Preparation And Properties Of Magnetic Chitosan Microsphere Sorbent Removal Of Heavy Metal Ions In Solution

Chitosan is the only natual alkaline polysaccharide,and its raw materials is rich.In recent years,the made of chitosan adsorption is more and more mature.Because of its unique features,chitosan is applied in the field of medicine,foodstuff,material and environment protection.There are lots of amino and hydroxyl groups in the chain of chitosan,which form equatorial bond.Therefore,it has certain removal efficiency on transition element ions.Chitosan absorption research has significant application value.In this experiment,magnetic chitosan microspheres were prepared by the way of reverse phase crossliking.Cross-liking agent,such as aldehyde,glutaraldehyde,was added to achieve chitosan molecules cross-lingking.In this process,attention was paid to control the mixing time,reaction pH,temperature and other steps,the product magnetic chitosan microspheres?M-CS?was prepared.The results of SEM showed that the prepared M-CS had good fineness and its size distribution was uniform.In this study,the M-CS adsorption properties for Cu²⁺,Zn²⁺ and Mn²⁺were investigated from four aspects:asdorption time,amount of adsorbent,pH value and initial concentration of stndard solution.According to the different factors of the study,the prepared M-CS was added to the three kinds heavy metal ion solution of different concentrations,and remove experiment proceeded.The results of adsorption kinetics showed that quasi-second-order kinetics model can better characterize the adsorption behavior of magnetic chitosan microspheres on Cu²⁺,Zn²⁺ and Mn²⁺,which indicates that the adsorption of heavy metal ions by magnetic chitosan microspheres is mainly controlled by chemical action.The results of adsorption thermodynamics showed that the experimental data are in accordance with the Langmuir isothermal adsorption equation better,compared with the Freundlich isothermal equation.Initial stage,adsorption reaction's speed is high,the reaction basically reached the adsorption balance after 1 to 2 hours.In the experimental range,the adsorption effect is optimal under the pH = 5 value.Under certain conditions,the equilibrium adsorption capacity of M-CShigh to Cu²⁺,Zn²⁺ and Mn²⁺ reached 166.34mg/g,165.42mg/g and 150.88mg/g respectively.M-CSlow adsorption capacity are 161.53mg/g,150.83mg/g and 151.32mg/g respectively.Experimental results show,the M-CShigh and the M-CSlow showed good adsorption properties for the three metal ions,and the adsorption capacity is ideal.The paramagnetism of magnetic chitosan microspheres were characterized by magnetic field precipitation experiments.Under the presence of magnetic field,M-CS has good magnetic separation performance,which contribute to be combined with high gradient magnetic separation technology to achieve rapid separation and recovery of M-CS from water.