Study on adsorption of methylene blue by activated carbon with acid/alkali synergistically modified fly ash
Fly ash and activated carbon were used as the raw materials.Sodium hydroxide,potassium hydroxide,phosphoric acid and hydrochloric acid solutions were used as the activators respectively.The modified fly ash microspheres were pre-pared by suspension solidification method,and the mixture was according to the design ratio m(activated carbon)∶m(fly ash)∶m(activator)∶m(H2O)=3∶7∶6∶14.The microspheres were characterized by XRD,SEM,BET and UV visible spectro-photometer.The effects of mass,concentration,temperature,time,and other factors on the adsorption of methylene blue on the microspheres were explored.The results showed that the microspheres had good pore size,good specific surface area value,and good adsorption effect.Among them,C-NaOH-FM,C-KOH-FM,and C-HCl-FM microspheres exhibited better adsorption performance than C-H3PO4-FM microspheres.At T=55℃,the removal rate of C-HCl-FM microspheres reached 100%.Under the conditions(m=0.10 g、ρ0=10 mg/L、T=25℃),the adsorption process of C-KOH-FM and C-HCl-FM mi-crospheres followed the pseudo-second-order kinetic equation,the equilibrium adsorption capacities were 8.93 mg/g and 9.07 mg/g,the removal rates were 90.05%and 95.36%.
fly ashactivated carbonacid/alkali synergistic modificationadsorptionmethylene blue
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