Preparation Of Magnetic Cationic Cyclodextrin Polymer And Its Adsorption Mechanism

Dye wastewater has the characteristics of larger discharge,complex components and difficult governance,which brings serious harm to human health and ecological environment.Currently,some reseachers used activated diatomite and cinder to deal with the dye wastewater,although excellent results has been abtained,the poor selectivity and separation also are concerned.Therefore,in this work,a multi-cavity cationic cyclodextrin polymer(GEP-CD)with numbers of active functional groups(-OH and-COOH),which was prepared by succinic anhydride(SA)and three epoxy propyl trimethyl ammonium chloride(GTA),and beta-cyclodextrin(p-CD),and those monomers occured self-polymerization under weak acid condition.The magnetic cationic cyclodextrin polymer(GEPCD-MNPs)with the performance of easy separation and high specific surface area was obtained from the esterification reaction between GEP-CD and Fe3O4 nanoparticles(MNPs).A series characterizes of GEPCD-MNPs,such as the chemical structure,the type of crystal,magnetic properties,morphology and thermal stability were investigated by infrared spectroscopy(FT-IR),X ray diffraction(XRD),hysteresis loop(VSM),automatic surface area and pore structure analysis(BET)data,photo of scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)and thermal(TGA)curve.Then the zata potential and contact angle were measured to characterize the isoelectric point and wettability of the product.In the adsorption performance evaluation of GEPCD-MNPs of Congo red(CR)and six chromium(Cr(VI)).Researches about adsorbent dosage,reaction time and temperature,the initial concentration of dye,pH and other factors based on adsorption process between the as-parepared adsorbent and the dye through the static adsorption test.The adsorption kinetics of dyes on GEPCD-MNPs was studied by the Pseudo-first-order model and the Pseudo-second-order model.The adsorption isotherm of CR and Cr(VI)on the GEPCD-MNPs were studied by Langmuir model,Freundlich model and Dubinin-Radushkevich model.The thermodynamic properties of dye adsorption were further studied according to the Van't Hoff equation.In this paper,the reuse performance of adsorbent was discussed,which shows the promising future for the practical application.The findings show that,1)the magnetic adsorbent GEPCD-MNPs was prepared at the optimal conditions.Series of characterization methods for this adsorbent reveals that it is a multi-cavity layered polymer(SEM),showed better superparamagnetic properties(VSM)and has a large number of active groups(FT-IR)and a certain amount of positive charge(Zata).2)The maximum adsorption capacity of GEPCD-MNPs for CR and Cr(?)were 389.1mg/g and1l8mg/g,respectively.3)The adsorption data of GEPCD-MNPs for CR,Cr(?))and CR-Cr(?)were in accordance with the pseudo-second-order model.The adsorption isotherm,both of Congo red and six chromium adsorbed on GEPCD-MNPs can be well described by Freundlich isotherm model.The thermodynamic data show that the adsorption process of GEPCD-MNPs for CR and Cr(?)is endothermic process and the adsorption process is a process of entropy increase,and the adsorption process of GEPCD-MNPs of CR and Cr(?)is spontaneous.4)The adsorption of GEPCD-MNPs on CR is economically feasible.