scholarly journals Low-Temperature Selective Catalytic Reduction DeNOX and Regeneration of Mn–Cu Catalyst Supported by Activated Coke

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5958
Author(s):  
Xusheng Ren ◽  
Zhiliang Ou ◽  
Bang Wu
Keyword(s):  
Calcination Temperature ◽  
Total Pore Volume ◽  
Space Velocity ◽  
Underlying Mechanism ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Thermal Regeneration ◽  
Water Washing ◽  
Scr Catalysts ◽  
Activated Coke

The activated coke is a promising support for catalysts, and it is important to study the performance of the activated coke catalyst on the removal of NOx. In the current research, a series of the activated coke-supported Mn–Cu catalysts are prepared by the incipient wetness impregnation method. The effects of the molar ration of Mn/Cu, the content of Mn–Cu, the calcination temperature, and reaction space velocity on NO conversion are investigated, and it was found that the 8 wt.% Mn0.7Cu0.3/AC had the best catalytic activity when the calcination temperature was 200 °C. The existence of SO2 caused the catalyst to deactivate, but the activity of the poisoning catalyst could be recovered by different regeneration methods. To uncover the underlying mechanism, BET, XPS, XRD, SEM and FTIR characterizations were performed. These results suggested that the specific surface area and total pore volume of the poisoning catalyst are recovered and the sulfite and sulfate on the surface of the poisoning catalysts are removed after water washing regeneration. More importantly, the water washing regeneration returns the value of Mn3+/Mn4+, Cu2+/Cu+, and Oα/Oβ, related to the activity, basically back to the level of the fresh catalyst. Thus, the effect of water washing regeneration is better than thermal regeneration. These results could provide some helpful information for the design and development of the SCR catalysts.

scholarly journals Catalytic Oxidation of Chlorobenzene over Pd-TiO2 /Pd-Ce/TiO2 Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 347 ◽  
Author(s):  
Wenjun Liang ◽  
Xiaoyan Du ◽  
Yuxue Zhu ◽  
Sida Ren ◽  
Jian Li
Keyword(s):  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Calcination Temperature ◽  
Catalyst Activity ◽  
Space Velocity ◽  
Impregnation Method ◽  
Tio2 Catalyst ◽  
Metal Support ◽  
Oxidation Efficiency

A series of Pd-TiO2/Pd-Ce/TiO2 catalysts were prepared by an equal volume impregnation method. The effects of different Pd loadings on the catalytic activity of chlorobenzene (CB) were investigated, and the results showed that the activity of the 0.2%-0.3% Pd/TiO2 catalyst was optimal. The effect of Ce doping enhanced the catalytic activity of the 0.2% Pd-0.5% Ce/TiO2 catalyst. The characterization of the catalysts using BET, TEM, H2-TPR, and O2-TPD showed that the oxidation capacity was enhanced, and the catalytic oxidation efficiency was improved due to the addition of Ce. Ion chromatography and Gas Chromatography-Mass Spectrometer results showed that small amounts of dichlorobenzene (DCB) and trichlorobenzene (TCB) were formed during the decomposition of CB. The results also indicated that the calcination temperature greatly influenced the catalyst activity and a calcination temperature of 550 °C was the best. The concentration of CB affected its decomposition, but gas hourly space velocity had little effect. H2-TPR indicated strong metal–support interactions and increased dispersion of PdO in the presence of Ce. HRTEM data showed PdO with a characteristic spacing of 0.26 nm in both 0.2% Pd /TiO2 and 0.2% Pd-0.5% Ce/TiO2 catalysts. The average sizes of PdO nanoparticles in the 0.2% Pd/TiO2 and 0.2% Pd-0.5% Ce/TiO2 samples were 5.8 and 4.7 nm, respectively. The PdO particles were also deposited on the support and they were separated from each other in both catalysts.

scholarly journals The Role of Impregnated Sodium Ions in Cu/SSZ-13 NH3-SCR Catalysts

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 593 ◽  
Author(s):  
Chen Wang ◽  
Jun Wang ◽  
Jianqiang Wang ◽  
Zhixin Wang ◽  
Zexiang Chen ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Acid Sites ◽  
Particulate Filter ◽  
Kinetic Temperature ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Hydrothermal Aging ◽  
Scr Catalysts ◽  
Na Ions

To reveal the role of impregnated sodium (Na) ions in Cu/SSZ-13 catalysts, Cu/SSZ-13 catalysts with four Na-loading contents were prepared using an incipient wetness impregnation method and hydrothermally treated at 600 °C for 16 h. The physicochemical property and selective catalytic reduction (SCR) activity of these catalysts were studied to probe the deactivation mechanism. The impregnated Na exists as Na+ on catalysts and results in the loss of both Brönsted acid sites and Cu2+ ions. Moreover, the high loading of Na ions destroy the framework structure of Cu/SSZ-13 and forms new phases (SiO2/NaSiO3 and amorphous species) when Na loading was higher than 1.0 mmol/g. The decreased Cu2+ ions finally transformed into CuxO, CuO, and CuAlOx species. The inferior SCR activity of Na impregnated catalysts was mainly due to the reduced contents of Cu2+ ions at kinetic temperature region. The reduction in the amount of acid sites and Cu2+ ions, as well as copper oxide species (CuxO and CuO) formation, led to low SCR performance at high temperature. Our study also revealed that the existing problem of the Na ions’ effect should be well-considered, especially at high hydrothermal aging when diesel particulate filter (DPF) is applied in upstream of the SCR applications.

scholarly journals Preparation of bimetallic Ni–Fe/MCM-41 catalysts and their catalytic activity for CO methanation

2019 ◽  
Vol 45 ◽  
pp. 146867831987032
Author(s):  
Zhang Jiaying
Keyword(s):  
Bimetallic Catalysts ◽  
Space Velocity ◽  
Molar Ratio ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Activity Increase ◽  
Co Methanation ◽  
Weight Hourly Space Velocity ◽  
Temperature Programmed ◽  
Mcm 41

A series of Ni–Fe/MCM-41 bimetallic catalysts and also Ni/MCM-41 and Fe/MCM-41 catalysts were prepared by the incipient-wetness impregnation method and tested for their activity for CO methanation in a continuous-flow microreactor. The results showed that the catalytic activities of the Ni–Fe/MCM-41 bimetallic catalysts were much higher than those of the Ni/MCM-41 and Fe/MCM-41 catalysts at low temperatures (200°C–325°C). The 10%Ni–5%Fe/MCM-41 catalyst showed the best activity with a CO conversion of almost 100% and a CH4 selectivity of 98% at 350°C under a pressure of 1.5 MPa with a 3:1 molar ratio of H2 to CO and a weight hourly space velocity of 12,000 mL h−1 g−1. The catalysts were characterized by N2 physisorption measurements, X-ray diffraction, and H2-temperature-programmed reduction. The results showed that the addition of Fe will lead to the formation of finer Ni particles and Ni–Fe alloy, which were the main reasons for the activity increase in the Ni–Fe/MCM-41 catalysts.

scholarly journals THE EFFECTS OF CERIUM PROMOTER ON THE PERFORMANCE OF COBALT-BASED CATALYSTS IN FISCHER TROPSCH SYNTHESIS FOR LIQUID FUEL PRODUCTION

2020 ◽  
Vol 21 (2) ◽  
pp. 1-11
Author(s):  
Ahmed Lateef Khalaf ◽  
Firas Khaleel Al-Zuhairi ◽  
Wafaa Abdul Kadhim ◽  
Mohd Hasbi Ab Rahim
Keyword(s):  
Space Velocity ◽  
Tropsch Synthesis ◽  
Feed Ratio ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Fuel Production ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Reaction Performance ◽  
Intensive Work

An intensive work of Fischer-Tropsch synthesis (FTS) on a cobalt-based catalyst supported with cerium as a promoter was presented. The influence of space velocity and inlet gas feed ratio on FTS reaction performance was studied for the synthesized catalysts. Incipient wetness impregnation method was utilized to synthesis both unpromoted (25%Co/?-Al2O3) and cerium promoted (1%Ce-25%Co/?-Al2O3) catalysts. The proposed catalysts were examined by N2 adsorption and temperature-programed reduction (TPR). The performance of Ce-promoted and unpromoted cobalt-based catalysts in FTS was assessed in terms of activity and selectivity to desired products (C5+). The obtained results revealed that the addition of cerium by impregnation notably favours the reducibility of cobalt oxides by reducing the reduction temperature. In addition, the promoted catalysts exhibited higher activity and selectivity toward desired products at low space velocity and high inlet gas feed ratio as compared with the unpromoted catalysts. In conclusion, a cerium based cobalt catalyst considered as a suitable candidate to be used in gas to the liquid conversion process. ABSTRAK: Kajian intensif sintesis Fischer-Tropsch (FTS) adalah tentang pemangkin berasas kobalt bersama penggalak cerium. Pengaruh tindak balas FTS pada halaju ruang dan nisbah suapan gas masuk dikaji menggunakan pemangkin yang disintesis. Kaedah impregnasi insipien basah telah digunakan bagi mensintesis pemangkin bukan penggalak (25%Co/?-Al2O3) dan penggalak cerium (1%Ce-25%Co/?-Al2O3). Pemangkin ini diuji dengan penjerapan N2 dan pengurangan suhu terprogram (TPR). Hasil tindak balas penggalak-Ce dan bukan penggalak berasas kobalt dalam FTS diperiksa dari segi aktiviti dan pemilihan hasil (C5+). Tindak balas menunjukkan dengan penambahan cerium melalui kaedah impregnasi dengan ketara mengurangkan kobalt oksida bersama pengurangan suhu. Di samping itu, pemangkin penggalak menunjukkan aktiviti dan pemilihan ke arah hasil pada halaju ruang dan nisbah suapan gas masuk yang tinggi berbanding dengan pemangkin bukan penggalak. Kesimpulan, pemangkin kobalt berasas cerium dianggap sesuai sebagai pemangkin sintesis bagi digunakan dalam proses penukaran gas ke cecair.

scholarly journals ADSORPTION OF CATIONIC DYE FROM AQUEOUS SOLUTION USING COMPOSITE CHICKEN EGGSHELL - ANTHILL CLAY: OPTIMIZATION OF ADSORBENT PREPARATION CONDITIONS

2019 ◽  
Vol 59 (2) ◽  
pp. 192-202 ◽  
Author(s):  
Adeyinka Sikiru Yusuff
Keyword(s):  
Aqueous Solution ◽  
Calcination Temperature ◽  
Quadratic Model ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Cationic Dye ◽  
Mixing Ratio ◽  
Calcination Time ◽  
Adsorption Sites ◽  
Preparation Conditions

A composite adsorbent was prepared from anthill and eggshell mixture, using an incipient wetness impregnation method and it was used for an adsorption of cationic dye (methylene blue, MB) from an aqueous solution. The effects of three preparation parameters including calcination temperature, calcination time and mixing ratio of eggshell to anthill on the MB uptake were investigated using the central composite design (CCD) of response surface methodology (RSM). A quadratic model was developed to predict the response with a high accuracy. The optimal adsorbent sample was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray fluorescence (XRF) spectroscopy. The obtained results revealed that the calcination temperature significantly affected the MB adsorption. The optimum MB uptake of 23.87 mg/g was achieved under the optimum conditions including a calcination temperature of 823.45 °C, calcination time of 3.54 h and eggshell/anthill mixing ratio of 1.89:1. A detailed characterization of an optimal adsorbent sample confirmed the presence of pores, active functional groups and various molecular adsorption sites on its surface. Equilibrium adsorption isotherms and kinetics were also studied and it was revealed that the isotherms and kinetics data fitted well to the Freundlich model and pseudo-second-order kinetics model, respectively.

The DeNOx Characteristics of V/Ti Plate SCR Catalysts

2011 ◽  
Vol 356-360 ◽  
pp. 1712-1715
Author(s):  
Qiang Lu ◽  
Shu Hua Su ◽  
Shi Ye Fen ◽  
Wei Liang Cheng ◽  
Chang Qing Dong
Keyword(s):  
Nitric Oxide ◽  
Catalytic Activity ◽  
Selective Catalytic Reduction ◽  
Flue Gas ◽  
Catalytic Reduction ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Negative Effects ◽  
V2o5 Content ◽  
Scr Catalysts

A series of V2O5/WO3/TiO2plate catalysts were prepared via the incipient wetness impregnation method, with the V2O5content of 0.68 wt%, 1.01 wt%, 1.19 wt%, 1.5 wt% and the WO3loading of 4.8 wt%, 6.2 wt%, 7.9 wt%, 9.2 wt%, respectively. Selective catalytic reduction of nitric oxide by ammonia (NH3-SCR) experiments were performed to investigate the effects of the several factors on the performance of the catalysts, including the V2O5, WO3and MoO3content in the catalysts and the O2concentration in the flue gas. The results indicated that as the rising of the V2O5 content, the SCR activity of the V2O5/WO3/TiO2catalysts was firstly increased and then slightly decreased, with the best activity obtained at the V2O5content of 1.19 wt%. As the increasing of the WO3content, the activity was firstly increased slightly and then almost kept constant. Furthermore, the loading of the MoO3on the V2O5/WO3/TiO2plate catalysts would bring negative effects to the catalytic activity. In addition, the capability of the catalysts would slightly increase as the O2concentration rising up to 7%, and then became stable at higher O2concentrations.

scholarly journals Tungsten Oxide-Modified SSZ-13 Zeolite as an Efficient Catalyst for Ethylene-To-Propylene Reaction

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 553
Author(s):  
Mansurbek Urol ugli Abdullaev ◽  
Sungjune Lee ◽  
Tae-Wan Kim ◽  
Chul-Ung Kim
Keyword(s):  
Tungsten Oxide ◽  
Fixed Bed ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Efficient Catalyst ◽  
X Ray ◽  
Propylene Selectivity ◽  
Temperature Programmed

Among the zeolitic catalysts for the ethylene-to-propylene (ETP) reaction, the SSZ-13 zeolite shows the highest catalytic activity based on both its suitable pore architecture and tunable acidity. In this study, in order to improve the propylene selectivity further, the surface of the SSZ-13 zeolite was modified with various amounts of tungsten oxide ranging from 1 wt% to 15 wt% via a simple incipient wetness impregnation method. The prepared catalysts were characterized with several analysis techniques, specifically, powder X-ray diffraction (PXRD), Raman spectroscopy, temperature-programmed reduction of hydrogen (H2-TPR), temperature-programmed desorption of ammonia (NH3-TPD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and N2 sorption, and their catalytic activities were investigated in a fixed-bed reactor system. The tungsten oxide-modified SSZ-13 catalysts demonstrated significantly improved propylene selectivity and yield compared to the parent H-SSZ-13 catalyst. For the tungsten oxide loading, 10 wt% loading showed the highest propylene yield of 64.9 wt%, which was 6.5 wt% higher than the pristine H-SSZ-13 catalyst. This can be related to not only the milder and decreased strong acid sites but also the diffusion restriction of bulky byproducts, as supported by scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS) observation.

A Ce-Zr-Ti Oxide Catalyst for Selective Catalytic Reduction of NO with Ammonia

2014 ◽  
Vol 535 ◽  
pp. 709-712
Author(s):  
Ye Jiang ◽  
Yan Yan ◽  
Shan Bo Huang ◽  
Xiong Zhang ◽  
Xin Wei Wang ◽  
...  
Keyword(s):  
High Activity ◽  
Selective Catalytic Reduction ◽  
Oxide Catalyst ◽  
Catalytic Reduction ◽  
Space Velocity ◽  
Impregnation Method ◽  
Reduction Of No ◽  
No Conversion ◽  
Temperature Range ◽  
Ti Oxides

A Ce-Zr-Ti oxide catalyst was prepared by an impregnation method and tested for the selective catalytic reduction of NO with NH3. The Ce-Zr-Ti oxide catalyst exhibited high activity and more than 95% NO conversion was obtained within the temperature range 300-500 °C at the high gas hourly space velocity of 50,000 h-1. The addition of Zr improved the activity of Ce-Ti oxides especially at higher reaction temperatures and their resistance to SO2.

Effects of Cu and K Promoters on the Catalytic Performance of Iron-Based Nanocatalyst for Fischer-Tropsch Synthesis

2013 ◽  
Vol 832 ◽  
pp. 15-20 ◽  
Author(s):  
Sara Faiz Hanna Tasfy ◽  
Noor Asmawati Mohd Zabidi ◽  
Duvvuri Subbarao
Keyword(s):  
Atmospheric Pressure ◽  
Fixed Bed ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Reactant Ratio ◽  
Impregnation Method ◽  
Fischer Tropsch ◽  
Heavy Hydrocarbons ◽  
Co Conversion ◽  
Iron Based

Iron-based nanocatalyst was prepared via impregnation method on SiO2 support. The effects of promoters, namely, K and Cu, on the physical properties and catalytic performance in FTS have been investigated. The FTS performance of the synthesized nanocatalysts was examined in a fixed-bed microreactor at temperature of 523K, atmospheric pressure, 1.5 reactant ratio (H2/CO) and space velocity of 3L/g-cat.h. In FTS reaction, Cu promoter resulted in a lower CO conversion and C5+ hydrocarbons selectivity but higher selectivity to the lighter hydrocarbons (C1-C4) comparedto those obtained using the K promoter. Higher CO conversion (28.9%) and C5+ hydrocarbons selectivity (54.4%) were obtained using K as a promoter compared to that of Cu promoter. However, the K-promoted nanocatalyst resulted in a lower CO conversion but higher selectivity of the heavy hydrocarbons (C5+) compared to those obtained using the un-promoted nanocatalyst.

Vapor-phase Oxidation of Cyclohexane over Supported Fe-Mn Catalysts: In-Situ DRIFTS studies

2021 ◽  
Author(s):  
Vijendra Kumar Yadav ◽  
Taraknath Das
Keyword(s):  
Surface Area ◽  
Raman Spectra ◽  
Vapor Phase ◽  
Oxide Catalysts ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Mn Oxide ◽  
Phase Oxidation

Alumina-supported Fe-Mn oxide catalysts were synthesized by the incipient wetness impregnation method. The catalysts were characterized by using various characterization techniques such as surface area, XRD, H2-TPR, and Raman spectra...

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