scholarly journals Low Temperature NH3-SCR over Mn-Ce Oxides Supported on MCM-41 from Diatomite

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3654 ◽  
Author(s):  
Mingxuan Ma ◽  
Xiaoyu Ma ◽  
Suping Cui ◽  
Tingting Liu ◽  
Yingliang Tian ◽  
...  
Keyword(s):  
Molecular Sieves ◽  
Synthesis Method ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Catalyst Carrier ◽  
Nh3 Scr ◽  
Catalytic Material ◽  
Lewis Acidic Sites ◽  
Acidic Sites ◽  
Mcm 41

A series of MCM-41 molecular sieves with different molar ratio of template to silicon were synthesized through hydrothermal synthesis method by using cetyltrimethylammonium bromide (CTAB) as the template, diatomite as the silicon source. By using impregnation method, the Mn-Ce/MCM-41 SCR molecular sieve-based catalysts were prepared. The results observed that when the molar ratio of template to silicon was 0.2:1, the MCM-41 as catalyst carrier has the highest surface area and largest pore volume, it also presented typically ordered hexagonal arrays of uniform channels. The denitration catalytic material based on this carrier has a high number of Lewis acidic sites, and the denitration efficiency can reach more than 93%.

scholarly journals Effect of Fe Additives on the Catalytic Performance of Ion-Exchanged CsX Zeolites for Side-Chain Alkylation of Toluene with Methanol

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 829 ◽  
Author(s):  
Zhang ◽  
Yuan ◽  
Miao ◽  
Li ◽  
Shan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Performance ◽  
High Yield ◽  
Side Chain ◽  
Impregnation Method ◽  
Basic Sites ◽  
Lewis Acidic Sites ◽  
X Zeolite ◽  
Acidic Sites ◽  
Negative Effect

The side-chain alkylation of toluene with methanol was investigated over some Fe-modified Cs ion-exchanged X zeolite (CsX) catalysts prepared via the impregnation method using different iron sources. The absorption/activation behaviors of the reactants on the surface of the catalysts were studied by in situ Fourier-transform infrared (FT-IR) spectroscopy and temperature programmed desorption (TPD) mass measurements. Modification of CsX with a small amount of FeCl3 could result in a considerable decrease in catalytic activity, due mainly to the remarkable decrease in the density of acidic and basic sites of the catalysts. Interestingly, the Fe(NO3)3-modified CsX with an optimum Fe loading of 0.15 wt.% shows improved catalytic activity and high yield compared to the side-chain alkylation products. Modification of CsX with Fe(NO3)3 could also result in a decrease in basic sites of the catalyst. However, such a change does not bring an obvious negative effect on the adsorption/activation of toluene, while it could effectively inhibit the generation of the undesired bidentate formate. Furthermore, the introduced FeOx species (derived from the decomposition of Fe(NO3)3) may also act as new Lewis acidic sites to participate in the activation of methanol and to stabilize the formed active intermediates (i.e., unidentate formate). Therefore, modification of CsX with a suitable amount of Fe(NO3)3 may adjust its adsorption/activation ability for reagents by changing the acid–base properties of the catalyst, which can finally enhance the catalytic performance for the side-chain alkylation of toluene with methanol.

scholarly journals The Effect of Tourmaline on SCR Denitrification Activity of MnOx/TiO2 at Low Temperature

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1020
Author(s):  
Yizhe Helian ◽  
Suping Cui ◽  
Xiaoyu Ma
Keyword(s):  
Low Temperature ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Scr Catalyst ◽  
Highly Efficient ◽  
Nh3 Scr ◽  
Catalytic Material ◽  
Acidic Sites ◽  
Denitrification Activity ◽  
The Stability

Selective catalytic reduction (SCR) technology is the most widely used flue gas denitration technology at present. The stability of a catalyst is the main factor limiting the development of this technology. In this study, an environmentally friendly and highly efficient NH3-SCR catalyst was prepared by coprecipitation method from acidolysis residue of industrial waste and tourmaline. We found that the addition of tourmaline has an important impact on the denitration activity of the catalytic material. The NOx conversion exceeded 97% at 200 °C with the dosage of 10% tourmaline, which is about 7% higher than that without doping. The improvement of catalytic performance was mostly attributed to the permanent electrodes of tourmaline, which effectively promotes the dispersion of MnOx/TiO2 catalytic materials, increases the number of acidic sites and changes the valence distribution of manganese ions in products, which speeds up the diffusion of protons and ions, resulting in the acceleration of redox reaction. These as-developed tourmaline-modified MnOx/TiO2 materials have been demonstrated to be promising as a new type of highly efficient low-temperature NH3-SCR catalyst.

Preparation and Characterization of MnOX-CeO2/TiO2 Catalytic Material for SCR of NOX with NH3 at Low Temperature

2013 ◽  
Vol 743-744 ◽  
pp. 198-203
Author(s):  
Qi Dong Liu ◽  
Su Ping Cui ◽  
Hong Xia Guo ◽  
Ya Li Wang ◽  
Yun Feng Zhang
Keyword(s):  
Low Temperature ◽  
Surface Concentration ◽  
Manganese Chloride ◽  
Molar Ratio ◽  
Manganese Acetate ◽  
Impregnation Method ◽  
Manganese Nitrate ◽  
Catalytic Materials ◽  
Scr Of No ◽  
Catalytic Material

The MnOX-CeO2/TiO2 catalytic material for low temperature SCR of NOX with NH3 was prepared using aqueous solutions of three manganese salt as well as cerous nitrate and TiO2(anatase) powder by impregnation method. The properties of the catalytic materials were investigated by TG-DSC, XRF, XRD, XPS, BET and SEM. And the low temperature catalytic activity of the catalytic materials was measured. The results showed that, when manganese nitrate and manganese chloride and manganese acetate were used as precursors, respectively, the primary phases of catalytic materials were MnOx/MnO2, MnO2/Mn8O10Cl3 and Mn3O4/MnO2, the surface Mn/Ti molar ratio were 0.68, 0.19 and 0.88, the surface area were 45.1m2/g, 25.1 m2/g and 48.6 m2/g ,respectively. The optimum NOX conversion rate of catalytic material from manganese nitrate precursor and manganese chloride precursor and manganese acetate precursor were 97.9% at 483K, 86.6% at 513K, 97.2% at 423K, respectively. Consequently, the higher low-temperature activity of MnOX-CeO2/TiO2 from manganese acetate precursor may be attributed to higher surface and higher surface concentration of activity component.

Adsorption of Carbon Dioxide into Amine Functionalized Ordered Mesoporous Materials

2018 ◽  
Author(s):  
Marcela N. Barbosa ◽  
Maria J. F. Costa ◽  
Maricele N. Barbosa ◽  
Valter J. Fernandes Jr. ◽  
Giancarlo R. Salazar-Banda ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Molecular Sieves ◽  
Synthesis Method ◽  
Mesoporous Molecular Sieves ◽  
Carbon Dioxide Adsorption ◽  
X Ray ◽  
Ordered Mesoporous ◽  
Mcm 41

The adsorption of carbon dioxide on amino silanes-functionalized MCM-41 and SBA-15 materials is reported. The functionalization of mesoporous silicas was made by post-synthesis method, by impregnation of 3-aminopropyltriethoxysilane. The obtained materials were characterized by X-ray diffraction, scanning and transmission electron microscopies, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy measurements. The carbon dioxide adsorption capacities for the samples were carried out under ambient pressures. The obtained results evidenced that amino-silanes with a terminal amine (–NH2) were functionalized through covalent coupling of this group on the surface of the channels in the ordered mesoporous silica, meaning that the amine is anchored on the surface of the bigger pores of the MCM-41 and SBA-15 support. For functionalized materials, the CO2 adsorption capacity of the AMCM-41 increased from 0.18 to 1.1 mmol·g−1, whereas for ASBA-15, it was from 0.6 to 1.8 mmol·g−1. The Lagergren kinetic algorithms were applied in order to validate the obtained results, evidencing the enhanced carbon dioxide adsorption capacity and stability of the functionalized ordered mesoporous molecular sieves.

scholarly journals Glycerol Acetylation with Propionic Acid Using Iron and Cobalt Oxides in Al-MCM-41 Catalysts

2020 ◽  
Vol 15 (3) ◽  
pp. 829-844
Author(s):  
Fabio Ribeiro Tentor ◽  
Diego Borelli Dias ◽  
Mateus Rosolen Gomes ◽  
João Guilherme Pereira Vicente ◽  
Lúcio Cardozo-Filho ◽  
...  
Keyword(s):  
Propionic Acid ◽  
Molecular Sieves ◽  
Sem Analysis ◽  
Cobalt Oxides ◽  
Glycerol Conversion ◽  
X Ray ◽  
Acid Ratio ◽  
Acidic Sites ◽  
Adsorption Desorption ◽  
Mcm 41

In this work, Al-MCM-41 molecular sieves were synthesized, containing iron and/or cobalt oxides, impregnated by incipient wetness method, characterized and applied as catalysts in the acetylation reaction of glycerol with propionic acid to produce green glyceryl propionate molecules of high commercial value. According to this, X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Fourier Transform Infra Red (FT-IR), adsorption/desorption N2 isotherms, textural analysis, and Scanning Electron Microscope (SEM) analysis were recorded to evaluate the main characteristics of materials. The presence of Lewis and Brønsted acidic sites and catalysts surface area were observed as important key points to functionalize acetylation reaction. Thus, time reaction, temperature, and glycerol / propionic acid ratio varied to improve the most suitable reaction conditions and behaviors. As a result, glycerol conversion was above 96%, followed by 68% of selectivity to glyceryl monopropionate as well as the formation of glyceryl di- and tri- propionate and a small amount of ethylene glycol dipropionate as an undesired product.  Copyright © 2020 BCREC Group. All rights reserved 

Esterification of Oleic Acid with Methanol Catalyzed by P-Toluene Sulphonic Acid/MCM-41

2013 ◽  
Vol 634-638 ◽  
pp. 869-872 ◽  
Author(s):  
Li Jing Gao ◽  
Wei Xu ◽  
Guo Min Xiao
Keyword(s):  
Oleic Acid ◽  
Active Catalyst ◽  
Acid Value ◽  
Solution Concentration ◽  
Sulphonic Acid ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Catalyst Amount ◽  
The Stability ◽  
Mcm 41

The p-toluene sulphonic acid (PTSA)/MCM-41 was prepared by impregnation method with self-synthesized MCM-41. The investigation of effects on PTSA solution concentration was investigated and the catalyst prepared with 0.1mol/L PTSA performed best. Oleic acid was chosen as a simulation of high-acid-value oil to esterify with methanol. The experimental results showed that PTSA/MCM-41 was a high active catalyst in esterification. The optimal condition was as following: the reaction temperature was 80°C, the methanol/oleic acid molar ratio was 5:1, the catalyst amount was 5% (wt. /wt.) of the oleic acid, and reaction time was 1h. Under this condition, the oleic acid conversion could reach 94.3%. The stability of the catalyst was very well for the oleic acid conversion can still maintain 92.8% after used four times.

Improve the Optical Properties of Rhodamine B by Encapsulating in Al-MCM-41

2011 ◽  
Vol 306-307 ◽  
pp. 792-795
Author(s):  
Dong Mei Li ◽  
Zhong Zhen Tian ◽  
Pei Feng Wei
Keyword(s):  
Optical Properties ◽  
Hydrothermal Method ◽  
Rhodamine B ◽  
Molecular Sieves ◽  
Mesoporous Molecular Sieves ◽  
Impregnation Method ◽  
Fluorescence Measurements ◽  
Mcm 41

M-MCM-41 (M = Al, Cu, Cr, Ti) were synthesized by hydrothermal method and characterized by XRD. Rhodamine B molecules were encapsulated into these mesoporous molecular sieves by impregnation method. Steady fluorescence measurements indicated that doping of Al ions into MCM-41 enhanced largely the fluorescence intensities, but more Al decreased the fluorescence intensities resulting from the formation of Al2O3.

Comparative Synthesis and Characterization of Nanostructured SAPO-34 Using TEA and Morpholine: Effect of Mono vs. Dual Template on Catalytic Properties and Performance toward Methanol to Light Olefins

2020 ◽  
Vol 23 ◽  
Author(s):  
Sogand Aghamohammadi ◽  
Mohammad Haghighi ◽  
Parisa Sadeghpour ◽  
Tayebeh Souri
Keyword(s):  
Molecular Sieves ◽  
Synthesis Method ◽  
Life Time ◽  
Light Olefins ◽  
Molar Ratio ◽  
And Performance ◽  
Light Olefins Selectivity ◽  
Mixed Template ◽  
Mto Process

Aim and Objective: Production of light olefins from methanol was studied over SAPO-34 molecular sieves exploring the effect of mono and dual templates. Herein, the single templates of TEA, morpholine and mixed template of TEA/morpholine (equal molar ratio of TEA and morpholine) were used to synthesize SAPO-34 catalysts. Materials and Methods: The prepared samples were prepared via hydrothermal synthesis method and characterized with XRD, FESEM, PSD, EDX, BET and FTIR techniques. Results: It was found that the crystallinity decreased upon applying TEA as template and also it can be noted that the intensity of the SAPO-34 phase peaks increased by increasing the morpholine in template mixture. Production of much smoother particles for the catalyst synthesized with binary template mixture of TEA/morpholine can be depended on the crystallinity increase. Si incorporation value was decreased for the catalyst with a major phase of SAPO-5 (topological structure of AFI). It is indicative that the TEA application would facilitate the formation of AFI structure which is incapable of the incorporating higher amounts of Si in to the crystallite framework. Conclusion: The nature of the template determines the morphology of final product due to different rate of crystal growth obtained in accordance with XRD and FESEM results. Therefore, the catalyst synthesized with TEA/morpholine mixture shows the best performance among synthesized samples in terms of life time in the MTO process sustaining light olefins selectivity at higher values (about 90% after 630 min TOS).

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.

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