Catalysts
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2019
·Vol. 9
·期 8
·682
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IF 3.444
Wenjie Sun,Xiaomin Li,Chao Sun,Zhen Huang,Hualong Xu,Wei Shen
Metal organic frameworks (MOFs) have recently been used as precursors of the catalysts for the combustion of volatile organic compounds (VOCs). In the present work, three kinds of CeO2catalysts were successfully synthesized from Ce-MOF-808, Ce-BTC, and Ce-UiO-66, with specific topological structures and coordinate environments. Catalysts with small particle size, stacking mode, and structural defects could be created by pyrolysis of Ce-MOFs, which affects the activity in the toluene combustion significantly. Raman spectra, XPS, and OSC studies were performed to reveal the formation of defect sites. The thermal redox properties were determined by H2-TPR. Catalytic activity tests were conducted on the toluene combustion, and CeO2-MOF-808 showed the best catalytic performance (T90 = 278 °C) due to its having the largest specific surface area, abundant active surface oxygen species, and low-temperature reducibility.Keywords:Ce-MOF;cerium oxide;catalytic combustion of toluene;environmental catalysis;pyrolysis process
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FUEL PROCESSING TECHNOLOGY
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2019
·
IF 4.507
Qingfeng Che,Minjiao Yang,Xianhua Wang,Xu Chen,Wei Chen,Qing Yang,Haiping Yang,Hanping Chen
Dual catalysts are proposed in this study to convert biomass pyrolysis vapors into aromatics. Metal oxides (CaO, Al 2 O 3 , and ZnO) and ZSM-5 were introduced into the catalytic upgrading process. In the pyrolysis process without ZSM-5, the addition of CaO effectively removed carboxylic organics and methoxyphenols, reducing the product yield with a hydrogen to carbon ratio of 0, and the size of phenol compounds. The addition of Al 2 O 3 greatly promoted the cracking of oxygenates with molecular weight above 109 g mol −1 , such as large-size methoxyphenols and sugars. It is found that the upgraded pyrolysis volatiles are more conducive to conversion for aromatics with a ZSM-5 catalyst. The addition of CaO increased the selectivity of xylene (15.9%), while Al 2 O 3 promoted the selectivity of toluene (18.3%). The highest yield of aromatics was obtained with CaO-ZSM-5 dual catalyst system, which was boosted by 6.14% compared to that of pure ZSM-5. To explore more effective methods for aromatics production, the arrangement of catalysts and temperature condition were investigated. Mixing CaO with biomass produced more aromatics than other methods, and the most suitable temperature for the formation of aromatic hydrocarbons was 600 °C.
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BIORESOURCE TECHNOLOGY
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2019
·
IF 6.669
Qingfeng Che,Minjiao Yang,Xianhua Wang,Qing Yang,Yingquan Chen,Xu Chen,Wei Chen,Junhao Hu,Kuo Zeng,Haiping Yang,Hanping Chen
The micropores present in ZSM-5 are beneficial to the production of aromatic compounds in biomass catalytic pyrolysis, although the small pore size leads to severe coke deposition on the catalyst. In this study, a micro-mesoporous structured ZSM-5 zeolite catalyst was synthesized and modified with green templates (sucrose, cellulose, and starch) to introduce additional mesopores. It was found that the catalysts modified using the sucrose and cellulose templates only exhibited a slight increase in their micropore volumes, while the mesopore volume of ZSM-ST (modified with the starch template) reached up to 0.359 cm 3 /g. This increase promoted the cracking of bulky oxygenates and suppressed the polymerization reaction on the ZSM-5 surface, thereby producing a greater number of aromatic products. Moreover, the benzene, toluene, and xylene (BTX) yields exhibited a positive correlation with the catalyst mesopore volume, with the highest BTX yield of 91.84 mg/g being obtained with 10% starch addition.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2019
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IF 4.084
Yang Liu,Haimiao Yu,Jiecheng Liu,Dezhen Chen
In this study, innovative Ni-based catalysts supported by five typical slag carriers (magnesium slag (MS), steel slag (SS), blast furnace slag (BFS), pyrite cinder (PyC) and calcium silicate slag (CSS)) were prepared by wet impregnation. With the prepared catalysts and Ni/γ-Al 2 O 3 catalyst, catalytic reforming of pyrolysis volatiles from pine sawdust for syngas production and tar removal was investigated. The catalysts were characterized by BET, XRD , SEM, TEM and Raman. The catalytic performances of the six catalysts were decreasing in the following order: Ni/MS > Ni/γ-Al 2 O 3 > Ni/SS > Ni/BFS > Ni/CSS > Ni/PyC. Ni/MS catalyst exhibited excellent catalytic reactivity as well as thermal stability in terms of tar conversion (95.19%), gas yield (1.46 Nm 3 /kg) and CO 2 capture ability (CO 2 yield of 0.5%). Both amorphous carbon and graphite-type carbon were formed on the catalysts after catalytic reforming and the D/G ratio (the relative intensity ratio of the D-band to the G-band) was positively correlated to the catalytic activity .
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Yubin Zou,Wentao Li,Lian Yang,Feng Xiao,Guangyu An,Yue Wang,Dongsheng Wang
Microalgae can be harmful to natural water in a variety of ways, and how to deal with this problem has received much attention. Magnetic nitrogen-doped microalgae-derived carbon (Fe-N@MC) was successfully prepared by pyrolysis under different temperatures. The sp 2 -hybridized carbon and C O bond structure were strongly dependent on the pyrolysis temperature, and Fe-N@MC500 had a higher ratio of sp 2 -hybridized carbon than other counterparts. The surface morphology and structure analysis indicated that the Fe 3 O 4 was successfully anchored into the carbon layer for magnetic separation. Ciprofloxacin (CIP) was selected as the indicator to test the catalytic performance. In the presence of peroxymonosulfate (PMS), the degradation efficiencies of nano-Fe 3 O 4 , N@MC500 and Fe-N@MC500 for CIP were 46.8%, 79.8% and 92.6% within 120 min. Under different reaction conditions (PMS dosage, pH, temperature), Fe-N@MC500 composite was shown to have superior efficiency and stability. Radical quenching experiments and electron spin resonance (ESR) indicated that singlet oxygen ( 1 O 2 ) was dominant in the reaction supplemented by OH and SO 4 − . It is believed that PMS could work as both acceptor and donor for efficient activation by sp 2 -hybird carbon structure and C O bond. This study successfully provides a feasible method for the synthesis of recycled Fe-N@MC with microalgae as a renewable carbon feedstock to deal with antibiotics.
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Journal of Cleaner Production
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2019
·
IF 6.395
Nan Zhou,Yifan Wang,Denghui Yao,Shikai Li,Jiajie Tang,Da Shen,Xiaoyu Zhu,Liyang Huang,Mei-e Zhong,Zhi Zhou
The enhancement of surface functional groups of biochar is essential to improving the biochar contaminant adsorption. Current pyrolysis methods that are accompanied by activation are energy consuming and costly. Herein, a novel wet-pyrolysis system that was carried out in open air, with simultaneous conversion and modification to produce an effective biochar adsorbent, is described. Within this system, the surface of the biochar was oxidized partially to produce sufficient functional groups at the surface, whereas carbonization of the biomass (miscanthus sacchariflora) occurs under an acidic catalyst. The characteristic results confirmed the attachment of abundant surface functional groups, including hydroxyl and carboxyl groups , which increased in content with the ongoing reaction time. Neutralization with sodium carbonate removed the hydrogen bonds and enhanced the adsorption properties. The biochar that was obtained by using this technique exhibited an excellent cadmium adsorption capacity of 197 mg .g −1 and a high removal efficiency of 99%. Analysis of the Cd-loaded biochar indicated that adsorption occurred via ion exchange, and formed cadmium complexes. It could be concluded that this novel wet-pyrolysis system is a promising approach to produce biochar efficiently and cost-effectively for heavy-metal remediation.
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POLYMER DEGRADATION AND STABILITY
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2018
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IF 3.193
Zhi-Zheng Wu,Yan-Peng Ni,Teng Fu,Bo-Wen Liu,Wan-Shou Wu,Lin Chen,Xiu-Li Wang,Yu-Zhong Wang
At present, developing a flame-retardant unit to solve the flammability and melt-dripping of poly(ethylene terephthalate) (PET) still is a key issue. To endow PET with good flame retardancy and low smoke releasing, a third monomer , N, N′-bis(2-hydroxyethyl)-biphenyl-3,4,3′,4′-tetracarboxylic diimide (BPDI) containing biphenyl biimide and without any traditional flame-retardant elements, is synthesized and incorporated to the main chain of PET to obtain the P(ET-co-BP) n copolyester via melt polymerization. The thermal stability, combustion and pyrolysis behaviors of the obtained copolyesters have been well investigated. Thermogravimetric analysis (TGA) results demonstrate that introducing BPDI into PET obviously improves its thermal stability and the forming ability of char residue. LOI, vertical UL-94 and cone calorimeter measurements have been applied to investigate the combustion behaviors of P(ET-co-BP) n . The results prove that P(ET-co-BP) n copolyesters containing biphenyl biimide show better fire safety, reflected by lower fire growth rate (FIGRA) and low smoke production. SEM and Raman results suggest that the char layers of P(ET-co-BP) n become denser and mainly consist of polyaromatic species with small and uniform microstructures. The pyrolysis behaviors of the copolyesters are investigated by Py-GC/MS, and the results showed that the biphenyl biimide structure units can lead to rearrangement reactions at high temperature, ultimately forming the phenanthrene ring structures during combustion. Without traditional flame-retardant elements like halogen and phosphorus, this novel PET copolyester is environmentally friendly and more safety.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2024
·Vol. 142
·期 3
·e56377
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IF 2.7
Yaqi Ge,Pengfei Diao,Xiangxu Li,Yukun Zhou,Zhenchun Xu,Huiguang Bian,Yao Xiao,Chuansheng Wang
In this paper, pyrolysis carbon black (CBp) was introduced into nitrile butadiene rubber (NBR), the effects of the ratio of CBp and carbon black (N326) on the properties of NBR composites were investigated, and the optimal ratio was determined. On this basis, the accelerator DPG, coupling agent KH550 and CBp were modified by ball milling and plasma. The results showed that when the ratio of CBp to N326 was 40:15, the overall properties of NBR composites was better. Compared with the unmodified CBp/NBR composites, the change rate of tensile product, resilience and DIN abrasion of ball milling-plasma modified CBp/NBR composites in oil environment were reduced by 52.96%, 12.81%, and 27.19%, respectively, and the tear strength after double damage by high temperature and oil bath was increased by 15.63%, which resulted in better oil and high temperature-resistance. In summary, the ball milling-plasma combined with DPG/KH550 modified CBp can not only replace N326 carbon black, but also realize the preparation of NBR composites with better oil and high temperature-resistance.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2016
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IF 3.652
Kuan Ding,Zhaoping Zhong,Bo Zhang,Jia Wang,Addy Min,Roger Ruan
Pyrolysis of waste tire with HY, HZSM-5 (HZ) and purified attapulgite (PA) catalysts to produce valuable aromatic hydrocarbons has been carried out in a Pyrolyzer- Gas Chromatograph/Mass Spectrum (Py-GC/MS) reactor. Likewise, d -limonene and polybutadiene rubber (BR), which played important roles in the pyrolysis process of waste tire, has also been pyrolyzed in the Py-GC/MS reactor with these catalysts. Based on the product distribution, the catalytic pyrolysis mechanisms of d -limonene were proposed, while those of BR were extended. With these mechanisms, the catalytic pyrolysis characteristics of waste tire could be explained reasonably. Results showed that HY promoted a dramatic increase of aromatics from pyrolysis of d -limonene and BR, leading to the considerable growth of aromatics in the degraded products of waste tire. The shape selectivity of HZ to mono-cyclic aromatics performed effectively in the pyrolysis of BR, yet it exhibited a weak performance in the pyrolysis of d -limonene. As a result, upon the catalytic pyrolysis of waste tire, HZ was inferior to HY in the aromatization ability. However, the selectivity of HZ to BTXE (benzene, toluene, xylene and ethylbenzene) was superior to that of HY. PA performed a weaker catalytic ability in promoting the production of aromatics during the pyrolysis of d -limonene, BR and waste tire.
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ANALYTICAL LETTERS
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2014
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IF 1.019
Na Wang,Jing Liu,Ling He,Tie Zhou,Bo Rong,Liang Wang,Xiang Zhao
An effective method for characterizing Chinese lacquer as binding medium in historical artwork has been developed by on-line methylation pyrolysis-gas chromatography–mass spectrometry (pyrolysis GC–MS). The characteristic pyrolytic components of Chinese lacquer were identified in artificially aged pure and pigmented lacquer. Methylation of urushiol (mainly composed of catechol derivatives) was performed by adding tetramethyl ammonium hydroxide to convert phenolic hydroxyl groups into methylated derivatives to improve the resolution of catechol derivatives and urushiol monomers. The mechanism of formation of small molecular components was proposed, and the influence of different mineral pigments (azurite, malachite, ochre, and cinnabar) on the determination of characteristic components was discussed. Aliphatic hydrocarbon components, benzene derivatives, catechol derivatives, and urushiol monomers were proposed as characteristic pyrolytic components. In addition to 3-pentadecene-catechol, 3-pentadecane-catechol, and 3-heptadecene-catechol, 3-pentadecene-phenol was also identified as an urushiol monomer in Chinese lacquer. Four pigments slightly reduced the detection of aliphatic hydrocarbon components, but were unconspicuous for the detection of benzene derivatives. Azurite, malachite, and cinnabar decreased the measurement of urushiol monomers, but ochre significantly increased their relative abundance. The established on-line methylation pyrolysis GC–MS procedure and summarized data were successfully applied to the identification of samples collected from Terra-Cotta Warriors and Horses of Qin Dynasty (221–207 BC), Han Yang Mausoleum of Han Dynasty (206 BC–24 AD), and Dazu Grotto of Tang Dynasty (618–907 AD).
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JOURNAL OF APPLIED POLYMER SCIENCE
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2014
·Vol. 131
·期 16
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IF 1.64
Xiu Qiang,Fang Chen,Xiao-Yan Ma,Xian-Bing Hou
Star-shaped polyhedral oligomeric silsesquioxane (POSS)–methacrylate hybrid copolymers with phenyl–triazole as terminal groups had been designed and synthesized via sequential atom transfer radical polymerization (ATRP), azidation, and phenylacetylene-terminated procedures, and the hybrid copolymers here could be denoted as POSS–(PXMA-Pytl) 8 , where X can be M, B, L, and S, represented four different methacrylate monomers, such as methacrylate (MMA), butyl methacrylate (BMA), lauryl methacrylate (LMA), and stearyl methacrylate (SMA), respectively. Thermal gravimetric analysis (TGA) and in situ Fourier transform infrared spectroscopy (FTIR) were applied for studying the thermal stability and degradation mechanism, and it was found that all of the POSS–(PXMA-Cl) 8 and POSS–(PXMA-Pytl) 8 copolymers exhibited excellent thermal stabilities, which had great potential in heat-resistant material application. Different tendencies of decomposition temperatures at 5% and 10% weight loss ( T 5 and T 10 ) dependent on the side-chain length and terminal group species were investigated respectively. The longer alkyl side chains of the monomers, the lower thermal stabilities, and enhanced T 5 and T 10 were also shown with the introduction of phenyl–triazole groups instead of chlorine groups. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40652.
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SURFACE & COATINGS TECHNOLOGY
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2013
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IF 1.941
Songbai Liu,Kuo Jiang,Hongbo Zhang,Yi Liu,Li Zhang,Bingye Su,Yibao Liu
Ceramics with structure on nanometer-length scales have a thermal conductivity much lower than their coarser-grained ceramics. But the relatively low activation energy for grain growth of nanoparticles limits the stability of nano-material at high temperatures. The objective of the present study was to investigate the preparation of the composite powders of nano (La,Gd) 2 Zr 2 O 7 and nano (Zr,Gd)O 2 − δ by a sol-spray pyrolysis method. The XRD results indicated that the reaction products of 0.2LaO 1.5 –xGdO 1.5 –(0.8 − x)ZrO 2 (0.15 ≤ × ≤ 0.25) ternary system were composed of pyrochlore (La,Gd) 2 Zr 2 O 7 and cubic (Zr,Gd)O 2 phases. The composition with 0.2LaO 1.5 –0.2GdO 1.5 –0.6ZrO 2 had a grain size much smaller than the lower GdO 1.5 content counterpart for both the (La,Gd) 2 Zr 2 O 7 and (Zr,Gd)O 2 − δ phases. The relationship between grain size and GdO 1.5 content was explained in terms of lattice matching.
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