Research progress on synthesis of zeolites from coal fly ash and environmental applications

Highlights

● Up-to-date information on the preparation of zeolite from CFA were summarized.

● The applications of CFA zeolites in environmental protection field were reviewed.

● The feasibility analysis of industrial production of CFA zeolites were discussed.

Abstract

The by-product of coal combustion, coal fly ash (CFA), has become one of the world’s most emitted solid wastes, and bulk utilization while achieving high value-added products is the focus of current research. Using CFA to prepare zeolite cannot only reduce environmental pressure, but also obtain high value-added products, which has a good market prospect. In this paper, the research progress of hydrothermal synthesis method of CFA zeolites is reviewed in detail and summarized several other synthetic methods of CFA zeolites. This review also presents an overview of CFA zeolites application in environmental applications like water treatment, gas adsorption and soil remediation. However, a considerable number of literature data have documented using CFA zeolites for water treatment, whereas research on CFA zeolites application to gas adsorption and soil remediation is still limited. In addition, the current status of basic research on the industrial production of CFA zeolites is briefly summarized, and the development trend of the synthetic zeolite of CFA is prospected. After the feasibility analysis of the industrial production of CFA zeolite, it is concluded that the only two methods with high feasibility for industrial application are two-step hydrothermal and alkali melting methods, and the industrial production technology still needs to be studied in depth.

Key words： Coal fly ash; Zeolite; Synthetic method; Environmental application; Industrialization

Acknowledgements

This work was supported by the National Natural Science Foundation of China (No. 51904278), the Fundamental Research Program of Shanxi Province (No. 202103021223277), the Taiyuan University of Science and Technology Doctoral Research Fund (No. 20212025), and the Natural Science Foundation of Shanxi Province (No. 20210302123218).

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

References

1 Abdelrahman E A, Abou El-Reash Y G, Youssef H M, Kotp Y H, Hegazey R M. (2021). Utilization of rice husk and waste aluminum cans for the synthesis of some nanosized zeolite, zeolite/zeolite, and geopolymer/zeolite products for the efficient removal of Co(II), Cu(II), and Zn(II) ions from aqueous media. Journal of Hazardous Materials, 401: 123813–123821

2 Ahmaruzzaman M. (2010). A review on the utilization of fly ash. Progress in Energy and Combustion Science, 36(3): 327–363

3 Ahmaruzzaman M, Gupta V K. (2012). Application of coal fly ash in air quality management. Industrial & Engineering Chemistry Research, 51(47): 15299–15314

4 Aldahri T, Behin J, Kazemian H, Rohani S. (2016). Synthesis of zeolite Na-P from coal fly ash by thermo-sonochemical treatment. Fuel, 182: 494–501

5 AmericanSociety for TestingMaterials (2005). Committee C-9 on Concrete and Concrete Aggregates, Standard Specifcation for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete. In: Annual Book of ASTM Standards 2005.Washington, DC: American Society for Testing and Materials Committee

6 Amoni B C, Freitas A D L, Bessa R L, Oliveira C P, Bastos-Neto M, Azevedo D C S, Lucena S M P, Sasaki J, Soares J B, Soares S A, Loiola A R. . (2022). Effect of coal fly ash treatments on synthesis of high-quality zeolite A as a potential additive for warm mix asphalt. Materials Chemistry and Physics, 275: 125197

7 Amrhein C, Haghnia G H, Kim T S, Mosher P A, Gagajena R C, Amanios T, de la Torre L. (1996). Synthesis and properties of zeolites from coal fly ash. Environmental Science & Technology, 30(3): 735–742

8 Antoniadis V, Polyzois T, Golia E E, Petropoulos S A. (2017). Hexavalent chromium availability and phytoremediation potential of Cichorium spinosum as affect by manure, zeolite and soil ageing. Chemosphere, 171: 729–734

9 Apiratikul R, Pavasant P. (2008). Sorption of Cu²⁺, Cd²⁺, and Pb²⁺ using modified zeolite from coal fly ash. Chemical Engineering Journal, 144(2): 245–258

10 Asl Hosseini S M, Ghadi A, Baei Sharifzadeh M, Javadian H, Maghsudi M, Kazemian H. (2018). Porous catalysts fabricated from coal fly ash as cost-effective alternatives for industrial applications: a review. Fuel, 217: 320–342

11 AtunGHisarlı GKurtoğluA E AyarN (2011). A comparison of basic dye adsorption onto zeolitic materials synthesized from fly ash. Journal of Hazardous Materials, 187(1–3): 562–573

12 Behin J, Bukhari S S, Dehnavi V, Kazemian H, Rohani S. (2014). Using coal fly ash and wastewater for microwave synthesis of LTA zeolite. Chemical Engineering & Technology, 37(9): 1532–1540

13 Belviso C. (2018). Ultrasonic vs hydrothermal method: different approaches to convert fly ash into zeolite. How they affect the stability of synthetic products over time? Ultrasonics Sonochemistry, 43: 9–14

14 Belviso C (2020). Zeolite for potential toxic metal uptake from contaminated soil: a brief review. Processes, 8: 820

15 Belviso C, Cavalcante F, Fiore S (2010). Synthesis of zeolite from Italian coal fly ash: differences in crystallization temperature using seawater instead of distilled water. Waste Management, 30: 839–847

16 Belviso C, Perchiazzi N, Cavalcante F. (2019). Zeolite from fly ash: an investigation on metastable behavior of the newly formed minerals in a medium-high-temperature range. Industrial & Engineering Chemistry Research, 58(44): 20472–20480

17 Boycheva S, Zgureva D, Lazarova H, Popova M. (2021). Comparative studies of carbon capture onto coal fly ash zeolites Na-X and Na-Ca-X. Chemosphere, 271: 129505

18 Bukhari S S, Behin J, Kazemian H, Rohani S. (2015). Conversion of coal fly ash to zeolite utilizing microwave and ultrasound energies: a review. Fuel, 140: 250–266

19 Cardoso A M, Horn M B, Ferret L S, Azevedo C M N, Pires M. (2015). Integrated synthesis of zeolites 4A and Na-P1 using coal fly ash for application in the formulation of detergents and swine wastewater treatment. Journal of Hazardous Materials, 287: 69–77

20 Chang H L, Shih W H. (2000). Synthesis of zeolites A and X from fly ashes and their ion-exchange behavior with cobalt ions. Industrial & Engineering Chemistry Research, 39(11): 4185–4191

21 Chen C T, Iyoki K, Yonezawa Y, Okubo T, Wakihara T. (2020). Understanding the nucleation and crystal growth of zeolites: a case study on the crystallization of ZSM-5 from a hydrogel system under ultrasonication. Journal of Physical Chemistry C, 124(21): 11516–11524

22 Chen H C, Khalili N, Li J J. (2018a). Development of stabilized Ca-based CO₂ sorbents supported by fly ash. Chemical Engineering Journal, 345: 312–319

23 Chen J B, Yang R J, Zhang Z Y, Wu D Y. (2022). Removal of fluoride from water using aluminum hydroxide-loaded zeolite synthesized from coal fly ash. Journal of Hazardous Materials, 421: 126817

24 ChenW TSong G QLinY YQiaoJ TWuT H YiX YKawi S (2021a). A green and efficient strategy for utilizing of coal fly ash to synthesize K-MER zeolite as catalyst for cyanoethylation and adsorbent of CO₂. Micropor. Mesopor. Mat. 326: 111353

25 Chen W T, Song G Q, Lin Y Y, Qiao J T, Wu T H, Yi X Y, Kawi S. (2021b). Synthesis and catalytic performance of Linde-type A zeolite (LTA) from coal fly ash utilizing microwave and ultrasound collaborative activation method. Catalysis Today, 397: 407–418

26 Chen Y, Chen J Q, Li L K, Yao Y Y, Yuan L Q, Li T, Ren B Z. (2018b). Progress in synthesis and application of fly ash zeolite. Bulletin of the Chinese Ceramic Society, 37: 3454–3459

27 Cheng W, Lei S G, Bian Z F, Zhao Y B, Li Y C, Gan Y D. (2020). Geographic distribution of heavy metals and identification of their sources in soils near large, open-pit coal mines using positive matrix factorization. Journal of Hazardous Materials, 387: 121666

28 Chindaprasirt P, Rattanasak U, Jaturapitakkul C. (2011). Utilization of fly ash blends from pulverized coal and fluidized bed combustions in geopolymeric materials. Cement and Concrete Composites, 33(1): 55–60

29 Choi C L, Park M, Lee D H, Kim J E, Park B Y, Choi J. (2001). Salt-thermal zeolitization of fly ash. Environmental Science & Technology, 35(13): 2812–2816

30 Cronstedt A F. (1756). Description and investigation of an unknown mountain species called Zheolites. Royal Swedish Academy of Sciences, 18: 111–113

31 Deng H, Ge Y. (2015). Formation of NaP zeolite from fused fly ash for the removal of Cu(II) by an improved hydrothermal method. RSC Advances, 5(12): 9180–9188

32 DerkowskiAFranus WBeranECzímerováA (2006). Properties and potential applications of zeolitic materials produced from fly ash using simple method of synthesis. Powder Technology, 166, 47–54

33 Ding Y H, Sartaj M. (2015). Statistical analysis and optimization of ammonia removal from aqueous solution by zeolite using factorial design and response surface methodology. Journal of Environmental Chemical Engineering, 3(2): 807–814

34 Du Plessis P, Ojumu T, Fatoba O, Akinyeye R, Petrik L. (2014). Distributional fate of elements during the synthesis of zeolites from south african coal fly ash. Materials (Basel), 7(4): 3305–3318

35 El-NaggarM REl-KamashA MEl-Dessouky M IGhonaimA K (2008). Two-step method for preparation of NaA-X zeolite blend from fly ash for removal of cesium ions. Journal of Hazardous Materials, 154, 963–972

36 Fan W, Morozumi K, Kimura R, Yokoi T, Okubo T. (2008). Synthesis of nanometer-sized sodalite without adding organic additives. Langmuir, 24(13): 6952–6958

37 FotovatFKazemian HKazemeiniM (2009). Synthesis of Na-A and faujasitic zeolites from high silicon fly ash. Materials Research Bulletin, 44, 913–917

38 Franus W, Wdowin M, Franus M. (2014). Synthesis and characterization of zeolites prepared from industrial fly ash. Environmental Monitoring and Assessment, 186(9): 5721–5729

39 Fukasawa T, Horigome A, Karisma A D, Maeda N, Huang A, Fukui K. (2018). Utilization of incineration fly ash from biomass power plants for zeolite synthesis from coal fly ash by microwave hydrothermal treatment. Advanced Powder Technology, 29(3): 450–456

40 Fukui K, Kanayama K, Yamamoto T, Yoshida H. (2007). Effects of microwave irradiation on the crystalline phase of zeolite synthesized from fly ash by hydrothermal treatment. Advanced Powder Technology, 18(4): 381–393

41 Gollakota A R K, Volli V, Shu C M. (2019). Progressive utilization prospects of coal fly ash: a review. Science of the Total Environment, 672: 951–989

42 He K, Chen Y, Tang Z, Hu Y. (2016). Removal of heavy metal ions from aqueous solution by zeolite synthesized from fly ash. Environmental Science and Pollution Research International, 23(3): 2778–2788

43 He X, Yao B, Xia Y, Huang H, Gan Y, Zhang W. (2020). Coal fly ash derived zeolite for highly efficient removal of Ni²⁺ in waste water. Powder Technology, 367: 40–46

44 He Y, Tang S W, Yin S H, Li S W. (2021). Research progress on green synthesis of various high-purity zeolites from natural material-kaolin. Journal of Cleaner Production, 306: 127248

45 HollmanG GSteenbruggen GJanssen-JurkovicovaM (1999). A two-step process for the synthesis of zeolites from coal fly ash. Fuel, 78, 1225–1230

46 Hong J L X, Maneerung T, Koh S N, Kawi S, Wang C H. (2017). Conversion of coal fly ash into zeolite materials: synthesis and characterizations, process design, and its cost-benefit analysis. Industrial & Engineering Chemistry Research, 56(40): 11565–11574

47 HuiK SChao C Y H (2006). Effects of step-change of synthesis temperature on synthesis of zeolite 4A from coal fly ash. Microporous and Mesoporous Materials, 88(1–3): 145–151

48 Hui K S, Chao C Y H. (2008). Methane emissions abatement by multi-ion-exchanged zeolite A prepared from both commercial-grade zeolite and coal fly ash. Environmental Science & Technology, 42(19): 7392–7397

49 Hums E, Baser H, Schwieger W. (2016). In situ ultrasonic measurements: a powerful tool to control the synthesis of zeolites from coal fly ash. Research on Chemical Intermediates, 42(10): 7513–7532

50 Hӧller H, Wirsching U. (1985). Zeolites formation from fly ash. Fortschritte der Mineralogie, 63: 21–43

51 InadaMEguchi YEnomotoNHojoJ (2005a). Synthesis of zeolite from coal fly ashes with different silica–alumina composition. Fuel, 84(2–3): 299–304

52 Inada M, Tsujimoto H, Eguchi Y, Enomoto N, Hojo J. (2005b). Microwave-assisted zeolite synthesis from coal fly ash in hydrothermal process. Fuel, 84: 1482–1486

53 Iqbal A, Sattar H, Haider R, Munir S. (2019). Synthesis and characterization of pure phase zeolite 4A from coal fly ash. Journal of Cleaner Production, 219: 258–267

54 ItskosGKoutsianos AKoukouzasNVasilatosC (2015). Zeolite development from fly ash and utilization in lignite mine-water treatment. International Journal of Mineral Processingnt, 139, 43–50

55 IzidoroJ D CFungaroD AAbbottJ E WangS (2013). Synthesis of zeolites X and A from fly ashes for cadmium and zinc removal from aqueous solutions in single and binary ion systems. Fuel, 103, 827–834

56 Ji X D, Zhang M L, Wang Y J, Song Y C, Ke Y Y, Wang Y Q. (2015). Immobilization of ammonium and phosphate in aqueous solution by zeolites synthesized from fly ashes with different compositions. Journal of Industrial and Engineering Chemistry, 22: 1–7

57 Jin J, Li X D, Chi Y, Yan J H. (2010). Heavy metals stabilization in medical waste incinerator fly ash using alkaline assisted supercritical water technology. Waste Management & Research, 28(12): 1133–1142

58 JosephI VTosheva LDoyleA M (2020). Simultaneous removal of Cd(II), Co(II), Cu(II), Pb(II), and Zn(II) ions from aqueous solutions via adsorption on FAU-type zeolites prepared from coal fly ash. Journal of Environmental Chemical Engineering, 8, 103895

59 Ju T Y, Han S Y, Meng F Z, Lin L, Li J L, Chen K L, Jiang J G. (2023). Porous silica synthesis out of coal fly ash with no residue generation and complete silicon separation. Frontiers of Environmental Science & Engineering, 17(9): 112

60 Ju T Y, Meng Y, Han S Y, Lin L, Jiang J G. (2021). On the state of the art of crystalline structure reconstruction of coal fly ash: a focus on zeolites. Chemosphere, 283: 131010

61 JuanRHernández SAndrésJ MRuizC (2009). Ion exchange uptake of ammonium in wastewater from a Sewage Treatment Plant by zeolitic materials from fly ash. Journal of Hazardous Materials, 161(2–3): 781–786

62 Kacirek H, Lechert H. (1976). Rates of crystallization and a model for the growth of sodium-Y zeolites. Journal of Physical Chemistry, 80(12): 1291–1296

63 KalvachevYZgureva DBoychevaSBarbovBPetrovaN (2016). Synthesis of carbon dioxide adsorbents by zeolitization of fly ash. Journal of Thermal Analysis and Calorimetry, 124, 101–106

64 KazemianHNaghdali ZGhaffariKashani TFarhadiF (2010). Conversion of high silicon fly ash to Na-P1 zeolite: alkaline fusion followed by hydrothermal crystallization. Advanced Powder Technology, 21, 279–283

65 Khaleque A, Alam M M, Hoque M, Mondal S, Haider J B, Xu B, Johir M A H, Karmakar A K, Zhou J L, Ahmed M B, Moni M A. . (2020). Zeolite synthesis from low-cost materials and environmental applications: a review. Environmental Advances, 2: 100019

66 Koshy N, Singh D N. (2016). Fly ash zeolites for water treatment applications. Journal of Environmental Chemical Engineering, 4(2): 1460–1472

67 KoukouzasNVasilatos CItskosGMitsisIMoutsatsou A (2010). Removal of heavy metals from wastewater using CFB-coal fly ash zeolitic materials. Journal of Hazardous Materials, 173, 581–588

68 KumarM MIrshad K AJenaH (2021). Removal of Cs⁺ and Sr²⁺ ions from simulated radioactive waste solutions using Zeolite-A synthesized from kaolin and their structural stability at high pressures. Microporous and Mesoporous Materials. 312: 110773–110779

69 Kumar M M, Jena H. (2022). Direct single-step synthesis of phase pure zeolite Na-P1, hydroxy sodalite and analcime from coal fly ash and assessment of their Cs⁺ and Sr²⁺ removal efficiencies. Microporous and Mesoporous Materials, 333: 111738

70 KuneckiPPanek RKotejaAFranusW (2018). Influence of the reaction time on the crystal structure of Na-P1 zeolite obtained from coal fly ash microspheres. Microporous and Mesoporous Materials, 266, 102–108

71 Kunecki P, Panek R, Wdowin M, Bień T, Franus W. (2021). Influence of the fly ash fraction after grinding process on the hydrothermal synthesis efficiency of Na-A, Na-P1, Na-X and sodalite zeolite types. International Journal of Coal Science & Technology, 8(2): 291–311

72 Kunecki P, Wdowin M, Hanc E. (2023). Fly ash-derived zeolites and their sorption abilities in relation to elemental mercury in a simulated gas stream. Journal of Cleaner Production, 391: 136181

73 Kwon E H, An H, Park M B, Kim M, Park Y D. (2021). Conjugated polymer–zeolite hybrids for robust gas sensors: effect of zeolite surface area on NO₂ sensing ability. Chemical Engineering Journal, 420: 129588–129591

74 Larosa J L, Kwan S, Grutzeck M W. (1992). Zeolite formation in class F fly ash blended cement pastes. Journal of the American Ceramic Society, 75(6): 1574–1580

75 Lou Y, Ma J, Hu W D, Dai Q G, Wang L, Zhan W C, Guo Y L, Cao X M, Guo Y, Hu P, Lu G Z. . (2016). Low-temperature methane combustion over Pd/H-ZSM-5: active Pd sites with specific electronic properties modulated by acidic sites of H-ZSM-5. ACS Catalysis, 6(12): 8127–8139

76 Ma H C, Yao Q T, Fu Y H, Ma C, Dong X L. (2010). Synthesis of zeolite of type a from bentonite by alkali fusion activation using Na₂CO₃. Industrial & Engineering Chemistry Research, 49(2): 454–458

77 Ma Y A, Yan C J, Alshameri A, Qiu X M, Zhou C Y, Li D. (2014). Synthesis and characterization of 13X zeolite from low-grade natural kaolin. Advanced Powder Technology, 25(2): 495–499

78 Maiti S, Raj H, Bisht R S, Minocha A K, Panigrahi S K, Alexander S, Sameer M. (2018). X-ray photoelectron spectroscopy study on adsorption property of harmful air pollutants on zeolite prepared from fly ash. Materials Research Express, 5(8): 085507

79 Makgabutlane B, Nthunya L N, Nxumalo E N, Musyoka N M, Mhlanga S D. (2020). Microwave irradiation-assisted synthesis of zeolites from coal fly ash: an optimization study for a sustainable and efficient production process. ACS Omega, 5(39): 25000–25008

80 Meng X, Xiao F S. (2014). Green routes for synthesis of zeolites. Chemical Reviews, 114(2): 1521–1543

81 Missengue R N M, Losch P, Sedres G, Musyoka N M, Fatoba O O, Louis B, Pale P, Petrik L F. (2017). Transformation of South African coal fly ash into ZSM-5 zeolite and its application as an MTO catalyst. Comptes Rendus Chimie, 20(1): 78–86

82 Mohebbi M, Rajabipour F, Madadian E. (2022). A framework for identifying the host phases in Coal-derived fly ash. Fuel, 314: 122806

83 MolinaAPoole C (2004). A comparative study using two methods to produce zeolites from fly ash. Minerals Engineering, 17, 167–173

84 Monasterio-GuillotLAlvarez-LloretPIbañez-Velasco AFernandez-MartinezA Ruiz-AgudoERodriguez-Navarro C (2020). CO₂ sequestration and simultaneous zeolite production by carbonation of coal fly ash: impact on the trapping of toxic elements. Journal of CO₂ Utilization, 40, 101263.

85 MondragonFRincon FSierraLEscobarJRamirezJ FernandezJ (1990). New perspectives for coal ash utilization: synthesis of zeolitic materials. Fuel, 69, 263–266

86 Moreno N, Querol X, Ayora C, Pereira C F, Janssen-Jurkovicová M. (2001). Utilization of zeolites synthesized from coal fly ash for the purification of acid mine waters. Environmental Science & Technology, 35(17): 3526–3534

87 MoriyamaRTakeda SOnozakiMKatayamaYShiotaK FukudaTSugihara HTaniY (2005). Large-scale synthesis of artificial zeolite from coal fly ash with a small charge of alkaline solution. Fuel, 84, 1455–1461

88 MurayamaNTakahashi TShukuKLeeHShibataJ (2008). Effect of reaction temperature on hydrothermal syntheses of potassium type zeolites from coal fly ash. International Journal of Mineral Processing, 87, 129–133

89 Murayama N, Yamamoto H, Shibata J. (2002). Mechanism of zeolite synthesis from coal fly ash by alkali hydrothermal reaction. International Journal of Mineral Processing, 64(1): 1–17

90 MuriithiaG NPetrikL FDoucetF J (2020). Synthesis, characterisation and CO₂ adsorption potential of NaA and NaX zeolites and hydrotalcite obtained from the same coal fly ash. Journal of CO₂ Utilization, 36, 220–230

91 Musyoka N M, Petrik L F, Fatoba O O, Hums E. (2013). Synthesis of zeolites from coal fly ash using mine waters. Minerals Engineering, 53: 9–15

92 Musyoka N M, Petrik L F, Hums E, Baser H, Schwieger W. (2012). In situ ultrasonic monitoring of zeolite A crystallization from coal fly ash. Catalysis Today, 190(1): 38–46

93 Nada M H, Larsen S C. (2017). Insight into seed-assisted template free synthesis of ZSM-5 zeolites. Microporous and Mesoporous Materials, 239: 444–452

94 Nguyen M, Tanner C. (1998). Ammonium removal from wastewaters using natural New Zealand zeolites. New Zealand Journal of Agricultural Research, 41(3): 427–446

95 Ojumu T V, Du Plessis P W, Petrik L F. (2016). Synthesis of zeolite A from coal fly ash using ultrasonic treatment-A replacement for fusion step. Ultrasonics Sonochemistry, 31: 342–349

96 PanekRWdowin MBanduraLWisła-WalshEGara PFranusW (2017). Changes in the textural parameters of fly ash-derived Na-P1 zeolite during compaction processes. Mineralogia, 48(1–4): 3–22

97 Park J, Hwang Y, Bae S. (2019). Nitrate reduction on surface of Pd/Sn catalysts supported by coal fly ash-derived zeolites. Journal of Hazardous Materials, 374: 309–318

98 ParkMChoi C LLimW TKimM CChoiJ HeoN H (2000). Molten-salt method for the synthesis of zeolitic materials. Characterization of zeolitic materials. Microporous and Mesoporous Materials, 37(1–2): 91–98

99 PedroloD R SQuinesL K D MSouzaG D MarcilioN R (2017). Synthesis of zeolites from Brazilian coal ash and its application in SO₂ adsorption. Journal of Environmental Chemical Engineer, 5, 4788–4794

100 Popova M, Boycheva S, Lazarova H, Zgureva D, Lázár K, Szegedi Á. (2020). VOC oxidation and CO₂ adsorption on dual adsorption/catalytic system based on fly ash zeolites. Catalysis Today, 357: 518–525

101 Qin L B, Song J, Liang Y S, Zhao B, Chen G, Han J. (2021). Preparation of Fe and Ca enriched sorbents derived from coal fly ash for arsenic capture from flue gas. Energy & Fuels, 35(14): 11203–11209

102 Querol X, Alastuey A, Lopez-Soler A, Plana F, Andres J M, Juan R, Ferrer P, Ruiz C R. (1997). A fast method for recycling fly ash: microwave-assisted zeolite synthesis. Environmental Science & Technology, 31(9): 2527–2533

103 QuerolXMoreno NUmañaJ  CJuanRHernández SFernandez-PereiraC AyoraCJanssen MGarcía-Martínez JLinares-SolanoA, . (2002). Application of zeolitic material synthesised from fly ash to the decontamination of waste water and flue gas. Journal of Chemical Technology and Biotechnology, 77, 292–298

104 QuerolXUmaña J CPlanaFAlastueyALopez-Soler AMedinaceliADomingoM JGarcia-Rojo E (2001). Synthesis of zeolites from fly ash at pilot plant scale, Examples of potential applications. Fuel. 80, 857–865

105 Radziemska M, Mazur Z. (2016). Content of selected heavy metals in Ni-contaminated soil following the application of halloysite and zeolite. Journal of Ecological Engineering, 17(3): 125–133

106 Rajendran S, Priya T A K, Khoo K S, Hoang T K A T K A, Ng H, Munawaroh H S H, Karaman C, Orooji Y, Show P L. (2022). A critical review on various remediation approaches for heavy metal contaminants removal from contaminated soils. Chemosphere, 287: 132369

107 Rayalu S S, Udhoji J S, Munshi K N, Hasan M Z. (2001). Highly crystalline zeolite-Aa from fly ash of bituminous and lignite coal combustion. Journal of Hazardous Materials, 88(1): 107–121

108 Remenárová L, Pipíška M, Florková E, Horník M, Rozložník M, Augustín J. (2014). Zeolites from coal fly ash as efficient sorbents for cadmium ions. Clean Technologies and Environmental Policy, 16(8): 1551–1564

109 Ren L M, Wu Q M, Yang C G, Zhu L F, Li C J, Zhang P L, Zhang H Y, Meng X J, Xiao F S. (2012). Solvent-free synthesis of zeolites from solid raw materials. Journal of the American Chemical Society, 134(37): 15173–15176

110 Ren X Y, Liu S J, Qu R Y, Xiao L F, Hu P, Song H, Wu W H, Zheng C H, Wu X C, Gao X. (2020). Synthesis and characterization of single-phase submicron zeolite Y from coal fly ash and its potential application for acetone adsorption. Microporous and Mesoporous Materials, 295: 109940

111 Sahoo P K, Kim K, Powell M A, Equeenuddin S M. (2016). Recovery of metals and other beneficial products from coal fly ash: a sustainable approach for fly ash management. International Journal of Coal Science & Technology, 3(3): 267–283

112 Shi D D, Haw K G, Kouvatas C, Tang L X, Zhang Y Y, Fang Q R, Qiu S L, Valtchev V. (2020). Expanding the synthesis field of high-silica zeolites. Angewandte Chemie International Edition, 59(44): 19576–19581

113 Sivalingam S, Sen S. (2018). Optimization of synthesis parameters and characterization of coal fly ash derived microporous zeolite X. Applied Surface Science, 455: 903–910

114 SlangenP MJansen J CVanBekkum H (1997). The effect of ageing on the microwave synthesis of zeolite NaA. Microporous and Mesoporous Materials, 9(5–6): 259–265

115 SoeJ TKim S SLeeY RAhnJ WAhnW S (2016). CO₂ capture and Ca²⁺ exchange using zeolite A and 13X prepared from power plant fly ash. Bulletin of the Korean Chemical Society, 37, 490–493

116 Srinivasan A, Grutzeck M W. (1999). The adsorption of SO₂ by zeolites synthesized from fly ash. Environmental Science & Technology, 33(9): 1464–1469

117 SteenbruggenGHollmanG G (1998). The synthesis of zeolites from fly ash and the properties of the zeolite products. Journal of Geochemical Exploration, 62, 305–309

118 Stoy L, Diaz V, Huang C H. (2021). Preferential recovery of rare-earth elements from coal fly ash using a recyclable ionic liquid. Environmental Science & Technology, 55(13): 9209–9220

119 Sui Y, Wu D, Zhang D, Zheng X, Hu Z, Kong H. (2008). Factors affecting the sorption of trivalent chromium by zeolite synthesized from coal fly ash. Journal of Colloid and Interface Science, 322(1): 13–21

120 TanakaHEguchi HFujimotoSHinoR (2006). Two-step process for synthesis of a single phase Na-A zeolite from coal fly ash by dialysis. Fuel, 85(10–11): 1329–1334

121 Tanaka H, Fujii A. (2009). Effect of stirring on the dissolution of coal fly ash and synthesis of pure-form Na-A and -X zeolites by two-step process. Advanced Powder Technology, 20(5): 473–479

122 Tanaka H, Fujimoto S, Fujii A, Hino R, Kawazoe T. (2008). Microwave assisted two-step process for rapid synthesis of Na-A zeolite from coal fly ash. Industrial & Engineering Chemistry Research, 47(1): 226–230

123 Tanaka H, Miyagawa A, Eguchi H, Hino R. (2004). Synthesis of a single-phase Na-A zeolite from coal fly ash by dialysis. Industrial & Engineering Chemistry Research, 43(19): 6090–6094

124 Tauanov Z, Shah D, Inglezakis V, Jamwal P K. (2018). Hydrothermal synthesis of zeolite production from coal fly ash: a heuristic approach and its optimization for system identification of conversion. Journal of Cleaner Production, 182: 616–623

125 Tauanov Z, Shah D, Itskos G, Inglezakis V. (2017). Optimized production of coal fly ash derived synthetic zeolites for mercury removal from wastewater. IOP Conference Series. Materials Science and Engineering, 230: 012044

126 Terzano R, Spagnuolo M, Medici L, Dorriné W, Janssens K, Ruggiero P. (2007). Microscopic single particle characterization of zeolites synthesized in a soil polluted by copper or cadmium and treated with coal fly ash. Applied Clay Science, 35(1–2): 128–138

127 Vassilev S V, Menendez R, Alvarez D, Diaz-Somoano M, Martinez-Tarazona M R. (2003). Phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization, characterization of feed coals and fly ashes. Fuel, 82(14): 1793–1811

128 Vassilev S V, Vassileva C G. (2005). Methods for characterization of composition of fly ashes from coal-fired power stations: a critical overview. Energy & Fuels, 19(3): 1084–1098

129 Verrecchia G, Cafiero L, de Caprariis B, Dell’Era A, Pettiti I, Tuffi R, Scarsella M. (2020). Study of the parameters of zeolites synthesis from coal fly ash in order to optimize their CO₂ adsorption. Fuel, 276: 118041

130 VisaMChelaru A M (2014). Hydrothermally modified fly ash for heavy metals and dyes removal in advanced wastewater treatment. Applied Surface Science, 303, 14–22

131 Visa M, Isac L, Duta A. (2012). Fly ash adsorbents for multi-cation wastewater treatment. Applied Surface Science, 258(17): 6345–6352

132 WangCLi JSunXWangLSunX (2009). Evaluation of zeolites synthesized from fly ash as potential adsorbents for wastewater containing heavy metals. Journal of Environmental Sciences-China, 21, 127–136

133 Wang C, Xu G G, Gu X Y, Gao Y H, Zhao P. (2021). High value-added applications of coal fly ash in the form of porous materials: a review. Ceramics International, 47(16): 22302–22315

134 WangJ CLi D KJuF LHanL NChangLP BaoW R (2015). Supercritical hydrothermal synthesis of zeolites from coal fly ash for mercury removal from coal derived gas. Fuel Processing Technology, 136, 96–105

135 WdowinMFranus MPanekRBaduraLFranusW (2014). The conversion technology of fly ash into zeolites. Clean Technologies and Environmental Policy, 16, 1217–1223

136 Wdowin M, Macherzynski M, Panek R, Gorecki J, Franus W. (2015). Investigation of the sorption of mercury vapour from exhaust gas by an Ag-X zeolite. Clay Minerals, 50(1): 31–40

137 Wu D, Sui Y, He S, Wang X, Li C, Kong H. (2008). Removal of trivalent chromium from aqueous solution by zeolite synthesized from coal fly ash. Journal of Hazardous Materials, 155(3): 415–423

138 Wu Q, Wang X, Qi G, Guo Q, Pan S, Meng X, Xu J, Deng F, Fan F, Feng Z. . (2014). Sustainable synthesis of zeolites without addition of both organotemplates and solvents. Journal of the American Chemical Society, 136(10): 4019–4025

139 Xie J, Wang Z, Wu D Y, Zhang Z J, Kong H N. (2013). Synthesis of zeolite/aluminum oxide hydrate from coal fly ash: a new type of adsorbent for simultaneous removal of cationic and anionic pollutants. Industrial & Engineering Chemistry Research, 52(42): 14890–14897

140 Xu M X, Wu Y C, Zhang P X, Liu Z S, Hu Z, Lu Q. (2022). Green and moderate activation of coal fly ash and its application in selective catalytic reduction of NO with NH₃. Environmental Science & Technology, 56(4): 2582–2592

141 YanJ LChang B J (2017). The development and optimization of co-production process of extracting alumina and 4A zeolite from high alumina fly ash. Light Metals. 4, 9–12

142 Yang L, Qian X, Yuan P, Bai H, Miki T, Men F X, Li H, Nagasaka T. (2019a). Green synthesis of zeolite 4A using fly ash fused with synergism of NaOH and Na₂CO₃. Journal of Cleaner Production, 212: 250–260

143 Yang T, Han C, Liu H, Yang L, Liu D, Tang J, Luo Y. (2019b). Synthesis of Na-X zeolite from low aluminum coal fly ash: characterization and high efficient As(V) removal. Advanced Powder Technology, 30(1): 199–206

144 Yao Z T, Ji X S, Sarker P K, Tang J H, Ge L Q, Xia M S, Xi Y Q. (2015). A comprehensive review on the applications of coal fly ash. Earth-Science Reviews, 141: 105–121

145 Yu Y Q, Li X L, Zou X L, Zhu X B (2014) Effect of seawater salinity on the synthesis of zeolite from coal fly ash. Frontiers of Environmental Science & Engineering, 8(1): 54‒61

146 YeY PZeng X QQianW LWangM W (2008). Synthesis of pure zeolites from supersaturated silicon and aluminum alkali extracts from fused coal fly ash. Fuel, 87, 1880–1886

147 Zaheer A. (2022). Carbonaceous adsorbent from waste oil fly ash: surface treatments and hydrogen sulfide adsorption potential. Chemicke Zvesti, 76(8): 5145–5158

148 Zhang P, Li S Q, Guo P H, Zhang C Q. (2020a). Seed-assisted, OSDA-free, Solvent-free synthesis of ZSM-5 zeolite from iron ore tailings. Waste and Biomass Valorization, 11(8): 4381–4391

149 Zhang P, Li S Q, Guo P H, Zhao X. (2020b). Synthesis of ZSM-5 microspheres made of nanocrystals from iron ore tailings by the solid-phase conversion method. Langmuir, 36(22): 6160–6168

150 Zhang P, Li S Q, Zhang C Q. (2019). Solvent-free synthesis of nano-cancrinite from rice husk ash. Biomass Conversion and Biorefinery, 9(3): 641–649

151 Zhang P, Wang L, Ren L, Zhu L, Sun Q, Zhang J, Meng X, Xiao F S. (2011a). “Solvent-free” synthesis of thermally stable and hierarchically porous aluminophosphates (SF-APOs) and heteroatom-substituted aluminophosphates (SF-MAPOs). Journal of Materials Chemistry, 21(32): 12026–12033

152 Zhang X, He X, Li J, Davi N, Chen Z, Cui M, Chen W, Li N. (2011b). Effects of sodium carbonate and sodium chloride additives on alkaline fusion of coal fly ash. Journal of Central South University, 42: 1220–1225

153 ZhangYDong JGuoFShaoZWuJ (2018). Zeolite synthesized from coal fly ash produced by a gasification process for Ni²⁺ removal from water. Minerals, 8, 1–14

154 Zhang Y N, Han H J, Wang X H, Zhang M, Chen Y G, Zhai C X, Song H, Deng J T, Sun J, Zhang C L. (2021). Utilization of NaP zeolite synthesized with different silicon species and NaAlO₂ from coal fly ash for the adsorption of Rhodamine B. Journal of Hazardous Materials, 9: 6894–6911

155 ZhangZ HXiao Y FWangB DSunQLiuH D (2017). Waste is a misplayed resource: synthesis of zeolites from fly ash for CO₂ capture. Energy Procedia, 114, 2537–2544

156 Zhao H, Huang X, Liu F, Hu X, Zhao X, Wang L, Gao P, Ji P. (2020). A two-year field study of using a new material for remediation of cadmium contaminated paddy soil. Environment and Pollution, 263: 114614

157 ZhaoM QMa X QChenD JLiaoY N (2022). Preparation of honeycomb-structured activated carbon-zeolite composites from modified fly ash and the adsorptive removal of Pb(II). ACS Omega, 7, 9684–9689

158 Zhao Y X, Wang J C, Han L N, Chang L P, Bao W R. (2016). Synthesis of zeolite from fly ash by alkali fusion-supercritical hydrothermal method. Modern Chemical Industry, 36: 141–145

159 Zhao X L, Wang X J, Lou T. (2021). Preparation of fibrous chitosan/sodium alginate composite foams for the adsorption of cationic and anionic dyes. Journal of Hazardous Materials, 403(124054): 1–10

160 Zheng X J, Chen M, Wang J F, Liu Y, Liao Y Q, Liu Y C. (2020). Assessment of zeolite, biochar, and their combination for stabilization of multimetal-contaminated soil. ACS Omega, 5(42): 27374–27382

161 Zhou T X, Wang B D, Dai Z D, Jiang X J, Wang Y. (2021). Organotemplate-free synthesis of MOR zeolite from coal fly ash through simultaneously effective extraction of Si and Al. Microporous and Mesoporous Materials, 314: 110872

162 Zhu L, Ji J Y, Wang S L, Xu C X, Yang K, Xu M. (2018). Removal of Pb(II) from wastewater using Al₂O₃-NaA zeolite composite hollow fiber membranes synthesized from solid waste coal fly ash. Chemosphere, 206: 278–284

163 ZhuTZhangX HanYLiuT WangBZhang Z (2019). Preparation of zeolite X by the aluminum residue from coal fly ash for the adsorption of volatile organic compounds. Frontiers in Chemistry, 7, 1–8