The development of sustainable alternatives to petroleum-based food packaging has increased interest in biodegradable edible films derived from renewable resources. In this study, powdered lemon ( Citrus limon ) and pomegranate ( Punica granatum ) peels were directly incorporated into starch gelatin matrices to produce edible films through a simple waste valorization approach. The effects of peel type on the morphology, water holding capacity, and mechanical behavior of the films were comparatively investigated. The pomegranate peel-reinforced films exhibited higher load-bearing capacity, whereas the lemon peel-reinforced films showed higher water holding capacity and greater flexibility. Scanning electron microscopy revealed distinct morphological differences between the two formulations, with the lemon peel-reinforced film exhibiting a relatively rougher and more heterogeneous surface, while the pomegranate peel-reinforced film displayed a comparatively smoother and more continuous morphology. These morphological differences were consistent with the observed differences in hydration and mechanical behavior. Overall, the findings demonstrate the potential of whole fruit peel powders as sustainable bio-based reinforcements for starch–gelatin edible films and highlight their potential for biodegradable food-packaging applications.
This work demonstrates how shell waste can be upcycled into advanced polymer composites, thereby contributing to sustainable materials research. In this study, waste oyster shells were employed as a sustainable source for the preparation of nano chitosan, which was successfully used as a reinforcing agent in unsaturated polyester resin composites. We prepared chitin from Crassostrea madrasensis oyster shell wastes, and nano chitosan was obtained by deacetylating the synthesized chitin with sodium hydroxide under autoclave conditions. Characterization techniques such as FTIR, XRD, SEM, and TEM clearly indicate the formation of chitin and chitosan, and TEM observations evidently specify the formation of nano chitosan flakes. We developed a composite material by incorporating unsaturated polyester resin with nano chitosan. Mechanical properties of unsaturated polyester resin are found to be enhanced by the addition of nano chitosan. Utilising this biopolymer derivative to improve the properties of unsaturated polyester resin (UPR) composites presents an innovative avenue for environmentally sustainable product development. These nano chitosan–UPR composites could potentially find applications in environmentally friendly coatings, structural materials, and bio-based polymer reinforcement.
This study presents a sustainable approach for the epoxidation of red palm oil (RPO) using a natural zeolite catalyst via an in situ peracid mechanism. The process addresses the limitations of conventional homogeneous acid systems by reducing corrosive waste and improving catalyst recoverability while valorizing an underutilized palm fraction. The effects of temperature and hydrogen peroxide concentration on oxirane formation were evaluated through oxirane oxygen content (OOC) and relative conversion to oxirane (RCO). The optimum temperature of 65°C produced the highest RCO (≈25–30%) at the early reaction stage, while excessive oxidant and prolonged reaction time promoted oxirane ring opening. FTIR analysis confirmed the formation of epoxy groups, and kinetic modeling showed excellent agreement with experimental data (R 2 = 0.9778; Error = 0.0469). The synthesized epoxidized RPO demonstrates strong potential for application in bio-based polymer systems, including polyols for polyurethane production, plasticizers, coatings, and environmentally friendly resins, highlighting its relevance for sustainable industrial applications.
The tertiary treatment of industrial wastewater using metallic nanoparticles anchored onto polymeric matrices presents a promising alternative to conventional bactericidal techniques, enabling material recovery after treatment and ensuring water quality. In this study, silver nanoparticles (AgNPs) were synthesized by chemical reduction and successfully confirmed by UV-Vis spectroscopy, exhibiting characteristic surface plasmon resonance bands around 390 nm. Chitosan beads containing AgNPs were then prepared and crosslinked with glutaraldehyde, and their structural and thermal properties were evaluated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), evidencing reduced crystallinity and changes in thermal behavior due to crosslinking. A 2 3 factorial design with a central point was employed to optimize the production of chitosan beads, considering acetic acid concentration, glutaraldehyde volume, and AgNPs content as independent variables, while bactericidal activity against Escherichia coli and Staphylococcus aureus was used as the response variable. Statistical analysis revealed that acetic acid concentration was the most significant factor influencing antibacterial performance. The optimized beads, prepared with 0.75 mol L −1 acetic acid, 60 µL glutaraldehyde, and 30% (v/v) of AgNPs colloidal solution, exhibited the largest inhibition zones against both bacterial strains. These optimized materials were subsequently applied to disinfect wastewater from a local industry, and after 3 h of treatment, complete inactivation of Escherichia coli and a 47% reduction in total fecal coliforms were achieved. Inductively coupled plasma optical emission spectrometry (ICP-OES) analyses indicated no detectable silver leaching, ensuring compliance with Brazilian regulations for industrial wastewater disposal. Overall, these findings demonstrate that AgNPs-loaded chitosan beads combine favorable structural properties with effective antibacterial activity and environmental safety, highlighting their potential for tertiary industrial wastewater treatment.
This study presents the development of a bio-based flame retardant derived from renewable soybean oil to improve the flame retardant performance of poly (lactic acid) (PLA). Soybean oil phosphate ester (SOPE) was synthesized from epoxidized soybean oil (ESO) and incorporated into PLA at loadings of 0.5–2 phr via twin-screw extrusion. FT-IR and NMR analyses confirmed the successful synthesis of SOPE. Thermal analysis revealed that the incorporation of SOPE influenced the thermal degradation behavior and crystallization properties of PLA. PLA containing 2 phr SOPE achieved a limiting oxygen index (LOI) value of 26% and attained a V-0 rating in the UL-94 vertical burning test, indicating effective flame retardancy at a low loading level. TGA results showed a relatively low char yield, suggesting that the flame retardant mechanism did not predominantly occur in the condensed phase. Py-GC/MS analysis detected phosphorus-containing radical species (PO• and PO 2 •), indicating that the flame retardant action mainly proceeded via a gas-phase radical trapping mechanism. However, the incorporation of SOPE led to a reduction in molecular weight and mechanical properties due to the hydrolytic degradation of PLA. Overall, the results demonstrate that soybean oil–derived phosphate ester can serve as a bio-based and effective flame retardant for PLA.
