Smart- and Zero-Energy Utilization of Coal Ash from Thermal Power Plants in the Context of Circular Economy and Related to Soil Recovery

Zgureva, Denitza; Boycheva, Silviya; Behunova, Dominika Marcin; Václavíková, Miroslava

doi:10.1061/(asce)ee.1943-7870.0001752

Cited by 10 publications

(10 citation statements)

References 28 publications

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“…Zeolite FAU is obtained as a metastable phase and, upon prolonged alkaline treatment, it recrystallizes to a more stable zeolite phase, but with a lower surface area. Similar observations have been made in our previous studies on self-crystallization of FA investigating the influence of the reaction mixture alkalinity on the final product [11]. The raw fly ash SS is highly amorphous, which predetermines faster kinetics of its alkaline conversion.…”

Section: Surface Properties Of Coal Fly Ash Zeolitessupporting

confidence: 86%

Quasi Natural Approach for Crystallization of Zeolites from Different Fly Ashes and Their Application as Adsorbent Media for Malachite Green Removal from Polluted Waters

et al. 2020

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Worldwide disposal of multi-tonnage solid waste from coal-burning thermal power plants (TPPs) creates serious environmental and economic problems, which necessitate the recovery of industrial waste in large quantities and at commercial prices. Fly ashes (FAs) and slag from seven Bulgarian TPPs have been successfully converted into valuable zeolite-like composites with various applications, including as adsorbents for capturing CO2 from gases and for removal of contaminants from water. The starting materials generated from different types of coal are characterized by a wide range of SiO2/Al2O3 ratio, heterogeneous structure and a complex chemical composition. The applied synthesis procedure resembles the formation of natural zeolites, as the raw FAs undergo long-term self-crystallization in an alkaline aqueous solution at ambient temperature. The phase and chemical composition, morphology and N2 adsorption of the final zeolite products were studied by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-Ray Diffraction (XRD) and Brunauer–Emmett–Teller (BET) analyses. The growth of faujasite (FAU) crystals as the main zeolite phase was established in all samples after 7 and 14 months of alkaline treatment. Phillipsite (PHI) crystals were also observed in several samples as an accompanying phase. The final products possess specific surface area over 400 m2/g. The relationships between the surface properties of the investigated samples and the characteristics of the raw FAs were discussed. All of the obtained zeolite-like composites were able to remove the highly toxic dye (malachite green, MG) from water solutions with efficiency over 96%. The experimental data were fitted with high correlation to the second-order kinetics.

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Section: Surface Properties Of Coal Fly Ash Zeolitessupporting

confidence: 86%

Quasi Natural Approach for Crystallization of Zeolites from Different Fly Ashes and Their Application as Adsorbent Media for Malachite Green Removal from Polluted Waters

et al. 2020

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“…In this conversion approach, slurries of coal fly ash in 1.5 mol/L NaOH are incubated continuously at room conditions. A detailed method of the synthesis and characterization of zeolites is described in [17].…”

Section: Methodsmentioning

confidence: 99%

“…Agglomerations of indistinguishable particles are observed before milling with octahedral-shaped crystallites typical of the FAU phase. Inclusions of particles from other zeolite phases are also found, which often accompany the crystallization of FAU from coal fly ash [17]. After the mechanical processing, a clear separation of the individual particles of about 1-1.5 μm in size is observed.…”

Section: Zeolite Sizementioning

confidence: 95%

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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“…Between 2017 and 2018, countries such as India, China, United States, and Germany produced around 350 million tons of residual ash, with an estimated 700 million tons worldwide [1,3]. These residual ashes from the burning process are usually used on an industrial scale to make construction materials like Portland cement and/or refractory bricks, but the unused parts of this waste end up being stored in an area of the industry or disposed of as garbage, which can lead to soil degradation and pose a risk to groundwater bodies [4][5][6]. To avoid this risk, the use of these residual ashes for the synthesis of zeolitic material has been studied in the literature [7,8].…”

Section: Introductionmentioning

confidence: 99%

Production of nanostructured crystalline composite using residual ashes from flocculated sludge burning process in a poultry slaughterhouse wastewater treatment system

et al. 2022

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Nanostructured crystalline composite (activated carbon) was synthesized from residual ashes of the burning process of the sludge generated in the flotation step of a poultry slaughterhouse and was used for Allura red dye adsorption. The ashes were chemically activated using two types of reagents, H 2 O 2 and H 3 PO 4 , and the structure, morphology, and surface of the adsorbents were characterized by different techniques such as scanning electron microscopy with energy dispersive spectroscopy (SEM/ EDS), N 2 adsorption/desorption isotherms with Brunauer-Emmett-Teller (BET) method and Barret-Joyner-Hallenda (BJH) method, Fourier transform infrared spectroscopy (MID/FTIR), X-ray diffraction (XRD), and the point of zero charge (PZC). The adsorbent synthesized with H 3 PO 4 at 400 ºC displayed the best performance in removing dye molecules in 10 mg.L -1 solution, with a removal rate of approximately 100% when using a concentration of 2 g.L -1 in particle size of 0.42 mm. Besides that, the adsorbent synthesized with H 3 PO 4 had a particle diameter of approximately 15 Å, a size corresponding to the nanometer range, presented a crystallinity structure with well-defined phases such as quartz and the major elements in the composition were carbon and silicon. The surface area of the ashes enlarged from 14.71 to 448.1 m 2 .g -1 when H 3 PO 4 was used as an activator, producing a high-quality adsorbent, with an excellent cost-benefit, being it possible to be produced for a price of 9.35 USD.kg -1 , a price lower than the commercial activated carbon, making it a promising candidate for application in an industrial environment.

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Smart- and Zero-Energy Utilization of Coal Ash from Thermal Power Plants in the Context of Circular Economy and Related to Soil Recovery

Cited by 10 publications

References 28 publications

Quasi Natural Approach for Crystallization of Zeolites from Different Fly Ashes and Their Application as Adsorbent Media for Malachite Green Removal from Polluted Waters

Quasi Natural Approach for Crystallization of Zeolites from Different Fly Ashes and Their Application as Adsorbent Media for Malachite Green Removal from Polluted Waters

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

Production of nanostructured crystalline composite using residual ashes from flocculated sludge burning process in a poultry slaughterhouse wastewater treatment system

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