Synthesis Zeolite NaA(X Type) From Fly Ash Via Alkaline Fusion Method And Their Adsorption Of Basic Dye In Wasterwater

Single-phase zeolites NaA and NaX were synthesized from fly ash using alkaline fusion method via hydrothermal reaction.Experimental results show that NaOH/fly ash molar ratio and crystallization time of aluminosilicate gel affect the progress of products.Analysis of XRD and IR spectra shows that the synthesized products possess the structure of zeolites NaA and NaX without the presence of other phases,respectively.SEM observation illustrates that the synthetic products are cubic and octahedral zeolitic particles,respectively.DTA curves indicate the presence of zeolitic water in the synthetic products.The CEC values,surface area and pore volume of the synthetic zeolites NaA and NaX from fly ash reach to 82.93%and 84.31%;83.6%and 66.9%;83.6%and 66.9%when compare with these of the corresponding commercial zeolites,respectively.The removal performance of a basic dye,methylene blue, in aqueous solution were investigated by adsorption process on the synthetic zeolites A and X from fly ash.Batch method was employed to study the influential parameters including initial pH value of the solution,temperatures and adsorbents dosage on the adsorption process.The suitability of Langmuir and Freundlich isotherms to the equilibrium data were studied in the solid-liquid system while the Langmuir model produces the best results.Thermodynamic data (ΔH,ΔS andΔG)corresponding to methylene blue uptake were evaluated from the Langmuir model.The existing fashion and size of MB in aqueous solution are important influential factors on adsorption behavior.Moving Boundary Model analysis shows that the adsorption rate of MB was mainly governed by liquid film diffusion.The adsorption processes of MB follow a pseudo-second-order kinetic model.In all the experiments,adsorption capacity of the synthetic zeolite X was found to be higher than that of the synthetic zeolite A.Attempts were also made to recover methylene blue and regenerate adsorbents.