Studies on non-modified and copper-modified coal ash zeolites as heterogeneous catalysts for VOCs oxidation

Boycheva, Silviya; Zgureva, Denitza; Václavíková, Miroslava; Kalvachev, Yuri; Lazarova, Hristina; Popova, Margarita

doi:10.1016/j.jhazmat.2018.07.020

Cited by 51 publications

(28 citation statements)

References 30 publications

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“…The process of adsorption of organic molecules is an important step and can be affected by the surface properties of the catalysts. The activity in the total oxidation of VOC is connected with the interaction of aromatic electrons from organic compounds with copper ions, acting as Lewis acid sites, increasing the possibility of electrophilic attack of adsorbed oxygen and combustion of VOC molecules [12][13][14][15]26]. The zeolite support has positive influence on the formation of Cu 2+ /Cu + ions and finely dispersed CuO nanoparticles below the XRD limit, which are active sites on the catalytic reaction.…”

Section: Catalytic Tests Of Calcined Cu-loaded Exhaust Zeolitesmentioning

confidence: 99%

“…Volatile organic compounds (VOCs) are atmospheric pollutants that contribute to the greenhouse effect, mainly generated from fossil fuel, biofuel and waste incineration installations, petroleum refineries, diesel engines, other industrial productions, and from utilization of organic solvents. [11][12][13][14][15]. Therefore, the development of inexpensive and effective catalysts for VOCs degradation is of great scientific and technological interest.…”

Section: Introductionmentioning

confidence: 99%

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Removal of Copper from Aqueous Solutions with Zeolites and Possible Treatment of Exhaust Materials

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Arčon

Kovač

et al. 2021

Chemie Ingenieur Technik

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The mechanism of Cu 2+ loading into commercially available natural HEU-type and synthetic LTA-type zeolites for their possible use in environmental processes, such as water and air treatment applications, was studied. Elemental analysis, SEM/EDXS, XRD, XAS and XPS analyses revealed 4-fold coordination of Cu 2+ cations with oxygen atoms in the pores, a predominant location of copper atoms on the surface of crystallites and retained crystallinity of zeolites throughout the processes. The post-treatment of Cu 2+ -loaded samples with HCl and/or NaCl solutions confirmed the predominantly reversible sorption of copper on zeolites from aqueous solutions by ion-exchange mechanism and, therefore, excellent regeneration possibilities for both types of zeolites. Furthermore, with the calcination of exhaust metal-loaded zeolites, catalysts for total toluene oxidation reaction, as a model VOC pollutant, were obtained.

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Section: Catalytic Tests Of Calcined Cu-loaded Exhaust Zeolitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Removal of Copper from Aqueous Solutions with Zeolites and Possible Treatment of Exhaust Materials

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Arčon

Kovač

et al. 2021

Chemie Ingenieur Technik

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“…The alkaline conversion of CFA to zeolites is consisting of dissolution of the aluminosilicate components from the raw material in alkaline media, formation of hydrogel and its subsequent heterogeneous crystallization onto the insoluble particles [21]. The homogenization of the reaction mixtures by ultrasonic treatment instead of magnetic stirring results in nanocrystalline morphology of CFAZ obtained [22]. Processing of CFAZ by the FH method leads to the highest yield of the zeolite phase in the final product due to the alkaline dissolution of the total aluminosilicate constituents in the CFA composition, even the most resistant ones, such as Quartz, Anorthite and Mullite, stipulated by the solidliquid interactions between the CFA components and the alkaline activator during the fusion stage.…”

Section: Processing Of Coal Ash Zeolite Nanocompositesmentioning

confidence: 99%

“…The simultaneous presence of Fe 2+ /Fe 3+ in CFAZ stipulates their catalytic performance and adsorption ability. [22]. Examples on the catalytic activity of CFAZ nanocomposites and CuO-modified CFAZ nanocomposites against the total oxidation of toluene are presented in Figure 7.…”

Section: Processing Of Coal Ash Zeolite Nanocompositesmentioning

confidence: 99%

Processing of high-grade zeolite nanocomposites from solid fuel combustion by-products as critical raw materials substitutes

et al. 2020

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High-grade zeolite nanocomposites are synthesized utilizing solid by-products from combustion of coal for energy production in Thermal Power Plants applying alkaline aging, hydrothermal and fusion-hydrothermal activation procedures. The obtained coal ash zeolites were studied with respect to their chemical and phase composition, morphology, surface parameters and thermal properties. It was found that they are distinguished in nanocrystalline morphology and significant content of iron oxide nanoparticles (γ-Fe2O3, α-Fe2O3, γ-Fe3O4) and doping elements (Cu, Co, Mn, V, W, etc.) transferred from the raw coal ash, and therefore they are assumed as nanocomposites. Coal fly ash zeolite nanocomposites are characterized by a mixed micro-mesoporous texture, significant concentration of acidic Brønsted centers due to their high surface insaturation, high chemical and thermal stabilty. This unique combination of compositional and textural properties predetermines the application of these materials as catalysts for thermal oxidation processes, anticorrosion barrier coatings, carbon capture adsorbents, matrices for hosting functional groups, detergents etc. Examples for coal fly ash zeolite applications for substitution of critical raw materials in practice are provided.

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“…Coal fly ash zeolites of the FAU type (CFAZ-FAU) are easily synthesized by the alkaline conversion of coal fly ash, saving raw materials by utilizing solid waste [5]. In particular, CFAZ-FAU has potential and can be used for traditional applications in waste water and gas purification by adsorption or separation [5][6][7]. Recently, novel advanced applications of zeolite materials have been extensively explored [1,8].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Size of Coal Ash FAU Zeolites Used as Dopants on the Sensing Properties of Nb2O5 Thin Films

Lazarova

Boycheva

Vasileva

et al. 2020

2nd Coatings and Interfaces Web Conference (CIWC-2 2020)

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In this study, solid waste from coal combustion in thermal power plants (TPPs) was used for the synthesis of zeolite Na-X samples. They were prepared by the long-term alkaline atmospheric conversion of coal ash collected from the electrostatic precipitators in the TPP “AES Galabovo”. When used in the form of thin films/layers, the optical detection of volatile organic compounds (VOCs) is possible due to a change in their reflectance spectra and color. In order to improve the sensing properties of synthesized zeolites, they were wet milled for 60 s and both milled and unmilled zeolites were used as dopants for the niobium oxide matrix in the form of thin films deposited by the spin-coating method on a silicon substrate. The surface morphology and structure of both zeolite powders were studied by scanning electron microscopy, while their size was determined by dynamic light scattering (DLS) spectra. Optical constants (refractive index, n, and extinction coefficient, k) and the thickness of the films were calculated from reflectance measurements. The change in the reflection coefficient ∆R of the films was determined from measured reflectance spectra prior to and after exposure to probe acetone molecules. An increase in the reaction of the films with milled zeolites to acetone, compared to the samples with unmilled zeolites, is demonstrated.

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Studies on non-modified and copper-modified coal ash zeolites as heterogeneous catalysts for VOCs oxidation

Cited by 51 publications

References 30 publications

Removal of Copper from Aqueous Solutions with Zeolites and Possible Treatment of Exhaust Materials

Removal of Copper from Aqueous Solutions with Zeolites and Possible Treatment of Exhaust Materials

Processing of high-grade zeolite nanocomposites from solid fuel combustion by-products as critical raw materials substitutes

Influence of the Size of Coal Ash FAU Zeolites Used as Dopants on the Sensing Properties of Nb2O5 Thin Films

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