Modification of MCM-22 Zeolite and Its Derivatives with Iron for the Application in N2O Decomposition

Layered 2D zeolite MCM-22 and its delaminated derivative, ITQ-2, were modified with iron, by different methods (ion-exchange and direct synthesis), and with the use of different precursors (FeSO4∙7H2O, Fe(NO3)3∙9H2O, and [Fe3(OCOCH3)7∙OH∙2H2O]NO3 oligocations. The applied modifications were aimed at optimization of iron form in the samples (aggregation, amount, location, and reducibility), in order to achieve the highest catalytic activity in the N2O decomposition. The synthesis of the samples was verified with the use of XRD (X-Ray Diffraction), N2-sorption and ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy) techniques, while the form of iron in the samples was investigated by UV–vis-DRS (UV–vis diffuse reflectance spectroscopy), H2-TPR (Hydrogen Temperature-Programmed Reduction) and HRTEM (High-Resolution Transmission Electron Microscopy). The highest activity in the N2O decomposition presented the sample Fe(O,IE)MCM-22, prepared by ion-exchange of MCM-22 with Fe3(III) oligocations. This activity was related to the oligomeric FexOy species (the main form of iron in the sample) and the higher loading of active species (in comparison to the modification with FeSO4∙7H2O).

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Friedel-Crafts alkylation of benzene with benzyl alcohol over H-MCM-22

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2020-0175 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Deniz Karabulut ◽

Sema Akyalcin

Keyword(s):

Benzyl Alcohol ◽

Inductively Coupled Plasma ◽

Optical Emission ◽

Hydrothermal Condition ◽

Nitrogen Adsorption ◽

Product Distribution ◽

Emission Spectrometry ◽

Inductively Coupled ◽

Alkylation Of Benzene ◽

Temperature Programmed

Abstract MCM-22 was synthesized by using silicic acid powder as a silica source under the static hydrothermal condition and characterized by X-ray diffraction, nitrogen adsorption-desorption isotherms, scanning electron microscopy, inductively coupled plasma optical emission spectrometry, and temperature-programmed desorption of ammonia. The liquid phase benzylation of benzene with benzyl alcohol to diphenylmethane was investigated over H-MCM-22. The effects of reaction parameters on the conversion of benzyl alcohol and product distribution were determined. Under optimal reaction conditions, diphenylmethane yield of 92.1% was achieved for 99.3% conversion of benzyl alcohol in 3 h of reaction period. The reusability of the catalyst was also investigated after calcination of the catalyst in stagnant air at 500 °C for 4 h. The results show that the organic species produced during the reaction deposited in the catalyst lead to the deactivation of the catalyst and the calcination of the deactivated catalyst causes catalyst dealumination.

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Direct Synthesis of Highly Dispersible PACMA-Capped TiO2 Nanoparticles and Its Adsorption Properties towards Pb(II)

Journal of Nanomaterials ◽

10.1155/2018/4731970 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Marta Sanchez-Sala ◽

Concepción Domingo ◽

José A. Ayllón

Keyword(s):

Inductively Coupled Plasma ◽

Colloidal Suspension ◽

Direct Synthesis ◽

Optical Emission ◽

Powdered Material ◽

Organic Polymer ◽

Emission Spectrometry ◽

Characterization Methods ◽

Inductively Coupled ◽

Electron Microscopies

A simple low-temperature one-step synthetic method of a hybrid material involving TiO2 nanoparticles modified by an organic polymer is here reported. TiO2 nanoparticles were grown by hydrolysis of hexafluorotitanate using boric acid as a fluoride scavenger. TiO2 synthesis was performed in the presence of poly(acrylic acid-co-maleic acid) (PACMA). This procedure yields a crystalline TiO2 nanopowder capped with PACMA, termed PACMA@TiO2, according to X-ray diffraction and infrared spectroscopy characterization methods. Elemental analysis denotes the presence in the powder of a small amount of ammonium. Transmission and scanning electron microscopies show that the material is constituted by needles of ca. 200 nm in length, fused into star-like particles. Selected area electron diffraction analysis indicates that the particles are aggregated and only partially organized. The dried powdered material can easily be dispersed in water. The colloidal suspension obtained is highly stable, and its potential application in heavy metal adsorption is demonstrated with aqueous Pb(II), followed by using inductively coupled plasma optical emission spectrometry.

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