APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
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IF 19.503
Jyoti Gupta,Konstantinos Papadikis,Elena Yu. Konysheva,Yi Lin,Ivan V. Kozhevnikov,Jingjing Li
The impact of CaO on oakwood pyrolysis was explored by the Py-GC/MS at 500 °C. Ca(OH) 2 presents on the CaO surface, indicating its partial hydration (noted as CaO OH ). CaO OH promoted the ketonisation of carboxylic acids to aliphatic ketones, furfural to cyclopentanone/2-cyclopentenone, facilitated the elimination of the methoxy-phenolic compounds. The catalyst loading did not show any significant effect on the formation of acetone, while a noticeable reduction in the phenolics was revealed. Increasing catalyst loading almost eliminated CO 2 , acids, furans, aldehydes, ether groups, whilst the fractions of alcohols, esters, sugars, and alkoxybenzene decreased noticeably. The use of partially hydrated CaO OH in the CFP can create conditions where by-products generated during the ketonisation and phenolics upgrading reactions (CO 2 , H 2 O, CO) interact through the adsorption enhance water-gas-shift reaction and through coking reactions with formation of H 2 used for hydrogenation during multistep conversion of furfural to cyclopentanone in a vapour phase.
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COMBUSTION AND FLAME
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2020
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IF 4.57
Geyuan Yin,Jiawei Xu,Erjiang Hu,Qunfei Gao,Haochen Zhan,Zuohua Huang
A comprehensive experimental and kinetic study on the low temperature oxidation and pyrolysis of formic acid was conducted. Species profiles measurements were performed in a jet-stirred reactor (JSR) at the temperature range of 600–1100 K under atmospheric pressure, with a fixed residence time of 2.0 s and for the equivalence ratios ranging from 0.5 to ∞ (pyrolysis). High-level quantum calculation was used to obtain the accurate rate coefficients of missing reactions in Glarborg model. A detailed kinetic mechanism, derived from Glarborg model, has been developed based on high-level quantum calculation and validated with the species profiles obtained in this work and laminar flame speeds presented in our group. Reaction pathway and sensitivity analysis were investigated to get the deep insight of the oxidation of formic acid via the modified model. The results showed that unimolecular fuel decomposition reactions dominated the pyrolysis process while H abstraction reactions with the further consumption of the radicals are more important in the oxidation of formic acid. In addition, H abstraction reactions via HO2 become important at relatively low temperature.
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Journal of Environmental Chemical Engineering
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2020
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IF 4.3
Chao Li,Chenting Zhang,Guoming Gao,Mortaza Gholizadeh,Shu Zhang,Leilei Xu,Lijun Zhang,Qingyin Li,Xun Hu
In this study, the co-pyrolysis of pig manure with cellulose and glucose were investigated at various heating rates. The results demonstrated that potential cross-interaction of the volatiles from the co-pyrolysis facilitated the cracking reaction, resulted in the formation of less charry products and less tarry compounds in the co-pyrolysis. The volatiles interaction also enhanced the evolution of the organics with the π-conjugated ring structures in the bio-oil and remarkably affect the char properties. The dehydration and condensation reactions were promoted during the fast co-pyrolysis of manure with cellulose and glucose, leading to the increased carbon content (from 20.0%–46.5 and 43.0 %), the higher thermal stability, and the enhanced crystallinity of carbon structure in the char formed. In addition, the in-situ Diffuse Reflection Infrared Fourier Transform Spectroscopy (DRIFTS) characterization indicates that the interaction of volatiles in the co-pyrolysis obviously affected the evolution of the functionalities of the char and the reaction network. Additionally, the HHV (37.2 and 37.9 vs 28.0 MJ/Kg) and the energy yield (66.3 and 68.2 vs 66.2 %) of the char from the co-pyrolysis was higher than that of the manure, which was beneficial for the utilize of the char as solid fuel.
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BIORESOURCE TECHNOLOGY
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2020
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IF 7.539
Kai Li,Guan Zhang,Ze-xiang Wang,Bin Hu,Qiang Lu
An efficient process was developed to selectively produce monocyclic aromatic hydrocarbons (MAHs) from ex-situ catalytic fast pyrolysis (CFP) of pine assisted with calcium formate (CF) over bimetal-modified HZSM-5. Mo and another metal (Mg, Ga or Zn) were used to modify the HZSM-5, and the as-synthesized bimetal-modified HZSM-5 catalysts were utilized for both pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and lab-scale CFP tests with CF as a hydrogen donor to selectively obtain MAHs. The results revealed that the presence of CF and Mg-Mo modified HZSM-5 (0.5Mg1Mo/HZ) exhibited excellent capability for MAHs production with tiny generation of polycyclic aromatic hydrocarbons (PAHs). The maximum MAHs yield attained 12.79 wt% at 650 °C from Py-GC/MS with the CF-to-pine (CF-to-PN) ratio of 3 and catalyst-to-pine (CA-to-PN) ratio of 11, and became 9.67 wt% from lab-scale device with CF-to-PN and CA-to-PN ratios of 0.5 and 4, respectively. In addition, compared with HZSM-5, 0.5Mg1Mo/HZ possessed better anti-deactivation ability.
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PubMed
高影响因子
Journal of CO2 Utilization
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2020
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IF 5.993
Jinsong Shi,Hongmin Cui,Jianguo Xu,Nanfu Yan,Yuewei Liu,Shaowei Zhang
In the current work, we reported the synthesis of nitrogen doped carbons (NDCs) with a very convenient one-step strategy. Highly porous NDCs were successfully prepared from the direct pyrolysis of potassium phthalimide at 600−900 °C. The obtained carbon had a high specific surface area (2053 m 2 /g) and pore volume (1.14 cm 3 /g) after pyrolysis at 900 °C. The nitrogen content of the carbon was 3.3–9.1 wt%, and decreased with the increase of pyrolysis temperature. The combination of high porosity and nitrogen content made the synthesized NDCs attractive CO 2 adsorbents. At 25 °C, the carbon exhibited CO 2 uptakes of 1.1 mmol/g at 0.15 bar, and 3.4 mmol/g at 1 bar. The experiment results also revealed a linear relationship between the uptake at 0.15 bar and the CO 2 /N 2 adsorption selectivity. Small micropores and nitrogen containing functionalities had decisive effects on these properties.
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BIORESOURCE TECHNOLOGY
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2020
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IF 7.539
Lin Jiang,Yunpu Wang,Leilei Dai,Zhenting Yu,Qiuhao Wu,Yunfeng Zhao,Yuhuan Liu,Roger Ruan,Linyao Ke,Yujie Peng,Donghua Xia,Li Jiang
The composite catalysts were synthesized with SiC powder and ZSM-5 and were characterized by Brunauer-Emmett-Teller, X-ray diffraction, thermogravimetric analysis, pyridine-infrared spectroscopy, and scanning electron microscopy. The catalysts showed a high heating rate and excellent catalytic performance for pyrolysis vapors, and the product fractional distribution and chemical compositions of bio-oil in a tandem system (microwave pyrolysis and microwave ex-situ catalytic reforming) was examined. Experimental results confirmed the quality of bio-oil produced by the microwave-induced catalytic reforming was better than that product through electric heating. Additionally, 36.94 wt% of bio-oil was obtained using the catalyst with 20%ZSM-5/SiC under the following conditions: feed-to-catalyst ratio, 2:1; pyrolysis temperature, 550 °C; and catalytic temperature, 350 °C. The selectivities of hydrocarbons reached up to 75.88%. After five cycles, the activity of the regenerated composite catalyst was retained at 95% of the original catalyst.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2020
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IF 6.551
Wenmei Tao,Wenyan Duan,Chunbo Liu,Dongdong Zhu,Xiaoxi Si,Ruizhi Zhu,Patryk Oleszczuk,Bo Pan
The presence of persistent free radicals (PFR) in biochars may greatly broaden the application of biochars in pollution control , but may also cause negative impacts to the environment. Understanding the structural basis and the formation mechanisms of PFR is essential for a targeted biochar production and application. This study used rice straw (RS), a ubiquitous agricultural waste , to investigate the generation processes of PFR in relation to RS pyrolysis kinetics. Based on a detailed thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis, the activation energy was calculated by Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods. This work combined pyrolysis kinetics analysis and solid particle characterization. Our results showed that lignin started to pyrolyze at a lower temperature than cellulose and hemicellulose. Lignin was the main factor for PFR generation. Chemical bond breaking contributed only slightly to PFR formation. The reconfiguration of the carbonaceous structures may be a more important contributor to PFR formation, while the cross-linking between different compositions and the interactions between the chemical compositions and inorganic minerals may play a significant role for PFR generation and stabilization in RS. This study provides useful theoretical basis to understand the thermal pyrolysis process of RS and the manipulation of biochar properties.
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JOURNAL OF HAZARDOUS MATERIALS
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2021
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IF 10.588
Leilei Cheng,Yuyuan Zhang,Yazhuo Wang,Jing Gu,Haoran Yuan,Yong Chen
Converting plastic wastes into value-added products through energy-efficient pyrolysis is essential, and it requires lower pyrolysis temperatures and shorter processing times than that of other processes. An exothermic phenomenon was observed during the process high-pressure polyethylene pyrolysis. It was proven for the first time that the exotherm is caused by a pressure-induced phase transition, in which colossal heat release can be driven by relatively small pressures. A large temperature change (> 100 °C) leads to the deep cracking of polyethylene, although the set temperature is far lower than the required temperature for thermal cracking. Importantly, the heat input stops immediately when the set temperature is reached; thus, the external heating time is short. Polyethylene can be completely converted into liquid products in ~90 wt% yield and with a small number of gases. The self-exothermic phase transition only occurs within a certain range of material thickness, which is related to the corresponding phase behavior. In the self-exothermic pyrolysis process, with an increase in the thickness of polyethylene, the proportion of low-value olefins in oil products decreases gradually, while alkanes, isoalkanes and aromatics show an increasing trend, making the product composition closer to the fuel standard. This work provides a viable approach for plastic recycling at low pyrolysis temperatures and short external heating times with the help of a self-exothermic phase transition in the absence of a catalyst.
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ENVIRONMENTAL TECHNOLOGY
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2021
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IF 3.247
Wei Wang,Zhijuan Wang,Kai Li,Yuxin Liu,Delong Xie,Shaoyun Shan,Liang He,Yi Mei
The adsorption of chlorinated aromatic compounds (CACs) on pristine biochar was often limited. Surface modification can greatly improve the adsorption capacity of biochar. In this work, by pyrolysis activation of rubber-seed shell wastes, nitrogen auto-doped biochar (RSS-NBC) was synthesized and used for purifying CACs-containing wastewater. Systematic characterization results showed that after proper treatment, the as-prepared RSS-NBC had high specific surface area, abundant surface oxygen- and nitrogen-containing functional groups, and nano-scale pore structure. Batch adsorption experiments were conducted with using three typical CACs probing pollutants, i.e. 1,2-dichlorobenzene (1,2-DCB), 2,4-dichlorophenol (2,4-DCP) and 2,4-dichlorobenzoic acid (2,4-DCBA). The adsorption experiments results showed that the maximum adsorption amounts of 1, 2-DCB, 2,4-DCP, and 2,4-DCBA could reach 2284, 1921, and 1142 mg/g at 298.15 K. Moreover, 90% of the equilibrium adsorption amount can be reached within 0.5 h. The adsorption kinetic results showed that the adsorption processes of the three CACs followed the pseudo-second-order rate model and were dominated by chemisorption. Also, the adsorption isotherms of 1, 2-DCB and 2, 4-DCP belonged to the Freundlich model and were valid for multilayer adsorption, while the adsorption of 2,4-DCBA followed Langmuir model and single-layer adsorption. The thermodynamics data indicated that the spontaneous adsorption process of 1, 2-DCB and 2, 4-DCP was endothermic while that of 2,4-DCBA was exothermic. After 5 cycles of adsorption-regeneration, the removal efficiency of RSS-NBC particles still remained more than 80% for the three typical CACs, indicating that it could be reused as an effective and retrievable adsorbent in the treatment of CACs-containing effluents.
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COMBUSTION AND FLAME
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2019
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IF 4.12
Yan Zhang,Bowen Mei,Chuangchuang Cao,Xiaoyuan Zhang,Wenhao Yuan,Jiuzhong Yang,Yuyang Li
This work reports the investigation on pyrolysis and laminar flame propagation of sec- butylbenzene. The pyrolysis experiments were performed in a flow reactor using synchrotron vacuum ultraviolet photoionization mass spectrometry from 780 to 1166 K at 0.04 and 1 atm. The pyrolysis products were identified and their mole fraction profiles versus the heating temperature were evaluated. The laminar burning velocities of sec- butylbenzene/air mixtures were measured at the initial temperature of 423 K and initial pressures of 1–10 atm in a high-pressure constant-volume cylindrical combustion vessel with the equivalence ratio from 0.7 to 1.5. Furthermore, a kinetic model was developed to predict the pyrolysis and laminar flame propagation of sec ‑butylbenzene. Validation of the present model was performed against the new experimental data in this work. Rate of production analysis and sensitivity analysis were performed to provide insight into the chemistry in fuel decomposition and polycyclic aromatic hydrocarbons (PAHs) formation. In the flow reactor pyrolysis , the consumption of sec ‑butylbenzene is mainly controlled by the unimolecular decomposition reactions and H-atom abstraction reactions at both low and atmospheric pressures. Fuel specific pathways through propenylbenzene and α-methylstyrene become the dominant formation pathways of indene and naphthalene . In the laminar flame propagation, the laminar burning velocity of sec ‑butylbenzene is sensitive to the reactions of both small species and fuel-relevant intermediates under all investigated conditions. In particular, the pyrolysis reactions in the fuel sub-mechanism play inhibition effects on the laminar flame propagation of sec ‑butylbenzene under rich conditions. The laminar burning velocity of sec ‑butylbenzene is also compared with benzene, toluene and ethylbenzene under same initial conditions. Both the thermodynamic and kinetic effects are responsible for the difference in laminar burning velocities of these aromatic fuels.
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LANGMUIR
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2019
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IF 3.683
Dongjin Wan,Lairong Wu,Yongde Liu,Jing Chen,Hailiang Zhao,Shuhu Xiao
In this study, spent bleaching earth (SBE) and pyrolyzed SBE (SBE@C) were tested for their capacity to remove tetracycline hydrochloride (TCH) from aqueous solution. The maximum adsorption capacity obtained by the Langmuir model is 0.114 mmol/g for SBE@C and 0.087 mmol/g for SBE. The deleterious effects of coexisting cations were ranked in a decline: Al3+ > Mg2+ > Na+. The results of various characterization methods show that the adsorption mechanisms mainly included π–π interactions, hydrogen bonding, electrostatic interactions, and changes in physical and chemical properties. After 3 repeated cycles of pyrolysis, the adsorption capacity of SBE@C remained at 85.4%, with SBE@C potentially recycled 21 times before complete loss of adsorption capacity. Furthermore, the problem of secondary pollution caused by SBE and residual oil is resolved by the use of SBE@C. All results indicate that SBE@C is a likely candidate for the treatment of TCH wastewater in the coming practical applications.
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SOLAR ENERGY
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2019
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IF 4.674
Shuang Lu,Yinglin Wang,Chunxia Wu,Yichun Liu,Xintong Zhang
Searching for large-scale, non-Pt, efficient counter electrode (CE) materials is still a key challenge to realize the applications of high-performance dye-sensitized solar cells (DSSCs). Herein, we report the spray fabrication of stable, uniform and efficient CoS counter electrode at temperature no higher than 100 °C from CoS nanoparticles prepared by the ultrasonic spray pyrolysis (USP) method. The as-fabricated USP-assisted CoS CEs exhibit comparable electrocatalytic activity to the traditional thermolyzed Pt CE, generating a power conversion efficiency of 8.6% for unoptimized DSSCs. This CoS CEs also exhibited prominent electrochemical and mechanical stability, uniform electrocatalytic activity at the size of 10 × 10 cm, and good bending durability when deposited on flexible ITO/PEN conductive substrates, manifesting the merits of this USP-based strategy for the development of high-performance non-Pt electrocatalysts.
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