Study On The Adsorption Of Dye By Modified Illite And Oyster Shells

In the field of dyeing waste water treatment,clay mineral has been widely applied.Illite is a sort of typical clay minerals which has good decolorization and decontamination performance as a kind of wewage teeatment agent.Because of the electronegatifity of the natural illite,the adsorption of negative charged dye molecules is limited.After modification,the adsorption performance of negative charged dye molecules can be improved.As Fuzhou is a coastal city,large quantities of oyster shells are abandoned,which cause wasting of resoureces and environmental pollution.Based on using waste to treat waste,the adsorption of dyeing waste water by using oyster shells was studied,which offer theoretical evidence for the comprehensive utilization of oyster shell via preventing the dyestuff pollution.The surface modification of the illite by cetyl trimethyl ammonium bromide(CTMAB)and chitosan were studied,the surface modification of the oyster shells by chitosan was studied.Illite,CTMAB modified illite,chitosan modified illite,chitosan modified oyster shells were characterized by infrared spectroscopy(FTIR),scanning electron microscope(SEM),X-ray diffraction(XRD),and thermo gravimetric analysis(TG).The adsorption behavior of CTMAB modified illite for reactive brilliant blue K-GR,chitosan modified illite for reactive red KD-8B,chitosan modified oyster shells for direct red 4BS were studied.The evaluation of adsorption behavior was studied of adsorption mechanisms of modified adsorbents were focused on this study.Meanwhile,the adsorbents performance was investigated with simulated wastewater.The main research content and results of this work are drawn as follows:Influence of quality ratio,pH,dosage of the adsorbent and other factor to adsorption efficiency were researched in this paper,Results showed that:CTMAB modified illite owing significantly adsorbent capacity and high decolorization rate in treating simulated water reactive brilliant blue K-GR.the optimal adsorption condition was:0.125 as the mass ratio of CTMAB to illites,pH 3,0.3 g as the dosage of the adsorbents,90 min as the adsorption time.Chitosan modified illite owing good adsorption performance to reactive red KD-8B.the optimal adsorption condition was:0.13 as the mass ratio of chitosan to illites,pH 5,0.6 g as the dosage of the adsorbents,120 min as the adsorption time.Chitosan modified oyster shells owing good adsorption performance to direct red 4BS.the optimal adsorption condition was:0.08 as the mass ratio of chitosan to oyster shells,pH 2,0.7 g as the dosage of the adsorbents,120 min as the adsorption time.The evaluation of adsorption isotherms,adsorption kinetics and adsorption thermodynamic characteristics of those adsorption behaviors were focused on in this study.The Langmuir and Freundlich were used to simulate the sorption isotherms at four different temperatures and the thermodynamic parameters calculated from the temperature dependent sorption isotherms.The adsorption process conformed the pseudo-second-order reaction kinetics equation and the equilibrium isotherm was well described by Langmuir adsorption model.In thermodynamic studies,the parameters of ?G0<0,?H0>0,?S0>0 indicated that the adsorption process was spontaneous and endothermic with an increase in entropy.