Journal of Polymers and the Environment最新文献

This work studied the transformation of whey protein isolate (WPI) in a thermoplastic material (WPIT) with the addition of the antioxidant α-tocopherol, as known as vitamin E, and the plasticizer polyethylene glycol (PEG). The miscibility of the components was evaluated using the Flory-Huggins interaction parameters. WPIT samples were formulated following a Design of Experiments (DOE) factorial design 2² with a central point with vitamin E and PEG content as factors. Samples were prepared using a heat treatment for denaturation, dried in a vacuum oven, lyophilized, and cryogenically milled. The final properties obtained were evaluated by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetry (TGA), and moisture content. The results showed miscibility between PEG and WPI and partial miscibility between the pairs α-tocopherol/WPI and PEG/α-tocopherol. PEG and vitamin E exhibited a plasticizing effect on the polymer chains, reducing the contribution of extended β-sheet structures in the secondary structure of the protein, increasing the presence of α-helices, and decreasing the glass transition temperatures related to the protein. Vitamin E improved the thermal stability of WPIT, but its excess may lead to a pro-degradant effect. The amount of α -tocopherol and PEG influenced the moisture content. The hydrophobicity of vitamin E strongly influenced moisture content, keeping it low for samples with higher content of this additive.

Lignin, a renewable biopolymer sourced from plant cell walls, is gaining attention due to its extensive availability from natural resources, native functional groups, low cost, and biodegradability in various applications. In recent years, lignin and its derivatives have been utilized as adsorbents, flocculants, and sterilants in a broad range of applications, including wastewater treatment and sustainable packaging. The growing global demand for clean water—driven by rapid industrialization, urban expansion, and agricultural intensification—has made effective wastewater treatment a pressing environmental priority. In this effort, a dual-functionalization strategy to transform raw lignin into a high-performance adsorbent for the removal of hazardous anionic dyes from wastewater was attempted. Through sequential phenolation and amination via a Mannich reaction—enhancing phenolic hydroxyl groups and introducing nitrogen-rich amine functionalities, respectively—aminated phenolated lignin (Am-PL) was synthesized with nitrogen contents up to 9.6 at%. After each modification, chemical, thermal, and morphological properties of lignin were analyzed. Adsorption capacity and kinetics of Am-PL were investigated for two anionic dyes, Congo red (CR) and methyl orange (MO), as a function of pH and contact time. Am-PL exhibited strong affinity toward CR and MO, achieving maximum adsorption capacities of ca. 53 mg.g^− 1 and 18 mg.g^− 1, with removal efficiencies of 96% and 81%, respectively, under alkaline conditions after 96 h. Am-PL followed pseudo-second-order adsorption kinetics for both aqueous dyes examined. This study demonstrates a green and scalable route to valorize lignin into a next-generation bio-adsorbent, offering a promising solution for sustainable wastewater remediation.

The efficient synthesis of bio-based anionic flocculants is crucial for sustainable wastewater treatment. However, existing bio-based flocculants often compromise between performance and eco-friendliness. This study developed a one-step method to synthesize low degree substitution citrated starch-grafted polyacrylamide (St-CA-PAM) as an eco-friendly alternative to synthetic flocculants. Citrated starch (St-CA) was prepared by esterification with citric acid, achieving a low degree of substitution (DS = 0.061), optimized for solubility and graft polymerization. The polyacrylamide grafting onto St-CA was also confirmed by Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance (¹H NMR), zeta potential (ZP), and intrinsic viscosity measurement. The presence of representative peaks in the ¹H NMR and FTIR spectra, indicating amide and carboxylic groups, confirmed the successful simultaneous modification, supported by the viscosity increase from 0.80 dl/g (St-CA) to 1.18 dl/g (St-CA-PAM). St-CA-PAM exhibited superior flocculation efficiency, achieving 90% turbidity removal (< 20 Nephelometric Turbidity Units (NTU)) at 10 ppm, significantly outperforming St, St-CA, and St-PAM, with optimal clarification (98%, 2.42 NTU) under alkaline conditions. The flocculation mechanism involved electrostatic patch effects and polymer bridging, forming large flocs (~ 850 nm) and enhancing sedimentation. Given its bio-based composition, low dosage requirements, and anionic nature, St-CA-PAM presents a promising, scalable, and sustainable alternative for wastewater treatment.

In this study, we propose a facile and efficient approach to fabricate a biocomposite of Ficus carica fruit (FCF) extract incorporated into blue crab shells derived nanohydroxyapatite (nHAp) and marine fish collagen (COL) biocomposite for improved biomedical applications. The rod-shaped nHAp with an average particle size of 88.3 nm was synthesized via a thermal calcination technique. The FCF extract, known for its antibacterial, antioxidant, and anticancer activities, was incorporated into the nHAp matrix. The marine fish collagen acts as a biopolymer that can synthesise materials with flexible properties such as the biodegradability, biocompatibility, renewability, affordability and availability, all are vital for designing effective biocomposite. The characterization techniques including the DLS, FTIR, XRD, TGA, FESEM-EDX mapping confirmed the structural and compositional properties. The FESEM showed agglomerated rod-like nHAp particles, while biocomposite exhibited a more uniform and refined morphology. AFM analysis showed that nHAp/FCF/COL exhibited the smoothest and most uniform surface, indicating enhanced compatibility for cell attachment. The contact angle measurements showed an improved hydrophilicity, decreasing from 32.0° to 15.4°, and also showed the increased water absorption slightly from 10.6 to 26% after 48 h, indicating an enhanced hydrophilicity of the biocomposite. The enzymatic degradation also increased significantly in the biocomposite, reaching 46.2% over 14 days, when compared to 14.8% in the pure nHAp. The zeta potential ranged from − 16.7 mV to − 18.4 mV, showing a good surface charge stability. The Antibacterial testing revealed the maximum inhibition zones of 17 mm (Escherichia coli) and 15 mm (Klebsiella pneumoniae). The in vitro anticancer activity against MG63 osteosarcoma cells portrayed the dose-dependent inhibition, with 79.5% cell death at 200 µg/mL. The AO/EB staining confirmed apoptosis at the concentrations of 25–100 µg/mL. However, the results conclude that the nHAp/FCF/COL biocomposite exhibits an improved physicochemical, antibacterial, anticancer, degradability, hydrophilicity, and biocompatibility properties which makes it as a promising material for various biomedical applications.

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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.

Graphical Abstract

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.