Search Results (95)

This study evaluates, from energy, exergy, exergo-sustainability, and environmental perspectives, two combined-cycle configurations based on a supercritical CO₂ Brayton cycle coupled to an ORC: a simple reheat configuration (S-CO₂-ORC) and a recompression-reheat configuration (SRC-CO₂-ORC). Both were assessed under two thermal sources: concentrated solar power (CSP) and a hybrid biomass-CSP source using oil palm residues. Sizing was based on the cooling demand of a 130-home residential complex in Barranquilla, estimated at 152 kW through hourly simulation. The SRC-CO₂-ORC configuration delivered the best energy performance, reaching 138.38 kW and 55.34% with CSP and up to 157.28 kW and 57.66% under hybrid operation. The highest irreversibilities were concentrated in the solar field and receiver, while the thermal sources contributed more than 85% of the total carbon footprint. The lowest life-cycle impact corresponded to the SRC-CO₂-ORC-Solar configuration, at 0.0117 kg CO₂-eq/kWh, against 0.0194 kg CO₂-eq/kWh for the S-CO₂-ORC-Hybrid case. The results confirm the technical feasibility of these configurations for residential applications and reveal a clear trade-off between thermodynamic performance and minimum carbon footprint. Full article

The incorporation of supplementary cementitious materials derived from agro-industrial residues has emerged as a promising strategy to reduce the environmental impact associated with Portland cement production while promoting circular economy principles. This study investigates the influence of palm oil fuel ash (POFA) as a partial cement replacement on the mechanical and microstructural properties of concrete. Concrete mixtures containing 0%, 10%, 15%, and 20% POFA by mass of cement were produced using a constant water-to-binder ratio of 0.47. Compressive strength was evaluated at 7, 14, 28, and 56 days, while microstructural characterization was performed using scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM–EDS) to assess hydration products and the interfacial transition zone (ITZ). The incorporation of POFA resulted in lower compressive strength at early curing ages, with reductions of approximately 16–21% compared with the control mixture, reflecting the slower kinetics of pozzolanic reactions. However, prolonged curing promoted significant strength development. At 56 days, concretes containing 10% and 15% POFA exhibited compressive strengths 3.7% and 9.2% higher, respectively, than the control concrete, whereas the 20% replacement level resulted in a 14.6% reduction. SEM observations revealed a denser cementitious matrix, improved aggregate–paste bonding, and a more refined ITZ in mixtures containing 10–15% POFA. EDS analysis showed Ca/Si ratios of 1.22 and 1.08 for the 10% and 15% POFA mixtures, respectively, indicating the formation of silica-rich C–S–H gel associated with effective pozzolanic activity. The results demonstrate that POFA can be successfully utilized as a supplementary cementitious material in concrete. While the 15% replacement level produced the highest 56-day compressive strength, both the 10% and 15% mixtures exhibited favorable microstructural characteristics and effective pozzolanic activity, indicating that both replacement levels are suitable for sustainable concrete production. Full article

This study integrates microbial biotechnology, bioprocess optimization, and circular bioeconomy principles to valorize oilseed agro-industrial coproducts as low-cost inducing substrates for lipase production. Palm kernel cake (PKC), canola cake, andiroba cake, and brewer’s spent grain were evaluated as carbon sources for extracellular lipase production by the wild-type strain Trichoderma sp. LEPM-711 under submerged fermentation. Qualitative screening in olive oil/rhodamine B medium confirmed the strain’s lipolytic potential. Among the substrates tested, PKC showed the strongest induction, reaching 4.68 U mL⁻¹, and was therefore selected for nitrogen supplementation and statistical optimization. Peptone supplementation increased lipolytic activity to 8.41 U mL⁻¹ after 72 h. A Plackett–Burman design identified CaCl₂·2H₂O, CoCl₂·6H₂O, and peptone as significant medium components, while response surface methodology established the optimal operational conditions as pH 6.0, 10⁶ spores mL⁻¹, and 2% (w/v) PKC. Under these conditions, the crude enzymatic extract reached 18.31 U mL⁻¹ at pH 7.0 and 45 °C, corresponding to an approximately 3.9-fold increase over the initial PKC fermentation. These findings support the use of Trichoderma sp. LEPM-711 and oilseed coproducts as a sustainable platform for enzyme production and residue upgrading within applied natural sciences. Full article

The rapid expansion of oil palm cultivation in the Colombian Orinoquia has generated economic benefits but also environmental and social pressures associated with biomass residue management. In this context, residue valorization through bioproduct production has gained relevance as a strategy linked to circular bioeconomy and regional sustainability. This article analyzes the prioritization of socioeconomic impacts associated with the reuse of oil palm residues in the department of Meta, Colombia, using a participatory multicriteria approach. The method combined the Analytic Hierarchy Process (AHP), the Ratings technique, and the DEMATEL method to evaluate social, economic, and environmental dimensions identified together with territorial stakeholders. The assessment process involved 31 participants representing academia, public institutions, productive sectors, financial entities, and civil society organizations. The results showed greater prioritization of impacts associated with employment generation and local economic development. The DEMATEL analysis revealed that economic and employment-related criteria exerted stronger influence within the evaluated system. Environmental sustainability also reached high relevance, whereas gender equity and post-pandemic regional resilience obtained lower relative weights in the prioritization process. Full article

The present paper highlights a critical assessment of the large-scale production and accumulation of date palm (Phoenix dactylifera) by-products. These have been identified as both serious environmental problems and potential renewable energy sources. Landfilling, burning in fields, and other such poor methods are common among many of the countries producing dates as ways to dispose of huge amounts of date palm by-products. The current literature has been assessed for their utilization in energy generation in the form of a circular bioeconomy with respect to the characteristics and composition of date palm seeds, leaflets, rachis and fibers. The study reveals that thermochemical conversion methods such as pyrolysis, gasification and hydrothermal processes are very efficient for the conversion of date palm residues into bio-oil, syngas and biochar. The resulting bio-oils are, however, rich in oxygen, acidic and unstable in nature and need to be upgraded using a catalytic process. Moreover, the review highlights that advanced catalytic technologies can greatly improve the quality of fuel through deoxygenation and the synthesis of hydrocarbons, resulting in the production of “drop-in” gasoline components and SAFs that have characteristics close to those of regular petroleum-based fuels. Also, artificial intelligence- and machine learning-based modeling techniques appear to offer considerable prospects in the realm of thermokinetic studies, process design, and large-scale implementation. Furthermore, the results point out two environmental advantages that accrue from the date palm valorization process, since biochar generated via thermochemical transformation can be used for seawater desalination. Lastly, the techno-economic evaluation and roadmap of future development directions are provided. Full article

Babassu (Attalea speciosa) is one of the most abundant palm species in the Brazilian Amazon and an important unconventional crop, playing a key socioeconomic role due to the commercial exploitation of its oil-rich almonds. However, approximately 90–93% of the fruit biomass—mainly mesocarp, epicarp, and endocarp—is generated as underutilized residue. This systematic review aims to analyze extraction methods, phytochemical composition, and antioxidant capacity of bioactive compounds derived from different babassu fractions. Following PRISMA guidelines, searches of five databases (Embase, ScienceDirect, Scopus, PubMed, and Web of Science) retrieved 410 records, of which 23 met the inclusion criteria. The results show that, although research has predominantly focused on the almond fraction, non-edible parts contain significant levels of phenolic compounds, flavonoids, phytosterols, and other bioactive metabolites with antioxidant properties. Green and non-thermal extraction technologies, such as ultrasound-assisted extraction (UAE), supercritical CO₂ extraction (SC-CO₂), and pressurized liquid extraction (PLE), demonstrated advantages in improving extraction efficiency while reducing solvent consumption and thermal degradation. Overall, the available evidence indicates that babassu residues represent a promising and still underexplored source of bioactive compounds. Their valorization may contribute to sustainable extraction strategies, waste reduction, and the development of value-added products within agricultural and bioeconomic systems. Full article

Agricultural waste materials can serve as functional constituents in cement-based composites through three pathways: (i) organic bio-aggregates that lower density and alter thermal behavior, (ii) lignocellulosic fibers that control cracking and improve post-cracking resistance, and (iii) agro-ash supplementary cementitious materials (SCMs) that densify pore structure and reduce permeability when ash quality and curing are controlled. This review draws on 98 papers, with coconut shell aggregate and coir/coconut fibers as the core focus; agro-ash SCMs (notably palm oil fuel ash, POFA, and rice husk ash, RHA) enter where they clarify mechanisms or inform hybrid design. Rather than cataloging compressive-strength data, the synthesis is organized around controllable process inputs (feedstock conditioning, mix design, curing) and the interface-governed mechanisms that determine performance: interfacial transition zone (ITZ) character and pore connectivity. In coconut shell systems, density reductions come at a cost: elastic modulus drops and moisture sensitivity rises unless shell conditioning, particle packing, and matrix refinement are managed. In fiber systems, gains in toughness and residual capacity are bounded by mixing workability and by the long-term stability of the fiber–matrix bond under alkaline and wet–dry exposure. A mix must first meet strength, serviceability, and transport requirements before its embodied impact is compared with conventional alternatives. The contribution is to reframe these systems around controllable processing and interface mechanisms instead of tabulated strength values; preparation, treatment, and characterization data are consolidated into bounded design windows, an explicit core versus supporting evidence convention is applied, and sustainability is judged under functional equivalency rather than per-volume carbon. Full article

The transition toward a sustainable bioeconomy is increasingly recognised as a key pathway for resource efficiency and climate resilience in emerging economies. However, system-level analyses integrating biomass flows, governance structures, and actor dynamics remain limited, particularly in Sub-Saharan Africa. This study develops a systems-oriented analytical framework combining material flow assessment, stakeholder mapping, governance assessment, and innovation systems analysis to evaluate the structure, performance, and circularity of biomass systems in Ghana. The analysis focuses on six major biomass sectors: cocoa, cassava, maize, plantain, oil palm, and shea. The results show that Ghana generates substantial biomass resources, yet significant inefficiencies persist, with major residue streams such as cocoa pod husks (~9 million tonnes (Mt) annually) and cassava peels (2.6–3.8 million tonnes annually) remaining largely underutilised. Across sectors, residue utilisation rates remain low, while biomass leakage is driven by fragmented governance, weak coordination among actors, spatially dispersed production systems, and limited processing and technological capacity. Compared with more integrated biomass-based economies, Ghana remains at an early stage of circular transition, despite considerable potential for value addition and resource recovery. The study contributes a transferable systems-based analytical framework for diagnosing circularity gaps and system inefficiencies in data-constrained bioeconomy contexts. Strengthening institutional coordination, decentralised processing infrastructure, and innovation systems is identified as critical for advancing a more circular and inclusive bioeconomy in Ghana. Full article

The growing demand for sustainable, decentralized energy solutions has heightened interest in biomass-based technologies for rural applications. In Mexico, the expansion of oil palm cultivation in humid tropical regions has generated large quantities of agro-industrial residues that remain largely underutilized. This review analyzes the potential of oil palm residues as feedstock for small-scale thermochemical conversion, with a particular focus on gasifier stove technologies. Key residues, including empty fruit bunches, mesocarp fiber, and palm kernel shells, exhibit favorable physicochemical properties, including adequate calorific values and high volatile matter content, which support their suitability for gasification processes. However, challenges related to moisture content, ash composition, and tar formation may affect system performance and require appropriate pre-treatment and operational control. Gasifier stoves, especially fixed-bed and top-lit updraft (TLUD) configurations, represent a viable solution for decentralized energy generation in rural settings, improving combustion efficiency and reducing emissions compared to traditional biomass use. Despite their potential, current bioenergy policies in Mexico remain primarily focused on large-scale biofuel production, limiting the deployment of small-scale technologies. Overall, oil palm residues constitute a promising feedstock for gasifier stove applications, although their successful implementation depends on feedstock optimization, appropriate stove design, and the development of policy frameworks that support decentralized bioenergy systems. Full article

Accurate grading of Oil Palm Fresh Fruit Bunches (FFB) is pivotal for maximizing agricultural yield, yet manual assessment in unstructured environments remains labor-intensive and subjective. While Convolutional Neural Networks (CNNs) offer an automated solution, the conventional strategy of scaling network depth often yields diminishing returns or overfitting on moderately sized datasets. To overcome these limitations, this study proposes the Deep Feature Concatenation (DFC) framework. Rather than deepening a single architecture, this methodology synergizes the spatial hierarchy preservation of ResNet50 with the dense feature-reuse mechanisms of DenseNet121. This fusion creates a composite representation space that captures complementary inductive biases. To ensure computational efficiency, the framework decouples representation learning from inference. Principal Component Analysis (PCA) retains 99% of explained variance while compressing features by 68%. These optimized representations are classified using shallow linear probes. Validated on a single-source dataset expanded to 4000 images (derived from 466 original samples) using a rigorous “Parent–Child” split to prevent data leakage, DFC achieved a peak accuracy of 97.75%. McNemar’s statistical test indicated that this performance outperforms the ResNet50 baseline ($p=0.039$) for SVM classifiers. However, it is critical to note that these results represent a proof of concept based on a limited biological sample size, particularly for rare defect classes. While the model achieved 100% detection accuracy for critical defects within the specific validation set, the high synthetic-to-original ratio necessitates cautious interpretation regarding external validity. This framework provides a practical foundation for future research into high-precision, low-latency grading systems, but multi-center validation on larger, independent datasets is required to confirm broad generalizability across diverse plantation environments. Full article

The construction industry faces intensifying pressure to mitigate its environmental impact, particularly concerning the reliance on non-biodegradable materials and hazardous formaldehyde-based adhesives. Although bio-based alternatives are emerging, many still depend on virgin feedstocks, and the valorization rates for abundant waste streams like used cooking oil remain critically low. To bridge this gap, this study developed a sustainable, formaldehyde-free Modified Reused Palm Oil-Polyurethane (MRPO-PU) adhesive specifically for binding sugarcane bagasse particleboards. The synthesis process involved filtering used palm oil and subjecting it to epoxidation and hydroxylation reactions to yield a functional bio-polyol, the chemical structure of which was validated via Fourier Transform Infrared Spectroscopy (FTIR). This bio-polyol was subsequently mixed with polymeric diphenylmethane diisocyanate (pMDI) and combined with alkali-treated bagasse at varying adhesive ratios ranging from 15 to 85 wt%. Physical and mechanical evaluations demonstrated a robust positive correlation between adhesive content and composite integrity. Specifically, increasing the adhesive loading enhanced density up to 444 kg/m³ and minimized thickness swelling to 5.1%, while flexural and compressive strengths significantly improved. The data suggests an optimal efficiency range between 45 and 55 wt%. Ultimately, this research validates a dual-waste valorization strategy, offering a scalable circular economy model that transforms agricultural residues and spent oils into high-performance, eco-friendly construction materials. Full article

The valorization of waste cooking oils (WCOs) provides a strategy to reduce environmental impact while converting residues from the food industry into valuable products. This study developed and characterized antimicrobial soaps from purified WCOs (sunflower, palm, and pumpkin oils) enriched with natural bioactive ingredients. WCOs were purified by filtration, treatment with 10% NaCl, and bleaching with 3% H₂O₂, followed by cold saponification with NaOH. Twelve soap formulations were prepared, including six enriched with bee products (propolis, poly-floral honey, linden, acacia, honeydew, and sunflower) and six enriched with essential oils (EOs) (clove, rosemary, mace, nutmeg, white pepper, and juniper). The WCOs, natural bioactive ingredients, and soaps were characterized using physico-chemical methods (FTIR, GC-FID, phenols, flavonoids, etc.), while their antibacterial activity was determined against two microbial strains: Staphylococcus aureus and Escherichia coli. The antimicrobial activity of soaps is related to their alkaline pH, while the addition of honey, propolis, or EOs contributes to additional antimicrobial effects. Among honey- and propolis-enriched soaps, those with propolis produced the largest inhibition zones (up to 8.67 mm for S. aureus and 7.0 mm for E. coli). EO-based soaps exhibited higher activity, with rosemary EO-based soap showing the largest zones (up to 9.5 mm for S. aureus and 7.5 mm for E. coli). These data support the potential of enriched soaps containing honey, propolis, and EOs for antimicrobial applications, highlighting their value as a sustainable alternative in the valorization of WCOs. Full article

The global push for energy decarbonization has increased interest in hydrogen as a clean energy carrier. Biohydrogen from agricultural residues is a promising pathway for countries with strong agro-industrial sectors. This study evaluates the technical, economic, and environmental feasibility of hydrogen production from palm oil rachis in two post-conflict regions of Colombia: a large-scale facility in Bolívar and a small-scale plant in Santander. The assessment integrates Aspen Plus^® (version 14) simulations using the NRTL thermodynamic model, an attributional gate-to-gate Life Cycle Assessment (LCA) with ReCiPe Midpoint (H), and a techno-economic analysis. The simulated process includes biomass drying, decomposition, steam gasification, syngas cleaning, and methane reforming. A key technical finding was the non-linear relationship between feedstock composition and process yield. Although Santander’s biomass had a higher hydrogen content (9.42% vs. 6.58%), Bolívar achieved a much higher conversion efficiency (0.198 kg H₂/kg biomass) and produced over seven times more hydrogen while processing only 5.8 times more biomass. Environmental results showed clear advantages for Bolívar, which presented lower impacts across most categories compared to Santander and the fossil-based hydrogen benchmark. Bolívar achieved a Global Warming Potential of 2.47 kg CO₂ eq/kg H₂, far below the 15.03 kg CO₂ eq/kg H₂ of Santander, and showed favorable performance in particulate matter formation, acidification, and fossil resource scarcity. Economically, Bolívar was viable, with a Net Present Value of USD 25.01 million, a Benefit–Cost Ratio of 3.29, and a discounted payback period of 4.54 years. Santander was economically unfeasible under all conditions. Hydrogen production from palm rachis is technically feasible, environmentally beneficial, and economically viable when biomass availability and process integration are adequate, as illustrated by the Bolívar case. Full article

Second-generation bioethanol from food industry lignocellulosic residues offers a promising route toward low-carbon, circular bioenergy systems. However, the reported environmental impacts differ markedly across studies, challenging efforts to assess the true sustainability of these waste-derived bioethanol routes. This review synthesizes current knowledge on the production of bioethanol from key agro-industrial wastes including oil palm empty fruit bunches, sugarcane bagasse, brewers’ spent grain, spent coffee grounds, tea waste, citrus residues, and potato peel waste. We outline feedstock characteristics, availability, and prevailing management practices, and map the principal biochemical conversion routes to identify process steps that drive environmental performance. A systematic comparison of life cycle assessments reveals substantial methodological heterogeneity across functional units, system boundaries, allocation procedures, and impact assessment methods. Nonetheless, consistent hotspots emerge, particularly associated with pretreatment severity, enzyme production, thermal energy demand, and co-product handling. The review highlights robust cross-study trends, pinpoints methodological gaps, and proposes recommendations for harmonized LCA practice. By integrating technological and methodological perspectives, this work aims to support the development and policy uptake of sustainable, waste-based bioethanol within circular bioeconomies. Full article

This study analyzes the valorization of oil palm biomass residues within the framework of industrial symbiosis (IS), emphasizing their role in circular economy strategies and sustainable industrial development. Through a systematic literature review and snowball sampling, 156 articles indexed in Scopus and Web of Science were examined, classifying evidence by country, type of residue, derived products, economic sector (ISIC Rev. 4), and technological approach. The results show a strong geographical concentration of IS experiences in Asia, particularly Malaysia, Indonesia, and Thailand, where residues such as empty fruit bunches (EFB), palm kernel shells (PKS), oil palm mesocarp fibers, palm oil mill effluent (POME), and oil palm trunks (OPT) are integrated into processes for bioenergy, biochemicals, composite materials, construction products, biochar, and bioplastics. In contrast, applications in Latin America and Africa remain incipient, with high potential but limited industrial implementation due to infrastructural and regulatory gaps. Technological trends point toward thermo-chemical and biological conversion routes (pyrolysis, gasification, hydrothermal carbonization, anaerobic digestion), development of advanced materials and catalysts, and the emergence of integrated biorefinery models supported by computational optimization tools. The analysis highlights that palm biomass residues, far from being an environmental liability, constitute strategic resources for low-carbon value chains. However, scaling IS initiatives requires clear public policies, economic incentives, and stronger coordination between industry, government, and academia. The study provides a structured overview of current knowledge, identifies research gaps, and outlines future directions for leveraging oil palm residues as a key input for sustainable IS. Full article