Modification Of Fly Ash Research Articles

Synergistic removal of Hg0, HCl, and SO2 from flue gas in municipal solid waste incineration by mechanically modified fly ash.

The emissions of flue gas components (such as Hg0, SO2, HCl) and the generation of hazardous waste fly ash from municipal waste incineration pose a significant threat to environmental integrity. In this study, a mechanochemical method combined with a modifier is innovatively proposed for the modification of fly ash to remove Hg0. In the fixed bed adsorption experiment, the removal efficiency of up to 60 percent can be achieved by ball milling (700rap,30min) alone. The modification of fly ash by mechanical force coupling with pyrite can achieve Hg0 removal efficiency is increased to more than 90 percent. By taking advantage of the excellent adsorption capacity of modified fly ash for acidic gases, the enhancement of S and Cl∗ active sites on the surface of modified fly ash strengthened the removal efficiency of modified fly ash for Hg0. DFT simulations evidenced that the defective S sites caused by the ball milling process could enhance the adsorption capacity of pyrite for Hg0. The fly ash was modified with mechanically coupled pyrite and alkalis and was able to have good adsorption capacity for acidic gases, the highest removal effect reached 93.1% and 96.7% for SO2 and HCl, respectively. The adsorbed acid gases increased the S and Cl∗ active sites, which led to the removal of Hg0 from the modified fly ash to more than 94.4%, achieving the synergistic removal of acid gases and Hg0. This method can realize the integrated technical route of "Fly ash collection - Online modification - Timely injection". A novel investigation was conducted on the elimination of flue gas contaminants and the reutilization of perilous fly ash.

Stabilization of Pb/Zn mine tailings by modified fly ash: characterization, performance, and mechanism.

The presence of heavy metals in mine tailings poses a serious threat to the surrounding environment. In this study, we aimed to stabilize Pb/Zn-containing mine tailings using modified fly ash (FA) with various alkali solutions. Notably, the modification of FA with Na2SiO3 (NaSi-FA) resulted in the most significant structure changes. To understand the adsorption mechanism of Pb and Zn by modified FA, batch adsorption experiments were conducted. Doubling the adsorption capacity for both Pb and Zn was observed in the modified FA samples compared to unmodified samples. These results could be attributed to the enhanced surface area and porous structure, providing more anchor sites for the heavy metal ions. Additionally, the adsorption of Pb and Zn was found to follow the Langmuir isotherm and pseudo-second order kinetic. Molecular dynamics simulations further supported the notion that Pb and Zn ions could effectively exchange with Na ions within the N-A-S-H gel network, ultimately solidifying them in its structure. Stabilizing Pb/Zn tailings with NaSi-FA resulted in a significant decrease in the leaching of Pb and Zn. Specifically, the leading amount decreased by 55.2% for Pb and 35.3% for Zn, showcasing the superior performance of this stabilization method. This reduction in leaching indicates effective compliance with environmental regulations regarding the containment of Pb and Zn.

Denitration performance and mechanism of Mn-Ce supported alkali-modified fly ash catalysts for NH3-SCR

Ultrasonic impregnation method was used to prepare Mn-Ce composite catalysts with fly ash and alkali-modified fly ash serving as the catalytic carriers. The effects on the denitration activity and resistance of H2O and SO2 were studied. The structural characteristics of the catalysts were characterized and analyzed by XRD, XPS, SEM, TEM, TG, BET, and TPD/TPR. The results revealed that the active components Mn-Ce exhibited interaction, leading to a catalyst surface enriched with Mn4+, Ce3+, and chemisorption oxygen, thereby improving the catalytic activity. Through the alkali modification of fly ash, the structural properties of the carrier were changed, the distribution of active components was more uniform and the optimal loading capacity was increased. Alkali modified fly ash loaded with Mn and Ce had excellent surface acidity, redox characteristics, and abundant chemisorption oxygen, thereby enhancing the “rapid NH3-SCR” reaction. Finally, the catalytic resistance of H2O and SO2 was also excellent.

Preparation and thermal properties of phase change energy storage composite material based on modified fly ash

Fly ash (FA) is a kind of porous solid waste from coal-fired power plant, It is nominated as adsorption carrier for solid-liquid phase change material (PCM), While shape-stabilized composite phase change materials (SSCPCM) prepared directly has low thermal performance due to limited adsorption capacity of FA. Therefore, modification methods have become increasingly attractive, and four modification methods were investigated to improve the adsorption capacity of FA. Modification treatment experiment proved that the surface structure of FA is significantly corroded. Test analysis displays that the surface microspheres in FA have abundant particles and pores by destroying the Si–O–Si and Si–O–Al network structures. The mass ratio of Al/Si increased from 0.59 to 0.726, and the specific surface area of FA has been greatly increased. Experimental results indicate that alkali modification followed by high-temperature calcination is the desirable process for FA. For obtaining high thermal performance materials, two kinds of SSCPCM were prepared according to the mass ratio of 65:35 by vacuum adsorption while Alkali modified FA serves as carrier, binary eutectic of lauric acid-stearic acid (LA-SA) and lauric acid-myristic acid (LA-MA) serves as PCM respectively. The LA-SA/AFA-OH (NaOH alkali leaching treatment for FA) and LA-MA/AFA-OH (NaOH alkali leaching treatment for FA) could reach 54.49 J/g and 47.15 J/g and the phase transition temperature (PTT) is 37.45 °C and 32.36 °C, respectively. The SSCPCM has good thermal, chemical and morphological stability over 500 thermal cycles, while the LA-MA/AFA-OH had higher stability and less thermal performance slightly. Research finding provide a feasible process for composite modification of FA, and application scope is extended due to high thermal performance of composites.

Study on the modification of fly ash from domestic waste incineration and its adsorption performance on Pb2+

Study on the modification of fly ash from domestic waste incineration and its adsorption performance on Pb2+

Incorporation of Fly Ash in Flame-Retardant Systems of Biopolyesters.

The incorporation of fly ash in polybutyl succinate (PBS) and polybutyl adipate terephtalate (PBAT) in the partial replacement of ammonium polyphosphate and/or melamine polyphosphate is evaluated in the present work. Furthermore, the influence of the surface modification of fly ash with two silanes and titanate coupling agents was also studied. Cone calorimeter experiments, pyrolysis combustion flow calorimeters (PCFCs), and UL94V tests were used to assess the fire performance of the composites. Scanning electronic microscopy, X-microanalysis, and X-ray diffractometry analysis were carried out on cone calorimeter residues in order to access the fire-retardant mode of action. The formation of new components due to the presence of fly ash was highlighted by X-ray diffractometry, indicating the synergistic effects between the flame-retardant system and fly ash. The X-microanalysis results showed that the main fraction of initial phosphorous is present in the cone calorimeter residue, indicating that the proposed system acts in a condensed phase.

Study on the modification of fly ash as a coagulant

This study was carried out to produce a complex coagulant containing aluminum and iron salt from coal fly ash by H2SO4 acid. An application of this extracted solution as a coagulant was also investigated by the jar-test process. Fly ash collected at the Electrostatic precipitation (ESP) system in Mong Duong thermal power plant are mainly round and fine particles with diameters ranging from 0.2-8 μm, containing aluminum and iron of 15 and 6% respectively. At a room temperature of 25oC, with 1 M H2SO4 acid solution and the retention time of 20 minutes, the maximum contents of around 60.16 mg.l-1 of Fe and 4.37 mg.l-1 of Al were the most favorable to convert aluminum and iron from mineral forms to sulfate salt-based forms. The produced complex coagulants from fly ash of the Mong Duong power plant are proved to be effective for total suspended solids (TSS) removal from wastewater where the highest efficiency achieved 83.6% at the coagulant solution ratio of 5% (w/w) with a concentration of TSS in the initial wastewater was 60 g.l-1. The positive results from this study open a meaningful approach toward a huge of fly ash produced from thermal power plants as well as other coal-burn-related activities in Vietnam.

Facile surface modification of fly ash to obtain flexible cellulose composite dielectric films with enhanced breakdown strength and energy storage density

Facile surface modification of fly ash to obtain flexible cellulose composite dielectric films with enhanced breakdown strength and energy storage density

Surface modification of fly ash by waste engine oil under mechanical activation enhanced the sustainable service life of asphalt

Oxidative aging of asphalt leads to changes in its molecular structure and chemical composition, deteriorating the properties. Therefore, extending the service life of asphalt materials is essential for environmental protection and sustainable development. In this study, waste engine oil (WEO) with similar components and chemical composition to asphalt was used to modify the fly ash (FA) surface by a high-energy ball grinding process to produce a well-compatible compound fly ash modifier (CFAM). This process achieved ultra-refinement and surface modification in one step, enhancing the chemical bonding and anchoring force between FA and asphalt, thereby effecting the ageing resistance of the asphalt. Dynamic light scattering tests showed that the oil grinding process enhanced the stability of CFAM, whose median particle size (654 nm) increased by only 103 nm after four months of storage. Thermogravimetric (TG), BET tests showed that the FA surface was grafted with a large amount of WEO, and the CFAM after de-oiling and rinsing had a WEO content of 1.39 wt%, which gave it excellent compatibility with asphalt. The nano-indentation and Fourier transform infrared spectroscopy (FTIR) experiments showed that CFAM reduced the changes in micro hardness, modulus of elasticity, carbonyl content and sulfoxide group content of asphalt before and after ageing and provided an excellent anti-ageing effect. The oil grinding process activated the reactivity of the FA that could chemically bond with the carboxylic acids in the asphalt, stabilizing the chemical components of the asphalt and delaying the ageing of the asphalt, thus achieving sustainable service of the asphalt.

Utilization of KOH-modified fly ash for elimination from aqueous solutions of potentially toxic metal ions

Long-term accumulation of toxic heavy metals in the environment was a potential hidden danger. High energy consumption, complicated operation and low adsorption capacity were the disadvantages of most current adsorbents. This study used one-step modification of fly ash (FA) by low-temperature melting method with KOH as the activator to generate modified fly ash (KFA) with high adsorption capacity to remove heavy metals from aqueous solutions. Various characterization results revealed a destruction that occurred on the surface structure of adsorbent, 12 times increase in specific surface area, and metal ions were successfully adsorbed onto KFA surface. Furthermore, adsorption proceeded most favorably at pH of 5, the presence of ionic strength and co-existing cations significantly influenced the adsorption effects. The description of adsorption data was more suitable by pseudo-second-order kinetics and Langmuir isotherm models. And in single system at 25 °C, for Pb(II), Cu(II), and Cd (II), the qm were 337.41, 310.09 and 125.00 mg·g−1. However, in ternary system, the qm decreased for all three ions in the order Pb(II) > Cu(II) > Cd(II), which was different from the law in single system, and the Pb(II) adsorption was found to have a significant inhibited effect on adsorption of Cd(II) and Cu(II). The adsorption mechanisms including ion exchange, electrostatic attraction and complexation were revealed. And by exploring the bioaccessibility of absorbed heavy metals in four simulated digestive fluids, it was found that KFA could load heavy metal ions and enable their release in organisms and other aquatic environments, which provided the possibility for subsequent related studies. Therefore, KFA with low energy consumption and high adsorption capacity is equipped a prospective development space on removing heavy metals from wastewater.

Adsorption of cationic and anionic dyes on photocatalytic flyash/TiO2 modified chitosan biopolymer composite

This study evaluated the performance of TiO2 loaded flyash chitosan composite for the adsorption of anionic dye (congo red-CR) and catatonic dye (methylene blue-MB) dyes. Flyash was modified using HNO3 and H2SO4 to increase its surface area. The flyash and composites were characterized using morphological (scanning electron microscopy; Brunauer, Emmett and Teller surface area), spectral (Fourier-transform infrared; X-ray diffraction) and thermogravimetric techniques. The morphological analysis of the composite adsorbent revealed an irregular and rough surface, providing more adsorption sites for dye adsorption. The acid-activated adsorbents showed higher adsorption for CR than MB dye. For CR dye, the removal efficiencies were 98 %, 97 %, and 90 % for composite adsorbents MFA-1 (H2SO4 modified), MFA-2 (HNO3 modified), and UFA (raw flyash), respectively. For MB dye, the removal efficiencies were 60 %, 58 %, and 50 % for composite adsorbents MFA-1, MFA-2, and UFA, respectively. The maximum adsorption capacities of 163.51, 160.55 and 154.21 mg g−1 for MFA-1, MFA-2 and UFA, respectively, were observed for the CR dye. While for the MB dye, the maximum adsorption capacities of 55.75, 52.64 and 35.09 mg g−1 for MFA-1, MFA-2 and UFA, respectively. The improvement of dye removal on acid composites than unmodified flys ash compsitewas credited to the increased active sites due to acid modification of fly ash. The PSO kinetic model and Langmuir adsorption isotherms were the best fit for the experimental results. The incorporation of TiO2 inculcated photocatalytic regeneration ability in the composite adsorbents. This allowed the adsorbent to be utilized in several cycles without thermal or chemical treatment. This study concluded that the proposed adsorbent could be an effective solution for textile industry wastewater treatment.

The selective adsorption of rare earth elements by modified coal fly ash based SBA-15

The modification of fly ash based SBA-15 enables the selective adsorption of REE(III) with a high capacity. • The species distribution of rare earth elements ions was simulated. • DTPADA-SBA-15 owned high adsorption efficiency and selectivity for REE (III). • DTPADA-SBA-15 owned preferable reusability in acidic solution. Rare earth elements (REE) are strategic resources and the recycling of REE in alternative resources is urgent and gets increasingly attention. However, the separation of REE in these alternative resources is still a challenge due to the low concentration of REE and multi coexisted ions in acidic system. In this study, the species distribution of REE within the pH 0–8.0 was calculated. The SBA-15 originated from coal fly ash was modified by two steps with (3-aminopropyl) triethoxysilane (APTES) and diethylenetriaminepentaacetic dianhydride (DTPADA) to obtain DTPADA-SBA-15 adsorbent, which was applied to the selective adsorption of REE. The results showed that DTPADA-SBA-15 possessed excellent adsorption performance on the selective adsorption of REE, including Eu, Gd, Tb, Nd and Sm, in acidic solution (pH 2) with multi competing ions. The FT-IR and Zeta potential characterization verified that the chemical adsorption through the coordination of O in DTPADA-SBA-15 with REE was dominant at lower pH value. The study of adsorption kinetics indicated that the adsorption of rare earth metal ions followed pseudo-second-order kinetic, of which the adsorption process followed the Langmuir isotherm model.

Microstructure of gamma-ray developed polymeric nanocomposite respecting cesium and cobalt removal from aqueous solutions

The nanoparticles of fly ash (FA) were obtained by high energy ball milling of their parent Class C kind for subsequent synthesis of poly(acrylamide-acrylic acid)/fly ash (poly(AM-AA)/FA) nanocomposite. The gamma-radiation induced polymerization was applied to achieve this concern. Different techniques were utilized to characterize such nanocomposite. The sorption abilities of the synthesized nanocomposite toward 60Co2+ and 134Cs + radionuclides were evaluated using batch and fixed-bed column approaches. Batches were designed at constants of solution pH (6.5–7.0 ± 0.02), nanocomposite particle size and dosage (106–250 μm and 0.1 L/g, respectively). The microstructure of such nanocomposite (<100 nm) was mainly amorphous with porous rough surfaces containing homogenous distribution of the incorporated nano-FA. About 56.46 and 47.9 mg/g of Co2+ and Cs+ were sorbed at equilibrium with an ion exchange reaction mechanism. Langmuir, Freundlich and Dubinin–Radushkevich D–R isotherm model parameters were calculated indicating the favorability of all sorption processes. The spontaneous and endothermic natures of sorption were observed by the calculated ΔG° and ΔH° thermodynamic parameters, respectively. Thomas, Yoon–Nelson and Adams Bohart models were fitted to the fixed-bed column data at varied conditions. The predicted sorption capacities of Thomas were very close to those obtained experimentally. Modeling of the fixed-bed column data dominates that the external mass transfer kinetics was predominant in the initial parts of the fixed-beds. Values required for retaining 50% of the initial sorbate concentration were extended from 89.05 to 68.55 to 177.2 and 149.3 min for 60Co2+ and 134Cs + radionuclides, respectively, by increasing bed depth from 1.5 to 3.0 cm. Modification of FA to its nano-scale form with the subsequent synthesis of a nanocomposite material having sorption capabilities made a duplicate beneficial environmental concern.

Study on immobilization of nitrogen and phosphorus in sediments using modified fly ash composite material

Abstract In this paper, a new type of particle-modified fly ash composite material was prepared using fly ash as the main raw material, which could immobilize nitrogen and phosphorus pollutants in sediment and control its release into water. Preliminary modification of fly ash was achieved by soaking in NaOH and calcining at high temperature of CaO. The modified fly ash was mixed with four auxiliary materials, namely cement, slag, water glass and quartz sand, and was formed after 14 days of curing. X-ray diffraction (XRD) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS) were used to examine the material microstructure, element composition, crystal mineral changes, and also to further examine the physical indicators and mechanical properties of the material. In the end, we chose to use modified fly ash composite 10% cement to make granular modified fly ash composite materials. Taking the actual polluted river sediment as the research object, a 22-day coverage effect experiment was carried out, and it was finally found that the 2 cm-thick modified fly ash composite material cover layer inhibited the ammonia nitrogen (NH4+-N)、total nitrogen (TN) and total phosphorus (TP) of the sediments at 90.91%, 75.06% and 90.63%, respectively. This confirms that it is a material with good performance and practical application value.

Upotreba letećeg pepela za adsorpciju flourida

The suitable characteristics of fly ash from thermal power plants make it a proper adsorbent for removing various pollutants from water and aqueous solutions. Valorization and utilization of fly ash can reduce the use of conventional adsorbents. The paper presents an overview of the possibility of using raw and modified fly ash to remove fluorides from water and aqueous solutions, as well as the influence of different process parameters (sorbent dose, contact time, pH value, temperature, etc.) on the value of adsorption capacity and adsorption efficiency of used sorbent. Fly ash can be used as an effective sorbent for the removal of fluoride, both in raw and modified form, with given optimal process parameters. Raw fly ash shows better adsorption properties when performing the experiment in a column, with a higher dose of sorbent and longer contact time, in an acidic environment (pH = 2-3), compared to batch experiments. Various authors have modified fly ash by treatment with certain chemical agents (HCl, Ca (OH)2…) or by synthesis of zeolite based on fly ash. Modification of fly ash improves its adsorption properties, so in slightly acidic conditions (pH = 6), for a relatively short contact time (10-30 min), in batch conditions, significant adsorption efficiency (~ 90%) can be achieved.

Low cost, eco-friendly, modified fly ash-based shape-stabilized phase change material with enhanced thermal storage capacity and heat transfer efficiency for thermal energy storage

Owing to the high thermal capacity and nearly constant temperature during phase change, phase change material has been considered one of the most promising solar thermal energy storage materials. However, the development of high-performance shape-stabilized phase change material (SSPCM) based on a low-cost and eco-friendly supporting material remains a big challenge. Herein, a systematic experimental framework is proposed and used to respond to the challenge. By applying this framework, acid-modified fly ash (AMFA) was firstly used as the supporting material for lauric acid (LA) to prevent its leakage, while carbon nanotubes (CNTs) were utilized to improve its thermal conductivity. Specifically, the LA/AMFA/CNTs composites were synthesized via a facile and low-cost direct impregnation method. Subsequently, the as-prepared composites were systematically investigated by various characterization techniques. The results of leakage tests exhibited that the acid treatment could improve the PCM loading of fly ash and the relevant mechanism of acid-modified fly ash was identified. With the introduction of CNTs, the heat transfer efficiency of LA/AMFA/CNTs had been enhanced substantially. More importantly, compared with conventional supporting materials, the used fly ash in this work revealed much better environmental sustainability which we believe is of vital importance for the large-scale application of SSPCMs. Therefore, the study results not only facilitate the development of the desirable SSPCM based on cheap and eco-friendly supporting material and promote its practical application, but also serve to improve the comprehensive utilization level of fly ash solid waste. • Acid modification of fly ash was carried out to improve the latent heat of the SSPCM. • Mechanism of the latent heat enhancement was in-depth analyzed. • Heat transfer enhancement mechanism of the SSPCM was provided. • Sustainable assessment of the prepared SSPCM was performed.

Significant enhancement of VOCs conversion by facile mechanochemistry coupled MnO2 modified fly ash: Mechanism and application

In this work, the modification of fly ash with mechanochemical coupled MnO2 was presented by balling milling to enhance its activity for volatile organic compounds (VOCs) oxidation. This simple processing significantly improved the toluene conversion, from 5% (untreated fly ash) to over 90% with the carbon balance efficiency over 94%. Microscopic characterization showed that ball milling increased the specific surface area of fly ash and the dispersion of MnO2 into the fly ash, both favoring the adsorption and oxidation of toluene. In addition, a two-stage reaction mechanism is proposed for the oxidation of toluene at the surface of modified fly ash. Based on the analysis of the valence state and reduction ability of MnO2, the reduction of MnO2 dominates the first stage to generate Mn2O3, which further oxidizes adsorbed toluene in the second stage. Furthermore, the outlet of the selective catalytic reduction (SCR) system was determined as the best location for injection of the modification fly ash for suitable temperature (around 300 °C). The results demonstrated the great potential of the MnO2-modified fly ash as a low-cost, highly active, and fully up-scalable material for VOCs conversion. More importantly, the simplicity and environmental-friendly nature of the presented modification is highly compatible with the fly ash injection system in coal-fired power plants.

Synergetic influence between adsorption and photodegradation of Rhodamine B using synthesized fly ash based inorganic polymer

Modification of fly ash using alkaline activator medium was implemented to develop fly ash-based inorganic polymer composite as an adsorbent and catalyst. The Physico-chemical properties of prepared material were characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersive X-ray (SEM/EDX), Transmission Electron Microscopy (TEM), Brunauer–Emmett–Teller (BET), Particle Size Analyzer (PSA) and UV–Vis spectroscopy (UV–Vis) analysis methods. Experimental and theoretical studies were done for the adsorption of Rhodamine B (Rh-B) on the inorganic polymer as an adsorbent. The effect of contact time was evaluated to characterize the mechanism of the Rh-B dye adsorption and photodegradation processes by inorganic polymer composite. The XRD, FTIR, SEM, PSA, and TEM characterizations showed the formation of new composite material. The bandgap of the inorganic polymer is found to be around 3.72 eV, proving the semiconductor state of this material. For a concentration of 30 mg/g, the efficiencies reach approximately 62.45 % and 31.62 %, respectively for adsorption and photodegradation processes leading to a synergistic efficiency of approximately 94.07 %. The kinetic data of Rh-B dye adsorption-photodegradation on the inorganic polymer composite were in good agreement with the pseudo-first-order model. Experimental and theoretical studies produce comparable results. From these conclusions, the inorganic polymer composite had great potential as an economical and efficient adsorbent and catalyst for removing Rh-B dye from aqueous solutions. Its application possibilities are important for the degradation and elimination of hazardous pollutants present in water.

Synthesis and characterization of magnetic adsorbent based on Fe2O3-fly ash from Pulang Pisau’s power plant of Central Kalimantan

One of the biggest producers of fly ash in Central Kalimantan is Pulang Pisau’s power plant. Fly ash, which is produced from burning coal or biomass, is a mixture of oxides with less combustible carbon and other minor inorganic compounds so that it has a dominant-negative surface charge and is a promising adsorbent. Modification of fly ash with Fe2O3 can affect the structure and morphology of the adsorbent, and the magnetic properties of the adsorbent can help in the process of separating the adsorbent after treatment. This study aims to study the synthesis and magnetic characteristics of magnetic adsorbent based on Fe2O3-fly ash from Pulang Pisau’s power plant. The proximate test results obtained showed that the SiO2 compound contained in fly ash was the highest with a percentage level of 32%. The optimum composition of fly ash and Fe2O3 ratio is 1: 2. Morphology of magnetic adsorbent based on Fe2O3-fly ash was observed using SEM EDX. The results showed Fe2O3 particles impregnated to the pores of fly ash particles which had 29, 11% of O and 70, 22% of Fe. The magnetic properties of magnetic adsorbent based on Fe2O3-fly ash from Pulang Pisau’s power plant were simply proven using an external magnetic field.

Characterization and utilization of coal fly ash: a review

Fly ash is a by-product, obtained mainly from thermal power plants, composed of silicon dioxide (SiO2) and aluminum oxide (Al2O3). Other oxides present in fly ash include iron (III) oxide (Fe2O3), calcium oxide (CaO), magnesium oxide (MgO) and so on. It may also contain some trace elements such as arsenic (As), zinc (Zn), lead (Pb), selenium (Se), gallium (Ga) and germanium (Ge) and some lesser amount of rare-earth elements. The particle size of fly ash normally ranges from 0.01 to 200 μm. Such variability in the particle size distribution of fly ash could influence the modification of fly ash into many useful products such as zeolites, geopolymers and other composite materials. The physical, chemical and mineralogical characteristics of fly ash combined with its easy availability make this an attractive raw material for various applications. In order to explore the potential use of fly ash, it is essential to look deeply into its characteristic properties. This review meticulously studies the characterization of fly ash by different modern techniques, including X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, thermogravimetric test, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, secondary ion mass spectroscopy and Raman spectroscopy and attempts to correlate the same with its potential applications.