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.
Biopolymers have attracted increasing scientific interest because of their biodegradability, low toxicity and potential environmental benefits. Among these materials, cellulose has emerged as one of the most prominent biopolymers in recent years. This study aims to develop a sustainable cellulose-based adsorbent from recycled carton paper, providing a sustainable approach for rare earth recovery. The cellulose was sequentially treated under acidic and alkaline conditions, followed by grafting with amino naphthol sulfonic acid, leading to the formation of a novel composite referred to as cellulose amino naphthol sulfonic acid (CANS), which was specifically designed for the extraction of rare earth element (REE) from chloride-rich solutions. The CANS adsorbent was characterized using a range of physicochemical techniques and subsequently applied as an adsorbent for REE recovered from monazite ore. The ideal pH for the process of sorption at 30°C was determined to be 3, with equilibrium attained within 60 minutes. Several kinetic and isotherm models were employed to evaluate the sorption behaviour, illuminating a maximum capacity of 196.5 ± 3.1 mg g −1 . The sorption process was best described by a pseudo-second-order kinetic model. Desorption studies showed that approximately 98% of the adsorbed REE were successfully released using 0.5 M H 2 SO 4 . Further separation of the contaminant elements from desorbed REE was achieved using 10% oxalic acid at pH 1, yielding preferential REE concentrate. These findings indicate that the CANS sorbent is a promising material for the selective recovery of rare earth elements from acidic leachate.
This study presents the development of hydrophobic polymeric films from bacterial cellulose (BC) produced by fermenting banana pseudostem juice and mature coconut water, two underutilized agricultural byproducts. Carnauba wax was applied as a surface coating in 1–3 layers, with and without hot pressing. The coating substantially increased hydrophobicity, with water contact angles rising from 56° in the uncoated film to over 100° in multilayer-coated films, although the films did not exhibit oleophobic behavior based on silicone oil contact angle measurements. The coating also significantly reduced water absorption from 91.45% in the uncoated film to 10.37% and 5.63% in the coated and coated–hot-pressed films, respectively, while water holding capacity decreased from 86.28% to 57.70% and 54.36%. Hot pressing produced a smoother and more homogeneous surface morphology, as observed by SEM. ATR–FTIR analysis supported the increase in hydrophobicity through reduced O–H and H–O–H band intensities. XRD analysis confirmed that the cellulose I crystalline structure remained intact after coating, while additional peaks corresponding to crystalline carnauba wax were observed. DSC revealed a melting transition of carnauba wax around 52°C, with hot-pressed samples showing an additional higher-temperature melting event. TGA indicated reduced moisture uptake but lower thermal stability, with degradation onset decreasing from 267°C in the uncoated film to 200–212°C in coated samples. Overall, multilayer carnauba wax coating provides a simple, solvent-free approach to improve the water resistance of BC films while preserving their structural integrity, making them promising for moisture-sensitive food packaging applications.
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.
