Synthesis and characterization of high siliceous ZSM-5 zeolite from acid-treated palygorskite

Jiang, Jinlong; Duanmu, Chuansong; Yang, Yong; Gu, Xing; Chen, Jing

doi:10.1016/j.powtec.2013.10.020

Cited by 58 publications

(33 citation statements)

References 22 publications

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“…5a. The XRD pattern of MMT, MMT-CN x , and Pd/MMT-CN x all shows the typical XRD peaks of quartz at 2θ of 20.1°a nd 26.8° [39,40]. This implies that the octahedral crystal structure of MMT is destroyed by the acid solution, which is attributed to the dissolution of octahedral cations (e.g., Mg 2+ , Al 3+ , and Fe 3+ ) in MMT crystal structure and the resulting strengthened quartz diffraction peak.…”

Section: Materials Characterizationsmentioning

confidence: 96%

CN x -modified montmorillonite as support to immobilize Pd and its enhanced electrocatalytic activity for formic acid oxidation

Tian

Chen

Zhang

et al. 2014

Ionics

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Nature clay, i.e., montmorillonite (MMT), can be used as support materials of anode electrocatalyst in the direct formic acid fuel cell. The nitrogen-containing composite support (MMT-CN x ) was prepared via carbonizing MMT which was covered by polyaniline. Pd/MMT-CN x and Pd/C catalysts were prepared as formic acid oxidation catalysts using an improved liquid reduction method. The composite, structure, surface properties, and electrical conductivity of the supports and catalysts were studied by energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical impedance spectroscopy (EIS). The results showed that welldispersed Pd nanoparticles with a narrow size distribution of 3.5-5.5 nm could be easily prepared on the MMT-CN x . Larger electrochemical specific area (ECSA) was obtained for Pd/ MMT-CN x than Pd/C according to CO-stripping voltammetry. Cyclic voltammetry (CV) and chronoamperometry (CA) measurements showed better catalytic activity and stability of the Pd/MMT-CN x catalyst than the conventional Pd/C catalyst for formic acid electrooxidation. Larger ECSA and doped nitrogen in the support of the Pd/MMT-CN x catalyst may be the main reason of higher activity and better stability for formic acid oxidation compared with the Pd/C catalyst. The results offered potential application of composite support (MMT-CN x ) for the catalyst of the direct formic acid fuel cell.

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Section: Materials Characterizationsmentioning

confidence: 96%

CN x -modified montmorillonite as support to immobilize Pd and its enhanced electrocatalytic activity for formic acid oxidation

Tian

Chen

Zhang

et al. 2014

Ionics

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“…For the activation assays, it was treated, under magnetic stirring, an amount of palygorskite in hydrochloric acid at concentrations of 2, 4, 6 mol L -1 at 90 °C with reaction times of 2 or 4 hours [9][10][11] . The mixture was stirred in a becker with a cover in order in order to maintain the constant volume of solution used, with the mass ratio of the clay/solution volume, 1 g : 10 mL.…”

Section: Acid Activationmentioning

confidence: 99%

“…Appropriate acid treatments of clay minerals modify their surface area and/or the number of acid sites by disaggregation of clay particles, elimination of mineral impurities, removal of metal-exchange cations and proton exchange. For palygorskite, acid activation can eliminate impurities, change its composition, generate more active OH -groups on its surface, increase its area and pore volume as well as the number of adsorption sites by disaggregation of palygorskite paticles [9][10][11] . Thus, acid treatment have been used for increasing the surface area of clay minerals and for obtaining from these minerals solids with a high numbers of acid centers, properties that influence the application of these materials in descolourization, adsorption and catalysis in reactions in which catalysis with acidic properties are requerid 10 .…”

Section: Introductionmentioning

confidence: 99%

Effects of acid treatment on the clay palygorskite: XRD, surface area, morphological and chemical composition

Xavier

Santos

et al. 2014

Mat. Res.

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The palygorskite is an aluminum-magnesium silicate that has a fibrous morphology. Their physicochemical characteristics are the result of high surface area, porosity and thermal resistance which make it an attractive adsorbent. Its adsorption capacity can be increased through chemical reactions and/or heat treatments. The objective of this work is to verify the effects of acid activation on the palygorskite, treated with HCl at 90 °C at concentrations of 2, 4 and 6 mol L -1 in 2 and 4 hours, with clay/acid solution ratio 1 g 10 mL -1 and characterized by techniques: XRF, XRD and surface area. A significant increase in specific surface area was observed in the sample treated with HCl at the concentration 6 mol L -1 . The changes were more pronounced at stricter concentrations of acidity, with decreasing intensity of reflection of the clay indicated in the XRD. These changes were confirmed in the XRF with the leaching of some oxides and with increasing concentration of SiO 2 .

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“…The residue removal step may improve the purity of zeolite, but another new solid waste will be produced [38,39]. Given the circumstances, the in-situ crystallization technique (ISCT), which is the combination of the above two methods, has been proposed to produce high purity zeolites and eliminate any waste generation [16,40].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Na-A zeolite from coal gangue with the in-situ crystallization technique

Qian

2015

Advanced Powder Technology

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Synthesis and characterization of high siliceous ZSM-5 zeolite from acid-treated palygorskite

Cited by 58 publications

References 22 publications

CN x -modified montmorillonite as support to immobilize Pd and its enhanced electrocatalytic activity for formic acid oxidation

CN x -modified montmorillonite as support to immobilize Pd and its enhanced electrocatalytic activity for formic acid oxidation

Effects of acid treatment on the clay palygorskite: XRD, surface area, morphological and chemical composition

Synthesis of Na-A zeolite from coal gangue with the in-situ crystallization technique

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