Fragile fruits, which are prone to mechanical damage and microbial infection, necessitate protective materials that possess both cushioning and antimicrobial properties. In this study, we present a novel genipin-crosslinked chitosan/gelatin aerogel (CS/GEL/GNP) synthesized through direct mixing and free-drying techniques. The mechanical properties and cushioning capacities of the CS/GEL/GNP aerogel were thoroughly characterized, alongside an evaluation of its antimicrobial efficacy. The composite aerogel demonstrated remarkable compressibility and shape recovery characteristics. In a transportation simulation test, the aerogel effectively protected strawberries from mechanical damage. Furthermore, the composite aerogel exhibited enhanced antimicrobial activities against Escherichia coli, Staphylococcus aureus and Botrytis cinerea in vitro. The quality of strawberries was successfully maintained at ambient temperature when packaged with the CS/GEL/GNP. Notably, the aerogel could be completely degraded in the soil within 21 days and is nontoxic to cells. Consequently, the dual-functional CS/GEL/GNP aerogel presents a promising option for packaging materials aimed at protecting delicate fruits.

Due to the serious environmental pollution generated by plastic packaging, chitosan (CS)-based biodegradable films are gradually gaining popularity. However, the limited antioxidant and bacteriostatic capabilities of CS, the poor mechanical properties and water resistance of pure CS films limit their widespread adoption in food packaging. In this study, new multifunctional bioactive packaging films containing monosaccharide-modified CS and polyvinyl alcohol (PVA) were prepared to address the shortcomings of pure CS films. Initially, Maillard reaction (MR) products were prepared by conjugating chitosan with galactose/mannose (CG/CM). The successful preparation of CG/CM was confirmed using UV spectroscopy, fluorescence spectroscopy, fourier transform infrared spectroscopy (FTIR) and high-performance gel permeation chromatography (HPGPC). At an 8 mg/mL concentration, the DPPH radical scavenging activities of CM and CG were 5 and 15 times higher than that of CS, respectively. At the maximum concentration of 200 mu g/mL, both CM and CG exhibited greater inhibitory effects on the growth of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, compared to CS. Additionally, CM and CG demonstrated significantly stronger protection against oxidative damage in Vero cells than CS. These results indicate that CG and CM possess superior antioxidant and antibacterial capabilities in comparison to CS. Then, the effects of the MR on the structures and functional properties of chitosan-based films were extensively examined. Compared with pure CS films, the MR in the CG/CM films significantly changed the film microstructure, enhanced the UV-barrier property and water resistance, and only slightly reduced thermal stability. The MR reduced the tensile strength but increased the elongation at break. Meanwhile, the composite films hold good soil degradation ability. Moreover, the CG/CM films possessed excellent antioxidant and antibacterial properties and demonstrated superior fresh-keeping capacity in the preservation of strawberries and cherry tomatoes (effectively prolonged for at least 2 days or 3-6 days). Our study indicates that CG/CM films can be used as a promising biodegradable antioxidant and antibacterial biomaterial for food packaging.

The discharge of heavy metals (HMS) from industrial production has severely damaged the natural environment and human health. To address the challenges posed by heavy metals, a novel almond shell biochar (FeSCTS@nBC) modified with FeS and chitosan (CTS) was prepared. Scanning electron microscopy and X-ray photoelectron spectroscopy observations revealed a uniform distribution of FeS particles on the biochar. Adsorption thermodynamics experiments showed that the maximum adsorbed amounts of cadmium (Cd), lead (Pb), and chromium (Cr (VI) and Cr (III)) in FeS-CTS@nBC were 85.6, 89.63, 94.2, and 75.62 mg/g, respectively. Results of soil incubation experiments indicated that FeS-CTS@nBC had a desirable immobilization effect on heavy metals, decreasing the bioavailability of Cd, Pb, Cr (VI), and Cr (III) by 29.43%, 23.93%, 5.75% and 5.23 %, respectively. Density functional theory (DFT) calculations, revealed that the oxygen-containing functional groups on the biochar exhibited stronger adsorption capacities for heavy metals. Plant potting experiments indicated that the paddy grew well in the soil remediated with FeS-CTS@nBC. The Cd content in the roots and leaves of the paddy after nBCS2 repair was reduced by 28.01 % and 55.73 %, respectively. Overall, this work provides a promising low-cost method with a simple production process for mitigation of heavy metals from water and soil.

Eco-friendly materials have gained significant attention for soil stabilization and reinforcement in road construction and geo-environmental infrastructure, as traditional additives pose notable environmental concerns. In this study, three concentrations of Chitosan Biopolymer (CBP) (1.5 %, 3 %, and 4.5 %) as a bio-stabilizer, three proportions of Rice Husk Biochar (RHB) (0.5 %, 1 %, and 1.5 %) as a waste-derived filler, and three dosages of Hemp Fiber (HF) (0.2 %, 0.4 %, and 0.6 %) as reinforcement were used to treat sand-kaolinite mixtures (SKM). The samples were cured for 1, 7, 14, 21, and 28 days and subjected to varying numbers of freeze-thaw (F-T) cycles. A diverse range macro-scale laboratory tests, encompassing compaction, unconfined compressive strength (UCS), indirect tensile strength (ITS), F-T durability, ultrasonic pulse velocity (UPV), and thermal conductivity (TC), were performed on the treated samples. In addition, microstructural analyses using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were conducted to correlate mechanical behavior with micro- scale properties. The optimal dosages of CBP and RHB were first determined through UCS tests, with 3 % CBP and 1 % RHB proving the most effective. These dosages were then used to analyze their impact on other mechanical properties. Results showed that the compressive and tensile strengths of the bio-stabilized soil at the optimum contents of additives increased by 2410.7 kPa and 201.2 %, respectively, compared to the control samples. Incorporating HF into the SKM-CBP-RHB mixtures significantly enhanced their F-T durability after 10 consecutive cycles, reducing strength deterioration and performance degradation compared to the untreated soil. The optimum composition (3 % CBP, 1 % RHB, and 0.4 % HF) led to a 6.1-fold increase in ITS and a minor 2 % reduction in performance after 10 F-T cycles. Moreover, HF incorporation improved the failure strain and reduced the brittleness of the stabilized soil. UPV and TC tests revealed that incorporating HF at levels up to 0.4 %, combined with the optimum CBP-RHB mixture, enhanced soil stiffness by 963.7 MPa and reduced thermal conductivity by 0.76 W & sdot;m-1 & sdot;K-1. The microstructural analysis confirmed these findings, showing enhanced interlocking between SKM and fibers via hydrogel formation. Overall, the study demonstrates that the CBP-RHB-HF composite markedly enhances soil strength and durability, making these additives highly suitable for applications like landfills, embankments, and slopes.

To enhance the mechanical properties and water resistance of chitosan (CS) films while imparting additional functionalities, this study incorporated a hydrophobic deep eutectic solvent (DES) composed of menthol and pyruvic acid into the CS matrix. At an optimal DES content of 15 %, compared to pure CS films, the elongation at break increased by 77 %, while swelling degree and solubility decreased by 94.44 % and 60.71 %, respectively. The lowest water vapor permeability (11.55 x 10-11 g & sdot;m- 1 & sdot;s- 1 & sdot;Pa- 1) demonstrated enhanced moisture barrier properties. These improvements were attributed to the synergistic effects of hydrogen bonding and ionic crosslinking, reinforcing the network structure and restricting water penetration while maintaining molecular mobility. The films also exhibited excellent ultraviolet-shielding (ultraviolet C transmittance of 3 %) with high transparency, making them suitable for light-sensitive packaging. Additionally, they achieved complete biodegradation in soil within 10 weeks, highlighting their potential as sustainable alternatives to petroleumbased plastics. This study presents a novel approach to enhancing bio-based packaging materials through hydrophobic DES, expanding their applications in sustainable food and pharmaceutical packaging.

Electronic waste (e-waste) from nonbiodegradable products present a significant global problem due to its toxic nature and substantial environmental impact. In this study novel electrically conductive biodegradable films of uncured natural rubber (NR) incorporating graphite platelets and chitosan were developed via a latex aqueous microdispersion method. Chitosan was added as a dispersing and thickening agent to encourage the uniform distribution of graphite in the NR matrix at loadings of 20-60 parts per hundred rubbers (phr). FTIR confirmed interactions between NR, graphite, and chitosan. FE-SEM and Synchrotron XTM analyses demonstrated uniform graphite dispersion. The result of XRD revealed the greatest crystallinity at 86.9% with 60 phr graphite loading. Mechanical properties testing indicated a significant increase in Young's modulus to 58.2 MPa, or about 470-fold improvement over the pure NR film. The composite films demonstrated improved thermal and chemical resistance, and their electrical conductivity could rise dramatically to 1.22 x 10-5 S cm-1 at 60 phr graphite loading, or about six orders of magnitude higher than pure NR film. The composite films exhibit antibacterial activity against Staphylococcus aureus and some inhibition against Escherichia coli. In addition, the NR composite films exhibited biodegradability ranging from 16.7% to 25.1% after three months of soil burial, declining with increased graphite loading. These results demonstrate the potential of NR-graphite composites as conductive materials for flexible electronics, such as thin-film electrodes in energy storage devices and sensors.

The degradation and erosion of wood and its products caused by microorganisms remains a persistent challenge, which leads to significant economic and property losses and poses a potential health threat to users due to the presence of pathogenic microorganisms. In light of the recent COVID-19 pandemic, this issue has become increasingly urgent to address in modern society due to the increasing focus on private health. In this work, the carboxymethyl chitosan nano-silver (CMCS-Ag) was prepared through a microwave-assisted method, where the CMCS-Ag was ultrasonically blended with waterborne paint to obtain a waterborne antimicrobial wood coatings. Compared with commercial nano-silver with the same particle size, due to the unique system, the CMCS-Ag exhibited superior antibacterial efficacy and lower Ag+ release. CMCS-Ag exhibited effective dispersion within waterborne coatings, leading to a significant improvement in both the mechanical and antimicrobial performance of the coatings. With a CMCS-Ag content of 10 wt%, the coating films exhibit high elastic modulus, tensile strength and shore hardness, 78%, 33% and 69% higher than the control, respectively. Moreover, antimicrobial tests confirm that CMCS-Ag wood coatings inhibit Escherichia coli (24 h sterilization rate: 99.99%), Aspergillus niger (28 days without erosion), and soil decay fungi (56 days undecayed), while minimizing wood product appearance deterioration and mass loss from microbial erosion. These findings not only provide valuable insights into enhancing the antimicrobial of wood and its products but also reduce possibilities for people exposed to pathogens.

Bacterial cellulose (BC), known for its exceptional physical properties and sustainability, has garnered widespread attention as a promising alternative to petrochemical-based plastic packaging. However, application of BC for packaging remains limited due to its hygroscopic nature, poor food preservation capabilities, and low optical transparency. In this study, a novel in-situ spraying method for chitosan (CS) encapsulation was developed to fabricate BC/CS hybrid structure layer by layer. The resulting composites exhibit effective antimicrobial activity against both Gram-positive and Gram-negative (> 75 %) bacteria, ensuring food preservation and safety. The BC/CS composites were modified through mercerization and heat drying (mBC/CS), transforming the cellulose crystal structure from cellulose I to the more stable cellulose II and inducing the alignment of a compact structure. Following waterborne polyurethane (WPU) coating, the mBC/CS/WPU composites acquired hydrophobic and heat-sealable properties, along with an 80 % reduction in haze and light transmittance exceeding 85 %. Further, they exhibited exceptional mechanical properties, including an ultimate tensile strength exceeding 200 MPa and omnidirectional flexibility. These composites could also preserve the freshness of sliced apples (< 20 % weight loss) and poached chicken (< 3 % weight loss) after one week of storage, comparable to commercial zipper bags, and also prevent food contamination. Notably, the mBC/CS/WPU composites displayed no ecotoxicity during decomposition and degraded completely within 60 days in soil. This study provides a valuable framework for functionalizing BC-based materials, promoting sustainable packaging, and contributing to the mitigation of plastic pollution.

Slow-release fertilizers show great promise for advancing agricultural sustainability by enhancing nutrient efficiency and mitigating environmental impacts. Herein, we propose an approach that embeds chitosan hydrogel membranes with metal-modified biochars to encapsulate N-P-K compound fertilizers, referred to as CS-MBCSRFs. Our results demonstrate that CS-MBC-SRFs exhibit superior slow-release performance for N, P, and K compared to others (commercial NPK compound fertilizers, chitosan-coated, and biochar-embedded chitosancoated fertilizers). Over a 33-day soil column test, CS-MBC-SRFs showed cumulative leaching ratios of <8.93 % for N, 18.4 % for P, and 14.4 % for K. Incorporating metal-modified biochar into the chitosan hydrogel membrane significantly enhances its swelling and mechanical properties while maintaining biodegradability and water-retention capacity. Mechanistic investigations reveal that nutrient release from CS-MBC-SRFs primarily occurs via diffusion through the hydrogel membrane, with the metal-modified biochar surface enhancing nutrient adsorption and delaying release. Additionally, the metal-modified biochars improved swelling and mechanical properties of the chitosan hydrogel membrane, significantly reducing nutrient diffusion. Pot tests demonstrated that CS-MBC-SRFs effectively promoted chili plant growth, ensuring high N-P-K utilization and improving chili fruit nutritional indices. Economic analysis further highlights the promising application prospects of CS-MBC-SRFs.

This work focused on the development of a hydrophobic biocomposite film reinforced with natural jute fiber. The biocomposite was made using a blend of chitosan and guar gum and reinforced with varying concentration of jute fiber followed by casting and air drying in petri dishes. Microscopic analysis of the cross-sectional structure of the films revealed a dense, compact morphology and FTIR result shows evidence of chemical interaction of the composite components. The inclusion of Jute fiber was found to increase the water repellant capacity of the films. The film water vapor permeability (WVP) was reduced from 4.1 x 10(-10) (g/m(2)center dot day center dot kPa) to 1.2 x 10(-10) (g/m(2)center dot day center dot kPa) with addition of jute fiber. Although the presence of Jute affects color properties of the films, it significantly improved their ability to block UV-Vis light. The tensile strength and elongation at break of CS/GG 0 % JT film, CS/GG/1 % JT, CS/GG/1.25 %JT and, CS/GG/1.5 % JT film was turned out to be (38.4 MPa, 45.3 MPa, 51.6 MPa and 60 MPa), (15.33 %, 17.66 %, 21.33 % and, 14 %) respectively. Notably, an increased in the DPPH radical scavenging assay was also observed from similar to 87 % in CS/GG composite to 99.4 % (1 % JT film), 99.66 % (1.25 %JT film) and 99.83 % for 1.5 % JT reinforced films respectively. Furthermore, all films showed excellent antimicrobial activity against the foodborne pathogen Escherichia coli and Fusarium oxysporum fungi highlighting their potential as active food packaging material. Signs of biodegradation were observed following four month of soil burial test, confirming the environmental sustainability of the produced biocomposite film.