Search Results (4,873)

The use of black alder (BA) bark biomass in rigid polyurethane (PUR) foam compositions was the main task of investigation. Extractive compounds isolated from the bark through hot water extraction were used as precursors for bio-polyol synthesis via acid-free liquefaction with the polyether polyol Lupranol 3300 and through oxypropylation with propylene carbonate. The OH functionality and composition of the polyols were analyzed via wet chemistry and FTIR spectroscopy. The solid remaining after the isolation of extractive compounds was also utilized as a natural filler in PUR foams. The effects of replacing commercial polyols with bio-polyols on the foam rising rate and their mechanical properties, morphology, thermal conductivity, and thermal degradation characteristics were examined. The oxypropylated extractive-based PUR compositions demonstrated the most favorable balance between the biomass content and material properties. At an apparent density of 40 kg/m³, the compressive strength of the produced foams was enhanced by 1.4–1.5 times, while the maximum thermal degradation rate in air decreased by 3.8–6.5 times compared to reference materials without adversely affecting the foam morphology. The composition based on liquefied extractives showed lower performance but still improved properties relative to the reference foams. Introducing 3.7–14% of extracted bark into the foam compositions increased the biomass content to 22–24%, although this led to a decrease in the compressive strength and thermal stability. It was shown that partially substituting fossil-derived components with renewable bark biomass in the composition of PUR foams allows for materials with characteristics similar or better to petrochemical-based materials to be obtained. Therefore, the results presented can be considered a contribution to addressing environmental problems and promoting the development of a sustainable economy. Full article

The present research aims to valorize biofloc waste by extracting polyphenols via alkaline hydrolysis, utilizing them as reducing and stabilizing agents in the optimization of green synthesis of silver nanoparticles (BIOAgNPs). For the alkaline extractions, potassium hydroxide (KOH) concentrations of 0 to 4 M were used in combination with ultrasound. Total polyphenol content and antioxidant activity were evaluated. BIOAgNPs synthesis was optimized using the response surface methodology and central composite design. The parameters time, temperature, AgNO₃ concentration, and the percentage of the biofloc extract (2 M KOH), with measurements taken for the area under the curve (AUC) (400–500 nm) and the mean hydrodynamic diameter (DLS), were evaluated. Antibacterial activity was determined for Gram-negative and Gram-positive bacteria. Higher polyphenol content and antioxidant activity were observed using 2 M KOH. The optimized model for DLS and the AUC was obtained in 4 h, at 40 °C, using 2.4 mM AgNO₃ and obtaining 2.5% of extract. Optimized BIOAgNPs had a diameter of 22.4 nm, hydrodynamic diameter of 106.5 nm, zeta potential of −28 mV, and polydispersity index of 0.26. BIOAgNPs demonstrated bactericidal activities. This study enhanced the valorization of aquaculture residues through improved polyphenol extraction techniques and developed an effective methodology for synthesizing silver nanoparticles with antimicrobial activity. Full article

Green chemistry focuses on reducing the environmental impacts of chemicals through sustainable practices. Traditional methods for extracting bioactive compounds from Eucalyptus marginata leaves, such as hydro-distillation and organic solvent extraction, have limitations, including long extraction times, high energy consumption, and potential toxic solvent residues. This study explored the use of supercritical fluid extraction (SFE), pressurized liquid extraction (PLE), and gas-expanded liquid (GXL) processes to improve efficiency and selectivity. These techniques were combined in a single mixture design, where CO₂ was used in the experiments carried out under SFE, while water and ethanol were used for the PLE and GXL experiments by varying the concentration of the solvents to cover all the extraction possibilities. The neuroprotective activity of the extracts was evaluated by measuring their antioxidant, anti-inflammatory, and acetylcholinesterase inhibition properties. The optimization resulted in a novel GXL extraction with an optimal ternary mixture of 27% CO₂, 55% ethanol, and 18% water, with a high degree of desirability (R² = 88.59%). Chromatographic analysis carried out by GC-MS and HPLC-ESI-MS/MS identified over 49 metabolites. The designed sustainable extraction process offers a promising approach for producing phenolic-rich plant extracts in industrial applications. Full article

Natural resources are currently overexploited to provide food supply for the ever-increasing world population, and because of the intensification of agricultural and food production, there is a growing rate of waste generation. This waste biomass is usually dumped into landfills, causing unprecedented damage to ecosystems. Nowadays, circular economy strategies are channeled towards waste harnessing, aiming at reducing the irrational use of resources and minimizing waste generation. Potatoes are the second largest food crop after cereals, and there is an overwhelming amount of waste derived from potato tuber processing, composed almost exclusively of peels. Potato peels (PPs) are considered a source of polyphenolic compounds, largely represented by chlorogenic acid and other structurally related hydroxycinnamates, which possess a spectrum of bioactivities; however, there is a lack of analytical data compilations that could be of assistance in pertinent studies. With this as the conceptual basis, the scope of this review focused on a particular class of polyphenols, the so-called hydroxycinnamates, to deliver compiled data associated with the occurrence, retrieval, and application of this group of compounds derived from potato waste with major emphasis being given to PPs. It is believed that the collection of data of this nature, due to their undisputed significance in studies pertaining to bioeconomy, biorefinery, and food waste valorization, would provide a highly useful contribution to the field. Full article

The grapevine industry is confronted with challenges such as plant stress from environmental factors and microbial infections, alongside the need for sustainable waste management practices. Natural polymers offer promising solutions to these issues due to their biocompatibility, biodegradability, and functional versatility. This review explores the dual role of natural polymers in enhancing the grapevine industry: as protective agents against various stressors and as carriers for the delivery of valuable compounds recovered from grapevine wastes. We examine the use of natural polymers such as chitosan, alginate, and cellulose in formulating bio-based protective coatings and treatments that bolster plant resistance to abiotic stress, pathogens, and pests. Additionally, the review delves into the innovative utilization of grapevine residues, including skins, seeds, and stems, as sources of polyphenols and other bioactive compounds. These compounds can be efficiently encapsulated in natural polymer matrices for applications in agriculture, food, and pharmaceuticals. Key topics include the mechanisms of action, benefits, and limitations of natural polymer-based interventions, as well as case studies demonstrating their practical implementation in vineyards. The review also addresses future research directions, emphasizing the need for integrated approaches that enhance sustainability and economic viability in the grapevine industry. Full article

This study examines calcium extraction from Bottom Ash (BA) and the use of Solid Residue (SR) as a substitute for White Lump Clay (WLC) in brick production. Experimental analyses identified calcium and silicon as the main elements in BA, with 50% of calcium carbonate recovered through leaching. SR was a viable alternative to WLC in ceramic bricks, as SEM-EDS and FTIR analyses revealed changes in composition and microstructure. This approach promotes circular economy principles by recovering resources and reducing waste. Calcium extraction from BA can produce 29,000 tons of CaCO₃ annually for industrial use, while substituting SR for WLC in brick production could replace 30% of clay, saving 1500 tons of clay and producing millions of bricks annually. Less than 50% of incinerated Municipal Solid Waste (MSW) would require landfilling. The process supports sustainable construction by conserving natural resources, reducing landfill waste, and lowering CO₂ emissions. It offers annual cost savings of 2,639,250 USD and preserves 74,812.5 tons of resources through waste and clay reduction. By demonstrating a scalable model for waste valorization, this research aligns with global goals for sustainable development, resource efficiency, and ecological balance. Full article

The growing challenges of climate change, the depletion of fossil fuel reserves, and the urgent need for carbon-neutral energy solutions have intensified the focus on renewable energy. In this perspective, the generation of green hydrogen from renewable sources like biogas/landfill gas (LFG) offers an intriguing option, providing the dual benefits of a sustainable hydrogen supply and enhanced waste management through energy innovation and valorization. Thus, this review explores the production of green hydrogen from biogas/LFG through four conventional reforming processes, specifically dry methane reforming (DMR), steam methane reforming (SMR), partial oxidation reforming (POX), and autothermal reforming (ATR), focusing on their mechanisms, operating parameters, and the role of catalysts in hydrogen production. This review further delves into both the environmental aspects, specifically GWP (CO₂ eq·kg⁻¹ H₂) emissions, and the economic aspects of these processes, examining their efficiency and impact. Additionally, this review also explores hydrogen purification in biogas/LFG reforming and its integration into the CO₂ capture, utilization, and storage roadmap for net-negative emissions. Lastly, this review highlights future research directions, focusing on improving SMR and DMR biogas/LFG reforming technologies through simulation and modeling to enhance hydrogen production efficiency, thereby advancing understanding and informing future research and policy initiatives for sustainable energy solutions. Full article

This study investigates the potential of utilizing livestock waste and vineyard residues for sustainable energy production in Portugal. Through the physical and chemical characterization of swine waste, grape seeds and skins, cork powder, sawdust, and biochar, 53 distinct samples, including 11 individual biomasses and their derived mixtures, were analyzed to identify optimal combinations for biofuel pellet production. The best-performing mixture, composed of 50% swine waste, 25% grape seeds and skins, and 25% cork powder, achieved a Lower Heating Value (LHV) of 18.34 MJ/kg and low ash content, qualifying it as a class B pellet. This mixture offers significant energy potential while minimizing environmental impacts. The research also presents three energy valorization scenarios, with the most balanced scenario meeting up to 6% of Portugal’s electricity demand and providing energy savings equivalent to 485,463 tons of oil equivalent (toe) annually. A case study on a “Case Study Farm” in the Douro region, managing 2000 pigs and producing 500 tons of wine grapes annually, demonstrated that implementing the optimal biomass mixture could generate 3854 MWh of heat and 1156 MWh of electricity per year. This could result in annual revenues of EUR 189,258 from pellet sales, covering the initial investment of EUR 283,938 within 6.36 years, with a total surplus of EUR 689,666 over 20 years. These findings highlight the economic viability and environmental benefits of converting agricultural waste into renewable energy, contributing to Portugal’s carbon neutrality and reducing energy dependence. Full article

This study investigates the potential of sequential solid-state and submerged fermentation (SeqF) to enhance lipase production by Yarrowia lipolytica using by-products from the palm oil production chain. Palm fiber and palm oil deodorizer distillate (PODD) were utilized as substrates in both fermentation stages. Solid-state fermentation (SSF) yielded significant lipase activity when palm fiber was used alone (1.55 U/g in 48 h), while submerged fermentation (SmF) showed improved enzymatic production with the combination of fiber and PODD (1171 U/L in 72 h). The integration of SSF and SmF in SeqF achieved superior lipase activities, reaching 4464.5 U/L, an 8.3-fold increase compared to SmF alone, in Erlenmeyer flasks. SeqF-lyophilized biocatalysts from Erlenmeyer experiments showed better hydrolytic activity (131 U/g) when the best conditions were reproduced in a 4 L bioreactor (33 U/g). The SeqF-lyophilized biocatalyst was employed in esterification reactions to synthesize mono- and diacylglycerols, achieving a 24.3% conversion rate. The study highlights SeqF as a promising and sustainable approach for valorizing agro-industrial residues, contributing to biocatalyst production and advancing circular bioeconomy initiatives. Full article

Augmented reality (AR) offers several advantages in the commercialization of wood products, increasing both the efficiency and the attractiveness of the process of presenting and selling them. The digitization and virtualization of wood features/products for the purpose of their economic valorization represent a significant advance in technology and its application in traditional industries such as wood processing and trade. We present a concrete process of digitization and virtualization of wood features through AR for the purpose of its commercial valorization. Three methods of object scanning are tested: convergent photogrammetry, LiDAR scanning using an iPhone, and handheld scanners. Wood samples with different textures, shapes, and surface properties were used for the research, while each method was tested on a trio of models. The methods showed specific limitations: convergent photogrammetry is time-consuming and prone to human error, LiDAR iPhone scanning provides lower output quality and struggles with reflective surfaces, while handheld scanners are expensive and require additional tools for capturing color. Convergent photogrammetry was evaluated as the optimal and available method for the widest range of users. The 3D models were integrated into the Virtual Wood Market application, created in the Unreal Engine environment. The use of augmented reality in wood product commercialization offers significant benefits, including enhanced material efficiency, improved design and fabrication processes, better supply chain management, and increased customer engagement. These advantages can lead to more sustainable practices and higher customer satisfaction, ultimately driving the success of wood product commercialization. Full article

Lignin is considered a renewable source for the production of valuable aromatic chemicals and liquid fuel. Solvent depolymerization of lignin is a fruitful strategy for the valorization of lignin. However, Kraft lignin is highly prone to produce char (a by-product) during the hydrothermal depolymerization process due to its poor solubility in organic solvents. Therefore, the minimization of char formation remains challenging. The purpose of the present study was to fractionate Kraft lignin in methanol to obtain low-molecular-weight fractions that could be further depolymerized in supercritical methanol to produce aromatic monomers and to suppress char formation. The results showed that the use of methanol-soluble lignin achieved a bio-oil yield of 45.04% and a char yield of 39.6% at 280 °C for 2 h compared to 28.57% and 57.73%, respectively, when using raw Kraft lignin. Elemental analysis revealed a high heating value of 30.13 MJ kg⁻¹ and a sulfur content of only 0.09% for the bio-oil derived from methanol-soluble lignin. The methanol extraction process reduced the oxygen content and increased the hydrogen and carbon contents in the modified lignin and bio-oil, indicating that the extracted lignin fraction had an enhanced deoxygenation capability and a higher energy content. These findings highlight the potential of methanol-soluble Kraft lignin as a valuable resource for sustainable energy production and the production of aromatic compounds. Full article

The solvent-free hydrogenolysis (HDL) of benzyl phenyl ether (BPE), a model for the C–O (α-O-4) linkage in lignin, was investigated using NiMo-pillared clay catalysts in their reduced (NiMoPR) and sulfided (NiMoPS) forms. NiMoPS show higher activity and selectivity to give an equimolar mixture of toluene and phenol, demonstrating selective cleavage of the C_aliphatic–O of BPE, while non-equimolar amounts were found for NiMoPR. Strong acid sites are dominant in NiMoPS, giving a higher total acidity compared to NiMoPR, which explains the higher selectivity of the sulfided catalyst towards the HDL products and monomeric aromatics. To understand the interaction of BPE on the catalyst surface, we carried out a comprehensive investigation of the 2D potential energy surface (PES) of BPE and the vibrational spectra using neutron scattering and computational studies. The results suggest that BPE is weakly adsorbed on NiMoPS and the pillared clay support (PILC) via a van der Waals or H-bonding interaction, but they are strongly chemisorbed on the NiMoPR due to covalent bonding. Weakly adsorbed BPE allows higher mobility during diffusion to the catalytic site, which promotes the higher activity of NiMoPS for the HDL. This work demonstrates the potential use of clay-supported NiMo catalysts for lignin valorization and the future circular economy. Full article

The combustion of renewable solid fuels, such as biomass, is a reliable option for heat and power production. The availability of biomass resources within urban areas, such as tree leaves, small branches, grass, and other green city waste, creates an opportunity to valorize such resources. The energy densification of such resources using hydrothermal carbonization (HTC) and pelletization of the carbonized material could create a new generation of domestic boiler biofuel. However, combustion efficiency and emission assessments should be carried out for HTC pellets. The primary objective of this study is to assess HTC pellets, provided by a waste upgrade company, in terms of kinetics, combustion efficiency, and emissions, taking as reference base ENplus A1 certified softwood pellets. Therefore, thermogravimetric analysis and combustion tests were conducted for both fuels to achieve this. It was observed that a third peak of the burning rate during the solid carbon oxidation of HTC pellets indicated a high activation energy. Combustion tests showed a 7% increase in boiler efficiency for HTC pellets compared to softwood pellets. However, higher particulate matter (PM), NO_x, and CO emissions were recorded during the HTC pellets test. The results suggest that optimizing the air/fuel ratio could further improve the performance of HTC pellets in domestic boilers. Full article

Marine invasive species pose significant ecological, economic, and social challenges, disrupting native ecosystems, outcompeting local species and altering biodiversity. The spread of these species is largely driven by global trade, shipping, and climate change, which allow non-native species to establish themselves in new environments. Current management strategies, including early detection, rapid response, and biosecurity measures, have had some success, but the complexity and scale of the problem require continuous monitoring. This review explores the possibility of using some marine invasive species as skincare ingredients and explores the Azorean islands as a case study for the valorization of biomass. Additionally, this review addresses legislative barriers that delay the development of sustainable cosmetic markets from invasive species, highlighting the regulatory landscape as a critical area. It concludes that marine invasive species present a regional and global problem that requires regional and global solutions. Such solutions strongly need to address environmental impacts and net socioeconomic benefits, but such solutions must also consider all regional differences, technical capacities and financial resources available. Thus, as a future perspective, strategies should emphasize the need for international collaboration and the development of more effective policies to prevent the spread of invasive species. There is still much work to be completed. By working together, the biodiversity for future generations will be better monitored and explored. Full article

Grape pomace (GP), a byproduct of winemaking, has gained significant attention as a sustainable and functional ingredient with applications in the food and nutraceutical industries. This review examines the potential of GP in meat products and analogs, functional foods, and nutraceuticals, highlighting its composition, health benefits, and role in enhancing nutritional and functional properties. Rich in dietary fiber, polyphenols, essential fatty acids, and bioactive compounds, GP exhibits antioxidant, anti-inflammatory, and gut health-promoting effects, making it suitable for various food applications. Its incorporation into meat products, such as sausages and patties, improves texture, enhances shelf life, and increases nutritional value while reducing the environmental footprint. GP is also effective in functional foods such as baked goods, dairy and plant-based yoghurts, smoothies, and snack bars, where it can enrich fiber and polyphenol content, aid in satiety, and provide health benefits beyond basic nutrition. The challenge is how to maintain the sensory properties characteristic of conventional, unmodified products. In nutraceuticals, GP’s polyphenolic compounds and dietary fiber support antioxidant, anti-inflammatory, and metabolic health functions, with applications as antioxidant supplements, gut health boosters, weight management aids, and cardiovascular health supplements. Despite challenges such as taste modification and optimizing bioavailability, GP’s versatility and sustainability highlight its value in developing innovative, health-oriented products. This review emphasizes the promise of GP as a valuable ingredient in functional foods and nutraceutical formulations, contributing to health, sustainability, and resource efficiency. Full article