scholarly journals Methanol Dehydration to Dimethyl Ether on Zr-Loaded P-Containing Mesoporous Activated Carbon Catalysts

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2204 ◽  
Author(s):  
José Palomo ◽  
José Rodríguez-Mirasol ◽  
Tomás Cordero
Keyword(s):  
Dimethyl Ether ◽  
Zirconium Phosphate ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Methanol Conversion ◽  
Methanol Dehydration ◽  
Olive Stones ◽  
Phosphorus Containing ◽  
Phosphate Species ◽  
Carbon Catalysts

Activated carbons have been prepared by the chemical activation of olive stones with phosphoric acid and loaded with Zr. The addition of Zr to the phosphorus-containing activated carbons resulted in the formation of zirconium phosphate surface groups. Gas phase methanol dehydration has been studied while using the prepared Zr-loaded P-containing activated carbons as catalysts. Carbon catalysts showed high steady-state methanol conversion values, which increased with Zr loading up to a limit that was related to P content. The selectivity towards dimethyl ether was higher than 95% for all Zr loadings. Zirconium phosphate species that were present on catalysts surface were responsible for the catalytic activity.

scholarly journals Deactivation of a Biomass-Derived Zirconium-Doped Phosphorus-Containing Carbon Catalyst in the Production of Dimethyl Ether from Methanol Dehydration

2021 ◽  
Author(s):  
Javier Torres-Liñán ◽  
Miguel García-Rollán ◽  
Juana M. Rosas ◽  
José Rodríguez-Mirasol ◽  
Tomás Cordero
Keyword(s):  
Dimethyl Ether ◽  
Methanol Dehydration ◽  
Carbon Catalyst ◽  
Phosphorus Containing

Phosphorus-Containing Mesoporous Carbon Acid Catalyst for Methanol Dehydration to Dimethyl Ether

2019 ◽  
Vol 58 (10) ◽  
pp. 4042-4053 ◽  
Author(s):  
María José Valero-Romero ◽  
Elisa María Calvo-Muñoz ◽  
Ramiro Ruiz-Rosas ◽  
José Rodríguez-Mirasol ◽  
Tomás Cordero
Keyword(s):  
Dimethyl Ether ◽  
Mesoporous Carbon ◽  
Acid Catalyst ◽  
Methanol Dehydration ◽  
Phosphorus Containing ◽  
Carbon Acid

Methanol Dehydration to Dimethyl Ether over Silica Derived from Rice Husk as the Component-Based Catalysts

2014 ◽  
Vol 931-932 ◽  
pp. 17-21
Author(s):  
Nattaporn Chaba ◽  
Sutasinee Neramittagapong ◽  
Arthit Neramittagapong
Keyword(s):  
Surface Area ◽  
Dimethyl Ether ◽  
Rice Husk ◽  
Reaction Temperature ◽  
Methanol Conversion ◽  
Packed Bed Reactor ◽  
Bet Surface Area ◽  
Gravimetric Analysis ◽  
Methanol Dehydration ◽  
X Ray

Dimethyl Ether (DME) an alternative fuel was synthesized by methanol dehydration over the silica-based catalysts. Silica extracted from both rice husk (A) and rice-husk ash (B) was used as the precursors for preparing the catalysts. The SiO2/Al2O3 and the SAPO catalysts prepared from that silica were analyzed using X-ray diffraction (XRD), N2 adsorption (BET surface area), X-ray fluorescence (XRF), NH3 temperature-programmed desorption (NH3-TPD), and thermal gravimetric analysis (TGA). The effects of reaction temperature on the methanol selectivity and conversion to dimethyl ether were investigated. The methanol dehydration reactions were carried out in a packed-bed reactor at the reaction temperature of 250-350°C. DME was the major product and formed with selectivity of 57% over SAPO-B. An increasing of the reaction temperatures resulted in the enhancing of methanol conversion. The highest methanol conversion of 93% was achieved at 325°C. The method of silica extraction had an effect on the selectivity to DME due to the higher BET surface area.

scholarly journals Adsorption of pharmaceutical residues on adsorbents prepared from olive stones using mixture design of experiments model

2019 ◽  
Vol 80 (5) ◽  
pp. 998-1009 ◽  
Author(s):  
F. Boudrahem ◽  
I. Yahiaoui ◽  
S. Saidi ◽  
K. Yahiaoui ◽  
L. Kaabache ◽  
...  
Keyword(s):  
Design Of Experiments ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Sorption Process ◽  
Mixture Design ◽  
Pharmaceutical Residues ◽  
Olive Stone ◽  
Olive Stones ◽  
Equilibrium Data ◽  
Experimental Values

Abstract In this work, inexpensive and easily available olive stone (OS) waste was used as the source material to prepare activated carbons (ACs) by chemical activation with phosphoric acid and zinc chloride. The mixture design of experiments (MDOE) method was applied to study the effect of the composition of the mixture of unmodified olive stones (UOS) and ACs prepared from olive stones activated with ZnCl2 (ACOS ZnCl2) and H3PO4 (ACOS H3PO4) on the absorption of pharmaceutical residues. The adsorbed tetracycline (TC) amounts at equilibrium predicted from the model equation developed using Microsoft Excel were found to be in good agreement with the experimental values (R2 = 0.999). Based on the results of the model, the amount of TC removed increased as the proportion of ACOS H3PO4 in the adsorbent mixture increased and the highest amount of TC adsorbed was obtained with an adsorbent made up entirely of ACOS H3PO4. Separate adsorption tests for sulfamethazine (SMT) and amoxicillin (AMX) on ACOS H3PO4 showed that SMT was adsorbed best (189.81 mg/g), followed by TC (183.11 mg/g) then AMX (155.69 mg/g). However, when these molecules were present together in the same solution, it was TC that adsorbed best, followed by SMT then AMX. In addition to this, the sorption process studied was best described by a pseudo-first-order model and it was the Langmuir model that satisfactorily described the equilibrium data.

scholarly journals A Kinetic Model Considering Catalyst Deactivation for Methanol-to-Dimethyl Ether on a Biomass-Derived Zr/P-Carbon Catalyst

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 596
Author(s):  
Javier Torres-Liñán ◽  
Ramiro Ruiz-Rosas ◽  
Juana María Rosas ◽  
José Rodríguez-Mirasol ◽  
Tomás Cordero
Keyword(s):  
Kinetic Model ◽  
Dimethyl Ether ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Methanol Conversion ◽  
The Other ◽  
Methanol Dehydration ◽  
Catalyst Activation ◽  
Other Hand ◽  
Adsorption Of Water

A Zr-loaded P-containing biomass-derived activated carbon (ACPZr) has been tested for methanol dehydration between 450 and 550 °C. At earlier stages, methanol conversion was complete, and the reaction product was mainly dimethyl ether (DME), although coke, methane, hydrogen and CO were also observed to a lesser extent. The catalyst was slowly deactivated with time-on-stream (TOS), but maintained a high selectivity to DME (>80%), with a higher yield to this product than 20% for more than 24 h at 500 °C. A kinetic model was developed for methanol dehydration reaction, which included the effect of the inhibition of water and the deactivation of the catalyst by coke. The study of stoichiometric rates pointed out that coke could be produced through a formaldehyde intermediate, which might, alternatively, decompose into CO and H2. On the other hand, the presence of 10% water in the feed did not affect the rate of coke formation, but produced a reduction of 50% in the DME yield, suggesting a reversible competitive adsorption of water. A Langmuir–Hinshelwood reaction mechanism was used to develop a kinetic model that considered the deactivation of the catalyst. Activation energy values of 65 and 51 kJ/mol were obtained for DME and methane production in the temperature range from 450 °C to 550 °C. On the other hand, coke formation as a function of time on stream (TOS) was also modelled and used as the input for the deactivation function of the model, which allowed for the successful prediction of the DME, CH4 and CO yields in the whole evaluated TOS interval.

Dimethyl Ether Synthesis via Methanol Dehydration over Diatomite Catalyst Modified Using Hydrochloric Acid

2014 ◽  
Vol 931-932 ◽  
pp. 42-46 ◽  
Author(s):  
Watcharakorn Pranee ◽  
Pornsawan Assawasaengrat ◽  
Arthit Neramittagapong ◽  
Sutasinee Neramittagapong
Keyword(s):  
Hydrochloric Acid ◽  
Dimethyl Ether ◽  
Active Sites ◽  
Fixed Bed ◽  
Methanol Conversion ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Methanol Dehydration ◽  
Dimethyl Ether Synthesis ◽  
Ether Synthesis

The synthesis of dimethyl ether via methanol dehydration has been carried out over untreated-diatomite catalyst (DM) and hydrochloric acid modified treatment on diatomite catalyst (DMHC). The reactions were carried out in a fixed-bed reactor. The effects of hydrochloric acid modifications of diatomite on its catalytic performance were studied. The characterization such as XRD, SEM, FT-IR and FT-Raman had no deformation after HCl-modified treatment on catalysts. DMHC catalyst apparently gave the higher methanol conversion rate than DM due to the acidity while the selectivity of dimethyl ether from 250 to 350°C was slightly changed. The acidity was depended upon Al(IV) ions; nevertheless, both Al(V) and Al(VI) were affected and hence increasing the basic active sites. Not only was the competitively catalytic methanol dehydrogenation preferred with basic condition but also methanol-blocking water molecule interaction was the unwanted reaction. In this investigation, the chemical-bond arrangements of silicon and aluminium ions were proposed with solid MAS/NMR. The DMHC catalyst exhibited better DME yield than the DM catalyst, and it could be used as a selective catalyst for DME synthesis from methanol.

Surface functionality and porosity of activated carbons obtained from chemical activation of wood

Carbon ◽  
2000 ◽  
Vol 38 (5) ◽  
pp. 669-674 ◽  
Author(s):  
H Benaddi ◽  
T.J Bandosz ◽  
J Jagiello ◽  
J.A Schwarz ◽  
J.N Rouzaud ◽  
...  
Keyword(s):  
Activated Carbons ◽  
Chemical Activation ◽  
Surface Functionality

scholarly journals Computer Analysis of the Effect of Activation Temperature on the Microporous Structure Development of Activated Carbon Derived from Common Polypody

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2951
Author(s):  
Mirosław Kwiatkowski ◽  
Jarosław Serafin ◽  
Andy M. Booth ◽  
Beata Michalkiewicz
Keyword(s):  
Activated Carbon ◽  
Porous Structure ◽  
Computer Analysis ◽  
Density Functional ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Geometrical Parameters ◽  
Activation Process ◽  
Microporous Structure ◽  
Activation Temperature

This paper presents the results of a computer analysis of the effect of activation process temperature on the development of the microporous structure of activated carbon derived from the leaves of common polypody (Polypodium vulgare) via chemical activation with phosphoric acid (H3PO4) at activation temperatures of 700, 800, and 900 °C. An unconventional approach to porous structure analysis, using the new numerical clustering-based adsorption analysis (LBET) method together with the implemented unique gas state equation, was used in this study. The LBET method is based on unique mathematical models that take into account, in addition to surface heterogeneity, the possibility of molecule clusters branching and the geometric and energy limitations of adsorbate cluster formation. It enabled us to determine a set of parameters comprehensively and reliably describing the porous structure of carbon material on the basis of the determined adsorption isotherm. Porous structure analyses using the LBET method were based on nitrogen (N2), carbon dioxide (CO2), and methane (CH4) adsorption isotherms determined for individual activated carbon. The analyses carried out showed the highest CO2 adsorption capacity for activated carbon obtained was at an activation temperature of 900 °C, a value only slightly higher than that obtained for activated carbon prepared at 700 °C, but the values of geometrical parameters determined for these activated carbons showed significant differences. The results of the analyses obtained with the LBET method were also compared with the results of iodine number analysis and the results obtained with the Brunauer–Emmett–Teller (BET), Dubinin–Radushkevich (DR), and quenched solid density functional theory (QSDFT) methods, demonstrating their complementarity.

scholarly journals An Evaluation of the Impact of the Amount of Potassium Hydroxide on the Porous Structure Development of Activated Carbons

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2045
Author(s):  
Mirosław Kwiatkowski ◽  
Elżbieta Broniek ◽  
Vanessa Fierro ◽  
Alain Celzard
Keyword(s):  
Density Functional Theory ◽  
Porous Structure ◽  
Potassium Hydroxide ◽  
Density Functional ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Appropriate Technology ◽  
Functional Theory ◽  
Homogeneous Surface ◽  
The Impact

This paper presents the results of an evaluation of the impact of the amount of potassium hydroxide on the obtained porous structure of the activated carbons derived from the shells of pistachios, hazelnuts, and pecans by carbonization and subsequent chemical activation with potassium hydroxide by different adsorption methods: Brunauer–Emmett–Teller, Dubinin–Raduskevich, the new numerical clustering-based adsorption analysis, Quenched Solid Density Functional Theory, and 2D-Non-linear Density Functional Theory for Heterogeneous Surfaces, applied to nitrogen adsorption isotherms at −196 °C. Based on the conducted research, a significant potential for the production of activated carbons from waste materials, such as nut shells, has been demonstrated. All the activated carbons obtained in the present study at the activator/char mass ratio R = 4 exhibited the most developed porous structure, and thus very good adsorption properties. However, activated carbons obtained from pecan shells deserve special attention, as they were characterized by the most homogeneous surface among all the samples analyzed, i.e., by a very desirable feature in most adsorption processes. The paper demonstrates the necessity of using different methods to analyze the porous structure of activated carbons in order to obtain a complete picture of the studied texture. This is because only a full spectrum of information allows for correctly selecting the appropriate technology and conditions for the production of activated carbons dedicated to specific industrial applications. As shown in this work, relying only on the simplest methods of adsorption isotherm analysis can lead to erroneous conclusions due to lack of complete information on the analyzed porous structure. This work thus also explains how and why the usual characterizations of the porous structure of activated carbons derived from lignocellulosic biomass should not be taken at face value. On the contrary, it is advisable to cross reference several models to get a precise idea of the adsorbent properties of these materials, and therefore to propose the most suitable production technology, as well as the conditions of the preparation process.

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