scholarly journals Studies on the Potential of Nonmodified and Metal Oxide-Modified Coal Fly Ash Zeolites For Adsorption of Heavy Metals and Catalytic Degradation of Organics for Waste Water Recovery

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 778 ◽  
Author(s):  
Silviya Boycheva ◽  
Denitza Zgureva ◽  
Simona Miteva ◽  
Ivan Marinov ◽  
Dominika Behunová ◽  
...  
Keyword(s):  
Fly Ash ◽  
Magnetic Nanoparticles ◽  
Coal Fly Ash ◽  
Surface Characteristics ◽  
Water Recovery ◽  
X Ray Diffraction ◽  
Wet Impregnation ◽  
Impregnation Technique ◽  
Monolayer Adsorption ◽  
Ultrasonic Assisted

A nanocrystalline zeolite of Na-X type (CFAZ) was synthesized by ultrasonic-assisted double stage fusion-hydrothermal alkaline conversion of lignite coal fly ash. Modified CFAZ with magnetic nanoparticles (MNP-CFAZ) was obtained by adding presynthesized magnetic nanoparticles between the synthesis stages. CFAZs loaded by particles of copper (Cu-CFAZ) and cobalt (Co-CFAZ) oxides were prepared by postsynthesis modification of the parent CFAZ, applying a wet impregnation technique. The parent and modified CFAZs were examined for their phase composition by X-ray diffraction, morphology by scanning electron microscopy, and surface characteristics by N2 physisorption. Comparative studies have been carried out on the adsorption capacity of the starting CFAZ and its derivatives with respect to Cd2+- and Pb2+-ions from aqueous solutions. Adsorption isotherms of Cd2+-ions on the studied samples were plotted and described by the adsorption equations of Langmuir, Freundlich, Langmuir–Freundlich, and Temkin. The best correlation between the experimental and model isotherms for the parent and modified CFAZ was found with the Langmuir linear model, assuming a monolayer adsorption mechanism. Parent and modified CFAZs were also studied as catalysts for heterogeneous thermal Fenton oxidation of methylene blue. At 90 °C, the higher catalytic activity exhibits the nonmodified sample, but with the decrease in temperature to 60 °C, the modified samples are more effective catalysts.

scholarly journals Characterization of Fly Ash Generated from Matla Power Station in Mpumalanga, South Africa

2012 ◽  
Vol 9 (4) ◽  
pp. 1788-1795 ◽  
Author(s):  
Olushola S. Ayanda ◽  
Olalekan S. Fatoki ◽  
Folahan A. Adekola ◽  
Bhekumusa J. Ximba
Keyword(s):  
Fly Ash ◽  
Inductively Coupled Plasma ◽  
Coal Fly Ash ◽  
Harmful Effect ◽  
Point Of Zero Charge ◽  
X Ray Diffraction ◽  
Power Station ◽  
X Ray ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

In this study, fly ash was obtained from Matla power station and the physicochemical properties investigated. The fly ash was characterized by x-ray fluorescence, x-ray diffraction, scanning electron microscopy, and inductively coupled plasma mass spectrometry. Surface area, particle size, ash and carbon contents, pH, and point of zero charge were also measured. The results showed that the fly ash is alkaline and consists mainly of mullite (Al6Si2O13) and quartz (SiO2). Highly toxic metals As, Sb, Cd, Cr, and Pb as well as metals that are essential to health in trace amounts were also present. The storage and disposal of coal fly ash can thus lead to the release of leached metals into soils, surface and ground waters, find way into the ecological systems and then cause harmful effect to man and its environments.

scholarly journals Alumina Extraction from Coal Fly Ash via Low-Temperature Potassium Bisulfate Calcination

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 585 ◽  
Author(s):  
Chunbin Guo ◽  
Jingjing Zou ◽  
Shuhua Ma ◽  
Jianlin Yang ◽  
Kehan Wang
Keyword(s):  
Fly Ash ◽  
Low Temperature ◽  
Extraction Efficiency ◽  
Coal Fly Ash ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Increasing Demand ◽  
Technology Effects ◽  
Best Fit

Owing to the depletion of bauxite and increasing demand for alumina, calcination methods for extracting alumina from coal fly ash (CFA) were developed. However, these methods have disadvantages such as the need for high temperatures and the emission of toxic gases. Hence, in this study, Al2O3 was extracted from CFA via low-temperature potassium bisulfate calcination technology. Effects of the potassium bisulfate amount, calcination temperature, and calcination time on the alumina extraction efficiency were investigated using X-ray diffraction, thermal gravimetry, scanning electron microscopy, differential scanning calorimetry, and energy-dispersive spectroscopy. It was found that this technique could recover alumina efficiently, and potassium bisulfate significantly contributed to the degradation of mullite and corundum phases. Al2O3 in CFA was converted into soluble K3Al(SO4)3. With a KHSO4/Al2O3 molar ratio of 7:1, calcining temperature of 230 °C, and calcining time of 3 h, the alumina extraction efficiency reached a maximum of 92.8%. The Avrami–Erofeev equation showed the best fit with the kinetic data for the low-temperature calcination of CFA with KHSO4. The activation energy was 28.36 kJ/mol.

scholarly journals Layer-by-Layer Assembly and Photocatalytic Activity of Titania Nanosheets on Coal Fly Ash Microspheres

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Xing Cui ◽  
Jianwen Shi ◽  
Zhilong Ye ◽  
Zhaoji Zhang ◽  
Bin Xu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Fly Ash ◽  
Coal Fly Ash ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Visible Absorption ◽  
Layer By Layer Assembly ◽  
Decoloration Rate ◽  
Layer Assembly

In order to address the problem with titania distribution and recovery, series of Ti0.91O2/CFA photocatalysts (Ti0.91O2/CFA-n,n=2,4,6,and8) were fabricated by assembling Ti0.91O2nanosheets on coal fly ash (CFA) microspheres via the layer-by-layer assembly (LBLA) process and characterized by scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), N2-sorption, and ultraviolet-visible absorption (UV-vis) techniques. The SEM images and UV-vis spectra illustrated that Ti0.91O2nanosheets were immobilized successfully on the CFA by the LBLA approach and changed the characteristics of CFA noticeably. The photocatalytic activity of Ti0.91O2/CFA was evaluated by the photodegradation of methylene blue (MB) under UV irradiation. The results demonstrated that Ti0.91O2/CFA-6 showed the best photocatalytic activity among the series of Ti0.91O2/CFA irradiated for 60 min, with a decoloration rate above 43%. After photocatalysis, the Ti0.91O2/CFA could be easily separated and recycled from aqueous solution and Ti0.91O2nanosheets were still anchored on the CFA.

Catalytic CO2/H2 Methanation Reaction over Alumina Supported Manganese/Cerium Oxide Based Catalysts

2015 ◽  
Vol 1107 ◽  
pp. 67-72 ◽  
Author(s):  
Salmiah Jamal Mat Rosid ◽  
Wan Azelee Wan Abu Bakar ◽  
Rusmidah Ali
Keyword(s):  
Cerium Oxide ◽  
Supported Catalysts ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Wet Impregnation ◽  
X Ray ◽  
Methanation Reaction ◽  
Calcination Temperatures ◽  
Impregnation Technique ◽  
Scanning Electron

The methanation reaction is a promising method for the purification of natural gas, in which the acid gases of CO2,is eliminated by catalytic conversion. The advantage of catalytic technology is the utilization of CO2present in the production of methane gas. The used of alumina supported cerium oxide as the based catalyst in CO2/H2methanation reaction have been investigated in this research by using manganese as the dopant and ruthenium as the co-dopantviawet impregnation technique. The series of cerium oxide catalysts were calcined at 400 °C for 5 hours had been prepared at the screening stage. Then, the catalysts were optimized by different calcination temperatures and different based oxide loadings. The potential catalysts of Ru/Mn/Ce (5:35:60)/Al2O3calcined at 700 °C gave 100 % of CO2conversion by using FTIR and yielded about 24 % of CH4respectively at reaction temperature of 400 °C. X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) showed that the supported catalysts were amorphous in structure. FESEM analysis illustrated the surface of the catalysts were covered with small and dispersed spherical particles. EDX analysis revealed that there was 1.02 % reduction of Ru in the Ru/Mn/Ce (5:35:60)/Al2O3used catalysts compared to fresh catalysts. Meanwhile NA analysis showed that Ru/Mn/Ce (5:35:60)/Al2O3catalysts attained surface area of 143.10 m2/g respectively.

scholarly journals Removal of Pb(II) from aqueous solutions using Acacia Nilotica seed shell ash supported Ni0.5Zn0.5Fe2O4 magnetic nanoparticles

2016 ◽  
Vol 6 (4) ◽  
pp. 562-573 ◽  
Author(s):  
Farshad Omidvar-Hosseini ◽  
Farid Moeinpour
Keyword(s):  
Magnetic Nanoparticles ◽  
Low Cost ◽  
Acacia Nilotica ◽  
Environmentally Benign ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Monolayer Adsorption ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Acacia Nilotica seed shell ash supported Ni0.5Zn0.5Fe2O4 magnetic nanoparticles were synthesized by a low-cost, simple, and environmentally benign procedure. The adsorbent was characterized by several methods including X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. Then, the potential of Acacia Nilotica seed shell ash supported Ni0.5Zn0.5Fe2O4 magnetic nanoparticles was investigated for adsorption of Pb(II). The effect of different parameters including contact time, pH, adsorbent dosage and initial Pb(II) concentration on the Pb(II) removal yield was studied. The experimental data were fitted well with the pseudo-second order kinetic model (R2 = 0.999). The adsorption isotherm was described well by the Langmuir isotherm (R2 = 0.900) with a maximum monolayer adsorption capacity of 37.6 mg g–1. The process for purifying water treatment presented here is easy using the magnetic nanoparticles. Therefore, this adsorbent was found to be useful and valuable for controlling water pollution due to Pb(II) ions.

scholarly journals Foam Glass Lightened Sorel’s Cement Composites Doped with Coal Fly Ash

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1103
Author(s):  
Adam Pivák ◽  
Milena Pavlíková ◽  
Martina Záleská ◽  
Michal Lojka ◽  
Anna-Marie Lauermannová ◽  
...  
Keyword(s):  
Fly Ash ◽  
Foam Glass ◽  
Coal Fly Ash ◽  
Mechanical Resistance ◽  
Cement Composites ◽  
High Porosity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructural Parameters ◽  
Strength And Stiffness

Lightweight Sorel’s cement composites doped with coal fly ash were produced and tested. Commercially available foam granulate was used as lightening aggregate. For comparison, reference composites made of magnesium oxychloride cement (MOC) and quartz sand were tested as well. The performed experiments included X-ray diffraction, X-ray fluorescence, scanning electron microscopy, light microscopy, and energy dispersive spectroscopy analyses. The macro- and microstructural parameters, mechanical resistance, stiffness, hygric, and thermal parameters of the 28-days matured composites were also researched. The combined use of foam glass and fly ash enabled to get a material of low weight, high porosity, sufficient strength and stiffness, low water imbibition, and greatly improved thermal insulation performance. The developed lightweight composites can be considered as further step in the design and production of alternative and sustainable materials for construction industry.

scholarly journals Morphology and Chemical Composition of Magnetic Particles Separated from Coal Fly Ash

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 528
Author(s):  
Tadeusz Czech
Keyword(s):  
Fly Ash ◽  
Magnetic Particles ◽  
Coal Fly Ash ◽  
X Ray Diffraction ◽  
Coal Seams ◽  
Globular Structure ◽  
Metal Compounds ◽  
X Ray ◽  
Cobalt Nickel ◽  
Energy Disperse Spectroscopy

Iron and other metal compounds are the materials that often appear in coal seams, because they also appear as a component of former organic matter in coal rocks. Although iron is the dominant element in coal rocks, other metals such as titanium, lead, cobalt, nickel, and copper are also present. In this study, the properties of magnetic particles of a size between 1 and 20 µm of globular structure and iron containing, were separated from coal fly ash, and studied using a scanning electron microscopy, energy disperse spectroscopy, and X-ray diffraction spectroscopy. The investigations were comprised of micrographs of the structure of these particles, their elemental composition, and phase analysis.

Characterization of Coal Fly Ash for Use in Synthesis of Zeolites

2018 ◽  
Vol 930 ◽  
pp. 578-583
Author(s):  
Augusto César Cavalcanti Gomes ◽  
Andrea de Vasconcelos Ferraz ◽  
Lucimar Pacheco Gomes da Rocha
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Coal Ash ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inorganic Oxides ◽  
Chemical Treatments ◽  
Xrf Scanning ◽  
The Matrix ◽  
Physical And Chemical

Due to the large quantity of fly ash produced during the combustion of coal, it has become necessary to give greater applicability to this residue of low commercial value. The residue contains inorganic oxides which can act on the crystalline structure of zeolites, namely silicon and aluminum oxide. The coal ash was submitted to physical and chemical treatments with the aim of potentiating the silicon and aluminum extraction from the residue. The pure ash and the treated ashes were characterized by: X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FTIR). By means of the carried out characterizations it was observed that the treatments were effective for the extraction of aluminosilicates from the matrix. The treatments did not affect the morphology, the crystalline phases and neither the chemical composition of the ashes. Seeing this, the coal ash and its treatments showed to be a precursor for the synthesis of zeolites.

Synthesis and Characterization of Cordierite, Mullite and Cordierite-Mullite Ceramic Materials using Coal Fly Ash as Raw Material

MRS Advances ◽  
2017 ◽  
Vol 2 (62) ◽  
pp. 3865-3872
Author(s):  
J. López-Cuevas ◽  
E. Interial-Orejón ◽  
C.A. Gutiérrez-Chavarría ◽  
J.C. Rendón-Ángeles
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Vickers Microhardness ◽  
Coal Fly Ash ◽  
Ceramic Materials ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Mullite Ceramic ◽  
Two Temperatures

AbstractCordierite (Mg2Al4Si5O18), Mullite (Al4+2xSi2-2xO10-x) and Cordierite-Mullite ceramic materials were obtained from a stoichiometric mixture of coal fly ash (CFA) as a source of SiO2 and Al2O3, plus high-purity MgO and Al2O3. The starting stoichiometric mixtures were homogenized, and then uniaxially pressed, cold isostatically pressed, and sintered at 1200-1600 °C for 2-5 h. The sintered materials were characterized by X-ray diffraction, scanning electron microscopy, Vickers microhardness, density and four-point flexural strength. In general, the desired phases tended to form in the composites at temperatures of 1350 or 1400 °C, with a considerable amount of glassy phase developing from 3 h onwards at one of those two temperatures, depending on the composite composition. The microstructure of the composites consisted of a matrix of Cordierite and interwoven needles of Mullite. The bulk density decreased, while the flexural strength and the Vickers microhardness increased with increasing nominal content of Mullite in the composites. A synergistic effect taking place between Cordierite and Mullite enhances the mechanical properties of the composites.

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