Search Results (1,323)

Conventional biochar-based solid base catalysts often suffer from cumbersome preparation procedures and pore blockage during the loading of active components. To overcome these limitations, we developed an in situ construction strategy to fabricate hierarchically porous solid-base catalysts via cross-linking and carbonization of alkali lignin. Using alkali lignin as the carbon precursor, a soft-template-assisted cross-linking system enables the simultaneous formation of a hierarchical carbon framework and in situ generation of basic active sites through one-step pyrolysis under alkaline conditions. The physicochemical properties of the catalysts, including specific surface area, pore structure, and surface basicity, are effectively tuned by adjusting the carbonization temperature (600–800 °C). The optimized catalyst, KLPF-800, exhibits a high specific surface area of 309 m²·g⁻¹ and a well-developed hierarchical pore architecture, delivering excellent catalytic performance in aqueous-phase glucose isomerization. A fructose yield of 33.21% is achieved at 120 °C within 20 min. This work provides a feasible strategy for valorizing lignin and designing efficient heterogeneous base catalysts. Full article

Nitzschia sp., a diatom isolated from Paposo (Antofagasta, northern Chile), was evaluated as a biological solution for removing kaolinite-type clay minerals from recycled process water in large-scale copper mining. Optimization of culture conditions to maximize extracellular polymeric substance (EPS) production revealed that supplementing with 0.1 gL⁻¹ of glucose yielded the highest EPS levels on day 17, reaching 1285 ± 58.9 mgL⁻¹ (control equal to 237.8 ± 34 mgL⁻¹ on day 17). However, maximum dry weight biomass productivity was achieved in the presence of sodium carbonate at a concentration of 1 gL⁻¹ (319 ± 12.5 mgL⁻¹d⁻¹), significantly exceeding the productivity of the control group (242.7 ± 5.4 mgL⁻¹d⁻¹). Notably, low glucose supplementation enhanced EPS synthesis. Application of control-derived EPS of 1 gL⁻¹ rapidly decreased kaolinite initial turbidity from ~2024 FNU to ~354 ± 0.74 FNU within one minute. Even more glucose-derived EPS (1 gL⁻¹) further reduced turbidity to ~22.2 ± 0.1 FNU at 5 min, achieving a flocculation efficiency of ~98.9% after 15 min. Genomic analysis and KEGG annotation identified abundant genes for EPS and carbohydrate metabolism, including numerous glycosyltransferases, glycoside hydrolases, and multiple copies of UDP-glucose 4-epimerase, consistent with strong polysaccharide-biosynthesis capacity. Physicochemical characterization (particle sizing, HPLC, SEM, zeta-potential and FT-IR) showed EPS comprised mainly of rhamnose, fucose, arabinose, xylose and glucose, featuring functional groups (–OH, C=O/COO–, O-acetyl, uronic/guluronic signatures) that interact with kaolinite to promote aggregation. These findings demonstrate that Nitzschia-derived EPS, especially from glucose-supplemented cultures, represent promising sustainable bioflocculants for treating kaolinite-contaminated recycled water in mining operations. Full article

Hard carbon (HC) materials are widely recognized as one of the most promising anode candidates for sodium-ion batteries (SIBs). Biomass-derived HC materials particularly possess the advantages of abundant sources, low cost, and high sodium-ion (Na⁺) storage capacity. In this work, the agricultural byproduct corn cob is employed as a raw material to prepare HC samples via a facile two-step approach of pre-carbonization and Joule heating treatment. Among the prepared HC samples, the CHC-1400 sample exhibits the optimal physiochemical properties. As a result, the corresponding CHC-1400 electrode not only delivers the highest initial reversible capacity of 263 mAh g⁻¹ with a corresponding initial coulombic efficiency (ICE) of 72% at 0.2 C, but maintains a high capacity retention of 91% after 300 cycles. The Na⁺ storage mechanism for the HC samples has thus been revealed. This study introduces a novel, time-saving, and cost-effective protocol for synthesizing biomass-derived HC anode materials, which is of great significance to the advancement of SIBs. Full article

To elucidate the mechanisms of nutrient cycling in rhizosphere soil and microbial metabolism during the prolonged continuous cropping of lavender, this study examined the rhizosphere soil of lavender with different continuous cropping years (1, 4, 7, 10, 15, and 20 years) in the Ili River Valley of Xinjiang, China, measuring physicochemical properties, microbial biomass C/N/P, and eight extracellular enzyme activities. Microbial carbon use efficiency (CUE) and nutrient limitation were quantified using vector analysis, threshold elemental ratios (TERs), and two derived indices (TER_EEA and TER_L). Soil properties exhibited distinct nonlinear patterns: SOC peaked at 4 years (p < 0.05), TN was highest at 20 years, and TP was lowest at 4–7 years. MBC and MBN peaked at 20 years, whereas MBP was significantly lower than in 1-, 4-, and 10-year fields (p < 0.05). EEC and EEN were highest at 20 years, while EEP was lowest at 4 years (p < 0.05). The activity of carbon-related acquisition enzymes increases from 134.81 μmol/g·h in the first year to 393.86 μmol/g·h in the 20th year, an increase of 192%; the activity of nitrogen acquisition enzymes increases from 686.11 μmol/g·h in the first year to 1430.58 μmol/g·h in the 20th year, an increase of 108%. This indicates that the decomposition of organic matter and the nutrient cycling capacity continue to enhance. Vector analysis showed a mean VA of 46° and VL of 0.25, with VA > 45° (P limitation) at 1–4 years shifting to VA < 45° (N limitation) at 20 years. Critically, TEREEA and TERL produced opposite dominant limitations due to differing normalization frameworks—TEREEA scales by microbial biomass stoichiometry—while TERL normalizes against enzyme-derived thresholds. CUET and CUEE ranged from 0.42 to 0.56, with the minimum at 10 years and relatively high values at 15–20 years (p < 0.05). RDA identified CBH (26.2%) and NO₃⁻–N (19.8%) as primary drivers, with extractable phosphorus exhibiting the strongest regulatory effect (pseudo-F = 26.0). These results demonstrate that multi-model stoichiometric assessment is essential, as single indices may yield contradictory diagnoses. These results demonstrate that multi-model stoichiometric assessment is essential, as single indices may yield contradictory diagnoses, and the observed nonlinear shifts in dominant limitation type provide a mechanistic basis for targeted nutrient management in sustainable lavender cultivation. Full article

Accurately mapping tree canopy heights of savanna ecosystems, which account for around 20% of the terrestrial land surface, is of great importance for global biomass estimation, carbon cycling, and biodiversity. The spaceborne lidar of Global Ecosystem Dynamics Investigation (GEDI) has great potential for measuring tree canopy heights in sparse savanna ecosystems due to its implicit three-dimensional structural information. However, the accuracy of the GEDI system may be affected by the random geolocation errors. In this study, we aim to develop a reliable method to mitigate the impact of low-quality and position-biased GEDI footprints. Then we generated 30-m resolution wall-to-wall mapping of tree canopy heights for 2020 by combining GEDI L2A footprints with spatially continuous multi-source information in the Kruger National Park, South Africa. Moreover, we explored the explanatory ability of multi-dimensional features derived from optical, radar, topographic, and artificial intelligence-based images and conducted a comparative analysis of relevant products. Validation results confirmed that integrating quality indicators, incorrect ground elevation estimation assessment, and optical and radar features could significantly improve the accuracy of GEDI-based tree canopy height estimation in savannas (i.e., Pearson’s r = 0.51, RMSE = 3.88 m, N = 6276). Compared to existing products, the model trained on comprehensively filtered footprints exhibited higher agreement with reference canopy height model data and lower estimation errors (i.e., Pearson’s r = 0.66, RMSE = 4.09 m, N = 10,469). We also found that features incorporating red-edge bands exhibited higher explanatory ability. This study showcases GEDI-based mapping of savanna tree canopy heights and provides a foundation for future large-scale research on savanna ecosystems. Full article

Reliable land cover information is essential for scaling plot-based measurements in national forest inventories (NFIs). This study compared the precision of key forest indicators in the Bangladesh NFI using remote sensing (RS)-derived and field-assigned land cover data. Field data from 1781 plots, collected as part of the Bangladesh NFI (2015–2019), were integrated with a 2015 national land cover map produced from SPOT-6/7, Landsat, and Sentinel-2 imagery. The precision of forest indicator estimates was evaluated across land cover domains and ecological zones. Results show that, under an unchanged NFI field measurement and estimation framework, RS-derived land cover reduced the width of confidence intervals (i.e., improved statistical precision) of estimates for most biomass related indicators, including above- and below-ground biomass, tree volume, basal area, and carbon pools, by 15–20% on average, with some reductions exceeding 50%. Improvements were less consistent for regeneration-related indicators (saplings, seedlings). The insights from this study highlight the advantages of remote sensing-derived land cover for improving NFI indicator precision, while underscoring the continued need for advancing ontology-driven approaches with necessary strengthening of field crew capacity to ensure the consistent application of land cover standards. Full article

Aqueous zinc-ion batteries (AZIBs) are highly promising for large-scale energy storage applications owing to their distinct merits, such as exceptional safety, abundant zinc reserves, high ionic conductivity, and facile manufacturing. Featuring natural abundance, low cost, environmental benignity, and high theoretical specific capacity, Mn₂O₃ has emerged as one of the most competitive cathode candidates for AZIBs. However, the low electrical conductivity of Mn₂O₃ impedes electron transport within the electrode, leading to significant polarization during charging and discharging and poor rate performance. Therefore, this study focuses on Mn₂O₃, and combines it with lignin-derived N,S-co-doped carbon dots (NS-CDs). Through a composite modification strategy, efficient conductive pathways are constructed and the structure of Mn₂O₃ is stabilized simultaneously, thereby effectively enhancing the electrical conductivity of the modified cathode. The incorporation of NS-CDs improves the high-rate response of the Mn₂O₃ cathode, with the optimized composite retaining capacity stability at 5 A g⁻¹. At 0.2 A g⁻¹, the specific capacity reaches 174 mAh g⁻¹, and at a current density of 1 A g⁻¹, the material can sustain 1000 cycles. These results highlight biomass-derived carbon dots as a viable interfacial modifier for Mn-based AZIB cathodes. Full article

Greenhouse gas (GHG) emissions from biomass combustion include carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O), which cause climate change and global warming. By measuring GHG emissions by biomass combustion, a potent protocol for the calculation of global warming potential (GWP), which is how much the global temperature has risen due to combustion processes, can be achieved, contributing to determining the mean reduction in global temperature rise and fostering a transition towards more sustainable energy systems. Additionally, warning can be given of the GHG and GWP risks associated with different species of biomass. This review includes the GHG emissions and GWP of biomass combustion and their measurement and estimation directly through biomass sample combustion, using unmanned aerial vehicles (UAVs) and satellite measurements of radiation interacting with atmospheric gases, or satellite-derived data and calculations according to IPCC guidelines. In addition, the relationship of lignocellulosic compounds and elements in biomass to HHV and GHG emissions is described. The key mechanism of molecular vibration of hydrogen bonds in biomass caused by NIR radiation related to GHG emissions is revealed and recorded regarding the possibility of using NIR spectroscopy for the prediction of GHG emissions and GWP. Calculation examples for sugarcane bagasse and other biomass species are shown. The comparative advantages and limitations of NIR spectroscopy with respect to other methods are included. These factors lead to elucidation of the possibility of using NIR spectroscopy for non-destructive prediction of GHG emissions. In this review, the feasibility of using NIR spectroscopy to evaluate GHG emissions, GWP and emission factors (EFs) as an alternative to IPCC estimation methods related to climate change by biomass combustion is confirmed. NIR spectroscopy is a novel methodology for predicting GHG emissions and GWP directly from intact chip or powder biomass spectral data without explicit gas measurement. This article records the essential spectroscopic knowledge of biomass polymer valorization that is of value in polymer science. Full article

The valorization of agro-industrial waste streams represents a promising strategy for reducing production costs in microalgae biotechnology while promoting circular economy approaches. In this study, wastewater derived from fig jam processing was evaluated as an organic carbon source for mixotrophic cultivation of Limnospira (Spirulina) platensis. Cultures were grown under four conditions: a control medium and three concentrations of fig wastewater (FW) at 0.75%, 1.5%, and 3% (v v⁻¹). The wastewater used in this study originates specifically from the washing and cleaning stages of dried fig processing, representing an early processing stream characterized by relatively high soluble sugar content and low thermal or chemical alteration. Biomass biochemical composition and bioactive compound production were investigated, including carbohydrates, proteins, lipids, photosynthetic pigments, polyphenols, antioxidant activity, and phycocyanin extraction yield and purity. The results showed that fig wastewater supplementation significantly influenced the metabolic profile of L. platensis. The highest protein content was obtained at 0.75% FW (44.90 ± 1.93 g 100 g⁻¹ DW), whereas lipid accumulation increased with FW concentration, reaching 9.45 ± 2.30 g 100 g⁻¹ DW at 3% FW. Antioxidant activity peaked at 1.5% FW (4.33 ± 0.43 μmol Trolox mg⁻¹ DW), suggesting stimulation of oxidative stress response pathways under moderate organic supplementation. Pigment production showed different responses, with relatively stable chlorophyll and carotenoid contents but decreasing phycocyanin levels at higher FW concentrations. Phycocyanin yield decreased from 9.82 ± 1.00 g 100 g⁻¹ DW in the control to 5.80 ± 0.22 g 100 g⁻¹ DW at 3% FW, while purity values were highest at the highest FW concentration. These findings demonstrate that fig processing wastewater can be effectively used as an alternative organic substrate for mixotrophic Spirulina cultivation, enabling simultaneous wastewater valorization and production of biomass rich in proteins and bioactive compounds. Full article

With increasing demand for fine-scale ecological management under carbon neutrality frameworks, multi-temporal assessment of carbon stock change (ΔC) at the individual-plant scale has become essential for understanding plant-level carbon dynamics and supporting management decisions. However, methodologies for repeated monitoring at this scale remain fragmented, showing limited cross-temporal comparability, weak cross-scale consistency, and insufficient integration across methods. Existing approaches can be grouped into three pathways: (i) process-based methods derived from CO₂ exchange measurements, (ii) state-based approaches estimating biomass and ΔC, and (iii) sensing-based approaches using structural, spectral, thermal, and fluorescence signals. These approaches offer complementary strengths, yet none simultaneously achieve high accuracy, temporal continuity, and operational scalability for multi-temporal ΔC estimation. Among these, stock-based and structural approaches form the primary estimation pathways, while flux-based and functional sensing methods provide complementary constraints. This review synthesizes and compares these approaches in terms of their theoretical basis, spatial support, temporal characteristics, and uncertainty structures. To address the lack of methodological integration, we propose a structure–function–scale framework that links heterogeneous observations across spatial and temporal domains and emphasizes cross-scale consistency as a prerequisite for reliable ΔC estimation. Within this framework, we further examine how multi-source integration can connect structural and functional observations through segmentation, co-registration, scaling, temporal alignment, and uncertainty propagation. By integrating traditional measurement logic with emerging remote sensing technologies, this review provides a unified methodological framework for ΔC estimation and identifies key directions for advancing fine-scale carbon monitoring, spatiotemporally consistent data fusion, uncertainty-aware inference, and MRV-oriented verification systems. Full article

Sustainable valorization of biomass through hydrothermal carbonization (HTC) represents an environmentally benign method for producing carbon materials for water treatment applications. This research aims to optimize the production of hydrochar from waste food by focusing on parameter optimization, physicochemical characterization, and the capacity of hydrochar to act as an adsorbent for the removal of the copper (II) ion from polluted water. A design of experiments using the RSM approach was employed to evaluate and optimize the influence of carbonization temperature, ranging from 180 to 250 °C, with a residence time of 2–5 h. The predictive ability of the MINITAB-generated model was close to accurate, as demonstrated by the design application for process simulation. The maximum % hydrochar yield was 72.65% for the experimental yield and 71.53% for the predicted yield, both obtained from a sample carbonized at 166 °C for 3.5 h. Batch adsorption experiments were conducted to assess the hydrochar’s ability to remove Cu²⁺ from aqueous solutions, and the Langmuir and the Freundlich isotherms were fitted at different pH levels. A comprehensive characterization of the produced hydrochar was conducted using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM-EDS). The results revealed significant modifications in surface morphology, pore development, and the presence of oxygen-containing functional groups. Based on the findings in this report, it is safe to conclude that hydrochar derived from food waste could serve as a potential adsorbent. Overall, the study demonstrates that sustainable hydrochar production from biomass can simultaneously address waste management challenges and provide an efficient solution for heavy metal removal, thereby advancing circular bioeconomy and environmental protection. Full article

Manganese dioxide (MnO₂) modified biochar catalysts derived from biomass and waste polymer feedstocks were synthesized and evaluated as heterogeneous Fenton-like catalysts for solar-driven degradation of Rhodamine B (RhB) in aqueous systems. Biochars produced from maple wood and plastic waste (high-density polyethylene) provided porous carbon matrices with oxygen-rich surface functionalities that enabled effective MnO₂ loading and catalytic activity. Photocatalytic experiments conducted under real sunlight using a solar-collector reactor demonstrated faster RhB degradation compared to a conventional ultraviolet (UV) system, confirming the advantage of solar-driven operation. Complete RhB removal was achieved at initial concentrations of 100–300 ppm, whereas higher dye concentrations (500 ppm) exceeded the catalytic capacity within the tested reaction time. Kinetic analysis revealed catalyst-dependent reaction behaviors, indicating that degradation pathways were strongly influenced by the biopolymer-derived carbon structure and MnO₂ dispersion. Degradation efficiency was correlated with solar irradiance and reactor temperature, with higher UV index conditions enhancing catalytic performance. Reusability tests showed that the catalysts remained active over multiple cycles, although gradual decreases in reaction rates and catalyst recovery were observed. These results demonstrate the potential of biopolymer-derived carbon materials as effective solar-driven catalysts for wastewater treatment applications. Full article

Sugarcane stores sucrose in a living culm for extended periods, yet the respiratory cost of maintaining this storage tissue remains poorly quantified. We quantified growth and maintenance respiration along the culm (internodes 1 to 12) in three genotypes at mid-season (rapid growth) and end-season (maturation) using a composition-based carbon accounting framework derived from measurements of biomass accumulation and composition. Growth respiration was highest in elongating internodes (3 to 6) and declined with maturation, whereas maintenance respiration increased progressively and dominated in mature storage internodes (10 to 12). Consequently, total sink demand remained substantial even after structural growth slowed, indicating that mature internodes continue to require significant metabolic input despite limited biomass production. To evaluate the potential impact of energetic constraints, we simulated reduced mitochondrial energy contribution to assess the sensitivity of respiratory carbon demand to decreased energetic efficiency. These simulations predicted an increase in glucose requirement for respiration across all internodes, with the largest proportional effect in mature tissue where maintenance costs dominated. Despite this predicted increase in respiratory demand, sucrose accumulation was maintained in mature culms, indicating that respiratory carbon loss remains constrained during storage. This suggests that storage tissue operates with relatively high carbon-use efficiency during maintenance-dominated metabolism. We interpret this pattern as consistent with metabolic configurations that reduce ATP demand, potentially involving partial substitution of ATP-dependent reactions by pyrophosphate (PPi)-dependent pathways, although this mechanism was not directly measured. These findings highlight the importance of maintenance respiration and energetic efficiency in determining sink strength and sucrose yield, and they provide a physiological framework for understanding carbon conservation in long-lived storage organs. Full article

The scalable and sustainable production of graphene remains a significant challenge due to the high cost, complex processing, and environmental impact associated with fossil-derived graphite precursors. In this work, we report a biorenewable pathway for producing graphitic carbon from industrial hemp biomass, yielding a plant-derived material called CleanGraphene. This approach provides a renewable and potentially scalable alternative to petroleum- and coal-based graphene production while maintaining competitive structural and electrical performance. CleanGraphene samples are systematically characterized using X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) to evaluate crystallographic order, layer stacking, defect density, surface chemistry, and thermal stability. The results show that optimized CleanGraphene materials consist of multilayer graphene-like platelets with compact interlayer spacing (d(002) ≈ 3.36–3.37 Å), extended crystallite coherence lengths (L_c up to ~75 nm), large in-plane sp² domains (L_a exceeding ~200 nm), and relatively low defect densities, indicating well-developed graphitic ordering. Electrical conductivity measurements using a binder-free pelletization method and four-point probe analysis demonstrate that the highest quality CleanGraphene samples achieve conductivities of (8.4–8.6) × 10⁴ S m⁻¹, surpassing leading commercial graphene benchmarks measured under identical conditions. Structure–property correlations confirm that electrical performance is governed primarily by crystallite coherence, defect density, and interlayer stacking order, while surface oxygen content plays a secondary role within an ordered graphitic framework. All CleanGraphene samples exhibit excellent thermal stability, retaining more than 95% mass up to ~800–900 °C under an inert atmosphere. Collectively, these findings establish quantitative quality benchmarks for hemp-derived graphene and demonstrate that biomass-based graphene can achieve electrical and thermal performance comparable to, and in some cases exceeding, conventional commercial products. This work highlights industrial hemp as a promising renewable precursor for the scalable production of high-performance graphitic nanomaterials for electrically and thermally conductive composite applications. Full article

This study investigates the synthesis and kinetic behavior of a magnetic biochar derived from avocado seed biomass for the removal of hexavalent chromium (Cr(VI)) from aqueous solutions. Magnetite (Fe₃O₄) was synthesized through different routes, including nitrogen-assisted coprecipitation, redox-controlled coprecipitation, polyol, sol–gel, and sonochemical methods, to evaluate their structural properties and iron incorporation efficiency. Based on compositional and crystallographic analyses, the coprecipitation under an inert atmosphere exhibited improved phase purity and higher Fe₃O₄ content, which was selected for in situ incorporation onto biochar produced by pyrolysis at 450 °C. The resulting magnetic material and composite were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS), confirming the suitability of the synthesis method and the successful deposition of magnetite onto the porous carbon matrix while preserving its structural integrity. Batch adsorption experiments were conducted at pH 2.0 to evaluate the effect of adsorbent dose and initial Cr(VI) concentration. The adsorption process reached equilibrium within 120 min and was better described by the pseudo-second-order kinetic model (R² ≥ 0.98), suggesting that chemisorption governs the rate-controlling step, with diffusion phenomena contributing but not dominating the overall mechanism. The maximum adsorption capacity predicted by the kinetic model reached 42.49 mg g⁻¹ at an initial concentration of 100 mg L⁻¹. The results demonstrate that avocado-seed-derived magnetic biochar represents a sustainable and effective material for chromium-contaminated water treatment, integrating agro-industrial waste valorization with enhanced adsorption performance and magnetic separability. Full article