Preparation Of Carbomethl Chitosan Magnetic Montmorillonite And Adsorption Properties For Pb(Ⅱ) And Ni(Ⅱ) Ions

At present,the frequently-used methods of separating adsorbent mainly include centrifugal separation,membrane separation,and magnetic separation,but all of them have problems such as complex process,time-consuming and energy-consuming.The research and development of adsorbents with high adsorption,easy separation,and recyclability have great significance for the treatment of actual sewage.Montmorillonite is a kind of natural mineral with abundant reserves,low processing cost and high adsorption property,which has great application potential in the field of heavy metal wastewater prevention.As a flocculant,carboxymethyl chitosan can promote the aggregation and sedimentation of the adsorbents and realize low-cost and rapid separation.Moreover,its structure contains a variety of functional groups,which can also improve the adsorption capacity to heavy metal ions.Therefore,in this paper,the carboxymethyl chitosan magnetic montmorillonite composite(CMC-Mt@MH)with excellent adsorption performance and easy separation was prepared by solvent thermal method,plasma surface modification and optimizing preparation technology.The surface morphology,structure,composition and other physical and chemical properties of the composites were studied by using the combination of modern characterization methods.The potential application of functionalized montmorillonite in the removal of Pb(Ⅱ)and Ni(Ⅱ)from wastewater was explored.The conclusions are as follows(1)The characterization results of SEM,EDS,XRD,XPS,FT-IR and others showed that carboxymethyl chitosan magnetic montmorillonite composite(CMC-Mt@MH)has been prepared successfully by solvothermal method and plasma technology(2)CMC-Mt@MH has superparamagnetism and can be quickly separated from water under the action of external magnetic force;Moreover,the composite material has good sedimentation ability and can be separated from water quickly and efficiently by self-weight The above operations increase the particle size of the material,so that the material has excellent properties of rapid sedimentation(3)The grafting of carboxymethyl chitosan can improve the adsorption capacity of Mt@MH for heavy metal ions.The adsorption rates of Pb(Ⅱ)and Ni(Ⅱ)on CMC-Mt@MH were increased by 33.13%and 39.48%,respectively.The-OH,-NH-and-COOH on the structure of carboxymethyl chitosan can effectively increase the binding sites of the material to heavy metal ions,thus improving the adsorption performance(4)The adsorption property of CMC-Mt@MH for Pb(Ⅱ)and Ni(Ⅱ)is related to the medium of solid-liquid mixture system,and the effect of solution pH value is the most significant.CMC-Mt@MH has fast and efficient adsorption behavior for Pb(Ⅱ)and Ni(Ⅱ),and it only takes 2 h to reach equilibrium.Meanwhile,The adsorption process of Pb(Ⅱ)and Ni(Ⅱ)can be described by the pseudo-second kinetic model and followed the Langmuir isotherm adsorption equation.Thermodynamic analysis shows that the adsorption of Pb(Ⅱ)on CMC-Mt@MH was exothermic reaction and the adsorption process of Ni(Ⅱ)was endothermic reaction.