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The effect of FER zeolite acid sites in methanol-to-dimethyl-ether catalytic dehydration

Journal of Energy Chemistry 2017年第3期26卷 406-415页

作者： Enrico Catizzone Alfredo Aloise Massimo Migliori girolamo giordano Department of Environmental and Chemical Engineering University of CalabriaVia P.BucciCubo 42aI-87036 RendeCSItaly

In this paper, the effect of acidity of zeolites with FER framework was studied in the methanol dehydration to dimethyl ether reaction, by comparing catalysts with different Si/Al ratios(namely 8, 30 and60). The aim of this work was to investigate how the acid sites concentration, strength, distribution and typology(Br?nsted and Lewis) affect methanol conversion, DME selectivity and coke formation. It was found that the aluminium content affects slightly acid sites strength whilst a relevant effect on acid sites concentration and distribution(Br?nsted/Lewis) was observed as 24% of Lewis sites were found on Alrichest samples, whilst less than 10% of Lewis acid sites were observed on FER at higher Si/Al ratio. All the investigated catalyst samples showed a selectivity toward DME always greater than 0.9 and samples with the lowest Si/Al ratio exhibit the best performances in terms of methanol conversion, approaching the theoretical equilibrium value(around 0.85) at temperatures below 200 °C. Turnover-frequency analysis suggests that this result seems to be related not only to the higher amount of acid sites but also that the presence of Lewis acid sites may play a significant role in converting methanol. On the other hand, the presence of Lewis acid sites, combined with a high acidity, promote the formation of by-products(mainly methane) and coke deposition during the reaction. As final evidence, all the investigated catalysts exhibit very high resistance to deactivation by coke deposition, over 60 h continuous test, and a GC–MS analysis of the coke deposited on the catalyst surface reveals tetra-methyl benzene as main component.

关键词： Methanol dehydration Dimethyl ether Lewis acid sites FER zeolite Coke formation

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Ferrierite vs. γ-Al_2O_3: The superiority of zeolites in terms of water-resistance in vapour-phase dehydration of methanol to dimethyl ether

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Journal of Energy Chemistry 2019年第3期28卷 162-169页

作者： Enrico Catizzone Massimo Migliori Antonio Purita girolamo giordano Department of Environmental and Chemical Engineering University of Calabria

The catalytic conversion of methanol to dimethyl ether(DME) over a series of home-made FER-type zeolites having different acidities and commercial γ-Al_2O_3 has been studied with the aim to understand the impact of adding water in the reactant stream on the catalytic behavior on investigated materials. Cofeeding water with methanol, the alcohol conversion was slightly reduced over the investigated zeolites while the catalytic activity of γ-Al_2O_3, the traditional catalyst of MeOH-to-DME conversion, was strongly inhibited. It was also found that, for the investigated zeolites, both the amount and the initial deposition rate of the coke formed during the reaction were reduced when water was co-fed with methanol while no significant effects on both methanol conversion and DME selectivity were observed under the investigated conditions.

关键词： Ferrierite Zeolites Methanol dehydration Dimethyl ether Coke

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Catalytic behavior in propane aromatization using GA-MFI catalyst

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Chinese Journal of Chemical Engineering 2017年第12期25卷 1863-1870页

作者： Alfredo Aloise Enrico Catizzone Massimo Migliori Janos B.Nagy girolamo giordano University of Calabria Department of Environmental and Chemical Engineering Via P. Bucci 1-87036 Rende CS Italy

Ga-Al-MFI samples were synthesized in hydrothermal conditions from gels of composition 1.08CH3NH2- 0.134TPABr-1SiO2-xAl2O3-yGa2O3-40H2O at 175 ℃ for 7 days, with x = 0.005 and 0.0025, y = 0.005, 0,010 and 0.020. The samples were characterized by XRD, BET measurements, thermal analysis （TGA-DTA） atomic absorption and high resolution solid state MAS 27Al and 71Ga NMR measurements. The aromatization of propane was studied as catalytic test. The activity and selectivity of the catalysts were determined for benzene, toluene and xylenes on the one hand and for methane and ethane on the other hand. The most active sample was obtained with the highest Ga/AI ratio. For this sample, the BTX selectivity obtained by aromatization was always higher than the hydrocracking selectivity leading to methane and ethane. The relative amount of toluene was higher than that of benzene and ofxylenes. The samples were deactivated by coke formation that was revealed more severe for the most active sample,

关键词： Propane aromatization Gallium ZSM-5 Coke formation Catalyst deactivation

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Modelling of adsorption of textile dyes over multi-walled carbon nanotubes:Equilibrium and kinetic

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Chinese Journal of Chemical Engineering 2017年第4期25卷 523-532页

作者： Danilo Vuono Enrico Catizzone Alfredo Aloise Alfonso Policicchio Raffaele G.Agostino Massimo Migliori girolamo giordano University of Calabria Department of Environmental and Chemical Engineeringvia P.Bucci1-87036 RendeCSItaly University of Calabria Department of Physicsvia P.Bacd1-87036 RendeCSItaly

The paper deals with the application of multiwall carbon nanotubes(CNTs) to the adsorption of dyes from wastewater. Textile dyes are dangerous and diffused pollutant in wastewater, and the paper results confirmed the good adsorption ability of CNTs, with respect to classic active carbon, even for different dye types. The effect of surface treatments of CNTs was primarily investigated, revealing that neither the presence of residual catalyst nor common surface treatment(oxidation) affects the CNT's performances. Therefore less expensive nonpurified CNTs were assessed as good and economically convenient alternative for the process. In order to gain in generality in adsorption kinetic modelling, the parameters of the "best fitting" pseudo-second order model have been correlated to the main process variables(the dye initial concentration and the specific mass of CNTs.) setting-up a predictive kinetic model useful design new application of these materials in currently operating industrial operations for adsorption. In addition, isothermal data were used to screen all the relevant adsorption isotherms models and the Temkin model was confirmed as the more effective to accurately fit equilibrium data for any of the considered different dye types.

关键词： wastewater walled classic isotherms dangerous pollutant economically expensive currently adsorbent

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