| Copper is one of the most important essential trace elements to all higher plants andanimals. but like most of the heavy metal ions, it is potentially toxic, and cause seriousdamage to human health and the surrounding ecosystem, as excess in the human body or theenvironment. So an efficient and rational processing technology for separation and recycle ofcopper will be of great significance in the industrial fields.A copper(II) ion imprinted polymer/aluminium oxide (IIP/Al2O3) has been prepared withthe surface-grafted and surface imprinting technologies for selective adsorption of Cu(II) fromaqueous solutions. Al2O3powder, modified with tetraethyl orthosilicate, was used as thecarrier material. Chitosan was employed as the functional monomer. The prepared IIP/Al2O3was characterized by using the infrared spectra, scanning electron microscopy, energydispersive X-Ray spectroscopy and thermogravimetric analysis. Results show that, the copperion imprinted chitosan was grafted on the surface of Al2O3, and the grafting ratio was3.42g/g.The behavior of static adsorption of Cu(II) on IIP/Al2O3were investigated in detail, theeffect of pH and initial concentration of Cu(II) on the adsorption capacity of IIP/Al2O3wereinvestigated, and the adsorption kinetic, adsorption isotherm, thermodynamics of IIP/Al2O3were also studied. Results show that, the kinetic data are fitted well by the pseudosecond-order model. The adsorption equilibrium data are fitted well by the Langmuirisotherm model. The thermodynamic parameters indicate that the adsorption of Cu(II) onIIP/Al2O3is an endothermic and spontaneous process. The adsorption equilibrium data arefitted well by the Langmuir isotherm model, and the maximum adsorption capacities ofIIP/Al2O3are31.35mg/g at298K,34.66mg/g at313K,38.91mg/g at318K and41.39mg/g at323K, respectively.Further, the selectivity experiment was done for the mixedsolutions containing Cu(II), Ni(II) and Zn(II). The selectivity factors of Cu(II) on IIP/Al2O3are much higher than those of other studied ions. After Cu(II) adsorption-desorption cycleswere repeated ten times by using the same IIP/Al2O3, the adsorption capacity of IIP/Al2O3isdecreased only2%. The IIP/Al2O3shows good stability and reusable propertiesThe behavior of dynamic adsorption of Cu(II) on IIP/Al2O3were investigated in detail,the effect of various parameters such as initial concentration of Cu(II), column height, flow rateand pH on the the breakthrough characteristics of the dynamic adsorption system wereinvestigated, and various models such as Thomas model, Yoon-Nelson model, Wolborskamodel and Bed Depth Service Time (BDST)model have been employed to fit theexperimental data. Further, a series of tests were performed to optimize the parameters of thedynamic desorption. The results indicated that, breakthrough capacity and dynamic adsorptioncapacity of the IIP/Al2O3were4.03and15.68mg/g, respectively, at Cu2+inlet concentrationof100mg/L, IIP/Al2O3column height of37.25mm, flow rate of1.0mL/min and pH value of5. The Thomas and Yoon-Nelson models fit well the experimental data of dynamic adsorption. BDST model is suitable to describe relationship between breakthrough time and the column height ofdynamic adsorption behavior of Cu2+on IIP/Al2O3column.15mL hydrochloric acid solution of0.6mol/L resulted in a good desorption of Cu2+at IIP/Al2O3column height of37.25mm and flowrate of1.0mL/min. Desorption time is short, and Cu2+was easily recycled. The IIP/Al2O3column showed good characteristics, such as high selectivity and good reusability. Theamount of breakthrough capacity and dynamic adsorption capacity were decreased only5.2%and3.0%respectively after adsorption-desorption cycles were repeated5times. |
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