of energy storage systems (ESSs). An overview of the recent research work adhering to each functionality of different polysaccharides in various storage systems is provided. Full article

The search for developing materials of natural origin has become imperative due to the resistance shown by phytopathogenic microorganisms to traditional antimicrobial agents. Natural polymers such as chitosan offer a new alternative to fungal infections because, in most cases, these polymers are biocompatible, nontoxic, and natural. This study aimed to synthesize nanochitosan using ultrasonication and evaluate its antifungal activity on Colletotrichum chrysophillum and Colletotrichum musae. Nanochitosan of 302.4 ± 92.3 nm and a zeta potential of +35.9 ± 2.3 Mv, amorphous in shape, and a rough surface, was obtained. Nanochitosan reduced the radial growth 21%, for C. chrysophillum while C. musae showed a maximum inhibition of 26% at a concentration of 1.5 mg mL⁻¹ of nanochitosan. C. musae was the species most affected, with a 38% increase in hyphal diameter to 12 h. Also, nanochitosan affected the integrity of the fungi cell walls, plasma membrane, and generated low oxidative stress level. Our findings indicate that nanochitosan induces notable changes in the intracellular structures of the tested phytopathogens. Nevertheless, additional investigations are required to clarify the mechanisms underlying adaptability or resistance in fungal strains that exhibit reduced sensitivity to this biopolymer. Full article

There are limited studies in the literature on the surface characterization of modified graphene and graphene oxide and the impact of these modified adsorbents on adsorption performance. In addition, the amine group essentially has a promising affinity for carbon dioxide (CO₂). Therefore, chitosan was used in this study to be grafted onto graphene and graphene oxide respectively. This study examines the effects of graphene, graphene oxide, and chitosan-modified graphene oxide thin films on the removal of carbon dioxide (CO₂). Thin films of graphene, graphene oxide, and their chitosan-modified counterparts were prepared via the methods of precipitation and grafting. The differences in the chemical structure, surface properties, and surface morphology of the films were evaluated, and their effect on the adsorption performance of CO₂ is discussed herein. The micrographs from a scanning electron microscope (SEM) show that the surface of graphene oxide appeared to be more porous than graphene, and the amount of grafted chitosan on graphene oxide is higher than that on graphene. An analysis of atomic force microscope (AFM) finds that the surface of chitosan-modified graphene oxide is rougher than that of chitosan-modified graphene. The results of energy-dispersive X-ray spectroscopy (EDS) spectra reveal that the composition of oxygen in graphene oxide is greater than that in graphene and confirm that the oxygen and nitrogen contents of chitosan-modified adsorbents are greater than those of the pristine materials. An analysis of Fourier-transform infrared spectroscopy (FTIR) shows that most of the oxygen-containing groups are reacted or covered by amide or amine groups due to modification with chitosan. The adsorption isotherms for CO₂ adsorbed by the prepared graphene and graphene oxide presented as type I, indicating great adsorption performance under low pressure. The appropriate amount of chitosan for modifying graphene oxide could be found based on the change in surface area. Although the breakthrough times and the thicknesses of the mass transfer regions for graphene oxide modified with 0.9% and 1.2% chitosan were similar, the modification of graphene oxide with 0.9% chitosan was appropriate in this study due to a significant decrease in surface area with 1.2% chitosan dosage. The adsorption uptake difference between chitosan-modified graphene oxide and graphene was greater than that without modification with chitosan due to more chitosan grafted on graphene oxide. The Toth adsorption isotherm model was used to fit the adsorption uptake, and the average deviation was about 1.36%. Full article

Nowadays, agricultural biomass is one the most valuable sources of natural polysaccharides. In addition to primary agricultural goods, agricultural waste is abundant, diverse, and renewable and can also be utilized as raw material for the production of polysaccharides and their derivatives. The extraction and purification of agri-waste-derived polysaccharides involves multiple processes that can vary depending on the type of raw material and the specific polysaccharides targeted. This study proposes a particular pathway from corn waste to hemicellulosic polysaccharides, which involves alkaline treatment and several physicochemical separation/purification phases using precipitation and ion exchange resins (Purolite A400, Purolite A100+, Purolite C100H). The ion exchange separation stage was optimized to retain most of the acid-soluble lignin derivatives from the extraction liquors. The process parameters considered for optimization included the solid (resin) liquid (black liquor pH 4.5) ratio, contact time, and temperature. These ranged from 0.05 to 0.15 g·mL⁻¹, 30 to 180 min, and 20 to 50 °C, respectively. The chemical composition of the separated hemicelluloses varied from 44.43 to 75.28% for xylan, 2.43 to 3.93% for glucan, 1.86 to 2.44% for galactan and 8.93 to 12.68% for arabinan. The total carbohydrate content increased from 57.65 to 96.3%. Full article

Dyes abundance in industrial wastewater exerts adverse effects on the environment and human health; adsorption represents a promising remediation strategy. Chitosan-based composites are interesting materials for dye adsorption. In this work, methyl orange (MO) adsorption using chitosan (CH) and chitosan–graphene oxide (CH-GO) aerogels produced by supercritical gel drying, performed at 200 bar/35 °C, was assessed by studying the effect of driving force (25–100 ppm) and adsorbent dosage (1–8 g/L). It was highlighted that the difference in the performance between the two adsorbents was non-negligible only at high concentrations: processing a 100 ppm MO solution, q_eq is 59 mg/g and 28 mg/g for CH-GO and CH, respectively. Starting from a 10 ppm MO solution, using a dosage of 8 g/L, it was possible to achieve adsorption efficiency of about 85%, meaning that small amounts of nanostructured devices can result in good process outcomes. Freundlich isotherm reliably describes the system behavior (R² = 0.99). The multi-linear IPD kinetic model confirms that in the case of nanostructured porous devices, there are different mass transfer phenomena that control molecule diffusion through the system. The research proposed in this work aims to explore, as a first assessment, the potential of nanostructured devices for adsorption purposes. Full article