Adsorption Of Uranium(?) In Water By MY@SiO₂-PEI Composite Biomaterials

Uranium mining and uranium utilization process will produce a large number of uranium containing wastewater,to the ecological environment and public health has brought serious threats,how to efficiently and safely treat radioactive wastewater has become an increasingly concerned problem.There are many methods to separate uranium in water,such as adsorption method,with the advantages of easy operation,low cost,high treatment efficiency and good selectivity,it is considered to be the most promising treatment of low concentration uranium-containing wastewater way.Single adsorbent or has the problem of low adsorption efficiency and high cost,composite biological adsorbents with its advantages in the removal cost and removal rate become the most attractive physical and chemical adsorbents substitute.Therefore,in this study,polyethylene imine(PEI)modified magnetic yeast composite biomaterial(MY@Si O₂-PEI)was prepared by two-step solution synthesis method to obtained Higher uranium removal efficiency.The samples were characterized by SEM-EDS,FTIR,Zeta potential and XPS.The distribution of U(VI)under different conditions was simulated by Visual MINTEQ,and different solutions were studied.In terms of temperature,reaction time,ionic strength and different initial mass concentration of U(VI),the effects of different factors on the U(VI)adsorption performance of MY@Si O₂-PEI were investigated,and the recycling ability of MY@Si O₂-PEI was also studied.The effects of six kinds of anions(CO₃^2-,PO₄^3-,SO₄^2-,Cl^-,NO₃^-,HA)on the adsorption performance of MY@Si O₂-PEI and MY@Si O₂-PEI on the adsorption performance of U(VI)were investigated by partial factor design.The specific work research and results of this paper can be divided into the following two aspects:In the first part,Polyethylenimine(PEI)modified magnetic yeast composite(MY@Si O₂-PEI)was prepared by a two-step solution synthesis method and used as an adsorbent to remove uranium ions from water.In the static adsorption test,it was found that the adsorption of U(VI)by adsorption materials showed strong p H-dependence,and the ionic strength had no significant interference on the adsorption effect,indicating that the reaction was mainly controlled by surface complexation.FTIR,XPS and Zeta potential analysis showed that the main factors that promoted the adsorption of U(VI)were the complexation and electrostatic attraction of different functional groups(N=C,NH(NH₂),C-N=C)and U(VI)on the surface of the material.The maximum adsorption capacity of MY@Si O₂-PEI can reach 173.99mg/g,and the adsorption equilibrium can be reached after 20min.The quasi-second-order kinetics and Langmuir isotherm equation can fit the adsorption process well,and thermodynamics shows that the adsorption process is spontaneous heat absorption process.In the second part,the effects of six kinds of inorganic electrolyte anions on the adsorption of U(VI)by polyethylenimine(PEI)modified magnetic yeast composite biomaterial(MY@Si O₂-PEI)were studied.The effects of six anions(CO₃^2-,PO₄^3-,SO₄^2-,Cl^-,NO₃^-,HA)on the adsorption of U(VI)by MY@Si O₂-PEI in a multicomponent system were investigated by using a 2^6-2 Fractional factorial design(FFD).The effects of six anions(CO₃^2-,PO₄^3-,SO₄^2-,Cl^-,NO₃^-,HA)on the adsorption of U(VI)by MY@Si O₂-PEI in a multicomponent system were investigated by using a 2^6-2 Fractional factorial design(FFD).In mono electrolyte,at low p H,the adsorption capacity of U(VI)is positively correlated with PO₄^3-and HA,but negatively correlated with SO₄^2-and CO₃^2-,and the presence of NO₃^-or Cl^-has little effect on the adsorption capacity of U(VI).According to FFD simulation calculation,it is estimated that the factor effect of six different anions on MY@Si O₂-PEI adsorption of U(VI)in the multi-ion system is CO₃^2->Cl^->HA>PO₄^3->SO₄^2->NO₃^-,according to the curve cross diagram,it can be seen that the joint effect of AB(Cl^-*NO₃^-)and BD(NO₃^-*SO₄^2-)has a significant impact on the removal of U(VI).