ACS Omega
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2021
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IF 3.512
Wenke Wang,Jie Zhao,Dandan Jia,Zhaolin Fu,Enhui Xing,Zhongpeng Zhu,Rui Yan,Zhiping Tao,Yibin Luo,Xingtian Shu
The fast deactivation caused by serious formation of coke is a major challenge in catalytic isomerization of endo-tetrahydrodicyclopentadiene (endo-THDCPD) into exo-tetrahydrodicyclopentadiene (exo-THDCPD) over the HY zeolite. In order to suppress the coke formation for the isomerization process, the conventional HY zeolite was modified with Pt at 0.3 wt %. Then, the hydroisomerization of endo-THDCPD into exo-THDCPD was evaluated over a fixed-bed reactor. The catalytic stability of Pt/HY was greatly enhanced in comparison to that of the HY zeolite. The Pt/HY catalyst provided 97% endo-THDCPD conversion and 96% selectivity for exo-THDCPD without deactivation after 100 h. Moreover, the formation mechanism of coke on the HY zeolite during the isomerization process was proposed based on the results of the coke analysis. It was indicated that the coke was generated from the oligomerization and condensation of olefin species, which originated from the β-scission reaction or hydride transfer reaction of intermediates. The lower coke formation over Pt/HY was attributed to the lower amount of coke precursors, which could be hydrogenated by activated H2 over Pt sites. Therefore, Pt on Pt/HY and H2 were two crucial factors in efficiently enhancing the catalytic stability of the HY zeolite for this isomerization reaction.
研究领域:
催化化学
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材料科学
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石油化工
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2022
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IF 8.91
Lu Wang,Yaqun Yu,Guoqiang Liu,Junhe Lu
Tetrabromobisphenol S (TBBPS), an emerging brominated flame retardant , can cause neurotoxic and cytotoxic effects to human physiology . In this study, the degradation of TBBPS in Co 2+ activated peroxymonosulfate (PMS) oxidation process was explored. In particular, brominated by-products formed during the degradation of the TBBPS were examined. It was found that TBBPS could be effectively removed in the Co 2+ /PMS oxidation process. The pseudo-first-order rate constants were 0.13 min −1 at 0.2 mM PMS and 0.5 μM Co 2+ initially. It appeared that TBBPS degradation occurred via and HO attacks, but played a dominant role. The presence of natural organic matter (NOM) greatly inhibited the transformation of the TBBPS, which can be explained by the scavenging of the radical species. β-Scission, debromination, and cross-coupling were identified as the main reaction pathways of TBBPS degradation in the Co 2+ /PMS system. Further oxidation and ring-opening of the intermediates generated brominated by-products including bromoform, monobromoacetic acid, and dibromoacetic acid. The formation of the brominated by-products increased gradually in approximately 48 h. But, the presence of NOM reduced the yields of the brominated -by-products. The findings of this study indicate that organic bromine contaminants can be effectively removed but lead to brominated by-products in the activated PMS oxidation process, which should be taken into consideration when -based oxidation technology is applied.
研究领域:
环境科学
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化学工程
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水处理
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产品关联
DOI
PubMed
高影响因子
ENERGY & FUELS
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2023
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IF 5.3
Xiaojun Dai,Yan Cheng,Tingting Liu,Lingjuan Mao,Qiang Wei,Yasong Zhou
SAPO-11 molecular sieves with different crystal sizes and particle sizes, especially nanosized small-crystal SAPO-11 molecular sieves, were successfully synthesized, and the corresponding NiWS-supported catalysts were prepared for the hydroisomerization of n-hexadecane. XRD, SEM, N2 adsorption–desorption, Py-IR, and HRTEM were used to analyze the effects of crystal size and particle size of the supports on their physicochemical properties, active phase properties, and catalytic performance of the catalysts. Through reaction evaluation and analysis of isomeric products, the effects of the size change of the support on the hydroisomerization performance of the catalyst and the hydroisomerization depth of n-hexadecane were determined. Through comprehensive analysis of the cracking products, it was determined that secondary cracking occurred when the conversion of n-hexadecane on the NiW/SAPO-11-S catalyst reached about 42.7%, and the secondary isomerization occurred when the conversion of n-hexadecane reached about 80%. The hydroisomerization reaction network of n-hexadecane over the NiWS/SAPO-11 catalyst was studied emphatically, and it was found for the first time that the secondary cracking of n-hexadecane during hydroisomerization followed the C3-β-scission mechanism.
研究领域:
化学工程
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催化
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材料科学
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Qilong Chen,Dezhen Zhang,Tao Wei,Zicheng Wang,Shangpu Zhuang,Xu Qiao,Zhuxiu Zhang
Polycyclic aromatic hydrocarbons (PAHs) are toxic environmental contaminants presented in most of environmental matrices. The mullite and Fe 2 O 3 were identified as the reactive species of coal fly ash for the cracking-oxidation of PAHs (3∼5 benzene rings, e.g., anthracene, pyrene, benzo(a)pyrene). The conversion of PAHs reached over 99 % at 250–300 ℃ with the non-methane total hydrocarbons (NMHC) in the off-gas being below 50 mg/m 3 . The in-situ DRIFTS and TGA/GC–MS revealed the synergy of Brønsted acid sites from mullite and oxidation active sites from Fe 2 O 3 for the pyrene decomposition. The reaction process was initiated by self-condensation of a minor fraction of pyrene that provide hydrogen radicals to convert remaining pyrene to dihydropyrene. Then dihydropyrene underwent a series of Brønsted acid-catalyzed β-scission and alkyl transfer reactions to form light hydrocarbons that were then converted to CO 2 and H 2 O over Fe 2 O 3 species. The cracking-oxidation of PAHs were furtherly verified in terrestrial/aqueous systems which is known as the most common environment matrices of PAHs. A demonstrative equipment comprised of a riser-downer reactor was used for such cracking-oxidation process to ensure particle fluidization, mass transfer and circulation efficiency. PAHs can be almost completely removed from the environment matrices with the NMHC concentration of 46.3–49.6 mg/m 3 in the off-gas and COD of 0.6–4.1 mg/L in the condensate water. The energy released from the exothermic cracking-oxidation reaction was re-utilized to heat the feed air, so the energy consumption and related operation cost outperformed those of traditional methods.
研究领域:
环境科学
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化学工程
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分析化学
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能源技术
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污染控制
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材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）