The Catalytic Performance of Sol-Gel Alumina Supported Ti-Ce Catalysts for H2S Selective Oxidation to Elemental Sulfur

2018 ◽  
Vol 17 (5) ◽  
Author(s):  
H. Mehmet Tasdemir ◽  
Yavuz Yagizatli ◽  
Sena Yasyerli ◽  
Nail Yasyerli
Keyword(s):  
Reaction Time ◽  
Selective Oxidation ◽  
Elemental Sulfur ◽  
Sol Gel ◽  
Lewis Acidity ◽  
Molar Ratio ◽  
Feed Ratio ◽  
Impregnation Method ◽  
Durability Test ◽  
Adsorption Desorption

Abstract In this study, alumina supported Ti-Ce catalysts (10 % by weight and Ti/Ce molar ratio is 4:1) were prepared by using wet impregnation method and their catalytic activities were tested in H2S selective oxidation to elemental sulfur. The support alumina was synthesized by classical (SGC) and modified (SGM) sol-gel methods. The N2 adsorption-desorption, XRD, XPS, EDS and FTIR techniques were used to characterize the synthesized catalysts. The N2 adsorption-desorption isotherms showed that both catalysts have mesoporous structure. Only γ-Al2O3 crystalline phase together with amorphous structure were observed in the XRD patterns. The pyridine adsorbed FTIR analyzes showed that 10 %Ti-Ce@SGC and 10 %Ti-Ce@SGM catalysts have the same Lewis acidity. The activity tests were carried out at 250 °C and with a stoichiometric feed ratio of O2 to H2S being 0.5 for two different reaction times as 150 and 510 min. Complete conversion of H2S was obtained during 180 min. and 330 min. of reaction time over 10 %Ti-Ce@SGC and 10 %Ti-Ce@SGM, respectively. However, all catalysts showed very high sulfur selectivity. Sulfur deposition was detected over 10 %Ti-Ce@SGC catalyst both 150 and 510 min. of reaction time while it was observed after 510 min. of durability test over 10 %Ti-Ce@SGM catalyst. This can be the reason for the earlier loss of catalytic activity 10 %Ti-Ce@SGC than 10 %Ti-Ce@SGM.

scholarly journals Modified sodium molybdate as an efficient high yielding heterogeneous catalyst for biodiesel from Ghanaian indigenous Camelina sativa as a non-edible resource

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Mohammed Takase ◽  
Paul Kwame Essandoh ◽  
Rogers Kipkoech
Keyword(s):  
Reaction Time ◽  
Sodium Molybdate ◽  
Normal Pressure ◽  
Camelina Sativa ◽  
International Standards ◽  
Lewis Acidity ◽  
Molar Ratio ◽  
Solid Catalyst ◽  
Atmospheric Conditions ◽  
Heterogeneous Solid

AbstractSodium molybdate (Na2MoO4) has been synthesized and investigated as a heterogeneous solid catalyst for biodiesel from Camelina sativa seed oil. Transesterification reactions occurred under atmospheric conditions with relatively, low temperature short reaction time and normal pressure. The prepared catalyst was characterised by means of SEM, TGA, UV, XRD and FTIR. The properties of the biodiesel were compared with international standards. The transesterification reaction was very efficient with the optimum yield higher than 95% at methanol to oil molar ratio of 17:1, catalyst amount of 6%, reaction temperature of 60 °C and reaction time of 2.5 h. The molybdate complex had a high Lewis acidity and most certainly act as alcohol O–H bond leading to a transient species which has high nucleophilic character. The catalyst was easily recovered and after being washed for three times, showed capacity of recyclability for another catalytic reaction of five cycles with similar activity. The properties of the biodiesel were comparable to international standards.

Experimental Study on Preparation and Operating Conditions over a Promising Monolithic Catalysts for NOx Removal: MnOx/TiO2/Cordierite

2017 ◽  
Vol 898 ◽  
pp. 1905-1915 ◽  
Author(s):  
Kai Qi ◽  
Jun Lin Xie ◽  
Feng Xiang Li ◽  
Feng He
Keyword(s):  
Low Temperature ◽  
Catalytic Reduction ◽  
Sol Gel ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Scope Of Application ◽  
Catalyst Dosage ◽  
Cordierite Honeycomb ◽  
Low Temperature Scr

The samples of MnOx/TiO2 catalysts supported on cordierite honeycomb ceramics were prepared by a sol-gel-impregnation method, and evaluated for low-temperature (353-473 K) selective catalytic reduction (SCR) of NOx with NH3. The influences of pretreatment on cordierite and catalyst dosage were investigated at first and optimized as follows: pickling for cordierite honeycomb ceramics with 1 mol/L HNO3 for 3 h prior to loading procedure as well as the catalyst dosage of 3-5 wt.%. The activity results indicated that there was an optimum working condition for MnOx/TiO2/cordierite catalysts: NH3/NO molar ratio=1.1, [O2]=3 vol.%, GHSV=5514 h-1, the highest activity of nearly 100% NO conversion could be obtained. As a comparison, the performances of commercialized vanadium-based honeycomb catalyst were also employed, which revealed the narrower scope of application of GHSV and the higher active temperature window. In conclusion, it turns out that the prepared MnOx/TiO2/cordierite catalysts are more applicable as a low-temperature SCR catalyst for NOx removal in a more complicated application environment.

scholarly journals ZnFe2O4-TiO2Nanoparticles within Mesoporous MCM-41

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Aidong Tang ◽  
Yuehua Deng ◽  
Jiao Jin ◽  
Huaming Yang
Keyword(s):  
Sol Gel ◽  
Rutile Phase ◽  
Band Gap Energy ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Agglomeration Of Nanoparticles ◽  
Adsorption Desorption ◽  
Mcm 41

A novel nanocomposite ZnFe2O4-TiO2/MCM-41 (ZTM) was synthesized by a sol-gel method and characterized through X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), N2adsorption-desorption, Raman spectroscopy, and ultraviolet visible (UV-vis) spectrophotometry. The results confirmed the incorporation of ZnFe2O4-TiO2nanoparticles inside the pores of the mesoporous MCM-41 host without destroying its integrity. ZnFe2O4nanoparticles can inhibit the transformation of anatase into rutile phase of TiO2. Incorporation of ZnFe2O4-TiO2within MCM-41 avoided the agglomeration of nanoparticles and reduced the band gap energy of TiO2to enhance its visible light photocatalytic activity. UV-vis absorption edges of ZTM nanocomposites redshifted with the increase of Zn/Ti molar ratio. The nanocomposite approach could be a potential choice for enhancing the photoactivity of TiO2, indicating an interesting application in the photodegradation and photoelectric fields.

scholarly journals Synthesis of Ca-Doped Three-Dimensionally Ordered Macroporous Catalysts for Transesterification

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Tanat Chokpanyarat ◽  
Vittaya Punsuvon ◽  
Supakit Achiwawanich
Keyword(s):  
Reaction Time ◽  
Catalyst Concentration ◽  
Sol Gel ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hierarchical Porous ◽  
Ordered Macroporous

The novel three-dimensionally ordered macroporous (3DOM) CaO/SiO2, 3DOM CaO/Al2O3, and 3DOM Ca12Al14O32Cl2 catalysts for biodiesel transesterification were prepared by sol-gel method. The 3DOM catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The hierarchical porous structure was achieved; however, only 3DOM CaO/Al2O3 and 3DOM Ca12Al14O32Cl2 catalysts were used for transesterification due to high amount of active CaO. Various parameters such as methanol to oil molar ratio, catalyst concentration, reaction time, and their influence on the biodiesel production were studied. The result showed that 99.0% RPO conversion was achieved using the 3DOM Ca12Al14O33Cl2 as a catalyst under the optimal condition of 12 : 1 methanol to oil molar ratio and 6 wt.% catalyst with reaction time of 3 hours at 65°C.

scholarly journals Effects of Al and Co Promoters on CuO/SBA-15/Kaolinite Catalyst Properties and CO2 Hydrogenation at Low Pressure

2021 ◽  
Vol 259 ◽  
pp. 04001
Author(s):  
Zane Abelniece ◽  
Valdis Kampars ◽  
Helle-Mai Piirsoo ◽  
Aile Tamm
Keyword(s):  
Fixed Bed ◽  
Mesoporous Structure ◽  
Xrd Analysis ◽  
Hydrogenation Reaction ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Kaolinite Clay ◽  
Post Synthesis ◽  
Adsorption Desorption ◽  
Hydrogenation Of Co

CuO on mesoporous silica catalyst was prepared with post synthesis impregnation method, and the effects of Al and Co promoters on CuO/SBA-15/kaolinite catalyst properties and CO2 hydrogenation were studied. The mixing technology with kaolinite clay (containing Al2O3) was used to obtain the granules and to enhance the CO2 conversion to methanol as a product. The performance of all catalysts for catalytic hydrogenation of CO2 was evaluated on a fixed-bed tubular micro-activity reactor at 20 bar and 250°C with H2/CO2 molar ratio 3:1. XRD analysis, N2 adsorption-desorption analysis and SEM-EDX analysis indicated that the mesoporous structure of SBA-15 remains after loading with CuO and promoters, and after mixing with kaolinite clay. Results were compared with results obtained with commercial CuO/Al2O3 catalyst, which showed high MeOH selectivity (78%) during CO2 hydrogenation reaction.

Catalytic Synthesis of Butyraldehyde Glycol Acetal with H4SiW12O40/MCM-48

2012 ◽  
Vol 531 ◽  
pp. 312-315 ◽  
Author(s):  
Ming Bo Xu ◽  
Jie Yang ◽  
Yong Kui Huang ◽  
Shui Jin Yang
Keyword(s):  
Reaction Time ◽  
Molecular Sieve ◽  
Catalytic Synthesis ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Mass Ratio ◽  
Optimum Conditions ◽  
Environmental Friendly ◽  
Ft Ir ◽  
Catalyst Dosage

A novel environmental friendly catalyst，H4SiW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of butyraldehyde glycol acetal catalyzed by H4SiW12O40/MCM-48 was studied with butyraldehyde and glycol as reactants. H4SiW12O40/MCM-48 was an excellent catalyst for the synthesizing butyraldehyde glycol acetal and Keggin structure of H4SiW12O40 kept unchanged after being impregnated on surface of the molecular sieve support. Effects of n(butyraldehyde)∶n(glycol), catalyst dosage, cyclohexane(water-stripped reagent ) and reaction time on yields of the product were investigated. The optimum conditions had been found, that is, molar ratio of butyraldehyde to glycol is1:1.4，mass ratio of catalyst used to the reactants is 0.4% and reaction time is 45 min. Under these conditions, the yield of butyraldehyde glycol acetal can reach 73.3%.

scholarly journals Synthesis and characterization of mesoporous gamma-alumina by glucose as soft-template for molybdenum-99 adsorption: high and low molar ratio of water to aluminium isopropoxide effect

2021 ◽  
Vol 927 (1) ◽  
pp. 012005
Author(s):  
I Saptiama ◽  
A Nurmanjaya ◽  
F Rindiantono ◽  
Marlina ◽  
A M Lestari ◽  
...  
Keyword(s):  
Sol Gel ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Molar Ratio ◽  
Soft Template ◽  
Gamma Alumina ◽  
Aluminium Isopropoxide ◽  
High Molar Ratio ◽  
Gel Treatment ◽  
Adsorption Desorption

Abstract The mesoporous gamma-alumina is a good material for metal adsorption. Its textural properties are excellent, mainly for molybdenum-99 radioisotopes adsorption as part of 99Mo/99mTc generator in nuclear medicine. In this work, we have prepared mesoporous gamma-alumina by sol-gel treatment in the presence of glucose as a soft template. The molar ratio of reactant (water: aluminium isopropoxide(AIP)) was applied in the high and low ratios (150:1 and 25:1). The resulted mesoporous gamma-alumina was investigated using characterization analysis of X-ray diffraction, Nitrogen adsorption-desorption, and FTIR. The results indicate that the mesoporous gamma-alumina in the high molar ratio of water to AIP had a higher surface area and better crystallinity than the low molar ratio of reactants. Furthermore, in the Mo adsorption test, the mesoporous gamma-alumina with the high molar ratio posed a higher Mo adsorption capacity up to 55.69 mg Mo g−1 adsorbent. In the future, the molar ratio of reactants should be tuned in the range of around 150:1 to obtain the optimal Mo adsorption capacities of the resulted mesoporous gamma-alumina using the glucose template.

scholarly journals Sol–Gel Approach for Design of Pt/Al2O3-TiO2 System—Synthesis and Catalytic Tests

Ceramics ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 667-680
Author(s):  
Marta Dobrosielska ◽  
Michał Zieliński ◽  
Miłosz Frydrych ◽  
Mariusz Pietrowski ◽  
Piotr Marciniak ◽  
...  
Keyword(s):  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Molar Ratio ◽  
Hydrogen Chemisorption ◽  
Titania Gel ◽  
Fourier Transformation Infrared Spectroscopy ◽  
Alumina Gel ◽  
Hydrogenation Of Toluene ◽  
Temperature Programmed ◽  
Adsorption Desorption

Al2O3-TiO2 systems with Ti:Al 0.1, 0.5 and 1.0 molar ratio obtained by the sol–gel method have been used as a platinum support. As a precursor of alumina gel, aluminum isopropoxide has been chosen. Titanium tert-butoxylate was applied to obtain titania gel and hexachloroplatinic acid was applied as a source of platinum. The systems have been characterized by the following methods: thermogravimetric analysis (TGA), Fourier transformation infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), low-temperature nitrogen adsorption–desorption isotherms (BET, BJH), temperature-programmed reduction with hydrogen (TPR-H2) and hydrogen chemisorption. Reactions of toluene to methylcyclohexane and selective o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN) hydrogenation were used as the tests of systems’ catalytic activity. The application of Al2O3-TiO2 as a support has enabled the obtaining of platinum catalysts showing high activities for hydrogenation of toluene and selective hydrogenation of o-chloronitrobenzene to o-chloroaniline in the liquid phase. The highest activity in both reactions has been found for Pt/Al2O3-0.5TiO2 catalyst and the highest selectivity for Pt/Al2O3-. The activity of Pt/Al2O3-TiO2 catalysts was higher than that of alumina-supported ones.

scholarly journals PEMBUATAN BIODIESEL DARI MINYAK DEDAK PADI DENGAN REAKSI TRANSESTERIFIKASI MENGGUNAKAN KATALIS HETEROGEN ZEOLIT ALAM YANG DIMODIFIKASI DENGAN KOH

2017 ◽  
Vol 6 (1) ◽  
pp. 12-18
Author(s):  
Taslim ◽  
Sri Zahrani Dwi Mauliyah Parinduri ◽  
Putri Retno Wahyu Ningsih
Keyword(s):  
Reaction Time ◽  
Heterogeneous Catalyst ◽  
Rice Bran ◽  
Natural Zeolite ◽  
Heterogeneous Catalysts ◽  
Zeolite Catalyst ◽  
Rice Bran Oil ◽  
Transesterification Reaction ◽  
Molar Ratio ◽  
Impregnation Method

Biodiesel was usually produced from transesterification using alchohol. In this research rice bran oil was used as feedstock and methanol was used as reagent. The transesterification of rice bran oil had studied using KOH/natural zeolite as a solid heterogeneous catalyst. The objective of this study was to discover the effectivess of using natural zeolite modified by KOH as heterogeneous catalysts in the production of biodiesel from rice bran oil (RBO). KOH/natural zeolite catalyst was prepared by modification through impregnation method which was conducted on various KOH concentration (75 gram/100 ml – 175 gram/100 ml).  Transesterification reaction was conducted at 60 ºC, 500 rpm, and various amount of catalyst (2-4%), reaction time (1,5-3,5 hour) and molar ratio alcohol/oil (8:1-12:1). The highest yield of biodiesel was 98,71%, which was obtained by using 2% catalyst, reaction time 2 hour, molar ratio alcohol/oil 10:1. Natural zeolite as heterogeneous catalyst which modified by KOH could get the higher yield biodiesel on transesterification.

scholarly journals PROCESS OPTIMIZATION OF BIODIESEL PRODUCTION FROM CRUDE COCONUT SEEDS OIL USING CAO/AL2O3 AS HETEROGENEOUS CATALYST

2020 ◽  
Vol 2 (1) ◽  
pp. 92-97
Author(s):  
Jamilu Usman ◽  
Bashar Abdullahi Hadi ◽  
Buhari Idris ◽  
Umar Musa Tanko ◽  
Bashar Usman ◽  
...  
Keyword(s):  
Reaction Time ◽  
Methyl Ester ◽  
Catalyst Concentration ◽  
Acid Methyl Ester ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Promising Alternative ◽  
Animal Fats

Biodiesel is an alternative diesel fuel consisting of the alkyl monoesters of fatty acids from vegetable oils or animal fats. Biodiesel is a promising alternative fuel derived from animal fats or vegetable oil through transesterification with methanol. Base catalyzed transesterification is the most commonly used technique as it is the most economical process. Presently, a lot of heterogeneous catalysts have been formulated that are more effective than the homogeneous catalysts. CaO/Al2O3 was synthesized using incipient wetness impregnation method. The biodiesel was developed and optimized using Box-behnken response surface methodology (RSM) design provided using MINITAP-17 statistical software. The four independent variables considered are: reaction time, methanol to oil ratio, reaction temperature and catalyst concentration. The response chosen was fatty acid methyl ester (FAME) yields which were obtained from the reaction. The result from analysis of variance (ANOVA) showed a satisfactory result. Moreover, the input variables showed greater significance on the response which are reaction time and temperature base on F and P-value. The statistical models developed for predicting biodiesel yield revealed a significant agreement between the experimental and predicted values (R = 0.9686). An optimum methyl ester yield of 93.29 % was achieved with optimal conditions of methanol/oil molar ratio of 6:1, temperature of 600C, reaction time of 120 min and catalyst concentration of 1.0 wt%. The properties of the biodiesel produced also falls within the range prescribed by ASTM standard

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