Cleaning ash deposition on heating surfaces is an unavoidable process in municipal solid waste incineration systems and can lead to large energy losses and pollutant emissions. Monitoring ash properties is important for scheduling efficient ash cleaning. Traditionally, characterizing ash deposition requires complex procedures and specialized equipment. This study proposes a rapid framework that combines infrared spectroscopy with gradient-boosting models to characterize ash deposition on heating surfaces. Ash samples were collected from seven full-scale incineration facilities across China. A generative adversarial network (GAN) was used to address the limited sample availability. After principal component analysis, the spectra were reduced to eight principal components and used to train GBDT, LightGBM, and XGBoost models. Hyperparameters were tuned with Optuna under five-fold cross-validation. A linear regression (LR) baseline was included. On the original 43-sample dataset, all models failed (R2 < 0.25 for all targets). After GAN-based augmentation, the three models reached mean R2 of 0.83–0.93 across the four targets (ash, moisture, volatile matter, and fixed carbon), exceeding the LR baseline (R2 = 0.52–0.80). A sensitivity analysis showed that eight principal components, capturing 98.1% of spectral variance, achieve a practical balance between accuracy and dimensionality. SHAP analysis combined with PCA loading spectra identified the leading principal components as primarily encoding silicate, carbonate, and metal-oxide spectral signatures, especially for ash and volatile matter. These findings demonstrate that FTIR spectroscopy can characterize ash-deposition samples and provide a proof-of-concept basis for future field validation and eventual online monitoring.

Current environmental and ecological risks associated with plastics are escalating. Cutting-edge research has focused on recycling waste plastics into monomers or energy resources. Fenton-like catalysis exhibits potential for technological development in this field. This study evaluates global warming potential (GWP), non-renewable energy use (NREU), and minimum selling price (MSP) during fuel recovery from waste plastics using Fenton-like processes. Adjusting operational strategies could enhance environmental sustainability and economic viability. Process parameters were optimized through controlled manipulation of catalyst pyrolysis temperature, catalyst concentration, hydrothermal temperature, and peroxymonosulfate (PMS) dosage. The optimization balanced environmental impact and economic returns in plastic recycling. Catalyst expenditure and PMS consumption emerged as primary barriers to sustainable and cost-efficient operations in homogeneous catalysis systems. When the superior-performance heterogeneous catalyst was used, Fenton-like process achieved 78% reduction in GWP, 99% decrease in NREU, and 63% MSP reduction for polypropylene (PP) recycling compared to homogeneous systems. With heterogeneous catalysis, polylactic acid (PLA) conversion demonstrates 29 times greater in terms of energy recovery efficiency for compared to PP processing. Sensitivity analysis revealed a variability of 8%-20% in outcomes due to oxidant loss. And the cost advantage for European operations compared to China was identified. The results underscored the importance of regional energy structures and process control for large-scale application. The system assessment framework has established quantifiable technical operation standards with the goal of environmental-economic benefits for implementing Fenton-like systems in plastic waste management. The results contribute directly to advancing circular economy principles and carbon reduction technologies.

Predictive modeling of catalytic biomass gasification suffers from simplified categorical representations of catalysts. This study developed a dual system machine learning framework coupling catalyst properties with gasification outputs. The Bayesian-optimized gradient boosting was utilized to train a catalytic model on 149 experimental datasets, achieving a carbon conversion efficiency prediction accuracy of R2 = 0.937. Principal component analysis was applied to compress seven catalyst descriptors (including specifies surface area and active site size) into a single performance score (PC1), explaining 47.3% of the variance. This score serves as the continuous input for the multi-output gasification model to predict CH4, H2, CO, and CO2 yields (R2 = 0.940, 0.976, 0.916, and 0.920, respectively). Independent validation using pine sawdust and calcium oxide confirmed that the model predicts syngas composition with less than five percentage points of absolute deviation. This framework provides a tool for catalyst screening and process parameter optimization in biomass clean energy conversion systems.

Addressing biogas residue utilization, this study proposes an anaerobic digestion-pyrolysis (AD-pyrolysis) coupling technology. Corn straw was subjected to anaerobic digestion for 0-51 days to produce biogas residues (CR-0 to CR-51), which were then pyrolyzed at 300 degrees C to prepare biochar (CBR-0 to CBR-51). The migration and transformation of key nutrients (N, P, K) during this process were systematically investigated. Results showed that: (1) The total phosphorus (TP) content of biogas residue peaked at 17.28 mg/g in CR-30, with further enrichment in its biochar (CBR-30: 27.12 mg/g). Pyrolysis converted unstable phosphorus forms (H2O-P/ NaHCO3-P) into stable forms (NaOH-P/HCl-P), accounting for over 74 % of TP, thereby reducing leaching risk and enhancing phosphorus slow-release performance. (2) The total nitrogen (TN) content of biogas residue reached a maximum of 22,532 mg/kg in CR-30, but pyrolysis led to a loss of over 99 % of inorganic nitrogen. More than 99 % of residual nitrogen in biochar existed in organic form, which requires microbial mineralization and is suitable for long-term soil amendment. (3) The total potassium (TK) content of biogas residue increased to 15.14 mg/g in CR-51, with further enrichment in its biochar (CBR-51: 19.95 mg/g). Pyrolysis promoted the conversion of potassium to slow-release forms, enabling sustained nutrient supply. This AD-pyrolysis synergy transforms biogas residue into high-value biochar, achieving both carbon sequestration and nutrient recycling.

Ultrasonic assistance can utilize the cavitation effect to significantly accelerate the reaction of biodiesel and effectively enhance the product yield. In the research, a magnetic lignin-supported heteropolyacid catalyst Fe3O4-LS@0.3HPW was successfully prepared via coprecipitation-impregnation method and applied in the ultrasound-assisted catalytic production of biodiesel from oleic acid. A variety of characterization techniques were employed to verify the feasibility of the catalyst. The specific surface area of 152.67 m2/g and pore volume of 0.1661 cm3/g demonstrate that the catalyst is capable of accommodating a greater number of active sites, while saturation magnetization of 27.36 emu/g enables rapid separation of the products from the catalyst. RSM-BBD was adopted to optimize the conditions. Under the optimal parameters (ultrasonic power is 96 W, catalyst dosage is 3.1 wt%, MOAMR is 9.4: 1, reaction time is 80 min), the conversion reached 96.46%. The catalyst exhibited excellent stability, maintaining a conversion rate of over 80% after 7 consecutive reuse cycles. An activation energy of 37.16 kJ/mol indicates that this reaction proceeds readily. In summary, the Fe3O4-LS@0.3HPW catalyst exhibits promising application prospects in the field of ultrasound-assisted biodiesel synthesis.

Investigating the reaction mechanism between 5-methylfurfural (5-MF) and hydrogen (H) is crucial for understanding the pyrolysis of furan-based fuels. However, current kinetic data on 5-MF + H remains scarce, particularly regarding the influence of methyl side chains, has not been thoroughly studied. In this work, quantum chemical methods and kinetic methods were employed to construct the reaction potential energy surface (PES) and calculate kinetic data for 5-MF + H system. The study indicate that under the high-pressure limit, the total rate of initial H-addition reactions is higher than that of H-abstraction reactions across the entire temperature range. H-abstraction preferentially occurs at the aldehyde site, while the initial H-addition preferentially occurs at C(1) and C(4) site of furan ring. In the temperature range of 298-1300 K and 1atm, the total rate via H-addition dissociation mechanism is higher than that via H-abstraction mechanism. Moreover, the competition between these two reaction mechanisms intensifies progressively, such that when the temperature exceeds 1300 K, the total rate via H-abstraction mechanism surpasses that via H-addition mechanism, becoming the dominant reaction mechanism. The subsequent reaction pathways of these intermediates generated via Haddition dissociation mechanism were explored, along with their temperature and pressure dependences. A comparison with the furfural (FF) + H reaction system indicates that the introduction of methyl branches can significantly enhance the reaction rate. Comparative studies between 5-MF + H and furfural (FF) + H reveal that methyl group significantly enhances reaction rate via H-addition mechanism, and the temperature dependence of two systems is roughly consistent. A detailed kinetic model for 5-MF pyrolysis was constructed based on the calculated results of this work, and the model shows good agreement in predicting fuel consumption. Rate of production (ROP) analysis reveals that, for temperatures above 1300 K, H-abstraction reactions play a more significant role in fuel decomposition than that via H-addition dissociation mechansim, consistent with the calculated reaction kinetics.

Cold plasma (CP) pretreatment offers a promising approach to overcome biomass recalcitrance and enhance its valorization. This study investigates the effects of CP pretreatment on cellulose using a dielectric barrier discharge (DBD) reactor under varying atmospheres (air, N2, Ar), voltages, and durations. Results show that CP treatment markedly altered cellulose surface morphology, reduced crystallinity, and decreased the average polymerization degree. The Air-CP treatment exerted the most significant impact, lowering the maximum weight loss temperature of microcrystalline cellulose from 346 degrees C to 334 degrees C and increasing total anhydrosugar yield from 24.58 wt% to 39.48 wt% in micro pyrolysis. In fixed-bed pyrolysis, it also raised liquid product yield from 37.66 wt% to 43.94 wt%. The correlation between the structural change and the formation of anhydrosugars in the CP treatment-based cellulose pyrolysis was carefully analyzed. The crystallized cellulose matrix was loosened, and active radical intermediates were generated during CP discharge, which facilitated the depolymerization and decomposition to generate anhydrosugars. This study offers crucial theoretical support for sustainable biomass pyrolysis based on CP pretreatment.

Syngas, a hydrogen-rich fuel derived from coal and biomass gasification, offers a promising pathway towards sustainable energy systems by reducing emissions, enabling carbon capture, and integrating with advanced power plants such as gas turbines (GTs), internal combustion engines (ICEs) and industrial furnaces and boilers. This review comprehensively examines syngas combustion from basic principles to industrial applications, addressing critical gaps between fundamental research and practical implementation. Experimental and modeling studies of combustion characteristics, covering fundamental aspects (e.g., ignition delay times, laminar burning velocities and kinetic mechanisms) and turbulent combustion phenomena (such as turbulent burning velocities, flame structures and preferential diffusion) are systematically reviewed to clarify the effects of syngas compositions, particularly H2/CO ratios and diluents, along with operating conditions on syngas combustion processes. This work further evaluates syngas utilization in GTs, ICEs, industrial furnaces and boilers, emphasizing innovative strategies like flameless combustion, dual-fuel operation and homogeneous charge compression ignition to reduce NOx emissions and enhance stability. Major challenges such as flashback risk, thermoacoustic instabilities and NOx emissions related to syngas variability are discussed. In addition, this work emphasizes the importance of combustion control strategies, hybrid power configurations (e.g., IGCC), and system-level assessments (e.g., TEA and LCA) in optimizing syngas-fueled combined heat and power systems. By integrating multidisciplinary insights, this review highlights the potential of adaptive combustion technologies and syngas/ammonia cofiring to accelerate the transition to carbon-neutral energy.

Innovation has long been regarded as a uniquely human capability; however, the rapid development of generative artificial intelligence, particularly large language models such as ChatGPT, is increasingly challenging this assumption. Taking environmental research as an example, this study evaluates the innovation-like behavior of ChatGPT through a proxy task of predicting future research hotspots. Fed with 20 years of previous literature from a professional environmental journal, the optimal ChatGPT setup correctly predicted 80

COx (CO and CO2) is an abundant and sustainable C1 feedstock, and its conversion into sustainable aviation fuel (SAF) or methanol as a green marine fuel for shipping applications offers a promising route to decarbonize the aviation and maritime sectors. However, conventional Fischer-Tropsch synthesis (FTS) is limited by the Anderson-Schulz-Flory (ASF) distribution, which restricts SAF selectivity to <= 41%, while methanol formation is not favored under typical reaction conditions. Herein, a tandem catalytic system integrating Fe sites with nanosheet-structured ZSM-11 is developed for the co-production of SAF and green methanol from CO2-rich syngas. Among the catalysts studied, 20% Fe/ZSM-11 exhibits the best performance, delivering significantly higher COx conversion and SAF selectivity compared with 15%, 25%, and 30% Fe loadings. Under optimal conditions (420 degrees C, 2 MPa, GHSV = 2200 mL center dot g-1 center dot h-1), COx conversion reaches 46.3% with a SAF selectivity of 47.9%, surpassing the ASF limitation. The nanosheet architecture of ZSM-11 promotes rapid diffusion of monocyclic intermediates and suppresses over-condensation, leading to product distribution dominated by monocyclic aromatics (83.7%) with limited polycyclic formation (14.5%). Meanwhile, green methanol accounts for up to 50.4% of the products, improving overall carbon utilization. The catalyst shows excellent stability over 100 h on stream, maintaining 43.5% COx conversion and 45.4% SAF selectivity. These results demonstrate a robust tandem Fe/ZSM-11 system for efficient COx valorization into SAF and green methanol.

The transformation of digested sludge into biochar-based catalysts exhibited great potential for PMS activation and pollutant degradation. However, the feasibility and environmental sustainability of the digested sludgebased biochar (DSB)/PMS system for pilot-scale applications remain unverified. In this work, granular DSB was prepared and filled in a columnar continuous flow reactor. DSB-800 enriched with defective structures, C--O, graphite N and Fe2 + sites had outstanding catalytic capability. The contributions of 1O2, center dot OH and SO4 center dot- for SMX degradation were 52.04%, 21.58% and 25.84% in the DSB-800/PMS system, respectively. The S-N and C-C bond breaking as well as the oxidation of the benzene ring amino group in SMX were mainly observed. A pilotscale column reactor (750 L) packed with granular DSB achieved efficient and stable removal of pollutants, including SMX, from municipal secondary effluent. Also, toxicity assays using Vibrio fischeri confirmed the environmental safety of the treated effluent after pilot-scale operation. This study proved the enormous promise of scalable production for DSB catalyst, advancing the application of the DSB/PMS system in AOPs.

An integrated process for producing gasoline-range hydrocarbons from biomass-derived syngas was developed and evaluated using Aspen Plus. The model couples a dual fluidized-bed (DFB) gasification unit with a syngas-to-gasoline (STG) reaction system, enabling continuous simulation of biomass conversion through a three-stage tandem reaction pathway. Thermodynamic equilibrium modeling was applied to predict product distributions, and the effects of key operating parameters, including temperature and pressure, on gasoline selectivity were systematically examined. Reaction temperature strongly influences carbon chain growth, with maximum gasoline-range hydrocarbon (C5-C11) selectivity obtained at 360 °C–380 °C, whereas higher temperatures favor the formation of heavier hydrocarbons. Moderate pressure (4 MPa) promotes chain growth and enhances gasoline selectivity. Under optimized conditions (gasification temperature of 800 °C, S/B ratio of 0.6, and STG pressure of 4 MPa), the overall carbon conversion reaches 18.0%, with a gasoline-range carbon conversion of 12.63% and an energy efficiency of 50.69%. Economic evaluation yields a total capital investment of approximately 2.3 × 108 CNY and a unit product cost of 8.47 × 103 CNY t−1. Environmental assessment gives a global warming potential of 41.71 kg CO2-eq h−1 and an acidification potential of 0.385 kg SO2-eq h−1, predominantly originating from the gasification unit. The integrated DFB-STG configuration enables continuous conversion of biomass to gasoline-range hydrocarbons and provides a quantitative basis for process optimization, techno-economic assessment, and scale-up of sustainable fuel production.

Soil salinization and phosphorus (P) scarcity constrain agroecosystem sustainability. In this study, Acorus calamus hydrochar (ACH) and chicken manure hydrochar (CMH) were prepared via hydrothermal carbonization and applied to achieve the simultaneous remediation and fertilization of saline-alkaline soil. The total P was enriched in the hydrochars (3.78-9.19 and 16.23-22.39 mg/g for ACH and CMH) and labile P was transformed to stable orthophosphates. Both hydrochars reduced salinity and improved fertility with distinct functions. ACH excelled in salinity alleviation and enhanced the availability of soil P, while increasing available potassium by 26.5% to 117.23 mg/kg. CMH provided a long-term P source via mineral crystallization, increasing available P (up 72.6% to 6.99 mg/kg) and P measured by diffusive gradients in thin films (up 74.0% to 234.29 mu g/L), while also enhancing available nitrogen by 29.1%. The microbial community analysis revealed ACH enriched Proteobacteria (54.65%) and saprotrophic fungi, which are associated with organic P cycling processes. In contrast, CMH promoted salt-tolerant Firmicutes (12.80%) and boosted phytase activities (up to 162%), facilitating P release. Therefore, the production and application of P-rich hydrochars could be a promising strategy for the amelioration of saline-alkaline soil, offering novel insights for P recycling and sustainable land management.

Abstract Ash deposition on heating surfaces can lead to clogging and corrosion of the incinerator and pipelines and heavy metal accumulation, significantly hindering the clean and stable running of municipal solid waste incineration (MSWI) systems. Relating deposit characteristics to operating descriptors is essential for developing evidence-based monitoring and mitigation strategies for heating surface deposition. In this study, ash samples were collected from heating surfaces along the flue gas path of seven full-scale MSWI plants. The correspondence between sampling conditions (location, temperature, aspect ratio, diagonal length, and flow rate) and the ash characteristics was discussed. According to the results, across all samples, the aspect ratio showed the clearest association with deposit roughness, while CaSO4 was the most frequently detected crystalline phase. The energy-dispersive spectroscopy data revealed a chloride-rich compositional pattern, although its strength varied across the sensitivity analyses. Pb showed the clearest decline with increasing temperature, whereas Cu, Zn, and As showed distinct associations with the flow rate or geometry. Integrated analysis separated carbonate- and chloride-rich patterns from sulfate- and metal-enriched patterns. Some of these overall relationships weakened when differences among plants were considered, highlighting the importance of the plant-specific conditions. Overall, geometry was more closely associated with deposit texture and capture-related patterns, whereas temperature was more closely associated with chemical evolution and volatile metal redistribution. This work provides an empirical framework for targeted deposit monitoring and corrosion risk assessment in full-scale MSWI systems.

Landfill-mined excavated waste (EW) contains aged plastics, textiles and humified organics that are difficult to recover mechanically yet retain considerable chemical energy. Co-pyrolysis with municipal solid waste (MSW) offers a practical route for energy recovery from EW during landfill reclamation, however, the synergistic effects of EW-MSW co-pyrolysis and the interactions among their major components remain insufficiently understood. In this work, EW-MSW blends were investigated using thermogravimetry coupled with Fourier-transform infrared spectroscopy and mass spectrometry (TG-FTIR/MS) together with iso-conversional kinetic analysis. A synergy window was observed at 40-60 wt% MSW, where the mean apparent activation energy decreased by similar to 13-23 % relative to EW, while the TG-derived volatile fraction at 10 degrees C min(-1) remained at similar to 74-77 wt%, indicating facilitated devolatilization without a marked loss of volatiles. Based on the evolution profiles of selected FTIR bands and MS fragments, increasing EW in the blends enhanced hydrocarbon-related signals (C-2-C-4 fragments) and reduced NH3- and HCl-related signals compared with MSW. Representative component-pair experiments further suggested that the plastic fraction in EW dominated light-hydrocarbon formation, whereas textiles contributed marginally to hydrocarbon evolution. The resulting char exhibited a high fixed-carbon content (similar to 60-65 wt%), indicating potential for further valorization. Overall, EW-MSW co-pyrolysis within the identified blending window can improve process reactivity while shifting volatiles toward more combustible hydrocarbon-rich profiles, supporting energy-oriented landfill-mining and decentralized waste-to-energy applications.

The management of end-of-life polyamide reverse osmosis membranes (EPAROM) from industrial wastewater treatment and seawater desalination has become a critical environmental and energy challenge. The present study constitutes a systematic investigation of the physicochemical characteristics and thermal conversion mechanisms of EPAROM. The EPAROM possess a high heating value (HHV) of 32.20 MJ/kg at 500°C pyrolysis. However, the hydrogen loss caused by excessive high-temperature (>500°C) pyrolysis offsets the HHV gain brought about by carbon enrichment. The dense and agglomerated microstructure of the raw material gradually evolves into a loose and porous stable carbon-based framework. Higher pyrolysis temperatures enhance the release of small-molecule gases, and the LHV of pyrolysis gas increases from 2.13 MJ/kg at 500°C to 9.71 MJ/kg at 700°C. High-temperature conditions have been demonstrated to offer significant advantages in terms of combustible gas production and the optimal gas quality. However, it should be noted that this process can result in an increase in NO and NO2 emissions. TG analysis indicates that the pyrolysis of the EPAROM mainly includes three stages: the organic impurity degradation stage (250-330°C), the residual volatile matter release stage of EPAROM (330-450°C), and the slow decomposition stage of residual char (>450°C). In accordance with the aforementioned points, three primary gasification reaction stages can be distinguished: the initial light volatile oxidation stage (250-350°C), the subsequent rapid oxidation stage of residual volatile matter (350-470°C), and the oxidation stage of residual char (470-610°C). The present study provides a theoretical basis for the efficient and clean gasification disposal of reverse osmosis membranes.

This study develops a ternary geopolymer system combining fly ash (FA), pyrolysis residue (PR), and ground granulated blast furnace slag (GGBS), designed to simultaneously enhance solidification performance and resource utilization. Unlike conventional binary FA-GGBS or PR-GGBS systems, the deliberate incorporation of PR (silica-rich, lamellar, and organically coated) enables complementary reactivity and microstructural densification, yielding a more robust immobilization matrix. Using a one-step dry-mix alkali activation route, hazardous FA and PR were converted into structural materials exhibiting high contaminant stabilization, including > 99 % Pb immobilization, while maintaining strong early mechanical strength (47.85 MPa at 7 days). Durability testing confirmed resistance to aggressive environments, even at 30 % waste substitution. Life-cycle analysis demonstrated reduced carbon emissions and net economic advantages relative to conventional disposal-based approaches. Mechanistic analysis indicates that the ternary system promotes synergistic stabilization through compact C-(A)-S-H gel formation, physical encapsulation, ion exchange, and metal-silicate bonding. These findings demonstrate that the FA-PR-GGBS ternary framework provides a scalable, low-carbon pathway that simultaneously addresses hazardous waste management and infrastructure sustainability.

In this work, hydrothermal liquefaction (HTL) experiments with glucose, glycine and their mixture were conducted in a flash-heating continuous HTL system (with the heating time and quenching time both << 1 s) at various reaction temperatures (300-360 degrees C) and reaction times (4-10 s), to investigate their reaction pathways and kinetics in detail. The overall activation energies of HTL for glucose, glycine, and the mixture were 83.0, 52.3 and 11.9 kJ/mol, respectively, indicating that the energetic barriers for glucose and glycine decomposition decreased significantly in co-fed HTL. According to the rate constants of the reactions, dehydration was the main reaction path of glucose at mild temperatures, but with increasing temperature, the C-C bond breaking rate accelerated and then dominated. Glycine primarily produced glycylglycine and amides by dehydration and decarboxylation at low temperature. However, when the temperature exceeds 320 degrees C, the glycylglycine was hydrolyzed to glycine again. Direct deamination of glycine was relatively slow below 340 degrees C, with ammonia mainly generated by secondary decomposition. In the co-fed HTL process, the Maillard and direct deamination reactions replaced the original decomposition reactions in individually-fed HTL, with their rate constants being about five times those of other pathways.