JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2022
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IF 6.437
Bingbing Luo,Kai Wu,Jiajun Yu,Siyu Wang,Yihan Wang,Chenyang Chu,Huiyan Zhang
Catalytic pyrolysis of biomass for efficient N-heterocycles production is highly promising but extremely challenging. Herein, catalytic co-pyrolysis of glycerol and cellulose under ammonia atmosphere was proposed to enhance the N-heterocycles yield. First, a solvolysis effect of glycerol, which could improve the thermal depolymerization of cellulose, was observed in thermogravimetric analysis (TGA). After that, the major influential factors, including Si/Al ratio, reaction temperature, and glycerol-to-cellulose (Gly:Cel) ratio, were investigated systematically. The N-heterocycles yield, as well as the comprehensive synergies of feedstocks, reached their maximum value under the conditions of Si/Al = 85, 550 ℃, and Gly:Cel = 5:1. The best synergistic extents for pyrroles , pyridines, and indoles were 105.3%, 71.3%, and 38.8%, respectively. The mechanism insight showed that, the thermal decomposition of cellulose was promoted while the coking of oxygenated molecules was suppressed during the catalytic co-pyrolysis process. Consequently, more oxygenated molecules were generated and retained for further catalytic conversion into imine intermediates and N-heterocycles.
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COMBUSTION AND FLAME
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2022
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IF 5.767
Jinhu Liang,Ruining He,Shijie Zheng,Fei Li,Yang Li,Jônatas Vicente,Amir Antônio Martins de Oliveira,Amir De Toni,Xin Bai,Xuebin Wang,Qian Yan
A new chemical kinetic mechanism of DMF (N, N-dimethylformamide) is proposed. To assess the reliability of the mechanism, high pressure shock tube, single pulse shock tube and constant volume reactor were used to experimentally evaluate ignition delay times, high temperature pyrolysis , and laminar flame speeds of DMF, respectively. Ignition delay times of DMF/ “air” were measured for equivalence ratios of 0.5, 1.0, and 2.0, pressures of 2.0 and 10.0 bar, and temperature ranging from 900 to 1430 K. Additionally, ignition delay times of DMF/acetone/air were measured for equivalence ratios of 0.5 and 1.0, pressures of 2.0 and 10.0 bar, and temperature ranging from 900 to 1430 K. High temperature pyrolysis products of DMF/acetone mixtures, diluted in argon, were studied at 5.0 bar, temperatures between 1000 and 1600 K. Flame speed measurements of DMF/air were obtained for pressures of 100 and 200 kPa, temperatures of 398, 423, and 448 K, and equivalence ratios from 0.7 to 1.4. Simultaneously, a chemical kinetics mechanism was developed to simulate the experimental results using ChemKin Pro, with sensitivity and flux analysis being carried out to elucidate limitations and possible refinements.
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Nanomaterials
·
2022
·Vol. 12
·期 9
·1416
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IF 5.719
Yining Jia,Rong Huang,Ruijuan Qi
Numerous efforts have been devoted to realizing the high loading and full utilization of single-atom catalysts (SACs). As one of the representative methods, atom migration-trapping (AMT) is a top-down strategy that converts a certain volume of metal nanoparticles (NPs) or metal-based precursors into mobile metal species at high temperature, which can then be trapped by suitable supports. In this study, high-loading iron single atoms anchored onto carbon matrix/g-C3N4hybrid supports were obtained through a single-atom migration-trapping method based on metal–organic framework (MOF) pyrolysis. It is confirmed, by high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), that the Fe(acac)3precursor is reduced to Fe single atoms (SAs), which are not only anchored onto the original N-doped carbon (NC), but also onto g-C3N4, with an Fe-N coordination bond. Further electrochemical results reveal that Fe-C3N4-0.075 possesses a better half-wave potential of 0.846 V and onset potential of 0.96 V compared to Fe-N-C, the product obtained after pyrolysis of Fe(acac)3@ZIF-8. As opposed to SAs prepared by the pyrolysis process only, SAs prepared by AMT are commonly anchored onto the surface of the supports, which is a simple and effective way to make full use of the source metal and prepare SACs with higher exposing active sites.Keywords:atom migration-trapping;single-atom catalysts;metal–organic frameworks
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PubMed
高影响因子
EUROPEAN POLYMER JOURNAL
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2021
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IF 4.598
Wenjian Guo,Shuxin Bai,Yicong Ye
Although numerous efforts have been focused on the high-value-added reutilization of resin matrix in abandoned composites, the evidence chain of whether high-value-added resin pyrolysis oil can be reused has not been comprehensively presented. Herein, the epoxy resin (EP) matrix in composite wastes was pyrolyzed into EP pyrolytic oil (EPO), and its detailed composition and effects on the microstructure, strength, and ablation of remanufactured carbon fiber (CF) composites were analyzed and evaluated. According to the results, more than half (57.8 wt%) of the EP matrix was converted into EPO, which mainly included phenol and its derivatives. Given that EPO contains a certain amount of phenol derivatives, the viscosity and wettability of EPO-formaldehyde (EPOF) prepolymer with CF was slightly poorer than that of industrial grade phenol formaldehyde (PF). In addition, CF reinforced EPOF (CF/EPOF) composites with strengths and ablation rates comparable to those of CF/PF composites were fabricated successfully, owing to good process performance of the EPOF prepolymer. The present work provides a comprehensive feasibility data support and basis for high-value-added reutilization of an abandoned resin matrix composite for the manufacture of composites.
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高影响因子
MOLECULES
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2023
·Vol. 28
·期 10
·4088
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IF 4.6
Feng Li,Wenzhi Lv,Dena Huang,Chenglu Zeng,Runping Wang
The molecular weight of lignin extracted from lignocellulosic biomass is an important factor in determining its valorization in industrial processes. Herein, this work aims to explore the extraction of high molecular weight and bioactive lignin from water chestnut shells under mild conditions. Five kinds of deep eutectic solvents were prepared and applied to isolate lignin from water chestnut shells. The extracted lignin was further characterized with element analysis, gel permeation chromatography, and Ultraviolet-visible and Fourier-transform infrared spectroscopy. The distribution of pyrolysis products was identified and quantified with thermogravimetric analysis—Fourier-transform infrared spectroscopy and pyrolysis-gas chromatograph-mass spectrometry. The results showed that choline chloride/ethylene glycol/p-toluenesulfonic acid (1:1.8:0.2 molar ratio) exhibited the highest fractionation efficiency for lignin (84.17% yield) at 100 °C for 2 h. Simultaneously, the lignin showed high purity (90.4%), high relative molecular weight (37,077 g/mol), and excellent uniformity. Furthermore, the aromatic ring structure of lignin remained intact, consisting mainly ofp-hydroxyphenyl, syringl, and guaiacyl subunits. The lignin generated a large number of volatile organic compounds during the depolymerization process, mainly composed of ketones, phenols, syringols, guaiacols, esters, and aromatic compounds. Finally, the antioxidant activity of the lignin sample was evaluated with the 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay; the lignin from water chestnut shells showed excellent antioxidant activity. These findings confirm that lignin from water chestnut shells has a broad application prospect in valuable chemicals, biofuels and bio-functional materials.Keywords:deep eutectic solvent;lignin;water chestnut shell;antioxidant activity;pyrolysis
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Journal of Environmental Chemical Engineering
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2023
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IF 7.7
Jiashu Liu,Lin Zhao,Hongzhi Geng,Bin Wang,Xuejiao Tong,Yihan Li,Daying Chen,Peizhe Sun,Yongkui Yang
Trichloroethylene (TCE) commonly exists in contaminated water as a persistent toxic pollutant . The advanced oxidation of persulfate (PS) is a promising method for degrading organic pollutants . Heterogeneous Fe-carbon composites prepared by pyrolysis with metal–organic frameworks (MOFs) have attracted attention. However, the intrinsic relationship between the physicochemical properties and catalytic performance of MOF-derived carbon compounds via PS is unclear. This study investigates TCE removal by Fe-MOF-derived carbon (MFC) with PS. The effects of the precursor template structure, pyrolysis temperature, and coexisting substances on TCE removal over the MFC/PS system are examined. Fe-MOF-derived from different precursor templates presented different TCE removal rates of 75.2–85.0%. The pyrolysis temperature of MFC alters the pore size, phase composition, and other properties, thereby affecting electron transport in the materials and catalyzing the degradation process. The total TCE removal reached 85.8% with MFC600, derived from MF88B and pyrolyzed at 600 ℃. This catalyst demonstrated excellent performance for PS degradation over a wide pH range (3−9). Moreover, free-radical and nonradical pathways coexist in the MFC600/PS system. During the TCE degradation process, oxygen vacancies, Fe species (Fe 0 , Fe 3 N, Fe 3 C, and Fe 3 O 4 ), and N species (pyridinic N and graphitic N) were active centers in the material and played a major role in catalytic degradation. They participated in the subsequent generation of HO•, SO 4 • - , and •O 2 - , and 1 O 2 . Furthermore, a possible degradation mechanism is proposed. This study elucidates the control of the physicochemical properties of carbon-based catalysts by exploiting MOF diversity.
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
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2023
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IF 5.9
Haoran Yuan,Chengyu Li,Rui Shan,Jun Zhang,Yong Chen
In the present study, selective transformation of waste cassava residues into aromatics via catalytic pyrolysis over as-prepared La and P modified ZSM-5 was systematically investigated, especially in the aspects of product regulation and kinetic analysis. Comprehensive physicochemical characterizations were undertaken for unveiling the essential structural properties of La and P modified ZSM-5. The introduction of La and P species significantly enriched the Lewis and Brønsted acid sites in ZSM-5, thus facilitating the directional pyrolysis of waste cassava residues into aromatics. Higher apparent activation energy for aromatics formation from waste cassava residues pyrolysis in the presence of La and P modified ZSM-5 might be due to the fact that the catalytic pyrolysis belonged to diffusion-controlled gas-solid reaction. In comparison with that of the parent ZSM-5, LaP 2 /ZSM exhibited better performance towards aromatics formation in waste cassava residues pyrolysis, wherein the relative content of aromatics reached 83.3% at a temperature of 650 °C. Gratifyingly, the relative content of aromatics was increased to 90.5% for the catalytic pyrolysis of acid pretreated cassava residue, in the case of LaP 1 /ZSM catalyst.
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COMBUSTION AND FLAME
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2021
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IF 4.185
Zhanjun Cheng,Hui Wang,Wenhao Yin,Jinglan Wang,Wei Li,Zhandong Wang,Lili Xing,Xuezhi Gao,Bowen Mei,Yan Zhang,Jiuzhong Yang,Lixia Wei,Xin Zhong,Hu Wang,Yuyang Li,Beibei Yan,Guanyi Chen
To explore the fuel isomeric effect on ether combustion characteristics, pyrolysis , and laminar flame propagation of di-n-propyl ether (DPE) and diisopropyl ether (DIPE) were investigated. A new kinetic model of DIPE was developed based on our recent DPE model [Fuel 298 (2021) 120797]. The pyrolysis experiments were carried out in two jet-stirred reactors at near-atmospheric pressure with good agreement on the measurements using synchrotron vacuum ultraviolet photoionization mass spectrometry and gas chromatography/mass spectrometry. The decomposition profile of DIPE showed a faster trend than that of DPE, which can be attributed to the faster alcohol elimination reaction of DIPE. The dominant roles of alcohol elimination reaction and H-abstraction reactions in fuel consumption explain the production of fuel-specific oxygenated species, i.e. n -propanol and propanal in DPE and i -propanol, acetaldehyde and acetone in DIPE. The laminar burning velocities of DPE and DIPE were also measured in a high-pressure constant-volume cylindrical combustion vessel at the initial temperature of 373 K and pressures of 1–10 atm. It was found that the linear DPE propagated faster than DIPE with the branched structure under all investigated conditions. Rate of production analysis and sensitivity analysis were also performed to elucidate the key radicals and reactions responsible for the remarkable reactivity of isomeric fuels. Fuel structures have a great influence on the distribution of radical pools, resulting in the easy formation of active radicals in DPE flames such as vinyl and ethyl and stable radicals in DIPE flames like methyl and allyl. The successive decomposition reactions of these dominant radicals promote the DPE flame and inhibit the DIPE flame propagation respectively, which explains the higher laminar burning velocities and reactivity of DPE than that of DIPE. Furthermore, the present model was also examined against the literature data, including pyrolysis and oxidation in the jet-stirred reactor and flow reactor.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2023
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IF 6
Chengxuan Zhou,Danni Deng,Chao Huang,Yu Xie,Hang Dong,Yujiao Wen,Bo Li,Zhi Zhou,Wei Luo,Zhonghua Zhou
The search for cost-effective, high-performance catalysts is crucial in catalytic co-pyrolysis. Different Fe-Mo@X catalysts (X = Al 2 O 3 , MgO) and reaction temperatures (600 ℃, 700 ℃, 800 ℃, 900 ℃) were tested to optimize hydrogen production and carbon quality while also exploring CNTs degradation performance. The results indicate that both catalyst type and operating parameters are highly dependent on the growth of carbon nanotubes and hydrogen. The FeMo@Al 2 O 3 catalyst exhibits superior catalytic activity attributed to its more abundant mesoporous structure and higher specific surface area. Specifically, FeMo@Al 2 O 3 achieved the highest yield of carbon nanotubes (84.42%) at 700 ℃, and attained the maximum hydrogen yield (49.57%) at 900 ℃. However, the CNTs synthesized from FeMo@MgO exhibited fewer defects, higher graphitization degree and purity (Raman and TPO). CNTs/MgO significantly enhanced the degradation efficiency of Clothianidin by virtue of their superior electron transport properties and chemical bonding between MgO and CNTs.
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高影响因子
WASTE MANAGEMENT
·
2023
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IF 8.1
Qingyu Liu,Bo Peng,Ning Cai,Yinhai Su,Siyu Wang,Peng Wu,Qi Cao,Huiyan Zhang
Upcycling waste plastics into valuable carbon nanotubes (CNTs) and hydrogen via catalytic pyrolysis is a sustainable strategy to mitigate white pollution. However, real-world plastics are complex and generally contain organic impurities, such as cellulose, which have a non-negligible impact on the catalytic pyrolysis process and product distribution. In this study, cellulose was chosen as a model compound to distinguish the effects of oxygen-containing components on the CNTs and hydrogen production during the catalytic pyrolysis of waste polypropylene. Different amounts of cellulose were mixed with polypropylene to regulate the O/C mass ratio of the feedstock, and the relationship between the O/C mass ratio and the yield of products has been built quantificationally. The results revealed that the relative content of CNTs increased to over 95%, and the stability and purity of carbon deposition increased accordingly when the O/C mass ratio is 0.05. This could be ascribed to the etching effects caused by small amounts of H 2 O and CO 2 on amorphous carbon. However, further increasing the amount of cellulose caused the deactivation of the Fe-Ni catalyst. This not only decreased the carbon yield but had an adverse impact on its morphology and graphitization, leading to the increase of amorphous carbon. This study can provide fundamental guidance for the efficient utilization of waste plastics that take advantage of organic impurities in waste plastic to promote the formation of high-purity CNTs.
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PubMed
高影响因子
WASTE MANAGEMENT
·
2023
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IF 8.1
Danni Li,Rui Shan,Jing Gu,Yuyuan Zhang,Xianhai Zeng,Lu Lin,Haoran Yuan,Yong Chen
To relieve the secondary contamination of heavy metals (HMs), the synergistic effect of co-pyrolysis of textile dyeing sludge (DS)/litchi shell (LS) and CaO on the migration of HMs was demonstrated in this study. The proportions of Cu, Zn, Cr, Mn, and Ni in the F4 fraction increased to 75%, 55%, 100%, 50%, and 62% at the suitable CaO dosages. When 10% CaO was added, the RI value of DLC-10% was reduced to 7.89, indicating low environmental risk. The characterizations of the physicochemical properties of biochar provided support for the HMs immobilization mechanism. HMs combined with inorganic minerals or functional groups to form new stable HMs crystalline minerals and complexes to achieve immobilization of HMs. The pH value and pore structure also play an important role in improving the immobilization performance of HMs. In conclusion, the results provided a new direction for the subsequent harmless treatment of HMs-enriched waste.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2023
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IF 6.1
Yuchen Jiang,Kang Zhang,Chao Li,Yuewen Shao,Lijun Zhang,Shu Zhang,Chuanjun Leng,Dong Wang,Zhenhua Cui,Xun Hu
Metal/biochar is an important catalyst with feature of easy recovering of metal via combustion of biochar carrier. During preparation of metal/biochar, interaction of metal with biochar affects evolution of pyrolytic products and dispersion of metal. Heating mode could influence interaction of metal with pyrolytic products. This was investigated by pyrolysis of sawdust loaded with nickel acetate at 400 or 600 °C with furnace and microwave heating, respectively. The results showed that cracking of biochar and volatiles was effectively promoted with Ni, generating more gases while reducing aliphatic organics and heavy phenolics in bio-oil. The enhanced cracking facilitated aromatization in microwave heating, forming biochar of higher thermostability and gases with more hydrogen. However, the furnace heating at 600 °C formed Ni/biochar of more developed pores than from microwave heating (409.1 versus 385.0 m 2 g −1 ). Microwave heating could induce merging of micropores on biochar, resulting in migration and aggregation of Ni. This led to lower capability for chemical adsorption of hydrogen and dispersion of nickel, further leading to inferior activity of Ni/biochar from microwave heating for hydrogenation of vanillin or furfural. The in-situ IR characterization of the pyrolysis showed the furnace heating reserved more oxygen-containing organics and aliphatic structures, promoting dispersion of nickel.
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