Journal of Polymers and the Environment最新文献

This study presents a sustainable approach for the extraction and functionalization of lignin from hemp biomass using choline chloride-based deep eutectic solvents (DES), formulated with hydrogen-bond donors such as lactic acid, ethylene glycol, and urea. Lignin was successfully extracted with a yield of 10.34% and subsequently converted into nanoparticles via anti-solvent precipitation and mechanical homogenization. To enhance adsorption performance, the nanolignin was chemically aminated using diethylenetriamine (DETA), introducing amine groups (-NH₂) that facilitate copper ion (Cu²⁺) binding through chelation and electrostatic interactions. Fourier Transform Infrared Spectroscopy (FTIR) confirmed successful amine functionalization with a characteristic peak at 1662 cm⁻¹. Field Emission Scanning Electron Microscopy (FE-SEM) revealed that the nanoparticles had an average size of approximately 50 nm. After amination, Dynamic Light Scattering (DLS) analysis showed an increase in particle size to around 280 nm following amination. Thermogravimetric analysis (TGA) indicated reduced thermal stability, which is consistent with the increased surface area observed in Brunauer-Emmett-Teller (BET) analysis (39.39 ± 0.18 m²/g). The aminated nanolignin exhibited a high copper adsorption capacity of 141.56 ± 0.72 mg/g. Copper was selected as the model contaminant due to its widespread presence in industrial wastewater, particularly from mining, electroplating, and electronics. In addition to its adsorption performance, the aminated nanolignin demonstrated strong UV absorption and achieved 99.99% antibacterial activity against Staphylococcus aureus (S. aureus), supporting its potential use in integrated UV-shielding and antibacterial applications. These results highlight the promise of aminated hemp-derived nanolignin as a renewable, cost-effective, and multifunctional nanomaterial for advanced wastewater treatment targeting heavy metal and pathogenic contaminants.

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Over the last few decades, prodrug nanoparticles have exhibited several appealing attributes and have eventually received impressive attention in the scientific communities. The current research study aimed to develop innovative coumaric acid (CA) grafted pullulan (Pull) based conjugates (CA-g-Pull) and their nanoparticles and evaluate their antioxidant and α-amylase/α-glucosidase inhibition potentials. In this context, variable amounts of CA were grafted with Pull via Steglich esterification reaction protocol and the resulting conjugates were structurally characterized with ¹H NMR, FTIR, DSC, TGA, XRD and SEM analyses. These conjugates spontaneously self-aggregated in an aqueous environment to yield nanoparticles (F-1– F-3), which illustrated acceptable particle sizes (276–296 nm), PDI values (0.313–0.460) and zeta potentials (-10 to -20 mV). The prodrug nanoparticles revealed their spherical structures under TEM analyses. Among various nanoparticles, formulation F-3 with the highest CA contents (DS, 0.26) conferred an improved DPPH and ABTS-free radical scavenging and α-amylase and α-glucosidase inhibition potentials, which were enhanced with increasing incubation time. These nanoparticles also depicted excellent cytocompatibility as evaluated through hemolysis assay, CCK-8 assay and live/dead cell staining protocols. Thus, the newly developed prodrug nanoparticles could be employed as promising biomaterials with acceptable antioxidant and α-amylase and α-glucosidase inhibition activities.

Pathogenic microbes pose a significant threat to human health due to their increasing resistance to standard antibiotics. Colon cancer is among the deadliest forms of cancer worldwide and often exhibits resistance to conventional treatments, highlighting the urgent need for alternative therapeutic agents. In this study, a SrO₂–SA–LA nanocomposite was synthesized via a green chemical approach using Bougainvillea glabra extract and evaluated for its anticancer, antioxidant, and antimicrobial potential. In this work, SrO₂-SA-LA nanocomposite was prepared via a green chemical approach using Bougainvillea glabra extract and evaluated for its potential anticancer, antioxidant, and antimicrobial properties. The nanocomposite was successfully synthesized and functionalized, as confirmed by characterization studies. XRD revealed a crystalline phase of tetragonal SrO₂. The calculated optical bandgap energies were 4.11 eV for pristine SrO₂ and 4.35 eV for SrO₂-SA-LA nanocomposite. DLS analysis indicated median particle sizes of 128.40 nm and 142.70 nm for SrO₂ and SrO₂–SA–LA, respectively. PL studies showed that the SrO₂–SA–LA nanocomposite exhibited green emission in the range of 494–534 nm, suggesting an increase in oxygen-related defect states compared to pure SrO₂. Disc diffusion assay revealed that SrO₂-SA-LA nanocomposite exhibited enhanced antimicrobial activity against common disease-causing pathogens, while MTT assay showed enhanced cytotoxicity against HCT-116 colon cancer cells. Additionally, the SrO₂-SA-LA nanocomposite exhibited superior free radical scavenging in DPPH assays, indicating high antioxidant potential. Furthermore, cytocompatibility studies using L929 fibroblast cells confirmed that both SrO₂ and SrO₂–SA–LA nanocomposite are non-toxic to normal cells, with cell viability exceeding 80%, indicating their biosafety. The results suggest that SrO₂-SA-LA nanocomposite is a promising candidate for applications in anticancer, antioxidant, and antimicrobial therapies with good biocompatibility.

In this study, a novel cryogel composed of Bassorin and carboxymethylcellulose that is crosslinked with calcium ions (BR-CMC-Ca) was developed and evaluated for its ability to remove crystal violet (CV) dye from aqueous environments. The material was fabricated using a simplified freeze-drying method and characterized through various analytical techniques, such as X-ray diffraction (XRD) for crystallinity assessment, energy-dispersive X-ray spectroscopy (EDAX) for elemental composition analysis, field emission scanning electron microscopy (FESEM) for surface morphologies, Fourier-transform infrared spectroscopy (FTIR) for functional group identification, and Brunauer–Emmett–Teller (BET) analysis for specific surface area determination. Zeta potential measurements indicated a surface charge of approximately − 75 mV at pH 10, suggesting favorable interactions with positively charged dye molecules. The adsorption performance was systematically investigated under varying experimental conditions, including contact time, initial dye concentration, solution pH, temperature, and adsorbent dosage. Mechanistic insights were achieved through adsorption isotherm, kinetic, and thermodynamic modeling. The BR-CMC-Ca cryogel exhibited a maximum adsorption capacity of 210.52 mg/g. Kinetic analysis confirmed that the pseudo-first-order model provided the best fit, while the equilibrium data were most accurately described by the Langmuir isotherm. Notably, the material maintained a high adsorption efficiency across five consecutive regeneration cycles. These findings underscore the potential of BR-CMC-Ca as a green, biodegradable adsorbent, offering promising scalability for wastewater treatment contaminated with dyes and in industrial filtration applications.

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Alginic acid is a non-water soluble polyanionic heteropolymer. However, sodium and potassium alginates can form viscous aqueous solutions in water and can easily cross-link with metal cations as Ca²⁺ and Fe^3+, forming gels with different morphologies, like films and capsules. Its combination with inorganic materials, such as laminar clays, allows the development of hybrid composites for the encapsulation of bioactive compounds. In this work, hybrid clay-biopolymer capsules, composed of montmorillonite laminar clay (Mt) and Sodium Alginate (SA), are designed and characterized using Nuclear Magnetic Resonance (NMR) relaxometry techniques. Particularly, Laurus Nobilis essential oil is encapsulated within these capsules. The T₁-T₂ relaxation maps show the position of each proton population: hydroxyls from the clay, confined water in the clay and the polymer matrix, and oil (confined in the polymer matrix and between the granules of the clay). The hydration-dependent behavior of Mt and SA is analyzed, and T₁-T₂ relaxation maps further reveal how water and oil penetration into the matrix correlates with the clay content in the sample. Additionally, the results demonstrated a linear relationship between the basal spacing (d001) and the relative humidity of the samples.

Water pollution with hexavalent chromium [Cr(VI)] poses a serious threat to both environmental and public health due to its extreme toxicity, mobility, and persistence. The present work aimed to develop an efficient, sustainable, and cost-effective biosorption technique for Cr(VI) removal using immobilized Spirulina platensis (SpiruSpheres), a filamentous cyanobacterium rich in metal-binding functional groups. SpiruSpheres were tested using a gravity-driven separation funnel, simulating continuous flow conditions, a novel approach not widely explored in previous studies on Spirulina-alginate biosorption. Comprehensive characterization using FTIR, SEM-EDX, BET, and TGA confirmed the presence of functional groups and a structure conducive to adsorption. Biosorption performance was statistically optimized using response surface methodology, with a focus on pH, contact time, and initial Cr(VI) concentration. Maximum removal efficiency of 84.05% was achieved under acidic conditions (pH 3.61) after 150 min, with an initial concentration of 20 mg/L. The kinetic modeling suggested that the process may involve chemisorption as a potential step in the removal of Cr(VI), although further thermodynamic validation is required to confirm this mechanism. Isotherm analysis showed that the Freundlich model best fit the data, suggesting multilayer adsorption on a heterogeneous surface. The reusability of SpiruSpheres was demonstrated over four cycles, maintaining structural integrity and high performance, which adds significant practical value to this biosorbent for large-scale applications. In conclusion, this work presents a promising, reusable, and eco-friendly solution for Cr(VI) removal, especially in regions lacking advanced treatment infrastructure, and contributes to the advancement of green water treatment solutions.

Biopolymers and mechanochemical processes are alternatives that have gained importance because of environmental concerns. In this study, the biopolymer acemannan (ACM) was extracted and processed via ultrasonication (US), which altered the ACM properties, including molecular weight and solubility. The short processing time of US promoted the scission of ACM chains, increasing their solubility and decreasing their viscosity. With increasing processing time, chain scission was observed, decreasing the number-average molecular weight (M_n) and polydispersity (Ð=M_w/M_n), as demonstrated by size-exclusion chromatography (SEC). The unprocessed ACM had a weight-average molecular weight (M_w) of 1783 kDa, whereas after 16 min of US processing, it reached 92.16 kDa, and the initial Ð changed from 2.84 to 2.24. The Ovenall model assumes a first-order kinetic behavior and is suitable for describing the chain scission mechanism. Viscosity measurements highlight the relationship between polymer‒solvent interactions and molecular weight. This work contributes to future studies on the mechanochemical processing of ACM with applications in health, food and the synthesis of functional biomaterials.

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Fungal species, especially those from underexplored ecological niches, offer a promising avenue for novel enzyme discovery due to their metabolic versatility and ability to secrete enzymes with favorable industrial properties. However, the biotechnological potential of fungi from extreme or unique biomes, such as the semi-arid Caatinga in Brazil, remains largely untapped. Moreover, although some fungal collagenases have been studied for therapeutic use, there is a lack of comprehensive research integrating the optimization of production steps and the development of efficient delivery systems. This study selected a new strain of Rhizopus microsporus (UCP 1296), isolated from soil in the Caatinga, a Brazilian biome, for collagenase production. A 2⁴-Full Factorial Design and a 2²-Central Composite Design, combined with the Response Surface Methodology (RSM), were used to optimize collagenase production in submerged liquid culture. Subsequently, the physicochemical characterization of the enzyme and its incorporation into galactomannan gel were performed. The combined application of statistical designs and RSM allowed for a 63% increase in collagenase production (872 ± 43 U/mg). The enzyme showed maximum activity at pH 8.0 and 40 °C, maintaining stability across a wide range of pH and temperature. It was strongly inhibited by phenylmethylsulphonyl fluoride (PMSF) and was capable of hydrolyzing type I collagen and azocoll. The experiments of collagenase incorporation in galactomannan gel demonstrated that no less than 72% of the enzyme was retained in the matrix, maintaining high activity after 24 h (305.11 U/mL). Furthermore, collagenase was released from the gel following a pseudo-Fickian behavior and did not exhibit cytotoxic effects on L929 fibroblasts, confirming its biocompatibility and suitability as a controlled release system. These results represent an advancement in the sustainable production of fungal collagenase and its incorporation into a galactomannan-based gel system, with potential for large-scale application in the pharmaceutical and cosmetic industries.

Cannabis sativa L. (hemp) is a renewable source of cannabinoids such as cannabidiol (CBD) and tetrahydrocannabinol (THC), known for their antioxidant and therapeutic properties. However, their clinical application is limited by poor water solubility, instability, and low bioavailability. This study explores the use of biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles to improve cannabinoid delivery. Cannabinoids were directly extracted from hemp leaves using ethanol maceration, yielding an extract rich in CBD (ca. 76 mg/g), with high antioxidant activity (IC₅₀ DPPH ca. 100 µg/mL), total phenolic content (ca. 81 mg GAE/g), and flavonoid content (ca. 20 mg QE/g). The extract was encapsulated in PLGA nanoparticles using a simple single emulsion evaporation method. Key formulation parameters, polymer concentration, homogenization time, O/W phase ratio, surfactant concentration, and cannabinoid concentration were optimized to achieve nanoparticle sizes below 200 nm, with high encapsulation efficiency and drug loading. The resulting nanoparticles exhibited a consistent size distribution, with reproducible diameters, high encapsulation efficiency (up to 98%), drug loading (ca. 7%), and storage stability for at least six months. In vitro drug release, assessed via direct dispersion and dialysis methods, revealed an initial burst profile followed by sustained release. Cytotoxicity assays were conducted using human colorectal carcinoma cells to demonstrate the non-cytotoxic nature of our nanoparticulate systems. This work highlights the potential of hemp leaf-derived cannabinoids in PLGA nanoparticle systems for controlled drug delivery. The approach offers a sustainable and scalable strategy to enhance cannabinoid bioavailability and therapeutic application.

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