Conversion of coal fly ash into nanozeolite Na-X by applying ultrasound assisted hydrothermal and fusion-hydrothermal alkaline activation

Boycheva, Silviya; Marinov, I.; Miteva, Simona; Zgureva, Denitza

doi:10.1016/j.scp.2020.100217

Cited by 30 publications

(36 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Si/Al molar ratio values highly correspond to the results obtained by other researchers [ 18 , 19 ]. Boycheva, with coworkers, determined a similar Si/Al molar ratio (1.37–1.60) for Na-X zeolite synthesized from coal fly ash by hydrothermal reaction and with preliminary fusion step [ 35 ].…”

Section: Resultsmentioning

confidence: 99%

Simultaneous Removal of Pb2+ and Zn2+ Heavy Metals Using Fly Ash Na-X Zeolite and Its Carbon Na-X(C) Composite

et al. 2021

View full text Add to dashboard Cite

Pure zeolite (Na-X) and a zeolite–carbon composite (Na-X(C)) were investigated as adsorbents of heavy metals—Pb2+ and Zn2+ from an aqueous solution. These materials were synthesized from fly ash—a waste from conventional hard coal combustion. Both solids were characterized using XRD, SEM-EDS, nitrogen adsorption/desorption, particle size and elemental composition analyses. The adsorption study was performed at pH 5 in the systems containing one or two adsorbates simultaneously. The obtained results showed that the pure zeolite was characterized by a more developed surface area (728 m2/g) than its carbon composite (272 m2/g), and the mean pore diameters were equal to 1.73 and 2.56 nm, respectively. The pure Na-X zeolite showed better adsorption properties towards heavy metals than its Na-X(C) composite, and Zn2+ adsorbed amounts were significantly higher than the Pb2+ ones (the highest experimental adsorption levels were: for Zn2+—656 and 600 mg/g, and for Pb2+—575 and 314 mg/g, on the Na-X and Na-X(C) surfaces, respectively). The zinc ions are exchanged with the cations inside the zeolite materials structure more effectively than lead ions with a considerably larger size. In the mixed systems, the competition between both heavy metals for access to the active sites on the adsorbent surface leads to the noticeable reduction in their adsorbed amounts. Moreover, the hydrochloric acid was a better desorbing agent for both heavy metals, especially Pb2+ one (desorption reached 78%), than sodium base (maximal desorption 25%).

show abstract

Section: Resultsmentioning

confidence: 99%

Simultaneous Removal of Pb2+ and Zn2+ Heavy Metals Using Fly Ash Na-X Zeolite and Its Carbon Na-X(C) Composite

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The technological stages of the three approaches are presented in Figure 1. The thermal conditions and alkalinity reported here are optimal for processing of Faujasite zeolite type (FAU; Na-X) [20]. However, different zeolite phases can be achieved by varying the temperature and duration of the hydrothermal activation, the type of the alkaline activator and its ratio against the CFA amount [10].…”

Section: Processing Of Coal Ash Zeolite Nanocompositesmentioning

confidence: 97%

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

et al. 2020

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…The XRD lines of the clay have a low intensity, indicating a low proportion of the identified clay minerals. For the synthesis, the alkaline fusion method recommended by various authors was used to obtain zeolites from clays, porcelain, and ashes (Ayele et al, 2016;Bai, Zha, Chang, Zhang, and Chu, 2018;Kongnoo, Tontisirin, Worathanakul, and Phalakornkule, 2017;Ke, Shen, and Yang, 2019;Boycheva, 2020;Wajima and Ikegami, 2009). It was possible to zeolitize the clay through the applied method, since the synthesis product has the characteristic XRD pattern of the Faujasite structure (Figure 2), without the presence of lines corresponding to other crystalline phases (Treacy and Higgins, 2001).…”

Section: Characterization Of Clay and Synthesized Zeolitementioning

confidence: 99%

Removal of Pb(II) in Aqueous Solutions Using Synthesized Zeolite X from Ecuadorian Clay

et al. 2021

View full text Add to dashboard Cite

Zeolite X was synthesized from clay using the alkaline fusion method and hydrothermal treatment to remove Pb(II) in aqueous solutions. Clay and zeolite were characterized through X-ray diffraction and fluorescence (XRD, FRX), as well as through specific surface area (SSA). The adsorbents were prepared as cylindrical extrudates using clay and a clay-zeolite combination (60-40%, respectively). The effects of pH, isotherm, and adsorption kinetics on the removal of Pb(II) in solutions of 80 mg Pb(II)/L were studied. It was possible to obtain a zeolite X from clay, with an SSA of 376 m2/g, 30 times greater than that of clay (12 m2/g). In the combined extrudate was present the zeolitic structure, with an SSA 12 times higher compared to the clay extrudate. The adsorption capacity, at 30 °C and V/m ratio of 1 g/L, is almost double compared to the clay extrudate (24 mg Pb(II)/g vs. 13 mg Pb(II)/g). Adsorption follows second order kinetics, and the Langmuir isotherm equation showed a good fit with the experimental equilibrium data for the two extrudates. The Webber-Morris and Bangham-Burt’s models suggest that pore and film diffusion influence the kinetic mechanism.

show abstract

Conversion of coal fly ash into nanozeolite Na-X by applying ultrasound assisted hydrothermal and fusion-hydrothermal alkaline activation

Cited by 30 publications

References 24 publications

Simultaneous Removal of Pb2+ and Zn2+ Heavy Metals Using Fly Ash Na-X Zeolite and Its Carbon Na-X(C) Composite

Simultaneous Removal of Pb2+ and Zn2+ Heavy Metals Using Fly Ash Na-X Zeolite and Its Carbon Na-X(C) Composite

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

Removal of Pb(II) in Aqueous Solutions Using Synthesized Zeolite X from Ecuadorian Clay

Contact Info

Product

Resources

About