Energies
·
2022
·Vol. 15
·期 7
·2620
·
IF 3.252
Fanjing Wei,Xiaoqin Guo,Weiren Bao,Liping Chang,Junjie Liao
The ultra-deep removal of thiophene is essential for the conversion of coke oven gas to methane and metal modified Y zeolite has excellent thiophene adsorption capacity. The effects of temperature on chemisorption between metal modified Y zeolite and thiophene and the reductive gases in coke oven gas on the thiophene adsorption performance still remains ambiguous. To address the aforementioned aims, series of NaMY (M = Ce, Ni, Zn and Ag) were prepared via ion-exchanged with Na+of NaY, and two comparable sets of thiophene adsorption evaluation were conducted in a fixed bed reactor: (1) NaY and NaMY were evaluated at different temperatures in simulated coke oven gas, and (2) NaCeY was evaluated in N2and different reductive atmospheres. The results show that NaNiY, NaZnY and NaAgY could adsorb thiophene via π-complexation, however, NaCeY mainly through S-Ce bond. Π complexation becomes weak above 150 °C, and the strength of S-Ce bond varies little when the temperature rises to 250 °C. Compared with that of other sorbents, the breakthrough adsorption capacity for thiophene (Qb-thiophene) of NaAgY reaches the highest 144 mg/g at 100 °C, but decreases sharply when temperature rises to 200 °C. NaCeY has relatively low variation inQb-thiophenefrom 100 °C to 200 °C. Moreover, Ce(IV) in NaCeY is more favorable for thiophene adsorption than Ce(III) in coke oven gas and the presence of H2and CO would reduce the desulfurization activity of NaCeY. For the industrial utilization of thiophene ultra-deep removal, NaAgY has an excellent potential below 150 °C, while NaCeY with more Ce(IV) has a good prospect at 150–250 °C.Keywords:coke oven gas;thiophene;adsorption;Y zeolite;metal modification
研究领域:
化学工程
·
环境科学
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产品关联
DOI
高影响因子
Frontiers in Chemistry
·
2022
·
IF 5.545
Zhao Jinchong,Jiang Jie,Wen Song,Zhang Jing,Zhang Changsheng,Sheng Nan,Liang Wei,Sun Bing,Xu Wei,Yang Zhe,Pan Yuan
A series of alkali metal (Li, Na, and K)-modified Pd catalysts and Pd/Al2O3 were prepared and used to remove oxygen in a propylene flow with hydrogen’s existence. The results showed that the alkali metals could enhance the performance of the Pd catalysts and the effect followed the order of K > Na > Li. X-Ray diffraction (XRD), N2-physisorption, transmission electron microscopy (TEM), hydrogen temperature programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) were carried out to investigate the alkali metal-modified Pd catalysts and the promotional effect mechanism was explained. The results showed that alkali metal modification increased the electron density of Pd atoms to induce the negatively charged Pd species, which could enhance the adsorption of oxygen while weakening the adsorption of propylene, and then enhance the performance of the modified catalysts for oxygen removal from unsaturated hydrocarbon. The Pd-K/A catalyst performed the best on both oxygen removal and propylene hydrogenation inhibition.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2017
·
IF 3.471
Yunwu Zheng,Fei Wang,Xiaoqin Yang,Yuanbo Huang,Can Liu,Zhifeng Zheng,Jiyou Gu
The main objective of this work was to study aromatics production via the catalytic pyrolysis upgrading of biomass using metal-loaded modified H-ZSM-5. M-ZSM-5 catalysts were prepared through the impregnation method with Zn, Ga, Ni, Co, Mg and Cu. The prepared M-ZSM-5 catalysts were evaluated by x-ray diffraction, thermal desorption spectroscopy and scanning electron microscopy. The properties, composition and product distribution of bio-oil were also analysed. Results showed that the M-ZSM-5 catalysts yielded a higher amount of non-condensable gas at the expense of the liquid yields. The Ga-ZSM-5 catalysts produced the highest yields of bio-oil (25.76 wt%), but the lowest amount of coke (22.08 wt%) compared with the unmodified ZSM-5 catalyst (33.38 wt%). The content of the single-ring aromatics prepared by using the Zn-ZSM-5 catalysts was the highest at 90.28 wt%, whereas that of the polycyclic aromatic hydrocarbon prepared by the Ni-ZSM-5 catalysts was the highest at 31.36 wt%. Moreover, the selectivity of the single-ring aromatic hydrocarbons, such as C7 and C8, were significantly affected by the use of the M-ZSM-5 catalysts. The Zn-ZSM-5 catalysts were the most selective for toluene and xylenes with contents of 36.52 wt% and 35.32 wt%, respectively, whereas the Co-based catalysts were the most selective for indene. The Ni-based catalysts can obviously improve the selectivities of benzene production and C10+ polycyclic aromatic hydrocarbons. Zn-ZSM-5 was the most effective catalyst that can be used in the production of aromatic hydrocarbons.
研究领域:
能源化学
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催化材料科学
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DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2015
·
IF 1.964
Chuan Yuan,Huayan Liu,Zekai Zhang,Hanfeng Lu,Qiulian Zhu,Yinfei Chen
Various ZSM-5 zeolites modified with alkali metals (Li, Na, K, Rb, and Cs) were prepared using ion exchange. The catalysts were used to enhance the catalytic dehydration of lactic acid (LA) to acrylic acid (AA). The effects of cationic species on the structures and surface acid-base distributions of the ZSM-5 zeolites were investigated. The important factors that affect the catalytic performance were also identified. The modified ZSM-5 catalysts were characterized using X-ray diffraction, temperature-programmed desorptions of NH 3 and CO 2 , pyridine adsorption spectroscopy, and N 2 adsorption to determine the crystal phase structures, surface acidities and basicities, nature of acid sites, specific surface areas, and pore volumes. The results show that the acid-base sites that are adjusted by alkali-metal species, particularly weak acid-base sites, are mainly responsible for the formation of AA. The KZSM-5 catalyst, in particular, significantly improved LA conversion and AA selectivity because of the synergistic effect of weak acid-base sites. The reaction was conducted at different reaction temperatures and liquid hourly space velocities (LHSVs) to understand the catalyst selectivity for AA and trends in byproduct formation. Approximately 98% LA conversion and 77% AA selectivity were achieved using the KZSM-5 catalyst under the optimum conditions (40 wt% LA aqueous solution, 365 °C, and LHSV 2 h −1 ).
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Yingjie Wen,Xu Chen,Linfeng Su,Shuqian Dong,Li Yi,Peilei He,Wen Yang,Zhiyi Lu
The catalytic ozonation-based advanced oxidation process (AOP) is applied to remove nondegradable chemical oxygen demand (COD), while the application in industry is limited by the economics and activity of catalysts. In this study, we demonstrate that by taking atrazine (ATZ) as a model pollutant, the removal rates of catalytic ozonation were negatively correlated with the interlayer water content of metal-modified montmorillonite (M x @MMT), instead of the loadings metals. Among the modified MMT, Zn 0.1 @MMT achieved 83.2% degradation of ATZ within 15 min, and corresponding removal rates of COD and total organic carbon (TOC) reached 40.3% and 46.5%, respectively. Detailed EPR and quenching experiments identified that hydroxyl radicals (HO•) were the main reactive oxygen species and QTOF/MS/MS analysis helped to propose a possible degradation pathway of ATZ. Moreover, the catalytic performance of Zn 0.1 @MMT under different conditions was also systematically evaluated.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Zhen-Qiang Yu,Yao-Xin Xiao,Dong Liang,Che Zhao,Zhen Huang,Gang-Qi Cheng,Rui Shan,Hao-Ran Yuan,Yong Chen
The chemical upgrade of the waste polyester coating on the surface of aluminum cans to value-added products can not only decrease the release of toxic substances, but also improve the quality of aluminum in the recycling process. In this study, different types of zeolite molecular sieve catalysts loaded with Ni, Mo and Co were synthesized, and utilized in the rapid catalytic pyrolysis of polyester coating. Among them, the Ni/ZSM-5 achieved the maximum aromatic compounds yield of 68.43 % at 600 ℃. A series of characterization results demonstrated that the embedding of transition metals (like Ni) could promote the cyclization and aromatization of products through deoxidation and dehydrogenation reactions by changing the pore structure and increasing total acid content (Brønsted and Lewis acids) of the ZSM-5 molecular sieve. Meanwhile, the thermodynamics of polyester coating during catalytic pyrolysis was studied by thermogravimetric method. The average activation energy of Ni/ZSM-5 catalytic pyrolysis of polyester coating is 238.65 kJ/mol. Furthermore, even after being reused for over 5 cycles, the catalyst can still maintain a relatively high yield of aromatic compounds (exceeding 60 %). Finally, the mechanism for aromatic compounds formation from Ni-modified ZSM-5 in-situ catalyzed polyester coating pyrolysis was proposed. This work provided useful ideas for the subsequent treatment of solid wastes.
研究领域:
环境科学
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化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CLAYS AND CLAY MINERALS
·
2019
·Vol. 67
·期 4
·325-333
·
IF 1.835
Guo Yu-Hua,Pan Guo-Xiang,Xu Min-Hong,Wu Tao,Wang Yong-Ya
Adsorption desulfurization is a potential new method for deep desulfurization of fuel oil. The development of adsorbents with high adsorption capacity and selectivity is the core of deep adsorption desulfurization. The adsorption behavior of thiophene in MCM-41 mesoporous materials modified by various metal ions was studied in order to understand the adsorption desulfurization process of molecular sieves. The Fe-, Co-, and Zn-modified MCM-41 materials were prepared using a one-step in situ hydrothermal synthesis method. The modified MCM-41 molecular sieves maintained the mesoporous structure, and the metal ions had specific dispersion on the surface of the molecular sieves. Adsorption of thiophene on the surfaces of molecular sieves had both physical and chemical characteristics. The adsorption desulfurization performance of the modified molecular sieve was superior to that of the pure silica molecular sieve. In the simulated gasoline with sulfur content of 220 μg/g, when the amount of adsorbent used was 100 mg, the adsorptive desulfurization performance tended to be in equilibrium, and the optimum adsorption temperature was 30°C. Fe-MCM-41 and MCM-41 molecular sieves reached adsorption equilibrium after ~60 min, but the desulfurization rate of Co-MCM-41 and Zn-MCM-41 still increased slightly. The kinetic simulation results indicated that the pseudo-second-order kinetics adsorption model described well the adsorption process of thiophene on molecular sieves. The molecular sieve Fe-MCM-41 had the best desulfurization performance with an equilibrium adsorption capacity of 14.02 mg/g and the desulfurization rate was ~90%.
研究领域:
材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Haoyue Fu,Weixin Qian,Haitao Zhang,Hongfang Ma,Weiyong Ying
Unmodified Cr/Al 2 O 3 and Cr/Al 2 O 3 doping with different alkali metals (Li, Na, K) were prepared by the incipient wetness impregnation method. The surface elements of all the catalysts are evenly distributed and well loaded, and the addition of alkali metals does not change the crystal structure and surface texture. Both Cr 6+ and Cr 3+ species exist on all catalysts, and the addition of alkali metals can increase the amount of Cr 6+ species, and Cr 6+ species are basically converted into active Cr 3+ species in the reaction thus increasing the initial propane conversion in the reaction. The addition of alkali metals reduced the amount of total acid sites and the strong acid sites of the catalyst, thus inhibiting the occurrence of side reactions and the formation of carbon deposition , and reducing the deactivation rate of the catalyst. Cr-0.5Na/Al 2 O 3 exhibited the best catalytic performance and the lowest carbon deposition.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2018
·
IF 3.468
Hao Chen,Hao Cheng,Feng Zhou,Kequan Chen,Kai Qiao,Xiuyang Lu,Pingkai Ouyang,Jie Fu
The synthesis of highly selective catalysts for the catalytic fast pyrolysis (CFP) of biomass into valuable aromatics remains a challenge. This report describes the synthesis of hierarchical ZSM-5 catalysts by the NaOH desilication of conventional HZSM-5 for the CFP of rice straw to aromatics in a Tandem μ-reactor system coupled directly to a GC/MS equipped with FID and TCD. Catalysts were treated with a mild HCl wash and metal loading to increase the catalytic activity and reduce the deactivation. The effects of acidity, mesoporosity and incorporation of metals on the production of aromatics were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption and desorption (N 2 -BET) and temperature-programmed desorption of NH 3 (NH 3 -TPD). The highest total acidity, especially the strong acidity, of the hierarchical ZSM-5 treated by 0.2 and 0.4 NaOH followed by HCl washing (AHZ-0.2 and AHZ-0.4) gave the highest yields of aromatics. Suitable mesopores introduced by alkali treatment enhanced mass transfer of reactants, increasing the yield of aromatics. Finally, the loading of a suitable amount of Ni and Cu produced more aromatics than standard HZSM-5 due to the improved decarboxylation/decarbonylation reactions leading to higher yields of olefins.
研究领域:
化学工程
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材料科学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2021
·Vol. 35
·期 11
·e6393
·
IF 4.105
Xiaoli Song,Yaming Pang,Liguo Gao
In this paper, dodecylamine (DDA) is used as the template, and ethyl orthosilicate (TEOS) is used as the silicon source. The HMS molecular sieve is prepared by in situ synthesis and modified by Cu, Ce, and Cu/Ce. The Cu/Ce-HMS molecular sieve catalyst was synthesized for the first time. Scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and Fourier transform infrared spectrometer (FTIR) were used to characterize the synthesized composite molecular sieve. The results showed that the metal was loaded on the HMS intact and did not change the morphology of the HMS. A mixture of n-hexane and dibenzothiophene (DBT) was used as the model oil, and the oxidation removal of DBT in the model oil was used as a probe reaction to study the photocatalytic oxidative desulfurization performance of the composite catalyst. The results show that the desulfurization rate after modification is Cu/Ce-HMS molecular sieve > Cu-HMS molecular sieve > Ce-HMS. Finally, we explored the reaction mechanism of catalyst desulfurization. The results of ultraviolet diffuse reflectance showed that the modified molecular sieve Cu/Ce-HMS had a smaller band gap, greater reaction activity, and stronger photocatalytic performance, which is benefit to improve the desulfurization efficiency. We report a simple and effective preparation method of composite molecular sieve catalyst, which provides a certain reference for future desulfurization research.
研究领域:
材料科学
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环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 19
·54628-54643
·
IF 5.8
Chen Aixia,Guan Juanjuan,Hu Ruirui,Wei Xiao,Zhang Yixuan,Lv Luxue,Wang Xinyuan,Zhang Lei,Ji Luqian
To solve the problems such as water eutrophication caused by excess phosphorus, the potential residual value of aluminum sludge was fully exploited and its phosphate adsorption capacity was further improved. In this study, twelve metal-modified aluminum sludge materials were prepared by co-precipitation method. Among them, Ce-WTR, La-WTR, Y-WTR, Zr-WTR, and Zn-WTR showed excellent adsorption capacity for phosphate. The adsorption performance of Ce-WTR on phosphate was twice that of the native sludge. The enhanced adsorption mechanism of metal modification on phosphate was investigated. The characterization results showed that the increase in specific surface area after metal modification was 9.64, 7.5, 7.29, 3, and 1.5 times, respectively. The adsorption of phosphate by WTR and Zn-WTR was in the accordance with Langmuir model, while the others were more following the Freundlich model ( R 2 > 0.991). The effects of dosage, pH, and anion on phosphate adsorption were investigated. The surface hydroxyl groups and metal (hydrogen) oxides played an important role in the adsorption process. The adsorption mechanism involves physical adsorption, electrostatic attraction, ligand exchange, and hydrogen bonding. This study provides new ideas for the resource utilization of aluminum sludge and theoretical support for preparing novel adsorbents for efficient phosphate removal. Graphical abstract
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2020
·
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.
研究领域:
化学工程
·
能源科学
·
生物质转化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）