Journal of Analytical and Applied Pyrolysis最新文献

{"title":"Deciphering thermal-state structure and thermal strength structure-property relationships via \"High-temperature quenching cross-state SEM analysis\"","authors":"Yanqing Dou ,&nbsp;Qi Liu ,&nbsp;Xinwei Liu ,&nbsp;Xu Wang ,&nbsp;Liangyu Chen ,&nbsp;Jin Li ,&nbsp;Ju Shangguan ,&nbsp;Shoujun Liu ,&nbsp;Song Yang","doi":"10.1016/j.jaap.2025.107210","DOIUrl":"10.1016/j.jaap.2025.107210","url":null,"abstract":"<div><div>This study investigates the structural drivers of high-temperature compressive strength degradation in metallurgical coke during pyrolysis (25–1200 °C) through an integrated approach combining in-situ mechanical testing and multi-scale characterization. A novel in-situ high-temperature compression system coupled with liquid nitrogen quenching enabled real-time strength measurements and thermal-state structure preservation. XRD, TEM, and BET revealed dual-regime behavior: Below 1000 °C, compressive strength remained stable (28.03 ± 0.77 MPa) due to C-O crosslinking networks, while exceeding this threshold triggered irreversible strength loss (21.54 MPa at 1200 °C). Graphitization dominated structural evolution, evidenced by decreased (002) interlayer spacing (0.3860→0.3774 nm) and increased graphitic stacking height (<em>Lc</em>: 0.67→0.77 nm). Specific surface area surged 149 % (4.23→10.51 m²·g⁻¹) above 1000 °C, with micropore volume growth indicating pore network reconstruction. XPS and FT-IR confirmed thermal cleavage of C-O bonds (25.36 %→9.84 %), destabilizing carbon matrices. Natural cooling leads to the collapse of the pore structure of coke and the fusion of pore walls, while the liquid nitrogen quenching process can clearly reveal the evolution law of pores. The deterioration mechanism links <em>sp</em>^<em>2</em> domain growth (7.74 %→65.41 %) to weakened interlayer cohesion and microcrack propagation. These findings establish a pyrolysis-structure-strength correlation model, providing actionable insights for designing coke with enhanced thermal stability in blast furnace operations.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107210"},"PeriodicalIF":5.8,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144272053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pyrolysis study and surrogate fuel construction of real RP-3 aviation kerosene with SVUV-photoionization molecular-beam mass spectrometry","authors":"Wei-Kang Dai ,&nbsp;Zhi-Min Wang ,&nbsp;Du Wang ,&nbsp;Kai-Ru Jin ,&nbsp;Ya-Wen Liu ,&nbsp;Xu Zhang ,&nbsp;Zhan-Dong Wang ,&nbsp;Zhen-Yu Tian","doi":"10.1016/j.jaap.2025.107217","DOIUrl":"10.1016/j.jaap.2025.107217","url":null,"abstract":"<div><div>The pyrolysis of real RP-3 aviation kerosene was studied experimentally in a jet-stirred reactor using synchrotron photoionization and molecular beam mass spectrometry in the range of 700–1050 K. The initial chemical constituents of the RP-3 aviation kerosene were meticulously identified through molecular beam mass spectrometry and gas chromatography. The compositional analysis divided the sample into three principal hydrocarbon groups: long-chain alkanes constituted the predominant fraction at 63.2 %, followed by cycloalkanes at 18.8 %, and aromatic hydrocarbons at 17.2 %. A three-component surrogate fuel was chosen to simulate the pyrolysis characteristics of RP-3 aviation kerosene, comprising 66.2 % n-dodecane (NC₁₂H₂₆), 18.0 % 1,3,5-trimethylcyclohexane (T135MCH), and 15.8 % n-propylbenzene (NPB). A comprehensive kinetic model for the surrogate fuel, involving 462 species and 3199 reactions was developed and validated against experimental data obtained from the pyrolysis of real RP-3 aviation kerosene. Furthermore, the pyrolysis process of the RP-3 was elucidated through a detailed analysis of the production rates of the initial components in the surrogate fuel, which can be classified into three primary reaction pathways. Alkane components undergo alkyl radical chain propagation processes, resulting in the formation of various alkenes. Aromatic components primarily convert into benzene and toluene, while only a small fraction undergoes benzene ring addition reactions to form polycyclic aromatic hydrocarbons (PAHs). Cycloalkanes mainly decompose via unimolecular pathways, generating alkenes, while a smaller proportion undergoes multiple H-abstraction reactions, ultimately transforming into aromatic compounds. Sensitivity analysis indicates that consumption of the fuel components is promoted by H/CH₃ radicals at low temperatures. As the temperature rises to 880 K, the insufficient supply of these radicals leads to a competing reaction between the fuel components and the pyrolysis products. The results of the study could contribute to analytical methods for complex mixture fuels and facilitate a comprehensive exploration of jet fuels under combustion conditions.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107217"},"PeriodicalIF":5.8,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144255284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative study of the pyrolysis of sawdust contaminated with hydraulic oil and metals from industrial activities and raw sawdust for the production of biochar and bio-oil","authors":"Mariem Ben Salem ,&nbsp;Lokmane Abdelouahed ,&nbsp;Bechara Taouk ,&nbsp;Mohamed Bouaziz","doi":"10.1016/j.jaap.2025.107203","DOIUrl":"10.1016/j.jaap.2025.107203","url":null,"abstract":"<div><div>Inappropriate disposal of contaminated sawdust by industry poses significant environmental and energy challenges. This study investigates the pyrolysis of raw sawdust (RWS) and sawdust contaminated with hydraulic oils and brass slag (SCH) in a discontinuous pyrolysis reactor system. SCH, composed of 49 % RWS, 44 % hydraulic fluid and 7 % brass slag, has a higher carbon content (18.71 %) and calorific value (28.67 MJ/kg) than RWS (13.05 % and 18.27 MJ/kg), but less volatile matter (70.33 % vs. 80.12 %).Thermogravimetric analysis (TGA/DTG) indicates that hydraulic oil contamination accelerates the decomposition of SCH, lowering its onset temperature and increasing its residual mass due to incomplete volatilization and metallic additives. Pyrolysis at 450–600°C produced less biochar from SCH (16.66 %), but higher yields of bio-oil (up to 59 %) and gas (71.66 %). Oxygenated compounds were the dominant compounds in the bio-oil composition, which included phenols, nitrogen-containing compounds, guaiacols, organic acids, ketones, sugars, hydrocarbons, esters, furans and alcohols.Biochar characterization revealed structural and chemical differences between SCH-derived and RWS-derived biochar.FTIR spectroscopy revealed similar functional groups in both biochars, but the SCH biochar exhibited faster volatilization of aliphatic components and higher reactivity. SEM-EDX analysis revealed a heterogeneous morphology containing embedded metal particles. SCH biochar showed increased porosity and a calorific value of 30.07–30.64 MJ/kg, comparable to that of low-grade coal. These results demonstrate the energy potential of contaminated sawdust in a discontinuous pyrolysis reactor system, but further assessment of its environmental impacts is required to ensure sustainable application.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107203"},"PeriodicalIF":5.8,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of pretreatment on the bond-breaking rules during pyrolysis of Shengli lignite and the construction of macromolecular structure model","authors":"Boyang Bai ,&nbsp;Ming Sun ,&nbsp;Luyao Qiang ,&nbsp;Yufeng An ,&nbsp;Shanshan Wei ,&nbsp;Feifei Wang ,&nbsp;Xiaoxun Ma","doi":"10.1016/j.jaap.2025.107215","DOIUrl":"10.1016/j.jaap.2025.107215","url":null,"abstract":"<div><div>Coal pyrolysis is a critical method for the clean and efficient utilization of coal, with its structural characteristics playing a decisive role in pyrolysis behavior. By modifying the coal structure via pre-treatment and subsequently examining the effects of these structural alterations on its pyrolysis characteristics, we can more effectively clarify the pyrolysis mechanism of coal. In this study, hydrothermal pretreatment (HTP) and solvent swelling pretreatment (SSP) were used to change the structure and composition of Shengli (SL) lignite. The structural changes in the pretreated coal were characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and solid-state ¹³C nuclear magnetic resonance (NMR). A macromolecular structure model of SL lignite/pretreated coal were constructed. The bond-breaking rules and pyrolysis characteristics of SL lignite/pretreated were investigated using thermogravimetric-infrared (TG-IR) analysis and a fixed-bed reactor, respectively. The results of the macromolecular structure model indicate that: compared with the SL lignite (600 kcal/mol), the total energy of HTP (679 kcal/mol) and SSP (686 kcal/mol) has significantly increased, which is more conducive to the depolymerization of coal molecules during the pyrolysis. Specifically, HTP can increase the H/C ratio and the proportion of phenolic hydroxyl groups in coal, while reducing the content of oxygen-containing functional groups. It also disrupts the cross-linking structure of SL lignite, promoting the cleavage of C_ar-O and C_al-C_ar bonds, which resulted in an increase in the yields of pyrolysis tar and light tar from 7.48 %, 41.68–9.40 %, 47.62 % respectively. On the other hand, SSP primarily destroys non-covalent bonds in coal and dissolves small molecular compounds to weakening the cross-linking structure, facilitating the cleavage of C_al-C_al, C_ar-O and C_al-C_ar bonds during pyrolysis, promotes the generation of tar. Accordingly, the tar yield and the content of light tar increased to 9.75 % and 47.88 %.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107215"},"PeriodicalIF":5.8,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selective hydrodeoxygenation of Dongming lignite ethanolysis-derived O-rich oil to fatty alcohols over a Ni-based LaMgAlOx","authors":"Guang-Hui Liu ,&nbsp;Han Wang ,&nbsp;Wei-Wei Yan ,&nbsp;Shi-Chen Feng ,&nbsp;Min Wang ,&nbsp;Yu-Hong Kang ,&nbsp;Yan-Jun Li ,&nbsp;Xian-Yong Wei","doi":"10.1016/j.jaap.2025.107216","DOIUrl":"10.1016/j.jaap.2025.107216","url":null,"abstract":"<div><div>The directional upgrading from lignite liquefied crude oils to value-added oxygenated chemicals is an important pathway to optimize the clean non-fuel conversion system of lignite. However, O-containing group diversities and substituent differences make it difficult for such crude oils to be converted to fatty alcohols by simple hydrogenation. In view of this, a two-step cascade extraction system using the ternary mixed solution (petroleum ether/carbon disulfide, methanol, and water) was designed in this paper, and used for rapid enrichment of O-containing portions in Dongming lignite ethanolysis-derived crude oil to obtain O-rich oil (SP_E). In addition, a Ni-based LaMgAlO_x composite solid base, Ni@La₃₀BMO, modified by doping La was also prepared and used for the directional upgrading of SP_E to fatty alcohols, especially alkyl cyclanols. The results show that Ni@La₃₀BMO has excellent aromatic ring hydrogenation, &gt;C-O- bridged bond cleavage, and &gt;C_alOH retention properties, which are attributed to the texture property improvement of La₃₀BMO by doping La and strong Ni-La₃₀BMO interaction. Benzyloxybenzene can be selectively converted to cyclohexanol and methylcyclohexane over Ni@La₃₀BMO. &gt;C_alOH retention is related to the synergistic transfer of H<strong>···</strong>H and ^δ+H<strong>···</strong>H^δ- after H₂ activation and the inhibition of H<strong>·</strong> and H⁺ transfer over basic sites modified by La. In addition, the total proportion of O-containing species in SP_E obtained by rapid enrichment is 81.3 %, and arenols (65.1 %) are dominant. After selective hydrofining, the proportion of fatty alcohols in refined oil (CHSP_E) increased significantly from 4.1 % to 79.0 %, and that of alkyl cyclanols reached 74.8 %. Overall, Ni@La₃₀BMO is a potential catalyst for the conversion of complex lignite-based crude oils into fine oxygenated chemicals of fatty alcohols, especially alkyl cyclanols. The step-wise directional conversion from complex derived crude oils to simple enriched oils and/or refined oils is a new idea worth considering.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107216"},"PeriodicalIF":5.8,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144255159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integration of pyrolysis and gas phase adsorption to enhance the quality of pyroligneous acid from cajuput (Melaleuca leucadendron) residues","authors":"Wahyu Anggo Rizal ,&nbsp;Satriyo Krido Wahono ,&nbsp;Muslih Anwar ,&nbsp;Ria Suryani ,&nbsp;Dwi Joko Prasetyo ,&nbsp;Reka Mustika Sari ,&nbsp;Andri Suwanto ,&nbsp;Ponco Yulianto ,&nbsp;Hernawan ,&nbsp;Roni Maryana ,&nbsp;Ahmad Tawfiequrrahman Yuliansyah","doi":"10.1016/j.jaap.2025.107213","DOIUrl":"10.1016/j.jaap.2025.107213","url":null,"abstract":"<div><div>The pyrolysis of <em>Melaleuca leucadendron</em> (cajuput) twig biomass produces pyroligneous acid (PA), a bioactive liquid with potential applications in food and pharmaceuticals. This study investigates an integrated process combining slow pyrolysis and gas-phase adsorption using biochar derived from the same biomass to improve PA quality. The physicochemical characteristics of the raw biomass, biochar adsorbents (natural and HCl-activated), and resulting PA were analyzed. The integration of gas-phase adsorption significantly improved PA composition by increasing acetic acid and phenolic content while effectively reducing tar and polycyclic aromatic hydrocarbons (PAHs), especially those with low to medium molecular weight. Among the samples, PABN-1 produced the highest acetic acid content (44.23 %), while PABA-1 showed the highest phenolic content (6.44 %) and superior antioxidant performance. Antioxidant activity assessed through the ABTS radical scavenging assay, revealed that PABA-1 had the lowest IC₅₀ value (2190.07 ppm), indicating enhanced radical scavenging capacity due to concentrated phenolic compounds. Furthermore, the antibacterial assay demonstrated strong inhibitory effects of PA against <em>Staphylococcus aureus</em> ATCC 25923 at 1.56 % MIC and <em>Escherichia coli</em> ATCC 8739 at 3.12 % MIC, particularly with PABA-2. The Activation of biochar with HCl further enhanced its adsorption performance by reducing tar and PAH content while enriching beneficial bioactive components. These findings highlight the effectiveness of integrating pyrolysis with gas-phase adsorption in upgrading PA for safer and more functional applications as a natural preservative and bioactive agent.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107213"},"PeriodicalIF":5.8,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144222540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enriching pyrrole components in bio-oil by nitrogen-rich pyrolysis of tobacco stem employing ZIF-67/ZSM-5 dual-catalyst","authors":"Xiaoyu Song ,&nbsp;Shanjian Liu ,&nbsp;Tianhao Li ,&nbsp;Hui Wang ,&nbsp;Fupeng Huang ,&nbsp;Xueyuan Bai ,&nbsp;Dongmei Bi","doi":"10.1016/j.jaap.2025.107212","DOIUrl":"10.1016/j.jaap.2025.107212","url":null,"abstract":"<div><div>Traditional pyrrole preparation methods have challenges such as operational complexity, harsh conditions. In this study, This study proposes a strategy for the preparation of pyrrole via nitrogen-rich catalytic pyrolysis of tobacco stems (TS) using a ZIF-67/ZSM-5 dual-catalyst system. Using urea as the exogenous nitrogen source, the in-situ catalytic pyrolysis experiment was carried out in a horizontal tube furnace, the mass ratio of the reaction raw materials (tobacco stem, urea and catalyst) was 5: 3: 5, the air was purged with argon gas before the reaction, the pyrolysis temperature was set to different gradients for the experiment, and the pyrolysis time was fixed at 15 min. Experimental data revealed that, with a 60 % addition of external nitrogen (urea) and a 4:1 molar ratio of ZIF-67, the ZIF-67/ZSM-5 dual catalyst achieved a notable increase in bio-oil yield, reaching 39.6 wt% at 450 ℃. Pyrrole compounds accounted for 45.5 wt% of the total, and the selectivity of nitrogen-containing compounds was remarkably high at 68.9 %. Compared with the pyrolysis of ZIF-67 and ZSM-5 alone, the relative content of pyrrole compounds increased by 7.1 % and 10.4 %, respectively. The ZIF-67 catalyst promotes redox and coordination catalysis to enhance the production of pyrrole precursors such as furans, hydroxyacetone, and aldehydes, ultimately increasing the relative content of Pyrrole compounds. Meanwhile, Utilizing acid catalysis and sieve properties, ZSM-5 suppresses dehydrogenation and nitrile formation. Therefore, the ZIF-67/ZSM-5 dual catalyst can effectively utilize the renewable waste TS and efficiently prepare the high-value chemical pyrrole.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107212"},"PeriodicalIF":5.8,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pyrolysis characteristics of pulverized coal in circulating fluidized bed with a multi-section variable-diameter riser","authors":"Xiaoyu Zhang ,&nbsp;Xiaobin Qi ,&nbsp;Wentao Wang ,&nbsp;Xinli Li ,&nbsp;Zhiping Zhu","doi":"10.1016/j.jaap.2025.107214","DOIUrl":"10.1016/j.jaap.2025.107214","url":null,"abstract":"<div><div>An innovative circulating fluidized bed (CFB) structure with a multi-section variable-diameter riser was proposed to pyrolyze pulverized coal for tar production in this study. Experimental investigations on pulverized coal pyrolysis were conducted to explore the operational characteristics and pyrolysis product distribution of this specially designed CFB reactor, as well as the interconversion mechanisms among distinct pyrolysis products. Results show that the riser’s constricted structure enables the spatially partitional reaction regime: a high-temperature dilute-phase char partial gasification occurs below the constricted section, while a low-temperature dense-phase coal pyrolysis above the constricted section. By adjusting the oxygen concentration and equivalence ratio in gasification zone, the sensible heat and composition of gas-solid heat carrier (GSHC) can be effectively controlled, thereby changing the temperature of the pyrolysis zone. Whether it is the increase of oxygen concentration or the increase of equivalence ratio would lead to the increase of syngas content and the decrease of char content. Under the same pyrolysis temperature, the increase of oxygen concentration in gasification zone led to the increase of pyrolysis tar content. A simple molecular model of pulverized coal was established by the FTIR and Raman analysis to reveal transformation of functional groups. The aromatic ether and carboxylic acid, situating at the periphery of molecular model, served as primary sources of oxygen-containing substances. Aliphatic hydrocarbons underwent condensation reaction around 600 ˚C, which enhanced the concentration of larger polycyclic aromatic hydrocarbons in pyrolysis tar.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107214"},"PeriodicalIF":5.8,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144255156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular structural evolution during coal oxidation based on in situ FTIR and Raman spectroscopy","authors":"Guoqing Chen ,&nbsp;Yongsheng Guan ,&nbsp;Jiaxun Liu ,&nbsp;Xiangxin Han ,&nbsp;Jianguo Liu","doi":"10.1016/j.jaap.2025.107209","DOIUrl":"10.1016/j.jaap.2025.107209","url":null,"abstract":"<div><div>The elucidation of surface functional groups and microcrystalline structures in coal is fundamental for exploring the advanced coal conversion processes and elaborate pollutant formation mechanisms. In this work, in situ Fourier transform infrared (FTIR) and in situ Raman spectroscopy were employed to characterize the evolution of surface functional groups and microcrystalline structures throughout the coal oxidation process. The results indicate that oxidation causes the decomposition of -OH and -COOH, an increase in C-O functional group content, and the cleavage of C<img>C bonds at high temperatures. As the temperature rises, aromaticity parameters (<em>f</em>_<em>a</em>, <em>I</em>) and condensation degree (<em>DOC</em>) generally increase, while the structural parameter ‘<em>C</em>’ for oxygen-containing groups decreases. Furthermore, Raman parameters show an increase in A_D/A_G (proportion of large disordered aromatic rings) and a decrease in A_(GR+VL+VR)/A_D (relative content of 3–5 ring aromatic hydrocarbons), which corroborate the FTIR aromaticity parameters. These results suggest that during the oxidation process, condensation reactions and aromatization of aromatic rings occur, resulting in a general rise in aromaticity. In addition, the anthracite HN coal undergoes significant graphitization at 500°C. Notably, during the comminution process, mechanical forces introduce an increase in -OH, C<img>C, and C<img>O content on coal surfaces, while C-O content decreases. Additionally, the reduction in particle size partially inhibits coal oxidation reactions in the initial stages, whilst accelerates the maturation of the aromatic system and the trend toward graphitization. These findings offer a theoretical foundation for analyzing the homogeneous and heterogeneous reduction mechanisms of NOx, and developing low-NOx combustion technologies.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107209"},"PeriodicalIF":5.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144222542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unravelling the molecular significance of Rock-Eval® S2 pyrograms from soil and geological samples","authors":"Jérémy Jacob ,&nbsp;Frédéric Delarue ,&nbsp;Yoann Copard ,&nbsp;Claude Le Milbeau ,&nbsp;Laurent Grasset ,&nbsp;Patrick Brockmann","doi":"10.1016/j.jaap.2025.107211","DOIUrl":"10.1016/j.jaap.2025.107211","url":null,"abstract":"<div><div>Rock-Eval® pyrolysis is dedicated to rapidly determining the quality and quantity of organic matter (OM) in environmental and geological samples. It has been proposed that detailed examination of S2 pyrograms acquired from a Flame Ionization Detector during the programmed pyrolysis of samples can provide complementary information to classical Rock-Eval® parameters. Previous mathematical deconvolution of the S2 pyrogram has been suggested to semi-quantify distinct thermal fractions that are assumed to be distinct in terms of chemical and/or biological lability. To date, there is no direct molecular support for such an assumption. This work proposes a methodological approach based on coupling a temperature-programmed pyrolyser to a standard mass spectrometer (Py-MS). A set of reference soil samples was analysed. The set was completed by dissolved OM, source rock and coal samples in order to test the relevance of this methodological approach to various OM types. Data analysis was based on Tpeak values defined at temperatures of maximum <em>m/z</em> fragment production during the temperature ramp. These Tpeak values were grouped into clusters of distinct <em>m/z</em> values for which a chemical attribution is proposed owing to an extensive literature survey. For the soil samples, all the pyrolytic fractions described in the literature from mathematical deconvolution of the S2 pyrogram were identified except for the most thermolabile fraction (280–320 °C). Fragments with Tpeak values between 330 and 390 °C were mainly attributed to proteins, lignin and carbohydrates. Tpeak values found in the 391–499 °C range corresponded to <em>m/z</em> fragments attributed to aliphatics, lignin and aromatics while fragments with Tpeak values higher than 480 °C were assigned solely to aromatics. In all samples, these fragments displayed a singular pattern of decreasing <em>m/z</em> with increasing temperature, the significance of which remains to be fully elucidated. This preliminary study provides key methodological guidelines for re-exploring Py-MS applications to disentangle the chemical nature of OM.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"191 ","pages":"Article 107211"},"PeriodicalIF":5.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144222541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}