Removal Of Copper And Lead Ions From Water By Molybdenum Disulfide Nanoparticles

With the rapid development of modern urbanization and industrialization,the environmental problems in today’s world are becoming more and more serious.Heavy metals in water are not only a serious threat to human health,but also break the balance of the ecosystem because of their wide range of pollution and can not be degraded.MoS₂ exists in nature in the state of molybdenite.Its structure is similar to graphene.It is hexagonal crystal structure with excellent physicochemical properties and stability.It is often used in lubrication,sensor,catalyst and other fields.Due to its high specific surface area,MoS₂ has become a great success in the field of heavy metal water pollution treatment because of its excellent adsorption performance.In this paper,three kinds of MoS₂ nanoparticles were synthesized by chemical method.The spherical MoS₂ ,the flake MoS₂ prepared by sodium sulfide and sodium molybdate,and the MoS₂ with the inducer acetamide were respectively recorded as p-MoS₂ ,s-MoS₂ and W-Mo S2.The structures and morphologies were characterized by XRD,SEM and XRF,and the pH and adsorption time of the solution were changed The adsorption properties of the three kinds of MoS₂ nanoparticles for copper ion and lead ion in water were comprehensively studied.Finally,the adsorption mechanism was analyzed by kinetic and thermodynamic models.On the basis of the above research,I mainly draw the following conclusions:（1）Three kinds of MoS₂ nanoparticles were prepared by chemical method.The results of XRD,XRF and Raman showed that MoS₂ nanoparticles were successfully prepared.The SEM images showed that s-MoS₂ was spherical particles with agglomeration phenomenon.P-MoS₂ showed sheet structure,w-MoS₂ was irregular shape,and the edge showed fold shape,and the specific surface area was large,which played a key role in the adsorption of heavy metal ions Use.（2）Copper ion solution and lead ion solution were prepared with copper sulfate pentahydrate and lead nitrate respectively for testing.Three kinds of prepared MoS₂ nanoparticles were put into the prepared solution for static adsorption.The effects of different adsorption factors on the adsorption effect were mainly studied.The results showed that under the conditions of pH 6,temperature 80℃,concentration 80 mg/L and adsorption time 8 h,the effect of s-MoS₂ on adsorption was studied The adsorption capacity of copper ion in water is 88.175mg/g.Under the conditions of pH7,temperature 80℃,concentration 80 mg/L and adsorption time 8 h,p-MoS₂ has the best adsorption effect on lead ion in water,and the adsorption capacity can reach106.64 mg/g.（3）At room temperature,the quasi second order kinetic adsorption model was used to describe the adsorption process of copper and lead ions by MoS₂ nanoparticles.In the adsorption isotherm model,Freundlich adsorption isotherm model was used to describe the relationship between the adsorption capacity and the concentration of the adsorbed solution.Parameters N and KP showed that the adsorption performance of s-MoS₂ copper ion was the best,and that of p-MoS₂ for lead ion was the best.Thermodynamic study found that when the Gibbs free energy changeΔg<0,the process of adsorption of heavy metal copper ions and lead ions by MoS₂ nanoparticles is spontaneous,and theΔg decreases continuously,which indicates that the higher the adsorption temperature,the better the adsorption effect.Moreover,the standard enthalpy changeΔH>0 and the standard entropy changeΔs>0,indicating that the adsorption of heavy metal ions by MoS₂ nanoparticles is spontaneous The endothermic process of.In conclusion,MoS₂ nanoparticles can be used as an effective nano material to remove heavy metal ions from water,which also proves that MoS₂ nanoparticles have broad application prospects in the field of water environment treatment.