scholarly journals Utilization of Coal Fly Ash and Rice Hull Ash as Geopolymer Matrix-cum-Metal Dopant Applied to Visible-Light-Active Nanotitania Photocatalyst System for Degradation of Dye in Wastewater

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 240 ◽  
Author(s):  
Eiza Shimizu ◽  
Michael Angelo Promentilla ◽  
Derrick Ethelbhert Yu
Keyword(s):  
Fly Ash ◽  
Visible Light ◽  
Dye Degradation ◽  
Coal Fly Ash ◽  
Rice Hull ◽  
Rice Hull Ash ◽  
Waste Products ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Visible Light Active

Geopolymer (GP) spheres made from coal fly ash (FA) and rice hull ash (RHA) waste products are utilized as both support matrix and dopant applied to titania (TiO2) photocatalyst for organic dye degradation in wastewater. Processing of FA and RHA via suspension-solidification method resulted in GP spheres with nanoporous morphology. The nanocrevices enabled low-energy sol-gel TiO2 coating technique because they served as anchoring sites on the geopolymer surface that favored rigidity and larger surface area. The GP-TiO2 system has been characterized by infrared spectroscopy, X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. Diffuse reflectance spectroscopy revealed a narrowing of the GP-TiO2 system optical band gap due to the interaction of metal dopants contained in RHA and FA with TiO2, thus making the GP-TiO2 system a visible-light-active photocatalyst, as confirmed by methylene blue dye degradation measured through UV-Vis spectroscopy.

scholarly journals Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash

Materials ◽  
2016 ◽  
Vol 9 (7) ◽  
pp. 580 ◽  
Author(s):  
Martin Kalaw ◽  
Alvin Culaba ◽  
Hirofumi Hinode ◽  
Winarto Kurniawan ◽  
Susan Gallardo ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Rice Hull ◽  
Ternary Blend ◽  
Rice Hull Ash ◽  
Coal Bottom Ash

HIGHLY CATALYTIC Ag/Co3O4 NANOCATALYSTS FABRICATED FOR RhB DYE DEGRADATION THROUGH A SIMPLE SILVER-MIRROR REACTION UNDER VISIBLE LIGHT

NANO ◽  
2014 ◽  
Vol 09 (08) ◽  
pp. 1450090 ◽  
Author(s):  
XIAOLEI SI ◽  
GUANGLIANG CHEN ◽  
ZHILI CHEN ◽  
JUN HUANG ◽  
SHIHUA CHEN ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Ag Nanoparticles ◽  
Dye Degradation ◽  
Precipitation Method ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Silver Mirror ◽  
Silver Mirror Reaction

In this paper, a highly catalytic and nanosized Ag / Co 3 O 4 composite for rhodamine B ( RhB ) degradation was fabricated by using the co-precipitation method at room temperature. The Ag / Co 3 O 4 structure and catalytic properties were characterized through scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) gas-sorption measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy. The results showed that the Co 3 O 4 nanosheets prepared by hydrothermal synthesis mainly exposed (2 2 0) and (1 1 1) facets, which played an important role in determining its catalytic oxidation performance. The Co 3 O 4 nanosheets doped with Ag nanoparticles by a simple silver-mirror reaction exhibited a stable and well-dispersed property in dye solution. Compared to the Ag and Co 3 O 4 nanostructure, the Ag nanoparticles with bigger diameter (10 nm) on Co 3 O 4 surface also readily produced surface-active oxygen species and exhibited a higher catalytic activity for the degradation of RhB solution (5 mg ⋅ L-1) under the visible light. The kinetic constant K of Ag / Co 3 O 4 catalyst for RhB degradation reaction was evaluated to 0.02724 min-1, which is relatively higher than those reported in the literatures.

Green synthesized Ag-TiO2 for degradation of organic dye through visible light driven photo-reactor and its kinetics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Titikshya Mohapatra ◽  
Sakshi Manekar ◽  
Vijyendra Kumar Sahu ◽  
Ashwini Kumar Soni ◽  
Sudip Banerjee ◽  
...  
Keyword(s):  
Visible Light ◽  
Mangifera Indica ◽  
Band Gap Energy ◽  
Photo Degradation ◽  
X Ray ◽  
Green Approach ◽  
Vis Spectroscopy ◽  
Rate Of Reaction ◽  
Visible Light Driven ◽  
Modification Of Titanium

Abstract This study reports a green approach for the modification of titanium dioxide (TiO2) nanoparticles with immobilization of silver nanoparticles. One of the natural sources i.e., Mangifera indica leaf extract was utilized as reducing and capping agent for the fabrication of Ag-TiO2 nanocatalyst. Further, the surface morphology and band-gap energy of prepared Ag-TiO2 were analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and UV–Vis spectroscopy. Also, it was characterized by X-ray Powder Diffraction (XRD) which provides the information regarding the crystallinity of the Ag-TiO2. Subsequently, photo activity of Ag-TiO2 was investigated for the degradation of methylene blue (MB) dye wastewater through visible light driven photoreactor. The Ag-TiO2 provided highest (68%) of photo-degradation efficiency within 110 min for 7.81 × 10−5 mol/L initial MB concentration at pH 8 by using 0.19 g/L photocatalyst. Further, addition of 10 mM H2O2 boost up the MB photodegradation to 74%. The kinetic study confirmed the MB degradation followed first order rate of reaction.

scholarly journals Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1267
Author(s):  
David Längauer ◽  
Vladimír Čablík ◽  
Slavomír Hredzák ◽  
Anton Zubrik ◽  
Marek Matik ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Product Analysis ◽  
Coal Combustion Products ◽  
X Ray ◽  
Wide Range ◽  
Silica Alumina

Large amounts of coal combustion products (as solid products of thermal power plants) with different chemical and physical properties cause serious environmental problems. Even though coal fly ash is a coal combustion product, it has a wide range of applications (e.g., in construction, metallurgy, chemical production, reclamation etc.). One of its potential uses is in zeolitization to obtain a higher added value of the product. The aim of this paper is to produce a material with sufficient textural properties used, for example, for environmental purposes (an adsorbent) and/or storage material. In practice, the coal fly ash (No. 1 and No. 2) from Czech power plants was firstly characterized in detail (X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), particle size measurement, and textural analysis), and then it was hydrothermally treated to synthetize zeolites. Different concentrations of NaOH, LiCl, Al2O3, and aqueous glass; different temperature effects (90–120 °C); and different process lengths (6–48 h) were studied. Furthermore, most of the experiments were supplemented with a crystallization phase that was run for 16 h at 50 °C. After qualitative product analysis (SEM-EDX, XRD, and textural analytics), quantitative XRD evaluation with an internal standard was used for zeolitization process evaluation. Sodalite (SOD), phillipsite (PHI), chabazite (CHA), faujasite-Na (FAU-Na), and faujasite-Ca (FAU-Ca) were obtained as the zeolite phases. The content of these zeolite phases ranged from 2.09 to 43.79%. The best conditions for the zeolite phase formation were as follows: 4 M NaOH, 4 mL 10% LiCl, liquid/solid ratio of 30:1, silica/alumina ratio change from 2:1 to 1:1, temperature of 120 °C, process time of 24 h, and a crystallization phase for 16 h at 50 °C.

Photocatalytic Degradation of Methylene Blue over Co-Ag3VO4 under Visible Light Irradiation

2011 ◽  
Vol 335-336 ◽  
pp. 1385-1390 ◽  
Author(s):  
Shuo Wiei Zhao ◽  
Hui Xu ◽  
Hua Ming Li ◽  
Yuan Guo Xu
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Absorption Edge ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Light Irradiation ◽  
Experimental Conditions ◽  
X Ray

In order to improve the photocatalytic activity, Co was successfully loaded into Ag3VO4 by using impregnation process. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectroscopy (DRS). The XRD and SEM–EDS analyses revealed that Co ion was dispersed on Ag3VO4. The DRS results indicated that the absorption edge of the Co–Ag3VO4 catalyst shifted to longer wavelength. The enhanced photocatalytic activity of Co–Ag3VO4 for Methylene Blue(MB) dye degradation under visible light irradiation was due to its wider absorption edge and higher separation rate of photo-generated electron and holes. In the experimental conditions, it is demonstrated that the MB was effectively degraded by more than 95% within 40 min when the Co–Ag3VO4 catalyst was calcined at 300°C with 1 wt.% Co content.

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.

Total reflection X-ray fluorescence analysis of fly ash from Bulgarian coal-fired power plants

2015 ◽  
Vol 69 (5) ◽  
Author(s):  
Albena K. Detcheva ◽  
Svilen E. Mitsiev ◽  
Paunka S. Vassileva ◽  
Juri H. Jordanov ◽  
Metody G. Karadjov ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Internal Standard ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
X Ray

AbstractThe contents of Cl, Ca, K, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Ba and Pb in raw coal fly ash from five Bulgarian power plants were determined by total reflection X-ray fluorescence (TXRF), using gallium as the internal standard. The samples were analysed as in slurry form in Triton

Photocatalytic Activity of CuO/ZnO Heterostructure Nanocrystals under UV-Visible Light Irradiation

2014 ◽  
Vol 787 ◽  
pp. 35-40 ◽  
Author(s):  
Xiao Yan Zhou ◽  
Peng Wei Zhou ◽  
Hao Guo ◽  
Bo Yang ◽  
Ru Fei Ren
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Cuo Nanoparticles ◽  
Light Irradiation ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Uv Visible

The p-n junction photocatalysts, p-CuO (at. 0-25%)/n-ZnO nanocomposite were prepared through hydrothermal method without using any organic solvent or surfactant. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-Ray spectroscopy, and UV-vis spectroscopy. The results demonstrated that the CuO/ZnO nanocomposite presented a two-dimensional morphology composed of sheet-like ZnO nanostructures adorned with CuO nanoparticles. The photocatalytic activity of CuO/ZnO with different Cu/Zn molar rations and pure ZnO synthesized by the identical synthetic route were evaluated by degrading methylene blue (MB) dye under UV-visible light irradiation. The CuO/ZnO with Cu/Zn molar ratio of 4% exhibits the highest photocatalytic activity compared that of the other photocatalysts under the identical conditions. It is mainly attributed to the increased charge separation rate in the nanocomposite and the extended photo-responding range.

Visible Light Active Nanocomposites for Photocatalytic Applications

2021 ◽  
pp. 709-729
Author(s):  
Rohini Singh ◽  
Suman Dutta
Keyword(s):  
Visible Light ◽  
Industrial Development ◽  
Hydrogen Generation ◽  
Dye Degradation ◽  
Industrial Effluents ◽  
High Energy ◽  
Effluent Treatment ◽  
Photocatalytic Hydrogen Generation ◽  
Visible Light Active ◽  
Alternative Sources

This chapter explores the concept of visible light active nanocomposites for the enhanced photocatalytic hydrogen generation and dye degradation. Since the late 1960s, A. Fujishima has been involved in unfolding the fascinating characteristics of titanium dioxide (TiO2) as semiconductor oxide. The increased growth in population and industrial development has tremendously increased the generation of waste products and consumption of energy worldwide. This situation creates an immense need of clean and sustainable alternative sources of energy. Hydrogen, having a high energy capacity, is considered as a reliable fuel for the future energy requirements. In addition to that, due to the rapid industrialisation, our water is being contaminated with various harmful industrial effluents. This chapter illustrates the significance of visible light nanocomposites for the photocatalytic application of hydrogen generation for future energy security and dye degradation for the effective effluent treatment of textile industries.

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