Study On The Adsorption Properties Of Metal Oxide Composite Nanofibers For Heavy Metal Ions And Organic Dyes In Water

The rapid development of industry in modern society has promoted the economic construction,but the industrial wastewater discharged in the production process has lead to a large area of environmental pollution.In order to reduce the pollution rate of industrial wastewater,the development of effective industrial wastewater treatment technology is of vital importance to the times and the situation.Among the existing treatment methods for heavy metal ions and dye wastewater,the adsorption method with high adsorption efficiency and adsorption rate has been widely used.However,the adsorption method is difficult to remove solid waste or suspended solids in the actual treatment of industrial wastewater.At the same time,the reusable performance of the adsorbent is low,so that this method has not been smoothly applied in actual situations.In order to make up for the shortcomings of traditional adsorbents,researchers turned their attention to nano-scale metal oxide adsorbents that have the advantages of excellent adsorption performance,easy modification and regeneration,fast adsorption rate,and high reactivity.Among them,iron oxides and manganese oxides are used as adsorption materials for wastewater treatment,which has always been a hot topic of investigation.The preparation method of hydrothermal synthesis has been frequently used by researchers because of its simple operation,controllable morphology of synthetic materials,high magnetic absorption ability of synthetic materials,better dispersion in liquid,low resource cost,high safety and low pollution rate.At the same time,the fiber produced by electrospinning technology has a large specific surface area,fine diameter,high porosity,and modifiable properties,so it is also used as an adsorption filter material.Therefore,in this paper,PAN/PEI electrospun nanofibers are used as the matrix materials,and a functionalized nano-metal oxide fiber adsorbent was prepared by hydrothermally supporting metal oxide.The structure and performance were characterized respectively,and the effect of adsorption performance was studied.The main research contents of this paper include the following two parts:1.PAN/PEI nanofibers were prepared by electrospinning technology,processed by ferrous sulfate heptahydrate(Fe SO₄�7H₂O),and then Fe₃O₄was loaded onto the surface of PAN/PEI nanofibers by hydrothermal synthesis to prepare PAN/PEI@Fe₃O₄nanofibers.The selective adsorption experiment was carried out to investigate the influence of p H value,adsorbent dosage,adsorption time and adsorption temperature on the adsorption performance of PAN/PEI@Fe₃O₄nanofibers.The results indicated that Fe₃O₄particles were successfully loaded on the surface of PAN/PEI nanofibers.The selectivity experiments results showed that PAN/PEI@Fe₃O₄nanofibers have a significant adsorption effect on methyl orange(MO)dye solution.The adsorption isotherm of MO conformed to the Langmuir model,and the maximum theoretical adsorption capacity was 277.78 mg/g.And the adsorption of MO by PAN/PEI@Fe₃O₄nanofibers conformed to the quasi-second-order kinetic model.Finally,through the adsorption-desorption experiment,the adsorbent PAN/PEI@Fe₃O₄nanofibers showed excellent ability to be reused.2.The PAN/PEI nanofibers were prepared by electrospinning technology.After KMnO₄solution treatment,MnO₂was loaded on the surface of the fiber by hydrothermal method to prepare PAN/PEI@MnO₂nanofibers.The adsorption performance of nanofibers lead ions(Pb²⁺)was investigated,and comparatively studied the removal rate of Pb²⁺by PAN,PAN/PEI,PAN/PEI@MnO₂three kinds of fibers.And the effect of coexisting ions on the adsorption of Pb²⁺by the adsorbent.The results indicated that the adsorption isotherm of Pb²⁺by PAN/PEI@MnO₂nanofibers conformed to the Langmuir model,the maximum theoretical adsorption capacity was 204.08 mg/g,and the adsorption process conformed to the quasi-second-order dynamic model.In the comparative adsorption experiment of the three fibers,it was found that the removal rate of Pb²⁺by PAN/PEI@MnO₂nanofibers was higher than that of the other two fibers.In the coexisting ion experiment,PAN/PEI@MnO₂nanofibers showed their superiority in removing Pb²⁺.Through five adsorption-desorption experiments,it was found that the PAN/PEI@MnO₂nanofibers could still adsorb more than 57%of Pb²⁺,and it was also proved that the fiber membrane had the reusability.XPS analysis showed that ion exchange was the main mechanism for the Pb²⁺adsorption.