Search Results (701)

The synthesis of sodium carboxymethylcellulose (NaCMC) from lignocellulosic pineapple stubble provides a renewable alternative to conventional cellulose sources for pharmaceutical applications. This study aimed to obtain NaCMC from pineapple biomass, characterize it according to pharmacopoeial specifications, and formulate hydrogels as a physicochemical proof-of-concept for future drug delivery and tissue regeneration applications. NaCMC was successfully synthesized and met the requirements of the Mexican Pharmacopoeia. Hydrogels were prepared by blending NaCMC with gelatin and crosslinking with citric acid. Spectroscopic, morphological, and thermal analyses confirmed the structural equivalence between pineapple-derived NaCMC (NaCMC-Pi) and commercial NaCMC (NaCMC-Co). Swelling and gel fraction studies showed that NaCMC-Pi hydrogels exhibited a higher gel fraction, indicating a more crosslinked network, which corresponded to lower swelling capacity but higher thermal stability compared to NaCMC-Co hydrogels. Overall, these results demonstrate that pineapple stubble is a viable source of pharmaceutical-grade NaCMC and that the resulting hydrogels provide a robust physicochemical basis for future biomedical validation. The use of agro-industrial residues additionally offers a complementary sustainability benefit without compromising pharmaceutical performance. Full article

Agricultural biomass has potential as a renewable and versatile carbon feedstock for developing eco-friendly and biodegradable polymers capable of replacing conventional petrochemical plastics. To address the growing environmental concerns associated with plastic waste and carbon emissions, lignocellulosic residues, edible crop by-products, and algal biomass were utilized as sustainable raw materials. These biomasses provided carbohydrate-, lipid-, and lignin-rich fractions that were deconstructed through optimised physical, chemical, and enzymatic pretreatments to yield fermentable intermediates, such as reducing sugars, organic acids, and fatty acids. The intermediates were subsequently converted through tailored microbial fermentation processes into biopolymer precursors, primarily polyhydroxyalkanoates (PHAs) and lactate-based monomers. The resulting monomers underwent polymerization via polycondensation and ring-opening reactions to produce high-performance biodegradable plastics with tunable structural and mechanical properties. Additionally, the direct extraction and modification of naturally occurring polymers, such as starch, cellulose, and lignin, were explored to develop blended and functionalized bioplastic formulations. Comparative evaluation revealed that these biomass-derived polymers possess favourable physical strength, thermal stability, and biodegradability under composting conditions. Life-cycle evaluation further indicated a significant reduction in greenhouse gas emissions and improved carbon recycling compared to fossil-derived counterparts. The study demonstrates that integrating agricultural residues into bioplastic production not only enhances waste valorization and rural bioeconomy but also supports sustainable material innovation for packaging, farming, and consumer goods industries. These findings position agriculture-based biodegradable polymers as a critical component of circular bioeconomy strategies, contributing to reduced plastic pollution and improved environmental sustainability. Full article

Fisheries and aquaculture residues pose escalating environmental challenges due to their high moisture content, nutrient loads, and pollutant potential when improperly managed. Conventional valorization routes, such as fishmeal, fish oil, and silage, offer partial mitigation but remain limited in scalability, conversion efficiency, and environmental performance. In this study, fish processing residues were subjected to hydrothermal carbonization (HTC) under controlled subcritical conditions (180–220 °C), along with a high-severity catalytic run (325 °C) using sodium bicarbonate (NaHCO₃) as an additive. The latter condition exceeded the typical HTC range and entered the subcritical hydrothermal liquefaction (HTL) regime. The resulting solid, liquid, and gaseous fractions were comprehensively characterized to assess their energy potential, chemical composition, and reactivity. Hydrochars achieved higher heating values (HHVs) ranging from 14.2 to 25.7 MJ/kg. These results underscore their suitability as renewable solid fuels. The gas products were dominated by CO₂ under standard HTC conditions. In contrast, the catalytic run in the subcritical HTL regime achieved a hydrogen enrichment of up to 30 vol.%, demonstrating the efficacy of NaHCO₃ in promoting the water-gas shift reaction. Subsequent air gasification confirmed the high reactivity of the hydrochars, producing syngas enriched in H₂ and CO at elevated temperatures. Overall, this study demonstrates a scalable multiproduct valorization route for fishery residues, supporting circular bioeconomy strategies and contributing to the achievement of UN Sustainable Development Goals (SDGs 7, 12, and 13). Full article

Indonesia faces growing pressure to strengthen waste management while expanding renewable energy generation, particularly from high-moisture biomass such as palm oil mill effluent (POME) and the organic fraction of municipal solid waste (OFMSW). Anaerobic digestion technology (ADT) is technically suitable for both feedstocks; however, its deployment depends on broader operational, financial, social, and institutional conditions. This study evaluates ADT readiness for biomass waste-to-energy (BWTE) development in Indonesia using a multistakeholder Japanese Technology Readiness Assessment (J-TRA) framework. The results and discussion are supported by a literature review, secondary data analysis, and interviews with government agencies, industry actors, financiers, non-governmental organizations, and researchers. The results reveal a clear divergence in readiness outcomes. POME-based ADT reaches Technology Readiness Levels (TRLs) of 6–8, supported by a stable and homogeneous feedstock supply, established industrial operations, and corporate incentives to mitigate methane emissions. Key remaining constraints relate to high capital costs for smaller mills, low electricity purchase tariffs, and competing export incentives for untreated POME. In contrast, OFMSW-based ADT remains at TRL 2–4, constrained by inconsistent waste segregation, insufficient operation and maintenance capacity, limited municipal budgets, residential safety concerns, and fragmented governance across waste and energy institutions. Across both cases, readiness is shaped by five interacting forces. The first three are technical: feedstock characteristics, operations and maintenance (O&M) capability, and financial certainty. The remaining two are enabling conditions: social acceptance and institutional coordination. This study concludes that Indonesia’s BWTE transition requires integrated technological, behavioral, and policy interventions, supported by further research on hybrid valorization pathways and context-specific life-cycle and cost analyses. Full article

Forests play a central role in climate change mitigation by acting as biogenic carbon reservoirs and providing renewable biomass for energy systems. In Portugal, where fire-prone landscapes and species composition dynamics pose increasing management challenges, understanding the carbon storage potential of forest biomass is crucial for designing effective decarbonization strategies. This study provides a comprehensive characterization of the Portuguese forest and quantifies the biogenic carbon stored in live and dead biomass across the main forest species. Species-specific carbon contents, rather than the conventional 50% assumption widely used in the literature, were applied to National Forest Inventory data, enabling more realistic and representative carbon stock estimates expressed in kilotonnes of CO₂ equivalent. While the approach relies on inventory-based biomass data and literature-derived carbon fractions and is therefore subject to associated uncertainties, it provides an improved representation of species-level carbon storage at the national scale. Results show that Pinus pinaster, Eucalyptus globulus, and Quercus suber together represent the largest share of carbon storage, with approximately 300,000 kilotonnes of CO₂ equivalent retained in living trees. Wood is the dominant carbon pool, but roots and branches also account for a substantial fraction, emphasizing the need to consider both above- and below-ground biomass in carbon accounting. In parallel, a bibliometric analysis based on the systematic evaluation of scientific publications was conducted to characterize the evolution, thematic focus, and geographic distribution of global research on forest-based biogenic carbon. This analysis reveals a rapidly expanding scientific interest in biogenic carbon, particularly since 2020, reflecting its growing relevance in climate change mitigation frameworks. Overall, the results underscore both the strategic importance of Portuguese forests and the alignment of this research with the broader international scientific agenda on forest-based biogenic carbon. Full article

Traditional fossil fuel consumption is the main contributor increased atmospheric PM2.5 concentration. In 2014, China designated 81 new-energy demonstration cities, aiming to replace traditional fossil fuel energy with renewable energy. This research aimed to forecast PM2.5 trends. Fractional policy shock term was introduced into grey model to simulate the temporal variability. This model was compared with several existing models to confirm its accuracy and efficacy. We also assessed the robustness characteristics of key parameter. This research found the following: (1) The new-energy demonstration policy achieved stable PM2.5 reductions in the Beijing-Tianjin-Hebei agglomeration. The policy showed strong regional linkages and marginal mitigation effects. (2) The fractional breakpoint grey model (FBGM(s,t)) outperformed existing classical forecasting models and neural networks in fitting and generalization capability. FBGM(s,t) decreased the MAPE by over 2% across all four cities. (3) Robustness analyzes confirmed that the model’s performance advantage remained stable under reasonable parameter variations. Full article

The co-gasification of bio-oil produced via fast pyrolysis and black liquor from the pulp industry may yield a valuable feedstock for renewable gasification. This study investigated the synergistic potential of this co-gasification process. Experiments were conducted in a miniature conical spouted-bed reactor at 800 °C using bio-oil/black liquor mixing ratios ranging from 1:9 to 9:1 under equivalence ratios (ER) of 0.1, 0.3, and 0.5. Syngas characteristics and gasification performance were assessed using the lower heating value (LHV), H₂/CO ratio, cold gas efficiency (CGE), and carbon conversion ratio (CCR). Increasing the bio-oil fraction increased CO and CH₄ concentrations due to its higher carbon content and lower moisture content, whereas black liquor promoted H₂ formation through moisture-driven water–gas shift reactions. Higher ER values intensified combustion, increasing CO₂ while reducing combustible gases. The most energy-rich syngas, with the highest LHV and CGE, was obtained using a 9:1 mixture at ER = 0.1. The CCR was greatest for pure bio-oil and the 5:5 ratio among mixtures, reflecting the catalytic effects of alkali species in black liquor. These results demonstrate that co-gasification can improve syngas quality and carbon utilization, with optimal performance depending on the intended application. Full article

Biogas production plays a key role in the development of renewable energy systems; however, forecasting biomethane yield remains challenging due to the nonlinear nature of anaerobic digestion. The objective of this study was to develop a predictive model based on Radial Basis Function Neural Networks (RBF-NN) to approximate biomethane production using operational data from the Przybroda biogas plant in Poland. Two separate models were constructed: (1) the relationship between process temperature and daily methane production, and (2) the relationship between methane fraction and total biogas flow. Both models were trained using Gaussian activation functions, individually adjusted neuron parameters, and a zero-level correction algorithm. The developed RBF-NN models demonstrated high approximation accuracy. For the temperature-based model, root mean square error (RMSE) decreased from 531 m³ CH₄·day⁻¹ to 52 m³ CH₄·day⁻¹, while for the methane-fraction model, RMSE decreased from 244 m³ CH₄·day⁻¹ to 27 m³ CH₄·day⁻¹. The determination coefficients reached R² = 0.99 for both models. These results confirm that RBF-NN provides an effective and flexible tool for modeling complex nonlinear dependencies in anaerobic digestion, even when only limited datasets are available, and can support real-time monitoring and optimization in biogas plant operations. Full article

Surfactants are essential in cosmetic and food formulations but are still dominated by petrochemical-derived anionic systems associated with irritation, aquatic toxicity and sustainability concerns. Plant-derived saponins offer renewable, biodegradable alternatives, yet only a small subset of saponin-producing species has been developed into commercial ingredients. The genus Albizia is chemically diverse and widely used in traditional medicine, with several species empirically employed as cleansers. This review examines Albizia amara and related Albizia species as prospective sources of plant-derived surfactants for cosmetic and food applications. We summarise ethnobotanical and phytochemical data with emphasis on saponins, flavonoids and macrocyclic alkaloids, and collate the limited quantitative evidence for surface activity, focusing on foaming behaviour, surface tension reduction and shampoo-type formulations, where A. procera provides the main interfacial benchmark within the genus. Potential roles of A. amara-derived fractions in hair-care products and prospective food systems are discussed alongside current knowledge on toxicity, safety and regulatory constraints. Overall, A. amara emerges as a promising but under-characterised saponin source. Priority areas for future work include robust tensiometric characterisation, surfactant-focused extraction and fractionation, systematic formulation studies, and dedicated safety and sustainability assessments to enable evidence-based evaluation against established plant and synthetic surfactants. Full article

Energy deficits have been a major challenge in Sub-Saharan Africa (SSA), particularly in Nigeria. Consequently, the integration of renewable energy (RE) is a crucial strategy for achieving energy transition goals and addressing climate change issues. Therefore, this article investigates the technical, energy, economic, and environmental impact of PV/Wind/BS/Converter, a standalone hybrid energy mix for electrifying a single-family residential building prototype in multi-regional parts of Nigeria. This study aims to examine the renewable energy potential of three locations using HOMER Pro. The results indicate that Kano exhibits the lowest economic performance indices, with a net present cost (NPC) of USD 32,212.52 and a cost of energy (COE) of USD 0.6072/kWh, followed by Anambra (NPC: USD 45,671.68; COE: USD 0.8609/kWh) and Lagos (NPC: USD 47,184.62; COE: USD 0.8706/kWh). Technically, this study shows that the higher the renewable potential of a site, the lower the energy cost and vice versa. The sensitivity cases of key energy parameters—including solar PV cost, wind turbine cost, wind speed, solar radiation, and inflation rate—were considered to compare multiple scenarios and assess renewable energy potential variability under certain decision-making conditions. Economically, the Kano system shows the feasible capital cost of the energy produced, replacement cost, and operation and maintenance cost (O&M) for wind turbines, compared to the nil cost for Anambra and Lagos. Environmentally, the energy systems revealed 100% renewable fractions (RFs) with zero emissions at the three sites under study, which can enhance Nigeria’s energy transition plan and help in achieving the Sustainable Development Goals. Integrating RE supports the successful implementation of the recommended energy policy strategies for Nigeria. Full article

Modern smart cities face increasing pressure to invest in sustainable and reliable energy systems while navigating uncertainties arising from fluctuating market conditions, evolving technology landscapes, and diverse expert opinions. Traditional multi-criteria decision-making (MCDM) approaches often fail to fully represent these uncertainties as they typically rely on crisp inputs, lack temporal memory, and do not explicitly account for stochastic variability. To address these limitations, this study introduces a novel Stochastic Fractional Fuzzy Tensor (SFFT)-based Group Decision-Making framework. The proposed approach integrates three dimensions of uncertainty within a unified mathematical structure: fuzzy representation of subjective expert assessments, fractional temporal operators (Caputo derivative, $\alpha =0.85$) to model the influence of historical evaluations, and stochastic diffusion terms ($\sigma =0.05$) to capture real-world volatility. A complete decision algorithm is developed and applied to a realistic smart city renewable energy selection problem involving six alternatives and six criteria evaluated by three experts. The SFFT-based evaluation identified Geothermal Energy as the optimal choice with a score of 0.798, followed by Offshore Wind (0.722) and Waste-to-Hydrogen (0.713). Comparative evaluation against benchmark MCDM methods—TOPSIS (Technique for Order Preference by Similarity to Ideal Solution), VIKOR (VIšekriterijumsko KOmpromisno Rangiranje), and WSM (Weighted Sum Model)—demonstrates that the SFFT approach yields more robust and stable rankings, particularly under uncertainty and model perturbations. Extensive sensitivity analysis confirms high resilience of the top-ranked alternative, with Geothermal retaining the first position in 82.4% of 5000 Monte Carlo simulations under simultaneous variations in weights, memory parameter ($\alpha \in [0.25,0.95]$), and noise intensity ($\sigma \in [0.01,0.10]$). This research provides a realistic, mathematically grounded, and decision-maker-friendly tool for strategic planning in uncertain, dynamic urban environments, with strong potential for deployment in wider engineering, management, and policy applications. Full article

Single- and two-stage anaerobic digestion (AD) of fallen tree leaves was conducted. The AD process was preceded by mechanical, chemical, and enzymatic pretreatment. The most efficient option was the use of sulfuric acid (1%) at 121 °C for 60 min, resulting in a reducing sugar yield of 28.2 g glucose/L. The highest methane yield for single-stage AD was achieved for the 1–2 mm leaf fraction, 1.5% H₂SO₄ at 121 °C for 90 min, at 115.54 dm³ CH₄/kg VS. For two-stage AD, 10.25 dm³ H₄/kg VS and 81.24 dm³ CH₄/kg VS were achieved for the variant fraction >2 mm, 1.5% H₂SO₄, 121 °C, 60 min. The AD process can be useful for utilizing fallen leaves. Therefore, fallen leaves from trees can be used as a renewable energy source. Full article

Invasive species are a recurring global problem, and the water hyacinth (Pontederia crassipes) is a well-known example. Various strategies have been explored to manage its spread, including its use as an agricultural amendment. However, when P. crassipes biomass is incorporated into soil and undergoes degradation, it may increase soil conductivity and promote metal leaching, potentially affecting soil biota, particularly microbiota. Saprophytic fungi play a key role in the decomposition and renewal of organic matter, and their resilience to stressors is crucial for maintaining soil function. Thus, the aim of this study was to evaluate the effects of P. crassipes biomass extracts on the saprophytic fungus Trametes versicolor by evaluating fungal growth and metabolic changes [including sugar content, phosphatase enzymatic activity, and reactive oxygen species (ROS) production]. The fungus was exposed for 8 days to a dilution series of extracts (100%—undiluted, to 3.13%) prepared from P. crassipes biomass collected at five locations in Portuguese wetlands. Two sites were in the south, within a Mediterranean climate (Sorraia and Estação Experimental António Teixeira), and three were in the north, within an Atlantic climate (São João de Loure, Pateira de Fermentelos, and Vila Valente), representing both agricultural-runoff–impacted areas and recreational zones. Extracts were used to simulate a worst-case scenario. All extracts have shown high conductivity (≥15.4 mS/cm), and several elements have shown a high soluble fraction (e.g., K, P, As, or Ba), indicating substantial leaching from the biomass to the extracts. Despite this, T. versicolor growth rates were generally not inhibited, except for exposure to the São João de Loure extract, where an EC₅₀ of 45.3% (extract dilution) was determined and a significant sugar content decrease was observed at extract concentrations ≥25%. Possibly due to the high phosphorous leachability, both acid and alkaline phosphatase activities increased significantly at the highest percentages tested (50% and 100%). Furthermore, ROS levels increased with increasing extract concentrations, yet marginal changes were observed in growth rates, suggesting that T. versicolor may efficiently regulate its intracellular redox balance under stress conditions. Overall, these findings indicate that the degradation of P. crassipes biomass in soils, while altering chemical properties and releasing soluble elements, may not impair and could even boost microbiota, namely saprophytic fungi. This resilience highlights the potential ecological benefit of saprophytic fungi in accelerating the decomposition of invasive plant residues and contribution to soil nutrient cycling and ecosystem recovery. Full article

Marine renewable energy technologies (MRE-T), which capture energy from oceans and seas, represent a pivotal area for sustainable energy development. These technologies, including wave energy converters, tidal energy systems, ocean thermal energy conversion, and salinity gradient power, offer the potential to diversify energy sources, reduce reliance on fossil fuels, and mitigate climate change impacts. Despite its vast potential, marine renewable energy currently constitutes only a small fraction of global electricity generation, highlighting the challenges and complexities associated with its development and deployment. This paper builds on original research undertaken in 2019 by the authors exploring the barriers for companies attempting to enter the Marine Renewable Energy-Supply Chain (MRE-SC). The aim of this paper is to adopt the Theory of Constraints (ToC) approach to develop a Future Reality Tree (FRT) which creates a roadmap to enable companies to successfully enter the MRE-SC. This will enable academics and practitioners to visualize the cause-and-effect relationships around market entry into MRE-SCs for companies, whilst outlining the future goals, and the pathways to achieving the desired results within a holistic system. Therefore, the FRT provides a bridge between current and future visions and provides a valuable strategic perspective on the way companies can transition into the MRE-SC, thereby enabling a future state to be described, guiding the identification of changes that are required to establish an effective change management approach. Full article

Despite growing interest in positive-energy and net-zero-energy buildings (NZEBs), few studies have addressed the integration of biobased construction with building-integrated photovoltaics (BIPV) under hot–dry climate conditions, particularly in Morocco and North Africa. This study fills this gap by presenting a simulation-based evaluation of energy performance and renewable energy integration strategies for a residential building in the Fes-Meknes region. Two structural configurations were compared using dynamic energy simulations in DesignBuilder/EnergyPlus, that is, a conventional concrete brick model and an eco-constructed alternative based on biobased wooden materials. Thus, the wooden construction reduced annual energy consumption by 33.3% and operational CO₂ emissions by 50% due to enhanced thermal insulation and moisture-regulating properties. Then multiple configurations of the solar energy systems were analysed, and an optimal hybrid off-grid hybrid system combining rooftop photovoltaic, BIPV, and lithium-ion battery storage achieved a 100% renewable energy fraction with an annual output of 12,390 kWh. While the system incurs a higher net present cost of $45,708 USD, it ensures full grid independence, lowers the electricity cost to $0.70/kWh, and improves occupant comfort. The novelty of this work lies in its integrated approach, which combines biobased construction, lifecycle-informed energy modelling, and HOMER-optimised PV/BIPV systems tailored to a hot, dry climate. The study provides a replicable framework for designing NZEBs in Morocco and similar arid regions, supporting the low-carbon transition and informing policy, planning, and sustainable construction strategies. Full article