Over the last few years, significant interest has been noted toward the utilization of natural fibers to develop sustainable composites. The demand for minimizing the use of synthetic fibers and replacing them with natural fibers in polymer composite is continuously increasing. Date palm tree has been a renowned source of lignocellulosic fibers/fillers in the development of polymeric composites. However, date palm leaves (DPL) have not been explored in woven form; therefore, in the current research endeavor, DPL have been weaved into woven mat form to investigate the DPL potential to be used as reinforcement in composite laminates. The DPL was modified with chitosan solution to enhance their thermal stability. The composite laminates were developed using direct compression molding using film stacking method. The influence of DPL reinforcement on mechanical, thermal, flammability, and dynamic mechanical behavior of the composites has been investigated and is reported. The tensile strength was found to decrease for PP-DP composites, while tensile modulus was found to increase, while, for chitosan-treated DPL reinforced composite (PP-DP-Cs), a slight improvement of about 0.81% in tensile strength was recorded, and tensile modulus was improved by 42.20%. Chitosan-modified DPL has resulted in enhanced thermal stability and recorded the reduced burning rate for the developed composites. Results indicated that with a slight compromise in mechanical properties, the developed material could be commercialized for non-structural applications under waste management scheme.
The development of science technology, growing demand for producing sustainable compounds in material science, has promoted newer innovations such as producing lightweight biocomposite material. The present study also aims to investigate the mechanical, wear, and thermal stability properties of bio-oil toughened polyester matrix reinforced under palm kernel fiber and chitosan biopolymer. Furthermore, for understanding the overall performance of the composite, and the durability of the material over a period of time, the present study examined the composite strength after the aging process, which is treating under varying atmospheric conditions, and it brings a novelty to this study. The chitosan is rich in amine groups, which promote the mechanical strength of the material, and it is bio-extracted from sea urchin species using alkali and acid treatment. Further, for promoting toughness and stiffness properties to the composite, the cardanol oil is blended with resin matrix. Finally, using those raw materials, the composite material is prepared under the hand layup method. The result of the study demonstrated that the addition of chitosan biopolymer of 3 vol.%, fiber of 40 vol.%, and cardanol oil of 20 vol.% on the composite PC5 shows better mechanical, wear, and thermal stability behavior when compared to aged composite material. The study findings concluded that the tensile and flexural strength of aged composite PC5 is 20% reduced strength when compared to unaged composite material. Further, the increase chitosan of 5 vol.% in composite (PC6) exhibited a COF of 0.45 and a specific wear rate of 0.005 mm3/Nm, representing reductions of 43.75% and 85.71%, respectively, compared to PC0. The thermogravimetric analysis (TGA) further highlighted the thermal stability improvements, with chitosan-reinforced composites exhibiting the highest resistance to thermal degradation. PC6 retained 80% of its weight at 500 °C compared to only 20% for the plain resin. The fatigue properties also followed a similar trend, with PC5 demonstrating fatigue lives of 20 × 103 cycles at 25% UTS, 18 × 103 cycles at 50% UTS, and 16 × 103 cycles at 75% UTS, indicating significant improvements over the plain resin. Thus, the overall study of the composite shows that reinforcement of kernel fiber, chitosan, and cardanol oil into the composite shows superior mechanical, wear resistance, and thermal stability properties; however, the composite under aging drops in strength property, and it is considerable. Due to such superior strength, wear resistance, and corrosive resistance even under the aging process, the biocomposite is applied in housing kitchens, washtubs, turbine blades, windmill sectors, interior door panels automotive, aviation sector, etc.
Emission of radio waves or electromagnetic waves is increasing in recent days due to emerging people to people connection and internet, mobile network connection. To reduce such electromagnetic interference (EMI), the shielding is used in those EMI caused equipment. The present study fabricated flexible polyvinyl alcohol (PVA) composites reinforced with rice husk microfiber, dragon fruit peel biochar, and cobalt nanoparticles which makes a novelty to this study. The composites were produced using the stir casting method, and test specimens were characterized according to ASTM standards. Among the composite designations, PF23 exhibited superior mechanical properties, including a tensile strength of 73 MPa and a low elongation of 142%, accompanied by a Shore-D hardness of 40. The incorporation of biochar and cobalt filler particles with rice husk microfiber significantly enhanced the mechanical properties of the matrix. Furthermore, the dielectric properties of PF23 demonstrated improvement, with dielectric permittivity values of 5.48, 4.1, 2.21, and 0.98 for frequency bands of 8 GHz, 12 GHz, 16 GHz, and 20 GHz, respectively. Similarly, PF23 exhibited enhanced magnetic permeability values of 3.42, 3.94, 4.43, and 5.99 for the same frequency bands. Moreover, PF23 demonstrated superior electromagnetic interference (EMI) shielding effectiveness, with total shielding values of 7.41 dB, 10.92d B, 16.45 dB, and 22.79 dB for frequency bands ranging from 8 to 20 GHz. Overall, the incorporation of rice husk microfiber, dragon fruit peel biochar, and cobalt nanoparticles resulted in multifunctional PVA composites with improved mechanical, dielectric, magnetic, and EMI shielding properties, making them promising candidates for various applications in electromagnetic shielding and related fields.
Food wastes are important raw materials for obtaining valuable ingredients with broad applications in the food, cosmetic, and pharmaceutical sectors. This work aims to optimize the high-power ultrasound-assisted extraction (UAE) of proteins from brewer’s spent grains (BSG) using a factorial design (23) and compare their nutritional and techno-functional properties with proteins obtained by conventional extraction (CME). The optimized UAE condition was 550 W, 10 min, and 65°C, resulting in concentrates with a protein content 8% higher than the CME in an extraction time reduced by 92%. Furthermore, the essential amino acid fraction was higher in UAE, providing good digestibility, antioxidant action, and technological properties (emulsification, foam, water and oil retention and solubility). Thus, the use of UAE to extract proteins from BSG is satisfactory, favoring the obtaining of protein concentrates with good technological, functional, and nutritional performances, enhancing their use as an ingredient in foods, pharmaceuticals, or cosmetics products.
Cellulose is one of the main constituents of plants and is present in a variety of renewable natural resources. Açaí, an Amazonian fruit, has gained popularity as a “superfood” due to its high levels of antioxidants and bioactive compounds like anthocyanins and flavonoids. The pulp comprises only 10% of its weight, and tons of açaí seeds are discarded without a structured waste management system. Considering the applications of agro-industrial residues in the development of new materials, it has been observed that there is potential for utilizing açaí seeds in the field of nanotechnology, with the sustainable production of cellulose nanocrystals and nanofibers. These nanomaterials offer potential for applications including packaging, textiles, biomedical devices, and environmental remediation. Therefore, this review presents alternative and sustainable sources of cellulose in the agrobiodiversity, with emphasis on the açaí berry, an important native fruit of the Amazon Forest. Techniques for the development of new cellulose-based materials that involve the use of nanotechnology are reported.
Over the past 10 years, there has been a growing interest in the field of hydrothermal processing of algal biomass. By making use of a thermochemical process, biomass can be transformed into char, biocrude, and other useful compounds. Because hydrothermal technologies are economical and environmentally benign and provide high-quality products, they are becoming more and more popular among thermochemical techniques. Examples of these technologies are hydrothermal carbonisation, liquefaction, and gasification. Different kinds of wet biomass are converted using hydrothermal technology into products with added value including syngas, bio-oil, and hydrochar. Because the biomass is treated wet in hot-compressed water as slurry, this method has been found to be particularly suitable for high-moisture aquatic biomass, such as macro- and microalgae. This article has provided an overview of the several methods for harvesting algae and the variables that impact its growth. The role of algae in hydrothermal processing and the mechanism of hydrothermal processing of algal biomass are put forward in this investigation in order to systematically grasp the current situation and create a basis for promoting the technology. This content has also emphasised the factors that affect the hydrothermal process, and the discussion has also been directed towards the diverse uses of hydrochar derived from algal biomass, including solid biofuel, adsorbent, carbon sequestration, nutrient retention, and supercapacitor applications. In order to achieve a comprehensive environmental profile, the life cycle assessment (LCA) concludes by discussing the limitations of the state of the art as well as the introduction of new possible input categories. The LCA of hydrothermal biomass conversion and hydrothermal technologies are the subjects of this comprehensive study.
Edible seaweeds have gained significant interest among the nutraceutical industries due to their rich content of amino acids, fatty acids, and minerals. The tank cultivation of edible seaweed like Ulva sp. generates a significant amount of spent seawater, which must either be reused or treated for safe discharge into coastal waters. This study aims to utilize spent seawater from Ulva sp. grown tanks for the production of marine microalgal biomass, focusing on the extraction of high-value lutein and protein. Accordingly, three major pre-treatment methods—autoclaving, filtration, and chlorination—were performed on spent seawater, both with and without medium supplementation, followed by the cultivation of marine Chlorella sp. 1151 as a model microalga. Among the treatment methods, spent seawater either sterilized by autoclave or chlorination with medium addition resulted in higher biomass (0.91–1.03 g L−1), lutein (1.10–1.88 mg g−1), and protein (64.86 – 68.83 mg g−1) yields, which were almost comparable to those obtained with fresh seawater supplemented with medium. Chlorella sp. 1151 efficiently utilized nitrate and phosphate by 95–97% in the spent seawater for the optimal experimental combinations as stated above. Further, analysis of heavy metals including Co, Cu, Fe, Mn, Zn, Ba, Ni, Mo, Pb, Cr, and Cd in the cultivated spent seawater were well below the permissible limits for safe discharge. This study demonstrates the novel approach of repurposing spent seawater from seaweed cultivation for the production of marine microalgal biomass- based lutein and protein.
Nigella sativa seed oil is widely used as an anti-inflammatory, antioxidant, and anticancer agent. However, its insolubility in aqueous media and low stability limit its practical biological applications. The aim of this study was to formulate and characterize Nigella sativa seed oil (NO) using β-cyclodextrin (β-CD). The preparation of the inclusion complexes was carried out by co-precipitation method and then validated by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), and dynamic light scattering (DLS). The encapsulation efficiency of the inclusion complexes formed was about 80.4% and 88.2% for the two ratios studied, 1:2 and 1:4 (w:w), respectively. The study showed that the Nigella oil encapsulation preserved the antioxidant activity against DPPH and, in particular, enhanced the antibacterial activity against Salmonella typhimurium, Staphylococcus aureus, and Bacillus cereus by a factor reaching fourfold. A minimum inhibitory concentration similar to that of ampicillin (0.078 mg/mL) was observed against Salmonella typhimurium when the complex β-CD/NO 1:4 (w:w) was used. The cytotoxicity study showed that the oil encapsulation in β-CD retained its anti-proliferative activity against HeLa cancer line cells. Using SwissADME prediction, the pharmacokinetic profile of all identified oil compounds was evaluated to define their absorption, distribution, metabolism, and excretion (ADME) properties. The results support the use of encapsulated Nigella oil for active food packaging or pharmaceutical formulations.
Rice is a major crop cultivated in Northern India. The open burning of stubble left after harvesting of this crop has severe impacts on environment despite various interventions for its in situ and ex situ management; large quantities of paddy straw continue to be burnt in open fields. Thus, there is pressing need to establish techno-economically viable applications for paddy straw. In the present study, paddy straw in pellet form was utilized as partial replacement of coal in brick kiln industry. The trials were conducted with combination of different ratios of paddy straws pellets (PSP), and coal is used in ratios 10:90, 15:85, 20:80, and 30:70. After mixing the PSP with coal, this mixture was fed in the feed holes of the brick kilns and their effectiveness for achieving the required temperature range, and energy for vitrification/baking of clay bricks was assessed. After conducting the trials, the optimum PS-based pellet to coal ratio could be obtained without any modification in the configuration of the kiln or process. Thus, after the investigation, it has been found that the coal can be replaced partially with 20% PSP. Further, the stack emission monitoring showed reduction suspended particulate matter (SPM) and sulfur dioxide (SO2) emissions. The values of brick quality test presents that the PSP co-fired bricks fall under Class 15 standard as per the IS code 1077 (1992): Common Burnt Clay Building Bricks-Specification.
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