Preparation And Performance Research Of Two Porous Materials For The Absorption Of Methylene Blue

In this paper,the gasification fly ash was used as raw material to synthesize zeolite molecular sieve by alkali fusion-hydrothermal synthesis method.The effects of ash/alkali ratio,calcination temperature,hydrothermal temperature and hydrothermal time on the crystallinity and type of zeolite were discussed and the optimum conditions for the synthesis of zeolite molecular sieves using gasification fly ash were optimized.The results showed that the optimum conditions for the synthesis of zeolite molecular sieves using gasification fly ash are as follows,ash-base ratio 1:1.5,calcination temperature 550 oC,hydrothermal crystallization temperature 80 oC and hydrothermal crystallization time 24 h.X-ray powder diffraction(XRD)analysis showed that Na X zeolite and Na A zeolite with high crystallinity and single crystal were successfully synthesized by gasification fly ash.Scanning electron microscopy(SEM)and nitrogen adsorption-desorption(BET)analyses showed that the synthesized Na X zeolite has an octahedral crystal structure and a large specific surface area.The corncob-based activated carbon were prepared using potassium hydrogencarbonate activation method and potassium hydroxide activation methods.SEM analysis showed that the corncob-based activated carbon has a regular layered structure and porosity.Fourier infrared spectroscopy(FT-IR)analysis indicated that the surface of the synthesized activated carbon contain a large amount of oxygen-containing functional groups.BET analysis showed that the specific surface area and total pore volume(VT)of the prepared corncob-based activated carbon using potassium hydrogencarbonate activation method are 1205.9 m2/g and 0.507 cm3/g,respectively,and the micropore volume(Vm)accounts for 91.7% of the total pore volume.The specific surface areas of activated carbon from the black liquid and residue of corncob by potassium hydroxide activation method were 1687.26.0 m2/g and 1914.15.0 m2/g,respectively,and the total pore volume(VT)were 0.77 cm3/g and 1.02 cm3/g,respectively.The prepared zeolite molecular sieve and corncob-based activated carbon were used as adsorbents to investigate the effects of adsorbent dosage,initial concentration,p H value,adsorption temperature and adsorption time on the adsorption performance of methylene blue in simulated wastewater.The adsorption kinetics and thermodynamics of MB adsorptionof onto zeolite molecular sieve and corncob-based activated carbon were discussed.The results showed that the optimal conditions for MB adsorption onto zeolite molecular sieve are as follows,adsorption dose 100 mg,initial solution concentration 100 mg/L,solution p H=7,reaction time 24 h.The optimal conditions for MB adsorption ontocorncob-based activated carbon prepared by potassium bicarbonate activation method as follows,adsorption dose 40mg,initial solution concentration 150 mg/L,solution p H=7,and reaction time 12 h.The adsorption of MB onto zeolite molecular sieve conformed to the pseudo-second kinetic model and the Langmuir adsorption isotherm,and the adsorption process is an spontaneous endothermic process.The adsorption of MB ont corncob-based activated carbon prepared by potassium bicarbonate activation method conforms to the pseudo-second order kinetic model and the Langmuir adsorption isotherm.The adsorption process of MB onto corncob-based activated carbon prepared by potassium hydroxide activation method conforms to the pseudofirst order kinetic model and the Langmuir adsorption isotherm,and the adsorption process is an endothermic process.