1. W. Kong, F. Zhao, H. Guan, Y. Zhao, H. Zhang, B. Zhang, Highly adsorptive mesoporous carbon from biomass using molten-salt route, J. Mater. Sci., 51 (2016) 6793–6800.
  2. Y.H. Magdy, H. Altaher, Kinetic analysis of the adsorption of dyes from high strength wastewater on cement kiln dust, J. Environ. Chem. Eng., 6 (2018) 834–841.
  3. N. Mokhtar, E.A. Aziz, A. Aris, W.F.W. Ishak, N.S.M. Ali, Biosorption of azo-dye using marine macro-alga of Euchema Spinosum, J. Environ. Chem. Eng., 5 (2017) 5721–5731.
  4. M. Bounaas, A. Bouguettoucha, D. Chebli, A. Reffas, I. Harizi, F. Rouabah, A. Amrane, High efficiency of methylene blue removal using a novel low-cost acid treated forest wastes, Cupressus semperirens cones: experimental results and modeling, Part. Sci. Technol., 6351 (2018) 1–10.
  5. M.T. Yagub, T.K. Sen, S. Afroze, H.M. Ang, Dye and its removal from aqueous solution by adsorption: a review, Adv. Colloid Interface Sci., 209 (2014) 172–184.
  6. T. Ngulube, J.R. Gumbo, V. Masindi, A. Maity, An update on synthetic dyes adsorption onto clay based minerals: a state-ofart review, J. Environ. Manage., 191 (2017) 35–57.
  7. G. Liu, Z. Hu, R. Guan, Y. Zhao, H. Zhang, B. Zhang, Efficient removal of methylene blue in aqueous solution by freeze-dried calcium alginate beads, Korean J. Chem. Eng., 33 (2016) 3141–3148.
  8. Y. Lu, H. Shang, H. Guan, Y. Zhao, H. Zhang, B. Zhang, Enhanced visible-light photocatalytic activity of BiVO4 microstructures via annealing process, Superlattices Microstruct., 88 (2015) 591–599.
  9. R.A. Reza, M. Ahmaruzzaman, Comparative study of waste derived adsorbents for sequestering methylene blue from aquatic environment, J. Environ. Chem. Eng., 3 (2015) 395–404.
  10. P. Luo, B. Zhang, Y. Zhao, J. Wang, H. Zhang, J. Liu, Removal of methylene blue from aqueous solutions by adsorption onto chemically activated halloysite nanotubes, Korean J. Chem. Eng., 28 (2011) 800–807.
  11. V.K. Gupta, D. Pathania, S. Agarwal, S. Sharma, De-coloration of hazardous dye from water system using chemically modified Ficus carica adsorbent, J. Mol. Liq., 174 (2012) 86–94.
  12. M. Ahmaruzzaman, A review on the utilization of fly ash, Prog. Energy Combust. Sci., 36 (2010) 327–363.
  13. A.Y.W. Sham, S.M. Notley, Adsorption of organic dyes from aqueous solutions using surfactant exfoliated graphene, J. Environ. Chem. Eng., 6 (2018) 495–504.
  14. C.F. Carolin, P.S. Kumar, A. Saravanan, G.J. Joshiba, Mu. Naushad, Efficient techniques for the removal of toxic heavy metals from aquatic environment: a review, J. Environ. Chem. Eng., 5 (2017) 2782–2799.
  15. L. Mouni, L. Belkhiri, J.-C. Bollinger, A. Bouzaza, A. Assadi, A. Tirri, F. Dahmoune, K. Madani, H. Remini, Removal of Methylene Blue from aqueous solutions by adsorption on kaolin: kinetic and equilibrium studies, Appl. Clay Sci., 153 (2018) 38–45.
  16. M.S.U. Rehman, M. Munir, M. Ashfaq, N. Rashid, M.F. Nazar, M. Danish, J.-I. Han, Adsorption of Brilliant Green dye from aqueous solution onto red clay, Chem. Eng. J., 228 (2013) 54–62.
  17. L.-G. Yan, L.-L Qin, H.-Q. Yu, S. Li, R.-R. Shan, B. Du, Adsorption of acid dyes from aqueous solution by CTMAB modified bentonite: kinetic and isotherm modeling, J. Mol. Liq., 211 (2015) 1074–1081.
  18. ENVIS Centre on Fly Ash GOI, 2017. Availabe at: fly ash.html
  19. H. Cho, D. Oh, K. Kim, A study on removal characteristics of heavy metals from aqueous solution by fly ash, J. Hazard. Mater., 127 (2005) 187–195.
  20. K. Rastogi, J.N. Sahu, B.C. Meikap, M.N. Biswas, Removal of methylene blue from wastewater using fly ash as an adsorbent by hydrocyclone, J. Hazard. Mater., 158 (2008) 531–540.
  21. S. Banerjee, G.C. Sharma, M.C. Chattopadhyaya, Y.C. Sharma, Kinetic and equilibrium modeling for the adsorptive removal of methylene blue from aqueous solutions on of activated fly ash (AFSH), J. Environ. Chem. Eng., 2 (2014) 1870–1880.
  22. Z. Liu, Y. Liu, Structure and properties of forming adsorbents prepared from different particle sizes of coal fly ash, Chin. J. Chem. Eng., 23 (2015) 290–295.
  23. L.D. Lin, Y. Lin, C.J. Li, D.Y. Wu, H.N. Kong, Synthesis of zeolite/hydrous metal oxide composites from coal fly ash as efficient adsorbents for removal of methylene blue from water, Int. J. Miner. Process., 148 (2016) 32–40.
  24. L. Li, S. Wang, Z. Zhu, Geopolymeric adsorbents from fly ash for dye removal from aqueous solution, J. Colloid Interface Sci., 300 (2006) 52–59.
  25. J. Davidovits, Geopolymers and geopolymeric material, J. Therm. Anal., 35 (1989) 429–441.
  26. R.S. Blissett, N.A. Rowson, A review of the multi-component utilisation of coal fly ash, Fuel, 97 (2012) 1–23.
  27. N.-U. Amin, A multi-directional utilization of different ashes, RSC Adv., 4 (2014) 62769–62788.
  28. K. Al-Zboon, M.S. Al-Harahsheh, F.B. Hani, Fly ash-based geopolymer for Pb removal from aqueous solution, J. Hazard. Mater., 188 (2011) 414–421.
  29. M.N. Mužek, S. Svilović, J. Zelić, Kinetic studies of cobalt ion removal from aqueous solutions using fly ash-based geopolymer and zeolite NaX as sorbents, Sep. Sci. Technol., 51 (2016) 2868–2875.
  30. Y. Zhang, L. Liu, Fly ash-based geopolymer as a novel photocatalyst for degradation of dye from wastewater, Particuology, 11 (2013) 353–358.
  31. M.I. Khan, T.K. Min, A.K. Azizli, S. Sufian, H. Ullah, Z. Man, Effective removal of methylene blue from water using phosphoric acid based geopolymers: synthesis, characterizations and adsorption studies, RSC Adv., 5 (2015) 61410–61420.
  32. J. Chen, Y. Wang, S. Zhou, X. Lei, Reduction/immobilization processes of hexavalent chromium using metakaolin-based geopolymer, J. Environ. Chem. Eng., 5 (2017) 373–380.
  33. T. Luukkonen, H. Runtti, M. Niskanen, E.T. Tolonen, M. Sarkkinen, K. Kemppainen, J. Rämö, U. Lassi, Simultaneous removal of Ni(II), As(III), and Sb(III) from spiked mine effluent with metakaolin and blast-furnace-slag geopolymers, J. Environ. Manage., 166 (2016) 579–588.
  34. S.S. Amritphale, D. Mishra, M. Mudgal, R.K. Chouhan, N. Chandra, A novel green approach for making hybrid inorganicorganic geopolymeric cementitious material utilizing fly ash and rice husk, J. Environ. Chem. Eng., 4 (2016) 3856–3865.
  35. U.E.ul Haq, S.P. Kunjalukkal, A. Licciulli, Synthesis and characteristics of fly ash and bottom ash based geopolymers—a comparative study, Ceram. Int., 40 (2013) 2965–2971.
  36. M.S. Al-Harahsheh, K. Al Zboon, L. Al-Makhadmeh, M. Hararah, M. Mahasneh, Fly ash based geopolymer for heavy metal removal: a case study on copper removal, J. Environ. Chem. Eng., 3 (2015) 1669–1677.
  37. H. Singh, G. Chauhan, A.K. Jain, S.K. Sharma, Adsorptive potential of agricultural wastes for removal of dyes from aqueous solutions, J. Environ. Chem. Eng., 5 (2017) 122–135.
  38. J. Liu, Y. Wang, Y. Fang, T. Mwamulima, S. Song, C. Peng, Removal of crystal violet and methylene blue from aqueous solutions using the fly ash-based adsorbent material-supported zero-valent iron, J. Mol. Liq., 250 (2018) 468–476.
  39. S. Kuai, Z. Nan, Formation of sandwich structured ZnCe0.03Fe1.97O4@nSiO2@SBA-15 and adsorptive removal of methylene blue from aqueous solution, Chem. Eng. J., 244 (2014) 273–281.
  40. E.I. El-Shafey, S.N.F. Ali, S. Al-Busafi, H.A.J.Al-Lawati, Preparation and characterization of surface functionalized activated carbons from date palm leaflets and application for methylene blue removal, J. Environ. Chem. Eng., 4 (2016) 2713–2724.
  41. P. Duxson, J.L. Provis, G.C. Lukey, S.W. Mallicoat, W.M. Kriven, J.S.J. van Deventer, Understanding the relationship between geopolymer composition, microstructure and mechanical properties, Colloids Surf., A, 269 (2005) 47–58.
  42. U. Rattanasak, P. Chindaprasirt, Influence of NaOH solution on the synthesis of fly ash geopolymer, Miner. Eng., 22 (2009) 1073–1078.
  43. S. Saha, C. Rajasekaran, Enhancement of the properties of fly ash based geopolymer paste by incorporating ground granulated blast furnace slag, Constr. Build. Mater., 146 (2017) 615–620.
  44. J. Davidovits, Geopolymer, Green Chemistry and Sustainable Development Solutions, Geopolymer Proceedings, 2005, p. 10.
  45. J. Ojima, Determining of crystalline silica in respirable dust samples by infrared spectrophotometry in the presence of interferences, J. Occup. Health, 45 (2003) 94–103.
  46. M.N. Mužek, J. Zelić, D. Jozić, Microstructural characteristics of geopolymers based on alkali-activated fly ash, Chem. Biochem. Eng. Q., 26 (2012) 89–95.
  47. T. Bakharev, Resistance of geopolymer materials to acid attack, Cem. Concr. Res., 35 (2005) 658–670.
  48. K. Somna, C. Jaturapitakkul, P. Kajitvichyanukul, P. Chindaprasirt, NaOH-activated ground fly ash geopolymer cured at ambient temperature, Fuel, 90 (2011) 2118–2124.
  49. S. Shakoor, A. Nasar, Groundwater for sustainable development adsorptive treatment of hazardous methylene blue dye from artificially contaminated water using Cucumis sativus peel waste as a low-cost adsorbent, Groundwater Sustainable Dev., 5 (2017) 152–159.
  50. R.K. Gautam, A. Mudhoo, M.C. Chattopadhyaya, Kinetic, equilibrium, thermodynamic studies and spectroscopic analysis of Alizarin Red S removal by mustard husk, J. Environ. Chem. Eng., 1 (2013) 1283–1291.
  51. N.A. Oladoja, Y.D. Aliu, Snail shell as coagulant aid in the alum precipitation of malachite green from aqua system, J. Hazard. Mater., 164 (2009) 1496–1502.
  52. M.K. Dahri, M.R.R. Kooh, L.B.L. Lim, Application of Casuarina equisetifolia needle for the removal of methylene blue and malachite green dyes from aqueous solution, Alexandria Eng. J., 54 (2015) 1253–1263.
  53. M.F. Elkady, A.M. Ibrahim, M.M.A. El-Latif, Assessment of the adsorption kinetics, equilibrium and thermodynamic for the potential removal of reactive red dye using eggshell biocomposite beads, Desalination, 278 (2011) 412–423.
  54. K.B. Fontana, E.S. Chaves, J.D.S. Sanchez, E.R.L.R. Watanabe, J.M.T.A. Pietrobelli, G.G. Lenzi, Textile dye removal from aqueous solutions by malt bagasse: isotherm, kinetic and thermodynamic studies, Ecotoxicol. Environ. Saf., 124 (2016) 329–336.
  55. S. Tunali, A.S. Özcan, A. Özcan, T. Gedikbey, Kinetics and equilibrium studies for the adsorption of Acid Red 57 from aqueous solutions onto calcined-alunite, J. Hazard. Mater., 135 (2006) 141–148.
  56. P. Patnukao, A. Kongsuwan, P. Pavasant, Batch studies of adsorption of copper and lead on activated carbon from Eucalyptus camaldulensis Dehn bark, J. Environ. Sci., 20 (2008) 1028–1034.
  57. J.-Q. Jiang, C. Cooper, S. Ouki, Comparison of modified montmorillonite adsorbents: Part I: preparation, characterization and phenol adsorption, Chemosphere, 47 (2002) 711–716.
  58. M. Diab, A.Z. El-Sonbati, A.A. El-Bindary, K.S. Mohamed, A.A. Al-Sarawy and M.A. Farid, Removal of hazardous azocoumarin dye from aqueous solutions using activated carbon prepared from rice straw, Desal. Wat. Treat., 57 (2016) 19391–19401.
  59. R.M. Novais, G. Ascensão, D.M. Tobaldi, M.P. Seabra, J.A. Labrincha, Biomass fly ash geopolymer monoliths for effective methylene blue removal from wastewaters, J. Cleaner Prod., 171 (2018) 783–794.
  60. Y. Liu, C. Yan, Z. Zhang, Y. Gong, H. Wang, X. Qiu, A facile method for preparation of floatable and permeable fly ashbased geopolymer block, Mater. Lett., 185 (2016) 370–373.
  61. Y. Liu, Y.-J. Liu, Biosorption isotherms, kinetics and thermodynamics, Sep. Purif. Technol., 61 (2008) 229–242.