| With the development of The Times,people’s material life is getting better at the same time,the degree of industrialization of various industries is also increasing,and the harm is also increasing.All kinds of wastes produced in industrial production activities are continuously discharged into rivers and lakes.Many of them contain heavy metals,and most of these heavy metals are radioactive and have a long decay period,which is difficult to disappear in a short time.When people misuse water containing these heavy metal ions,it will cause serious harm to human body.China is a country with a large population,but the water resources in our country are quite plentiful,and the water resources have been destroyed to different degrees for various reasons.Therefore,the remediation of polluted groundwater has become an urgent problem to be solved by all sectors of society.In this paper,the heavy metal uranium(U)and rhenium(Re)pollution in groundwater are studied,and the adsorption method is used to repair it.Firstly,a new nano-composite TNTs-Fe S was prepared from titanate nanotubes and ferrous sulfide by coprecipitation method,and was applied to the adsorption of U(Ⅵ)and Re(Ⅶ).Then,static batch experiment and dynamic column experiment were set up.In the static adsorption experiment,the influence of different factors on the adsorption was mainly considered,and the adsorption mechanism of TNTs-Fe S was analyzed by combining SEM-EDS,TEM,XRD and XPS characterization techniques.The dynamic column experiment considers the influence of velocity and adsorbed material on the experiment.According to the above experimental research,the following results and conclusions are drawn.(1)In the static adsorption experiment,p H,initial concentration,adsorbent dosage and time were used as variables to explore the adsorption effect of TNTs-Fe S on U(Ⅵ)and Re(Ⅶ).The optimum adsorption p H of U(Ⅵ)and Re(Ⅶ)is 7 and 12,respectively.The adsorption capacity of both increases with the increase of the concentration.On the contrary,the adsorption capacity of U(Ⅵ)and Re(Ⅶ)decreases with the increase of the dosage of TNTs-Fe S.The highest adsorption capacity of U(Ⅵ)is 290.40 mg/g,and the highest adsorption capacity of Re(Ⅶ)is 226.24 mg/g.Then,according to the results of batch experiments,different kinetic model fitting analyses were carried out on U(Ⅵ)and Re(Ⅶ)respectively.The results showed that both of them were in line with the quasi-second-order kinetic model.In the fitting analysis of isotherm model,the adsorption of TNTs-Fe S on U(Ⅵ)and Re(Ⅶ)was more in line with the Freundlich model.In other words,the adsorption process of U(Ⅵ)and Re(Ⅶ)is mainly chemisorption.The results show that TNTs-Fe S composite material can be used as adsorption medium to effectively remove U(Ⅵ)and Re(Ⅶ)pollutants.(2)In the dynamic column experiment,columns with different flow rates and adsorption materials were set respectively.No matter the flow rate was 6m L/h or 15 m L/h,the adsorption effect of quartz sand on Re(Ⅶ)was limited,but the adsorption rate increased significantly after adding TNTs-Fe S.The results show that TNTs-Fe S composites can increase the adsorption effect of natural quartz sand under the condition of groundwater flow,which indicates that TNTS-Fe S composites can still be used as a good adsorption medium to remove Re(Ⅶ)in groundwater under dynamic conditions. |
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