This study systematically conducted comparative experiments on individual and co-pyrolysis of biomass and plastic under both plateau low-pressure (Lhasa, 65.2 kPa) and atmospheric pressure (Tianjin, 101.3 kPa) environments. It investigated the effects of low pressure on pyrolysis product distribution, composition, and reaction mechanism. Through process optimization and catalytic upgrading, high-value-added aromatic hydrocarbons were obtained. The optimal conditions were determined through single-factor and orthogonal experiments. The results showed that the low-pressure environment significantly enhances the co-pyrolysis synergy by promoting rapid release of volatiles, prolonging free radical lifetime, and intensifying mass transfer. The core mechanisms operate through two primary pathways. The first is an intensified Diels-Alder reaction, which links olefins derived from plastics with furans derived from biomass. The second involves deoxygenation, where plastics function as hydrogen donors. Under optimal conditions, the aromatic hydrocarbon relative peak-area percentage in the bio-oil reached 77.87%, which could be further increased to 94.66% by adding a 100% HZSM-5 catalyst (with a 1:1 mass ratio of feedstock to HZSM-5 catalyst). This study provides a theoretical basis for the resource utilization of organic solid waste to produce high-value-added aromatics in high-altitude regions.

Landfill-aged municipal solid waste (AMSW) is a partially degraded waste of decades of disposal, regarded as an environmental liability and unexploited resource. Of the 1.34 billion tons of MSW landfilled each year, 49% still ends up in unregulated open dumps, and global MSW generation is projected to reach 3.40 billion tons by 2050. Landfills are the third-largest anthropogenic methane source, releasing ∼38 Mt CH4 annually (∼10% of anthropogenic methane). Previous reviews have treated AMSW technologies and policy instruments in parallel rather than as coupled systems. This review reframes AMSW as a joint technology and policy decision problem, addressing four persistent gaps: technology–policy fragmentation, missing cross-category performance benchmarks, the absence of a technology readiness assessment, and descriptive comparisons. Following PRISMA 2020, we screened 18,829 records from Web of Science and Scopus (2007–2025), retained 1450 studies, and complemented these with a structured comparison of legislative instruments across the EU, the United States, China, and emerging economies. In-situ pathways reduce handling, transport costs, and raise methane yields by 50–74%; however, stabilization still spans years to decades. Ex-situ pathways recover 3–8% metals, 8–15% plastics, and 8–15 MJ/kg of energy, with combined heat and power systems achieving up to 60% efficiency. From a governance perspective, flexible hybrid policy frameworks tailored to waste characteristics, urgency, and local environmental and social contexts are more effective than policies that rely on command-and-control mechanisms. Aligning instrument design with site-specific waste characteristics offers a tractable pathway from legacy liability to circular-economy resources and a measurable contribution to NDC methane targets.

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.

As global energy demands rise and environmental concerns intensify, biomass gasification has emerged as a critical area for sustainable energy development. However, despite extensive research efforts, there remains a lack of comprehensive bibliometric mapping that integrates publication trends, research hotspots, and emerging technological directions within the field. This study presents a bibliometric and content analysis of 8864 publications from 2000 to 2024, to assess the evolution and current state of biomass gasification. The analysis identifies three major research hotspots: optimization of gasification performance, strategies for tar removal, and innovative reactor designs, particularly dual fluidized bed and entrained flow gasifiers. Additionally, emerging trends such as the development of advanced catalytic materials, integration with anaerobic digestion, and the use of machine learning for process optimization are gaining prominence. The study also highlights challenges like economic feasibility and policy barriers, suggesting that future work should focus on techno-economic analysis, process integration, and life-cycle assessment. These insights provide a comprehensive understanding of the biomass gasification landscape and offer strategic directions for future research and implementation.

The activation of peroxymonosulfate (PMS) using waste-derived catalysts offers a sustainable approach for removing emerging organic pollutants (EOPs) from complex wastewater systems. In this study, Fenton iron sludge-derived biochar (FS@BC700) was synthesized and applied as a catalyst for PMS activation to degrade a mixture of EOPs, including sulfamethoxazole, ibuprofen, tetracycline, and bisphenol A (BPA) in real municipal secondary effluent. The FS@BC700/PMS system achieved complete removal of target pollutants within 60 min at a low PMS dosage (0.5 mM), along with a 68.3% reduction in chemical oxygen demand, demonstrating effective treatment under complex matrix conditions. Radical quenching experiments and electron paramagnetic resonance analyses identified superoxide radicals (O2 center dot-) as the dominant reactive species, with additional contributions from hydroxyl (center dot OH), sulfate (SO4 center dot-), and singlet oxygen (1O2). BPA degradation pathway analysis revealed a progressive oxidation process involving hydroxylation, bond cleavage, and ring-opening reactions, leading to low-molecular-weight products. Wheat seed germination assays showed that PMS treatment reduced BPAinduced inhibition of germination and radicle growth. To further screen potential phytotoxic risks, an interpretable XGBoost machine learning framework was used to predict the phytotoxicity of the identified transformation products and compared with conventional QSAR tools (T.E.S.T. and ECOSAR). No intermediate exhibited consistently higher predicted toxicity than BPA, suggesting that PMS treatment may not substantially increase phytotoxic risk under the assessed conditions. This study demonstrates an effective waste-to-resource catalytic system for wastewater treatment and establishes an integrated framework combining PMS-based degradation and machine learning-based toxicity prediction to support the environmental safety evaluation of advanced oxidation processes.

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.

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.

Persulfate-based advanced oxidation processes (PS-AOPs) coupled with anaerobic digestion (AD) present a novel strategy for efficient energy recovery and resource utilization of organic solid waste. In this integrated system, reactive oxygen species (ROS) play a critical role, yet the mechanism by which ROS from PS-AOPs pretreatment affects AD remains unclear. This review systematically assesses the roles of PS-AOPs in AD systems. ROS are produced through thermal, iron-based and carbonaceous activation. These ROS disrupt hydrophilic functional groups of lignocellulose and extracellular polymeric substances. Such reactions cause physical disintegration and chemical modification at the solid-liquid interface, thereby enhancing substrate bioavailability and solid-liquid separation. ROS-induced oxidative stress enriches stress-tolerant microbes, which generate small-molecule acids and facilitate methanogenesis. Small organics from ROS decomposition also stimulate anaerobic fermentative bacteria. Meanwhile, accumulated SO42- facilitates the proliferation of sulfate-reducing bacteria (SRB), reshaping metabolic functions. ROS oxidation yields small organic molecules. These compounds serve as electron donors and substrates. These organic molecules impose selective pressure to modulate system redox potential and enrich DIET-related microbes. Meanwhile, SRBs mediate sulfur cycling to lower hydrogen partial pressure and promote SCFAs conversion to HAc. The interaction accelerates interspecies electron transfer and methanogenesis. Additionally, ROS degrade emerging contaminants through ring-opening, deamination and hydroxylation reactions. Furthermore, functional degrading bacteria are enriched to construct a synergistic chemical-biological purification system. Finally, this review summarizes major existing challenges, such as microbial damage from excessive oxidation, imbalanced electron competition and toxic byproduct formation. The findings provide valuable references for practical application of PS-AOPs-assisted AD.

Anaerobic digestion (AD) is a viable means of reed stalk (RS) utilization, but the disposal of large quantities of digestate is a challenge. Given its wide range of substrate availability, can pyrolysis (PY) be used as a potential digestate treatment method? For this, the PY performance of RS and its digestate (DRS) were analyzed, and the energy balance of AD integrated PY was evaluated in this study. The results showed that the easily biodegradable components of RS were consumed in AD. While, the lignin content was enriched and the cellulose crystallinity was decreased, which affected the subsequent PY performance. Compared with RS, more char (38.92 wt%) and less oil (45.80 wt%) and gas (15.28 wt%) were obtained in the PY of DRS. TG/DTG analysis showed that AD reduced the release of volatiles during PY, but advanced the initial temperature of primary reaction and reduced the activation energy. For energy balance analysis, the heat generated in AD integrated PY system could fully support the heat demand required for the digestate drying. Moreover, 173.13 kWh of net electricity and 109.42 kWh of net heat were obtained from 1t RS by the AD integrated PY system. This study provides a new potential way to efficiently dispose of RS.

Supercritical water gasification (SCWG) offers a efficient route to convert wet biomass into hydrogen. While, the complex and variable chemistry makes it difficult to achieve stable control and production through empirical assessment. An interpretable predictive simulation might help to overcome the current obstacles. This study formulated hydrogen production prediction as supervised regression on tabular inputs and proposed a compact explainable deep network. The results showed that Chameleon Swarm Algorithm (CSA) identified the most accurate configuration. Across 10-fold cross-validation, the model attained high fidelity (R-2 up to similar to 0.98), and the CSA-optimized setting reached R-2 approximate to 0.993 with RMSE approximate to 0.443 mol/kg. Interaction analysis showed more hydrogen production was achieved at higher temperature with short-to-medium residence, and the levels of ash and nitrogen showed a more obvious influence on hydrogen production at high temperatures. This framework provides guidance for the prediction of hydrogen production and the optimization of operating conditions in SCWG.

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.

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

The electrocatalytic glycerol oxidation reaction (GOR) offers an energy efficient route for valorizing biodiesel derived waste, yet achieving high formate (FA) selectivity at industrial level current densities requires a molecular level understanding of how surface defects govern the reaction pathway. Here, we demonstrate that oxygen vacancies play a decisive role in promoting the in-situ generation of Mᴵᴵᴵ-OOH (M = Ni/Co) species, which serve as the genuine active centers for selective glycerol to FA conversion. A urea mediated synthesis was used to construct a hierarchical flower-like NiCo2O4 catalyst (Vo-U) with an oxygen vacancy rich surface, where the vacancy concentration governs the distribution of M3+ to M2+ redox couples. The Vo-U catalyst achieved a FA Faradaic efficiency of 96.3% at 1.49 V versus reversible hydrogen electrode and a production rate of 12.29 mmol cm-2 h-1 at a current density of 1.0 A cm-2. Operando Raman spectroscopy reveals that the oxygen vacancy rich surface promotes dynamic reconstruction into the active Mᴵᴵᴵ-OOH phase, which drives the reaction through a reversible M3+ to M2+ redox cycle. Electrophilic *OH species generated on this platform activate glycerol C-H bonds via a glyceraldehyde intermediate toward FA. Building on this anodic insight, a paired GOR||CO2RR electrolyzer was constructed that delivered a total FA Faradaic efficiency of approximately 190% and enables the direct synthesis of potassium diformate, yielding an economic benefit over threefold higher than that of formic acid alone.

This study systematically investigated the microwave co-pyrolysis of oily sludge (OS) and corn stalk (CS) using several microwave absorbents, including silicon carbide (SiC), biochar and OS derived residue. Thermal degradation behaviors were initially analyzed by thermogravimetry-mass spectrometry (TG-MS). Product yields and synergistic interactions at different OS/CS blend ratios were evaluated in a microwave pyrolysis reactor, followed by an assessment of biochar and OS derived residue as alternative microwave absorbents. The results showed that co-pyrolysis significantly enhanced the pyrolysis performance, with the comprehensive pyrolysis index (CPI) of the OS/CS mixture exceeding the calculated value by a factor of 8.36. Under microwave co-pyrolysis, increasing the blend ratio of CS evidently reduced the solid residue yield while enhancing the pyrolysis gas yield and H2 production rate (from 0.67 to 0.95 L/(kg·min)). An optimal OS/CS ratio of 5:5 was determined for subsequent investigations. Compared with conventional SiC, both biochar and OS derived residue as microwave absorbents exhibited superior performance in terms of waste volume reduction and pyrolysis gas production. Notably, biochar achieved an aromatics selectivity of over 90 area% in the liquid products via enhanced decarbonylation and decarboxylation reactions. This was attributed to the formation of localized hot spots on the biochar surface under microwave irradiation, which promoted heterogeneous cracking and reforming reactions. The synergistic interactions further promoted the cracking of heavy components and the decomposition of oxygenates. This work demonstrates that integrating biochar into the microwave co-pyrolysis of OS and biomass not only enables high-value waste valorization, but also offers a promising strategy for sustainable resource recovery and the implementation of a circular economy.

Biomass gasification shows potential to produce green fuels, i.e. green methanol. Cost-effective and deep removal of biomass tar is vital, but is still a bottleneck issue. In this study, photothermal catalytic reforming (PCR) was proposed for deep removal of tar. Different co-doped TiO2 photothermal catalysts were prepared by sol-gel method. The co-doped of Ni and N improved the optical absorption and electron-hole separation properties of the catalysts, and promoted more photoinduced charge carrier generation to participate in the reaction. Characterizations and density functional theory (DFT) calculations indicated Ni and N atoms induced the local charge redistribution and formed a unique charge-polarized surface. The Ni sites on the catalyst surface were activated which successfully achieved the photothermal synergistic effect and strengthened the creaking of tar. Accordingly, tar conversion ratio reached 100 % at 500 degrees C and was maintained for 10 h with a significantly inhibition of carbon deposition. Furthermore, a biomass gasification towards green methanol scenario was built, and different tar removal technologies, including PCR, partial oxidation, catalytic creaking, were compared. It was found PCR matches well for the deep removal condition without external heating, and can improve the hydrogen content in syngas, which improves the overall conversion efficiency and brings higher economic benefits. This work achieves thorough conversion of tar at low temperature, and provides insight for the design of high-efficient photothermal catalyst to help biomass utilization move into a new stage of high-value chemical synthesis.

Biomass gasification emerges as a potential technology for biochar production due to its carbon neutral property and independence to external energy sources. Compared to pyrolysis for producing biochar, the biomass gasification is more complex which contains pyrolysis, reduction, and oxidation stages. In this study, a series of experiment was performed to exactly control the heating rate and atmosphere in order to collect the biochars from different stages of gasification. With comprehensive characterizations, the evolution of biochar's physicochemical properties and the interaction between carbon and silicon during different stages of gasification were investigated. Biomass undergoes sequential dehydration, demethylation, decarboxylation, and secondary demethylation reactions. The graphitization of carbon begins during the pyrolysis stage, whereas the crystallization of silicon primarily occurs in the reduction and oxidation stages. The proportion of hydrogen bonding functional group rapidly declined during the oxidation stage, from 82.99 % to 14.32 %. A dense three-layer carbon-silicon-carbon structure forms. During the reduction and oxidation stages, a gradual occurrence of silicon-encapsulated carbon structures is found, and carbon is immobilized through the interactions with different types of siloxane. This work provides new insights into the preparation of biochar by gasification, which paves a way for the precise control and smart design of gasification process.

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.

Persulfate-based advanced oxidation processes (PS-AOPs) have gained extensive attention for removing refractory organic contaminants. In PS-AOPs, mineralization and polymerization pathways exhibit significant contrasts in removal mechanisms and product characteristics. This review established a comparative framework from three dimensions: catalyst performance, reactor design, and economic-environmental benefits. First, based on total organic carbon (TOC) removal efficiency and activity decay, catalyst activity and stability in both pathways were systematically compared and analyzed, with deactivation mechanisms and control strategies identified. Second, the adaptability and operational modes of existing reactors were evaluated, and design concepts including electrochemical regeneration and backwashing were proposed for polymerization applications. Finally, the economic cost and environmental benefits of two pathways were compared based on continuous-flow data. Results indicate that polymerization pathways achieve a TOC removal rate three times higher than mineralization, with single-atom and metal catalysts performing outstandingly, but the stability requires urgent improvement. In continuous operation, the dosage of oxidant was a key factor affecting the treatment cost and environmental benefit. Mineralization pathways are more economical for treating low-concentration wastewater, whereas polymerization pathways work better overall cost-effectiveness for high-concentration wastewater. This review examines the differences between mineralization and polymerization from a global perspective, providing a theoretical basis and practical guidance for adaptive regulation of PS-AOPs pathways.