The combined pretreatment of acid washing and torrefaction is an extremely effective method for upgrading biomass feedstocks, while both zeolites and metal oxides can promote the formation of target products during biomass pyrolysis, thereby increasing the yield of aromatics and producing high-quality bio-oil. In this study, the acid washing and torrefaction pretreatment of aqueous-phase bio-oil model compounds was coupled with dual catalysts (CaO/ZSM-5, MgO/ZSM-5) and applied to the catalytic pyrolysis of wheat straw, resulting in a significant improvement in the quality of the produced bio-oil. The results show that under the combined action of acid washing-torrefaction pretreatment and dual catalysts, the aromatic yields in wheat straw bio-oil increased to 79.91% (CaO/ZSM-5) and 70.45% (MgO/ZSM-5), respectively. The combined SBO-T pretreatment method removes AAEMs from wheat straw, achieving a removal rate of 97.81% for K. Thermogravimetric analysis indicated that the addition of ZSM-5 combined with CaO or MgO for catalytic pyrolysis reduced the maximum weight loss rate, making the pyrolysis process more facile. Compared with MgO, CaO exhibited superior deoxygenation and deacidification performance in catalytic pyrolysis, and the corresponding bio-oil achieved a monoaromatic hydrocarbon (MAH) yield of 68.38%, higher than the 59.19% obtained with the MgO/ZSM-5 system. This study provides theoretical basis and technical guidance for increasing the monoaromatic hydrocarbon content in bio-oil and producing high-value-added chemical products.

Since the widely used chain alkylamine-functionalized adsorbents for CO2 capture face several drawbacks, exploration of novel amines remains eager and important. In our previous study, one heterocyclic aminefunctionalized adsorbent, piperazine-impregnated silica, showed good adsorption capacity and stability. Moisture often co-exists with CO2 in flue gases. However, the influence of H2O on CO2 adsorption on the heterocyclic amine-functionalized adsorbent, and the mechanism are unclear yet. Herein, piperazine, as a representative heterocyclic amine, was impregnated onto a commercial carbon black BP2000 (PZ/BP2000). The optimal adsorbent exhibited high CO2 sorption uptake of 1.44 mmol/g at 40 degrees C (4 vol% CO2 balanced with N2) and could be regenerated at only 55 degrees C under N2 atmosphere. At 40 degrees C, the adsorbent exhibited a moderate H2O adsorption capacity of 4.71 mmol/g at 23 Torr, which was approximately twice the CO2 adsorption capacity of 2.21 mmol/g at ca. 760 Torr. In dynamic column breakthrough experiments for CO2/H2O co-adsorption, CO2 adsorption capacity increased from 1.34 mmol/g under dry conditions to 2.31 mmol/g at RH = 65% (40 degrees C and 4 vol% CO2 balanced with N2), indicating that moisture increased the saturated CO2 adsorption capacity. Co-adsorbed H2O slightly reduced the mass transfer rate of CO2, whereas pre-adsorbed water caused a significant decrease in mass transfer rate. In situ DRIFTS and DFT revealed the two pathways of CO2 adsorption with piperazine with or without H2O. Under dry conditions, PZ reacted with CO2 to form ammonium carbamate; whereas in the presence of water, it simultaneously generated hydronium carbamate and bicarbonate, the former of which showed higher binding energy. This work is the first to explain the mechanisms of CO2/H2O co-adsorption on heterocyclic amine-functionalized adsorbents.

The growing energy crisis and environmental pollution stemming from conventional fossil fuel consumption have intensified the search for sustainable and renewable energy alternatives. Among the various strategies, hydrogen production via the steam reforming of waste plastics and biomass represents a highly promising pathway. This study investigates this process using wheat straw and polyethylene as feedstocks, with steam as the gasifying agent. A composite catalyst support was prepared from biochar (derived from wheat straw pyrolysis) and CaO, which was then impregnated with nickel (Ni) as the active metal. The research systematically evaluated the influence of several key parameters: Ni loading, the catalyst support blending ratio, the catalytic reforming temperature, the steam flow rate, and the biomass-to-plastic ratio.Results demonstrate that the synthesized Ni/CaO-C catalyst possesses a rich porous structure and a high concentration of oxygen-containing functional groups. The optimal conditions for hydrogen production were identified as follows: a Ni loading of 15 wt%, a pyrolysis temperature of 600 degrees C, an equivalent catalyst support ratio (CaO to C of 5:5), a catalytic reforming temperature of 750 degrees C, a steam flow rate of 0.2 g/min, and a balanced biomass-to-plastic ratio of 5:5. Under this optimized configuration, the process achieved a total gas yield of 101.95 mmol/g, a hydrogen yield of 80.54 mmol/g, a hydrogen concentration of 79.01 vol%, and an H2/CO ratio of 5.82. This work provides an effective and novel approach for enhancing hydrogen generation from the steam conversion of waste materials.

Flue gas torrefaction is an emerging biomass pretreatment technology that utilizes industrial flue gas as a reactive medium to replace inert atmospheres. However, the intrinsic complexity of biomass and the catalytic interference of ash hinder mechanistic elucidation. This study investigated the torrefaction behavior of demineralized poplar wood under N2, CO2, dry flue gas (DFG), and wet flue gas (WFG) at 300 °C for 5-20 min. Thermogravimetric analysis combined with kinetic modeling (FWO, KAS, and CR methods) revealed that the apparent activation energy (Eα) varied non-monotonically with atmosphere oxidizability. Under N2, the average Eα was 177 kJ/mol following the three-dimensional diffusion model (D5). CO2 gave the highest average Eα (314 kJ/mol) with the Avrami-Erofeev nucleation model (A1/4). DFG and WFG significantly reduced the average Eα to 133 and 128 kJ/mol, respectively, both following the A1/3 model. Consistently, WFG yields the lowest char and the highest gas yield. XPS and FTIR analyses indicated that flue gas atmospheres, especially WFG, promoted deeper deoxygenation and aromatization of biochar. Tar composition underwent a noticeable transition from ketones to aldehydes and saccharides under flue gas conditions, with the most remarkable variation observed under WFG. Gaseous products were dominated by CO2 under N2 and by CO under CO2, while DFG and WFG produced moderate and stable gas compositions. These findings demonstrate that flue gas torrefaction, particularly under WFG, effectively enhances biomass effectively upgrades biomass quality by regulating pyrolysis kinetics and product distribution, and demineralized biomass is a suitable intermediate model for mechanistic investigation.

Pyrolysis of sludge is a promising method for energy and resource recovery from solid waste. However, the emission of odorous gases, especially those containing sulfur and nitrogen, poses significant environmental challenges. Therefore, this study investigated the release characteristics of organic sulfur, when it coexist with organic nitrogen. Focusing on the mechanism by which organic nitrogen affects the transformation pathways of organic sulfur. Co-pyrolysis experiments with organic sulfur model compounds 'benzyl sulfide (BS) and 4,4 '-dihydroxydiphenyl sulfide (DHS)' and nitrogen-containing model compounds 'proline (Pro) and aspartic acid (Asp)'. The presence of Pro and Asp lower the pyrolysis temperature and enhance the reaction extent of BS and DHS. The functional groups of organic nitrogen compounds, such as -H, -OH, and -C=O, promoted the production of sulfur-containing gases from organic sulfur compounds. Pro and Asp increase the yield of gas-S by 1.5 similar to 2 times and 3 times, respectively. Pro also reduced the energy barriers for key steps in H2S formation from BS, including the removal of -SH radical from benzyl mercaptan and thiophenol, and -SH hydrogenation, by 83.92 kJ/mol, 39.97 kJ/mol, and 135 kJ/mol, respectively. Asp promoted the cleavage of the C-aliphatic-S bond in BS and the C-aromatic-S bond in DHS, lowering the energy barriers by 74.05 kJ/mol and 160.27 kJ/mol, respectively. These findings elucidate the role of organic nitrogen compounds in organic sulfur release during sewage sludge pyrolysis, thereby providing a potential way for the synergistic removal of sulfur- and nitrogen-containing odorous gases.

Pyrolysis technique can effectively convert waste plastics into high-performance asphalt modifiers, improving the asphalt pavement performance, thus achieving the resourceful utilization of waste plastics as building materials. Selecting Polypropylene (PP) and polystyrene (PS) as raw materials, pyrolysis experiments were conducted to explore their synergistic interaction. Using Thermogravimetric analysis (TGA), tube furnace, and gas chromatography-mass spectrometry (GCMS), the effects of plastics mixing ratio and Ni loading in HZSM-5 on the pyrolysis products and heavy oil composition were investigated. Based on the optimal heavy oil, the high and low temperature performance and aging resistance of the heavy oil modified asphalt were quantitatively evaluated. The results showed that the PP/PS co-pyrolysis exhibited higher conversion efficiency, with a 1:3 ratio maximizing liquid yield at 74.26 %. Ni-modified HZSM-5 effectively boosted the production of aromatic hydrocarbons in heavy oil while inhibiting the generation of phenols, acids, organosilicons and other non-hydrocarbon byproducts. The optimal Ni loading was 10 wt%, which maximized aromatic hydrocarbon content at 81.36 % within 90.6 % polycyclic aromatic hydrocarbons (PAHs), achieving the best modulation of pyrolysis heavy oil components. The addition of heavy oil significantly improved the high-temperature stability and aging resistance of asphalt, though impairing low-temperature cracking resistance. The optimal oil content was 6 wt%, making the softening point increased by 10.3 degrees C. This advancement promoted the conversion of waste plastic heavy oil into high-performance asphalt modifiers to avoid difficult combustion, providing theoretical support and technical guidance for its high-value application in the asphalt pavement field.

The presence of nitrogen-containing compounds (NCCs) in bio-oil severely limits its downstream utilization as a clean fuel. To address this issue, a catalytic strategy combining hierarchical pore construction and bimetallic active-site modification was developed for the deep denitrogenation and upgrading of biomass pyrolysis oil. Bamboo (BB) and wheat straw (WS) were selected as representative forestry and agricultural residues, respectively, and Ni-Co bimetal-modified HZSM-5 catalysts were prepared. Appropriate alkali treatment significantly improved the pore structure of HZSM-5, increasing its specific surface area from 383.9 to 409.12 m2/g, while Ni and Co introduction effectively regulated the distribution of acidic sites. As a result, the modified catalysts enhanced the pyrolysis of BB and WS and improved the quality of the resulting bio-oils. Over 6Ni0.5Co-HR5, aromatic selectivity reached 51.06% for BB and 50.66% for WS. GC/MS analysis showed that the catalyst promoted the transformation of nitrogen species from kinetically unstable chain-like compounds into more stable cyclic structures, facilitating their further removal. Among the catalysts, 6Ni0.5Co-HR5 exhibited the best denitrogenation performance, reducing the relative total nitrogen content in BB- and WS-derived bio-oils to 0.89% and 0.67%, respectively, corresponding to decreases of 96.34% and 93.02% compared with non-catalytic pyrolysis. This superior perf ormance was attributed to the synergistic effect of the hierarchical pore structure and Ni-Co bimetallic sites. The results demonstrate good feedstock adaptability of the catalyst and provide an effective route for producing low-nitrogen, aromatic-rich bio-oil.

Global plastic production continues to grow rapidly, and the short service life of most plastics has intensified waste accumulation and environmental pressures. Most waste plastics contain over 90 wt% volatile matter, with extremely low ash and fixed carbon contents, making them ideal feedstocks for pyrolysis. Pyrolysis has emerged as a promising thermochemical pathway for transforming heterogeneous plastic waste into plastic pyrolysis oils (PPOs). Certain PPOs exhibit high heating values of 36.53–49.70 MJ/kg, highlighting their potential as liquid fuels and chemical feedstocks. This review provides a comprehensive and mechanistic assessment of PPOs production, emphasizing how the structural features of plastics dictate chain scission pathways, radical formation, aromatization, and heteroatom-related reactions. Key process parameters, including temperature control, heating rate, residence time, reactor configuration, and feedstock pre-treatment, are critically evaluated for their roles in determining PPOs yield and physicochemical properties. Catalytic pyrolysis using acidic zeolites and basic oxides can increase PPOs yield to over 80 wt%, promote gasoline- and diesel-range hydrocarbons, reduce moisture and oxygenated compounds, and remove impurities. Co-pyrolysis with biomass or other organic wastes is further shown to produce strong hydrogen-donation and deoxygenation synergies that improve oil quality. Emerging upgrading pathways, such as distillation, catalytic cracking, hydrotreating, and hydrocracking are discussed as complementary routes for specification-compliant fuels. Finally, techno-economic analysis and life-cycle assessment are integrated to assess cost-effectiveness, energy efficiency, and environmental implications. By consolidating mechanistic knowledge, process optimization strategies, and sustainability considerations, this review provides a comprehensive framework for developing cleaner, more efficient, and circular plastic-to-oil systems.

Sulfur cross-links strongly influence the thermal degradation chemistry of vulcanized natural rubber and promote the formation of sulfur-containing degradation products during waste-tire pyrolysis. However, the molecular origin of thiophenic sulfur formation remains insufficiently understood, particularly the connection between sulfur-induced chain cleavage, sulfur-containing radical evolution, and thiophene-type product formation. This study constructed an experimentally validated vulcanized natural rubber model and combined ReaxFF molecular dynamics simulations with density functional theory calculations to investigate sulfur transformation and thiophenic sulfur formation during pyrolysis. ReaxFF-MD simulations showed that increasing temperature promoted the decomposition of char-like and heavy-tar sulfur-containing fragments, enhanced sulfur redistribution into light-tar and gas fractions, and increased the proportion of thiophenic sulfur species in liquid products. Trajectory analysis revealed a stage-dependent evolution from polyisoprene backbone scission to sulfur-containing radical formation, identifying C5H7S·, S·, and ·SH as key intermediates. DFT calculations further demonstrated that sulfur incorporation perturbs the local electronic structure and cleavage behavior of adjacent polyisoprene segments, making sulfur-directed chain cleavage kinetically favorable for generating C5H7S·-type intermediates. Further pathway analysis identified the trajectory-derived C5H7S·-mediated intramolecular cyclization–dehydrogenation route as the most kinetically accessible pathway among the examined routes for 2-methylthiophene formation, whereas S· addition to ·C5H8 or ·C4H6 provides plausible but more kinetically demanding routes to 3-methylthiophene or thiophene, respectively. Beyond previous studies focused mainly on sulfur migration, this study establishes a molecular-level link between sulfur-directed chain cleavage, sulfur-containing radical evolution, and thiophenic product formation.

Since the extensive utilization of fossil fuels has led to a sharp increase in atmospheric CO2 levels, controlling CO2 emissions has garnered widespread attention. Carbon materials, as important CO2 adsorbents, are often functionalized with heteroatoms such as N and B. However, the influence of B/N co-doping on CO2 sorption remains unclear. In this study, a series of B/N co-doped lignin-derived carbons were synthesized via a one-pot pyrolysis using alkali lignin as the precursor and boric acid and glutamic acid as B and N dopants, respectively. The prepared samples were characterized using SEM, XPS, FTIR, and Raman spectroscopy. B/N co-doping enhanced the specific surface area, pore volume, and crystallinity of the carbon while introducing new surface functional groups such as BC2O and BCO2, without significantly altering the types or relative content of N-containing functional groups. The CO2 adsorption capacity of B/N co-doped lignin-based carbon reached 1.72 mmol/g at 25 degrees C under 1 bar, which was 5.9 times higher than that of unmodified lignin-based carbon (0.25 mmol/g). Density functional theory (DFT) calculations revealed that B-containing functional groups enhanced the nucleophilicity of B and the electronegativity of surrounding atoms (especially O). N-containing functional groups, especially pyridinic-N (N-6) and pyrrolic-N (N-5), which have high adsorption energies, could avoid excess B oxidation and provide Lewis base sites for CO2 sorption.

This study employed torrefied wheat straw (260 degrees C) as feedstock to synthesize a bifunctional metal-modified composite zeolite catalyst through alkali treatment (NaOH), dual metal loading (Fe and Ni), and hierarchical MCM-41 construction. Catalytically assisted pyrolysis behaviour was investigated using a tube furnace and Py-GC/MS system, evaluating the effects of pyrolysis temperature and catalyst/feedstock mixing ratio on product distribution and bio-oil composition. Results indicate that at a catalyst/feedstock ratio of 3:2, bio-oil yield peaked at 28.41 % at 500 degrees C, concurrently achieving a maximum monocyclic aromatic content of 66.36 %. Elevating pyrolysis temperature promoted aromatic formation while significantly suppressing oxygenated compounds; notably, phenolic components decreased by 13.94 % at 500 degrees C, indicating the 1Ni1FeHR@M catalyst's potent deoxygenation capability. Further optimization of the catalyst/feedstock blending ratio revealed that a 3:2 ratio yielded the highest combined bio-oil and monocyclic aromatic hydrocarbon production (18.62 %), confirming this catalytic strategy effectively shifts the product distribution towards higher-value hydrocarbon fuels.

This study employs density functional theory (DFT) calculations combined with wavefunction analysis to dissect the thermal decomposition pathways of lignin through cyclohexadienone-type (CHD) intermediates. Using 4(phenoxymethyl)phenol as a model dimer representing lignin's structural motif, systematic investigations are conducted into intra- and intermolecular reaction pathways during pyrolysis. The results demonstrate that both intra- and intermolecular hydrogen transfer processes occur, yielding CHD intermediates. Significantly, the intermolecular hydrogen transfer pathway exhibits a lower energy barrier, indicating its preferential contribution to intermediate formation under pyrolysis conditions. A comparative energetic analysis of cleavage pathways reveals that the cyclohexadienone intermediate-mediated cleavage (CHDM) occurs with substantially reduced energy barriers compared to direct bond scission, establishing CHDM as the kinetically favorable pathway. The addition of hydroxyl-containing compounds, such as phenol, glucose, and levoglucosan, further decreases the energy barriers for the cleavage of CHD intermediates by forming six-membered ring transition states. Among these intermediates, levoglucosan and glucose exhibit the most pronounced synergistic effects in facilitating barrier reduction. Electron localization function (ELF) analysis provides mechanistic insight, showing that hydroxyl groups enhance hydrogen atom mobility and promote alpha-O-4 bond cleavage by modulating electron density distribution at the reaction site.

A combined pretreatment of straw was carried out using acid washing and torrefaction methods. Metal-modified HZSM-5 core-shell molecular sieves were prepared by loading Zn (2, 4, and 6 wt%) and Ni (6, 8, and 10 wt%) on HZSM-5 molecular sieves and introducing MCM-41 core-shell structure. PY-GC/MS and a tubular furnace were employed to study the effects of pretreatment conditions and catalysts on the product composition distribution during wheat straw catalytic pyrolysis. XRD, SEM, BET, TPD and ICP were used to characterize the catalyst performance. It was found that the combined acid washing and torrefaction pretreatment reduced the oxygenated compounds in the bio-oil from straw catalytic pyrolysis and increased the bio-oil yield to 29.37 %. The incorporation of modified catalysts promoted the deoxygenation, zwitterionization and aromatization reactions during the straw-catalyzed pyrolysis. The monometallic loading of 4%Zn/HZ and 8%Ni/HZ catalyzed acid washing and torrefaction straw pyrolysis resulted in 54.2 % and 57.06 % yields of MAHs and 42.86 % and 38.58 % yields of BTX in bio-oil, respectively.Compared with the monometallic loading, 4%Zn8%Ni/HZ further optimized the bio-oil compositional distribution, with a MAHs yield of 64.76 %, a BTX yield of 54.69 %, and a deoxygenation performance of 81.34%.MCM-41-coated HZSM-5 produces a large mesoporous structure with channels with sufficient transport capacity, accelerating the cleavage of various types of oxygen-containing compounds in the bio-oil into smaller molecules for better conversion into aromatics. The 4%Zn8%Ni/H@M catalyst achieved a MAHs yield of 72.68 % and BTX yield of 63.43 % in the bio-oil during pyrolysis of acid-washed and torrefied wheat straw, with oxygen removal efficiency reaching 85.37 %. Therefore, the combination of feedstock pretreatment and metal-modified core-shell HZSM-5 molecular sieve could synergistically optimize both compositional distribution and production yield of bio-oil derived from biomass pyrolysis.

The oxidative pyrolysis of sewage sludge under smoldering conditions offers an efficient route for energy recovery but faces challenges from the release of sulfur-containing pollutants. This study systematically investigated the effects of different conditioners (CaO, Fe2O3, and FeCl3) and oxygen concentration on organic sulfur transformation. Results show that all conditioners significantly suppressed total gaseous sulfur emissions by 18.31-45.79% compared to raw sludge, primarily by promoting sulfur retention in char and dichloromethanesoluble fractions. CaO immobilized sulfur via gas-solid capture and synergistic oxidation with oxygen, effectively forming stable sulfone-S. Fe-based conditioners exhibited stronger oxidative capabilities but also catalyzed decomposition at high temperatures, leading to increased SO2 yields (by 8.01-17.11%) under higher oxygen concentrations. Density functional theory (DFT) calculations revealed that conditioners change the energy barriers of key reaction pathways, making the direct oxidation of organic sulfur the most kinetically favorable route. Notably, the introduction of Cl from FeCl3 inhibited direct oxidation but enhanced substitution reactions and SO2 formation (increased by 29kJ/mol) due to its high electronegativity. These findings clarify the distinct sulfur-fixation mechanisms governed by conditioner-oxygen synergy and provide crucial insights for the targeted control of sulfur during sludge-to-energy conversion.

For the recycling of waste wind turbine blades (WWTBs), pyrolysis has been proven to be a promising method for the recovery of organic components. This study systematically investigated the co-pyrolysis of polyethylene terephthalate (PET) and balsa wood (BW) blends by integrating thermogravimetry-mass spectrometry (TG-MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to explore their characteristics, kinetics, and underlying reaction mechanisms. Thermogravimetric analysis revealed significant interactions, evidenced by a decrease in the maximum decomposition temperature of PET and an increase in that of BW in the blends. A notable synergistic effect, optimally achieved at a 1:1 blending ratio, enhanced mass loss and reduced the apparent activation energy, as determined by model-free kinetic methods. Kinetic analysis via the distributed activation energy model (DAEM) indicated that the pyrolysis of PET and BW conformed to the single-Gaussian DAEM (SG-DAEM) and double Gaussian DAEM (DG-DAEM), respectively, with the mixture necessitating a triple Gaussian DAEM (TG-DAEM). The fitting further deconvoluted the co-pyrolysis process into distinct reaction stages corresponding to the decomposition of cellulose/hemicellulose, lignin, and PET. Moreover, their weighting factors effectively reflecting the contribution of each component. Py-GC/MS results demonstrated that co-pyrolysis significantly altered product distribution, promoting the formation of aromatics and aldehydes while suppressing phenols, esters, and ketones. A reaction mechanism was proposed, indicating that radicals and acids derived from BW pyrolysis catalyze PET depolymerization and facilitate secondary reactions, such as decarboxylation and esterification, thereby shaping the final product slate. This work provides fundamental insights and experimental data crucial for developing efficient pyrolysis-based recycling strategies for WWTBs.

The application of ammonia/methane (NH3/CH4) blended fuels in gas turbines has received considerable attention, and the development of their combustors requires the implementation of more precise and compact reaction mechanisms. In this work, we propose a new optimization mechanism for ammonia/methane and comprehensively verify the performance of the optimization mechanism. A detailed chemical mechanism with 65 species and 466 reactions (Detailed-Mech) was first assembled using models from the literature. A directed relation graph with error propagation (DRGEP) and computational singular perturbation (CSP) method were then used to obtain a 23-species, 73-reaction compact reaction model (Reduced-Mech). Finally, the pre- exponential factor (A) and activation energy (Ea) of five significant elementary reactions were optimized using an Artificial Neural Network (ANN) to obtain the optimized mechanism (ANN-Mech). The ANN-Mech was validated at ignition delay times (IDT), laminar burning velocity (LBV), plug flow reactor (PFR) species distribution, and in the 3-D combustion chamber. The study found that the logarithmic mean errors of IDT decreased by 3.9 %. The mean error of laminar burning velocity is reduced from 18.5 % to 9.5 %, and the prediction error of NOX in ANN-Mech is reduced by 47.5 %. The results of the premixed flames simulation indicate that the temperature and velocity fields of ANN-Mech at different ammonia fractions better agree with the Detailed-Mech. Additionally, the NO error of the outlet was reduced by 30 %. The calculation speed was also increased by ten times compared to the Detailed-Mech.

Flue gas desulfurization characteristics of Mn-Ce metal oxides supported by ceramic-based diatomite and SBA-15 were systematically examined. The diatomite-supported sorbent (M2C2D6) achieved 96 % desulfurization efficiency, which can be attributed to its robust mechanical integrity and high porosity. In contrast to the diatomitesupported sorbent, the SBA-15-supported counterpart (M2C2S6) exhibited more uniform active component dispersion, leading to a marked elevation in breakthrough sulfur capacity (TSC) from 162 mg-SO2/g-sorbent to 469 mg-SO2/g-sorbent. Conversely, due to its lower porosity and diminished metal oxide affinity, heterogeneous surface distribution was observed on M2C2S6, impeding molecular interaction between SO2 and active sites. Consequently, a reduction in desulfurization efficiency to 65 % was recorded for M2C2S6. Desulfurization mechanisms were elucidated through integrated analysis of chemical reactions, external mass transfer, and internal diffusion processes. A novel Mn-Ce/diatomite-SBA carrier-blended sorbent was developed by synergistically combining the advantages of both carriers. When the diatomite: SBA-15 wt ratio reached 3:2, the hybrid sorbent (M2C2D6S4) demonstrated 96 % SO2 removal efficiency and 193 mg-SO2/g-sorbent TSC. Notably, across five consecutive desulfurization-regeneration cycles, M2C2D6S4 consistently outperformed the single-carrier M2C2D6 in TSC, underscoring its superior durability.

Since fossil-fuel power plants emit humid flue gases, the competitive adsorption of CO2 with H2O is inevitable for adsorptive carbon capture technologies. Nitrogen- and oxygen-containing functional groups can enhance adsorption capacity and selectivity of biochar. However, the interaction between N/O functional groups and CO2 in the presence of H2O is not clarified. In this study, a series of nitrogen-doped biochars rich in oxygen-containing functional groups were synthesized using a facile method. The N-doping enhanced the CO(2 )sorption as the best sample showed a sorption uptake of 1.21 mmol/g at 25( degrees)C and 15 vol% CO2 (balanced with N-2). The saturated sorption amounts of CO2, H2O, and N-2 followed the order:qH(2)O(8.27 mmol/g)> qCO(2) (1.82 mmol/g) >> qN(2) (0.12 mmol/g). In CO2/H2O co-adsorption, CO2 sorption of the N-doped biochar was reduced only by 28.7 %. Therefore, sorption of H2O was more preferred than CO2 in terms of equilibrium; meanwhile, the sorption of H2O was restricted by slow kinetics. DFT simulations suggested that, except for quaternary nitrogen, the N/O functional groups increased the adsorption energies of CO2 and H2O and the adsorption energies of H2O were higher than those of CO2 (e.g. CO2 and H2O with pyridine-N were-26.47 and-34.53 kJ/mol, respectively), because N/O doping changed the polarity of biochar surface. The current study can improve the understanding of the competitive sorption of CO2 and H2O on N/O doped biochar, facilitating biochar application for CO(2 )capture from humid flue gas.

As traditional fossil fuels are gradually depleting, finding green and renewable alternative energy sources has become increasingly important. The steam reforming of waste plastics and biomass mixtures for hydrogen production is regarded as a promising solution. Biomass (wheat straw) and Plastic (low-density polyethylene) were picked as the study's basic materials, water (H2O) was employed as the gasification agent, and biochar (Wheat straw charcoal)-loaded nickel (Ni) was utilized as the catalyst. BET, XRD, FTIR, SEM, and ICP-OMS have been employed to examine the modified biochar's catalyst chemical makeup and structural characteristics. The impact of varying Ni loadings catalyst, catalytic reforming temperature, steam flow rate, and feedstock blending ratio on the process of steam reforming of biomass/plastics to hydrogen were investigated. The outcomes showed that the catalyst Ni/WB-C had functional groups that contained oxygen and a rich pore structure. The optimal experimental conditions for steam reforming of biomass/plastics to hydrogen were achieved at a Ni loading of 15 wt%, pyrolysis temperature of 600 degrees C, catalytic reforming temperature of 800 degrees C, steam flow rate of 0.2 g/ min, and biomass/plastic ratio of 5:5. In accordance with the aforementioned condition, the total gas yield, the H2 yield, and its percentage, and the H2/CO ratio, were found to be 109.4 mmol/g, 77.5 mmol/g, 70.8 %, and 3.97. Therefore, this study provides an effective new approach to enhance H2 production from steam reforming of waste plastics/biomass.

Catalyst deactivation caused by coke deposition is a major barrier in the catalytic fast pyrolysis (CFP) of biomass for the production of aromatic hydrocarbons. To mitigate this issue, timely oxidative regeneration of spent catalysts is essential. In this study, wheat straw was employed as the feedstock to evaluate the performance of fresh and regenerated HZSM-5 and core-shell structured M@3Ga-8Ni/AZ catalysts. A screw-type pyrolysis reactor, an oxidative regeneration system, and Py-GC/MS analysis were used to investigate the effects on product distribution and bio-oil composition. The catalytic activity index (Ac) was applied to assess catalyst deactivation and regeneration performance under continuous operation. When fresh HZSM-5 was used for five consecutive catalytic runs, the aromatic hydrocarbon (AHs) selectivity was 16.24 %, with an Ac of 45.45 %. After regeneration, AHs selectivity recovered to 47.59 %, and Ac reached 96.71 % in the first cycle. In contrast, M@3Ga8Ni/AZ showed significantly improved stability and regeneration performance, maintaining 67.46 % AHs selectivity and 84.44 % Ac after five runs, and recovering to 84.89 % AHs selectivity and 98.46 % Ac upon regeneration. The results demonstrated that the combined modification of HZSM-5 through alkali treatment, metal loading, and core-shell structuring significantly enhanced its deoxygenation efficiency and aromatic hydrocarbon selectivity, while effectively suppressing coke deposition in the pore channels. Accordingly, M@3Ga8Ni/AZ exhibits strong potential for industrial application in catalytic biomass pyrolysis.