Search Results (1,103)

Aflatoxin B1 (AFB1) contamination of feed used in poultry farming is an important issue in food safety since it compromises animal productivity and leads to the transfer of toxic waste to the food chain. In this sense, as an alternative to conventional mineral adsorbents, in the present study, two sustainable and low-cost biochars were obtained from agro-industrial waste of orange peel (B-OP) and guava leaves (B-GL) to evaluate their efficiency in the removal of AFB1 in an in vitro avian model. Biochars were obtained from pyrolysis and characterized in terms of particle size, surface area, morphology, surface charge, surface chemistry, and pore size. Furthermore, their adsorption capacity was evaluated in an avian in vitro model. The results showed that B-OP had a smaller particle size (55.30 µm), a larger specific surface area (31.50 m²/g), and a smaller pore size (2.38 nm) than B-GL (82.88 µm, 9.74 m²/g, and 6.24 nm). Furthermore, the biochars presented different morphologies, FTIR spectra, and zeta potentials. In the avian in vitro model, the feed matrix reduced the effectiveness of AFB1 removal compared to the in vitro model using only buffer solutions. However, B-OP (27.4%) significantly outperformed B-GL (22.7%) in the intestinal segment. The valorization of these agro-industrial wastes into biochar represents an economical and sustainable strategy for removing AFB1 and strengthening food security. Full article

The effects of pyrolysis temperature (400–500 °C) and time (30–90 min) on the yield and chemical and physical properties of biochar produced from almond and pistachio shells were studied using a fixed-bed pyrolyzer. Thermogravimetric analysis (TGA) was employed to characterize the kinetics of thermal degradation of the shells. This study compared the thermal behavior observed by TGA with biochar yields obtained from a fixed-bed pyrolyzer, providing insight into the agreement between laboratory-scale thermogravimetric measurements and fixed-bed pyrolysis performance. Fourier transform infrared spectroscopy (FTIR) was performed for each type of biochar. Results showed higher biochar yields from almond shells (35.0–41.3% dry basis) than from pistachio shells (26.8–36.7% dry basis). Shell type, pyrolysis temperature, pyrolysis time, and their interactions had significant effects on biochar yield. The Derivative Thermogravimetric (DTG) profiles showed distinct thermal decomposition patterns for almond and pistachio shells. Almond shells exhibited broader decomposition regions, while pistachio shells showed more distinct decomposition stages. FTIR analysis of both shell biochars indicated reduced O–H and oxygen-containing groups with increasing pyrolysis temperature and residence time, suggesting greater carbonization, aromatic enrichment, and formation of carbonaceous compounds. Greater biochar yields were obtained from the fixed-bed pyrolyzer than from TGA. A first-order kinetics model adequately described the thermal decomposition of both shell types. Apparent activation energies were 41.83–44.99 kJ mole⁻¹ for almond shells and 58.19–63.58 kJ mole⁻¹ for pistachio shells. Model validation showed a good agreement between the experimental and predicted conversion values. The results provide a basis for evaluating the potential of TGA-derived thermal behavior to inform biochar production conditions in fixed-bed pyrolysis. Full article

Slow pyrolysis of a plastic fraction isolated from municipal waste produced a char, which was then used as a precursor for the synthesis of activated carbon. The process involved thermal conversion at 800 °C and chemical activation using K₂CO₃. The resulting activated carbon was used to remove Pb(II), Cd(II), and Co(II) from aqueous solutions. Physicochemical, structural, and granulometric characterizations of the resulting adsorbent were performed. The obtained material had a specific surface area of 562 m²/g, a total pore volume of 0.328 cm³/g, and a micropore volume of 0.146 cm³/g. To determine the optimal adsorption conditions, the Box–Behnken experiment planning method was used, assuming solution pH, adsorbent mass, and initial metal ion concentration as independent variables, and the percentage removal of the contaminant as the response. Studies on sorption isotherms were conducted using a static method in a periodic system for initial metal ion concentrations ranging from 10 to 250 mg/dm³. The effect of temperature on the adsorption process was analyzed, and the kinetics sorption was investigated. Several adsorption isotherm models were used to describe the adsorption equilibrium. The maximum sorption capacity was 35.5 mg/g for Pb(II), 14.7 mg/g for Cd(II), and 11.6 mg/g for Co(II). The obtained results indicate that the plastic waste based adsorbent exhibits favorable sorption properties for the tested heavy metal ions and may be useful in water and wastewater treatment processes. Full article

The growing demand for renewable biomass energy has driven in-depth research into pyrolysis, in which particle size has emerged as a key factor influencing reaction kinetics and gas release. In this study, beech wood with four different sizes were prepared. A thermogravimetric analyzer (TGA 4000) and a Fourier transform infrared spectrometer (FTIR) were used to analyze the thermal behavior of the biomass under a high-purity N₂ atmosphere at heating rates of 10, 20, and 40 K/min. Conversion rates and activation energies were calculated from the thermogravimetric data using two model-free methods, while infrared spectroscopy was employed to analyze gas composition and release characteristics. The experimental results indicate that changes in particle size significantly affect the DTG curves: as particle size increases, the maximum rate of weight loss gradually rises. In terms of pyrolysis kinetic parameters, the activation energy of the biomass samples increased from 166.42 kJ/mol to 176.07 kJ/mol. Gas release peaks also exhibited a trend of shifting toward higher temperature regions. The primary gaseous products were classified into six functional group/gas categories, with their yields ranked in descending order as follows: CO₂ > CH₂O > CH₃OH > H₂O > CH₄ > CO. Except for CO₂, the yields of all other components increased with increasing particle size. These research findings provide data and guidance for the recovery and reuse of biomass resources, as well as for the modeling of biomass pyrolysis reactors, and the classification, pretreatment, and process optimization of biomass materials, thereby accelerating their practical application. Full article

Predicting the pore structure of lignocellulosic biochar from pyrolysis conditions without exhaustive experimental characterization remains an open challenge. We fit semi-empirical Arrhenius-type and power-law correlations linking pyrolysis temperature to $S_{\mathrm{BET}}$, $V_{\mathrm{T}}$, and ${\overline{d}}_p$ by nonlinear least squares, using 45 literature records from seven open access studies (12 feedstocks, 300–800 °C). The central finding is that feedstock category, not temperature alone, dominates variance in $S_{\mathrm{BET}}$: pooled calibration explains only $R^2=0.199$ (RMSE = 183 m² g⁻¹), whereas feedstock-stratified fitting recovers accuracy (e.g., RMSE = 43.6 m² g⁻¹ for grasses, a within-study estimate from a single source). The Arrhenius and power-law forms are statistically indistinguishable ($\Delta \mathrm{AIC}<2$); the Arrhenius form is adopted for physical interpretability. Pooled fits reach $R^2=0.691$ ($V_{\mathrm{T}}$) and $0.563$ (${\overline{d}}_p$). Leave-one-study-out cross-validation (RMSE = 184 m² g⁻¹) confirms that reliable prediction requires calibration data within the target feedstock category. The correlations are descriptive tools valid within their calibration envelope, not general predictive models. Estimation uses no machine learning; a benchmark against OLS and random forest models confirms that greater flexibility improves in-sample fit but not out-of-sample generalization. Full article

Pyrolysis is a leading route for valorizing lignocellulosic residues, yet detailed multi-step kinetic schemes have so far been deployed only in costly commercial simulators, limiting reproducibility. This work couples thermogravimetric (TGA) characterization with process simulation in the free, open-source simulator DWSIM to predict the pyrolysis product distribution of corn cob from Córdoba, Colombia. The lignocellulosic composition (hemicellulose 24.3 ± 2.9, cellulose 36.4 ± 3.0, lignin 39.3 ± 0.9 wt%) was obtained by deconvolving the derivative thermogravimetric (DTG) curve with a five-parameter asymmetric double sigmoidal (Asym2sig) function (R² > 0.9996). Pseudocomponent activation energies from the Coats–Redfern method (154.2, 124.6, and 29.9 kJ/mol) calibrated the primary reactions of a 17-reaction Ranzi scheme, extended with 18 secondary gas-phase steam reforming reactions. Validated against eight lignocellulosic biomasses, the calibrated model yielded a consolidated R² = 0.853 and average absolute deviation (AAD) = 9.8%, with char predictions most accurate (AAD = 8.9%). For corn cob, a bio-oil-optimized yield of 55.0 wt% was predicted at 500 °C, transitioning to a syngas-rich regime (51.0 wt% gas) at 750 °C. This constitutes the calibrated Ranzi-scheme implementation in DWSIM, offering an accessible, reproducible pathway for biomass pyrolysis modeling. Full article

Vacuum residue (VR) is one of the more difficult heavy fractions to process in petroleum refining, and the development of clean utilization technologies for vacuum residue has become a major research focus in the petrochemical industry. This paper discusses the compositional and structural characteristics of vacuum residue from Karamay (KVR) using methods such as ultimate analysis, FTIR, and TG-DTG. The thermal gravimetric kinetics analysis was conducted based on TG-DTG curves at different heating rates. Ultimate analysis revealed that KVR has a high H/C atomic ratio (1.84), and combined with the strong peaks at 2920 cm⁻¹ and 2850 cm⁻¹ in its infrared spectrum, it indicates that KVR is mainly composed of aliphatic compounds, with aromatic compounds being relatively few. High-temperature simulated distillation showed that KVR had a broad boiling-range distribution, with the temperature corresponding to a cumulative recovery of 86.4% exceeding 720 °C, indicating the presence of a certain proportion of ultra-high-boiling components in KVR. The Coats–Redfern kinetic model shows significant variations in activation energy (Ea) at different temperature ranges and reaction orders. Kinetic studies using non-model methods show smaller differences in Ea derived from four different non-model methods. Overall, KVR’s pyrolysis process is complex, with Ea ranging between 100 and 300 kJ/mol. Full article

Biomass-derived fast pyrolysis oil (PO) represents a promising alternative fuel for aviation and heavy transport. However, its high content of oxygenated organic molecules necessitates catalytic hydrodeoxygenation (HDO) before it is viable to be sent to a refinery. Single-step upgrading processes have encountered significant challenges, particularly reactor plugging and catalyst deactivation. To address these issues, an initial stabilization step at lower temperatures has been proposed to stabilize the most reactive compounds in the oil prior to hydrodeoxygenation. In this study, a range of different carbon- and Al₂O₃-supported catalysts (Ni/Al₂O₃, sulfided NiMo/Al₂O₃, Ru/C, Pd/C, Pd/Al₂O₃, Pt/C, and Pt/Al₂O₃) were evaluated for furfural stabilization in a batch reactor for 1 h with an initial pressure of 90 bar H₂ and 180 °C with and without sulfur present. Sulfur tolerance was assessed by repeating all experiments with the addition of 1170 wt-ppm sulfur to the feedstock. The most active catalysts—Ni/Al₂O₃, Ru/C, Pd/C, and Pd/Al₂O₃—also exhibited the highest susceptibility to sulfur poisoning. Although Pt/C did not demonstrate the highest overall activity, sulfur addition appeared to enhance its performance, both in terms of furfural conversion and liquid yield of desired products. Full article

The transition from a linear to a circular economic model is critical for the sustainability of the Amazonian bioeconomy. Although Amazon nuts (internationally recognized as Brazil nuts, Bertholletia excelsa) represent a major natural bioresource, their production chain faces structural challenges, particularly concerning the underutilization and disposal of agro-industrial residues. This narrative review analyzes the Amazon nut market, processing technologies, and supply chain, with a specific focus on biomass valorization. By evaluating the recent literature across major scientific databases, this study maps the technological readiness and feasibility of integrating a circular economy model. We critically examine alternative technologies for transforming specific residues, particularly the woody fruit pods, hard seed shells, and oil press cakes, into value-added bioproducts. Key valorization routes discussed include protein concentrates and amino acid supplements from the press cake, cellulose nanocrystals and organic panels from the hard seed shell, biosolvents, and bioenergy/biochar generation via pyrolysis. The review concludes that while the current industry remains strictly focused on kernel commerce, transitioning toward a circular model appears technically promising, but its economic feasibility remains unconfirmed for most valorization pathways. However, successful industrial implementation requires overcoming logistical supply chain barriers and advancing the technology readiness levels of these valorization pathways. Full article

This study investigated microstructural, optical, and thermal changes in spruce wood (Picea abies) exposed to controlled laboratory heating to identify indicators associated with the transition from progressive thermal degradation to the initial char formation. Cubic specimens measuring 20 × 20 × 20 mm were exposed to selected temperatures between 240 and 300 °C under atmospheric conditions, with a 15 min isothermal exposure period. Microstructural changes were evaluated by scanning electron microscopy (SEM) and quantitative tracheid double cell wall measurements, supported by simultaneous thermal analysis (STA) and color and reflectance analyses. Simultaneous thermal analysis (TG/DTG/DSC) was performed on separate specimens from the same wood material to provide complementary thermal evidence. The most pronounced microstructural changes were observed between 250 and 260 °C, including substantial thinning of tracheid cell walls, degradation of bordered pits, increased brittleness, and localized structural collapse. Quantitative measurements showed reductions in double cell wall thickness exceeding 50% at 260 °C. TG/DTG analysis indicated the onset of intensive thermal degradation at 254.2 ± 1.48 °C, while optical measurements showed pronounced darkening and reduced differentiation of reflectance spectra above approximately 260 °C. The combined evaluation of complementary analytical methods indicates that the 250–260 °C interval represents a condition-dependent microstructural transition associated with accelerated thermal degradation and the early development of a charred structure under the applied experimental conditions. These findings provide complementary experimental evidence for interpreting the early stages of wood charring and may support the interpretation and future refinement of heat transfer and pyrolysis models. They complement, rather than replace, the conventional 300 °C engineering char line criterion used in structural fire design. Full article

This study demonstrates the rapid microwave-assisted upcycling of diverse bio-wastes—including aloe vera industrial leaf waste (av), corn cob agricultural residues (cc), and soft slaughterhouse (sh) by-products (pork liver, lung, and heart) into high-surface-area activated carbons for efficient hexavalent chromium removal via ZnCl₂-activated microwave pyrolysis. To process the challenging high-moisture animal organs, a hybrid approach combining microwave-assisted hydrothermal pre-treatment with subsequent ZnCl₂-activated microwave pyrolysis was developed to promote chemical dehydration and aromatic network development. Structural characterization by N₂ porosimetry, FT-IR, Raman, and XRD confirmed the formation of stable, amorphous porous networks, with surface development strongly dependent on both precursor type and pyrolysis temperature. The materials exhibited high specific surface areas (BET) of 1442, 1120, and 775 m²/g for cc, av, and sh, respectively, and they also demonstrated high water dispersibility. Cr(VI) adsorption data were best described by the Langmuir isotherm model, while thermodynamic analysis confirmed the spontaneous and endothermic adsorption process. The maximum adsorption capacities (qmax) at pH 3 were 157, 112, and 71 mg/g for the activated carbons derived from cc, av, and sh, respectively. Agricultural-derived carbons exhibited superior adsorption performance, whereas all materials remained competitive, demonstrating a potential sustainable circular-economy strategy for waste valorization. Full article

Biochar synthesis is a complex process influenced by multiple factors and requiring an efficient optimization approach to maximize the yield and its physico-chemical properties. This study employs Response Surface Methodology (RSM) as a valuable tool that reduces the number of experiments needed to study multiple variables and their interactions based on three responses, including the yield percentage, the BET surface area, and the zeta potential. The Doehlert experimental design was applied to optimize biochar production from peas pods, using three key parameters: the impregnation ratio, pyrolysis temperature, and heating time. This design produced a highly accurate second-order quadratic model for three responses (R² = 0.985, 0.988, and 0.991), identifying significant interactions between the different synthesis parameters (p < 0.001). The experimental results revealed that both the pyrolysis temperature and impregnation ratio positively influenced the surface area of the biochar. In contrast, the heating time had a negative effect on the surface area. Furthermore, the impregnation ratio was found to significantly reduce the carbon yield. Two samples, representing low and high surface areas from the 15 experimental trials of the RSM, were selected for a further evaluation of their adsorption efficiency for hexavalent chromium (Cr(VI)) and carbon dioxide (CO₂). Full article

Despite recent Cambrian subsalt gas discoveries in the Keping fault-uplift, northwestern Tarim Basin, organic abundance, type, maturity, and depositional setting of Lower Cambrian source rocks remain poorly documented. We evaluated the Yuertusi and Lower Xiaoerbulake Formations using total organic carbon (TOC) analysis, Rock-Eval pyrolysis, kerogen microscopy, solid bitumen reflectance, X-ray diffraction, and ICP-MS trace-element analysis of samples from 11 wells and 6 outcrops. The Yuertusi Formation is organic-rich in northern Keping (TOC = 0.13–28.20%) but thins and deteriorates southward. The Lower Xiaoerbulake Formation (TOC = 0.10–9.68%; 70–160 m thick) is a widespread, moderate-to-good source rock, challenging the view that the Yuertusi Formation is the only Cambrian source rock. Sapropelinite-dominated kerogen (>80%) indicates Type I–II organic matter; equivalent vitrinite reflectance (2.28–3.50%) confirms overmature, gas-prone rocks. The Yuertusi Formation reflects upwelling-fed high productivity and anoxic–euxinic waters; the Lower Xiaoerbulake Formation, moderately high productivity and dysoxic waters. The subsalt gas is oil-cracked gas from marine sapropelic source rocks of either formation. Chloroform bitumen “A” estimates give in-place gas resources of 1121.4 × 10⁹ m³; the static share for southern Keping (20.1 × 10⁹ m³) understates its dynamic potential. A lower-generation/upper-reservoir, fault-controlled, near-source model favors Trap 1-1 for future drilling. Full article

The world’s food industry faces significant obstacles today as it strives to meet the nutritional needs of its rapidly expanding global population while also managing an immense amount of food processing waste (FPW) generated throughout the entire food supply chain. The widespread use of traditional disposal techniques for food waste (landfilling and incineration) regularly faces challenges related to environmental sustainability and economic efficiency. This manuscript reviews the necessary transition from a linear “take-make-dispose” approach to food production to a more circular model that recycles food waste into high-value intermediate chemicals and renewable energy through the development of biorefineries. The manuscript explores the biochemical composition of food waste, with carbohydrates, lipids, proteins, and bioactive materials, making it a suitable feedstock for different multi-stage biorefinery operations. In addition, this review will evaluate a variety of existing conversion technologies for food processing waste, such as biological methods (e.g., anaerobic digestion and fermentation) and thermochemical methods (e.g., pyrolysis, gasification, and hydrothermal liquefaction), to create various platform chemicals, including organic acids, bio-alcohols and volatile fatty acids (VFAs), as well as the production of sustainable biofuels and biopolymers. The review also elucidates the three most determinative constraints on large-scale industrial implementation of food waste valorisation: feedstock variability, techno-economic feasibility, and the need for comprehensive life cycle assessments (LCAs). The alignment of food waste management strategies with the UN SDGs (in particular, SDG 12 ‘Responsible Consumption and Production’ and SDG 13 ‘Climate Action’) reflects the opportunity for food waste to serve as a foundation for a carbon-neutral, sustainable future. This review provides a strategic roadmap for academics, practitioners, and policymakers to tap into the full potential of food waste through a sustainable circular economy model. Full article

Biomass-derived porous carbons are promising sustainable adsorbents for wastewater treatment. However, most reported materials require chemical activation, while the relationships between biomass precursor, pore structure, adsorption mechanism, and regeneration remain insufficiently understood. In this work, non-activated carbon materials were prepared from Juglans regia (JR) and Allium sativum (AS) biomass by pyrolysis at 400 and 900 °C and evaluated for the removal of methylene blue (MB), rhodamine B (RB), crystal violet (CV), and malachite green (MG). Carbonization at 900 °C markedly enhanced porosity, yielding a surface area of 790 m² g⁻¹ for JR900 and 177 m² g⁻¹ for AS900, together with predominantly microporous structures and negatively charged surfaces at neutral pH. The pseudo-second-order model best described adsorption kinetics, while intraparticle diffusion analysis indicated a multistep adsorption process. Equilibrium data were well fitted by both Langmuir and Freundlich isotherm models. JR900 exhibited the highest adsorption capacities for MB (321 mg g⁻¹) and RB (304 mg g⁻¹), whereas AS900 showed superior performance toward MG (278 mg g⁻¹). Stable dynamic filtration, efficient regeneration, and nearly complete dye recovery demonstrate the potential of these non-activated biomass-derived carbons for sustainable dye removal and recovery from water. Full article