Removal Of Heavy Metal Ions From Water Based On New Porous Magnetic Adsorption Materials

With the progress of social industrialization process,all kinds of industrial pollution is rampant in our daily life,among which the problem of heavy metals affecting human health is a hot spot of continuous attention.Heavy metal pollution in the water body has had a serious impact on food safety.The water polluted by heavy metal will not only directly enter the human body as food raw materials,but also indirectly enter the human body through the food chain through breeding,irrigation,livestock feeding and other ways.In recent years,researchers have developed various types of enriched materials based on heavy metal ion adsorption,among which magnetic materials represented by Fe3O4 have the advantages of easy solid and liquid separation,many active sites,easy functionalization modification and recycling,and the application in heavy metal enrichment shows a rapid rising trend.In this study,magnetic NH₂-Fe₃O₄was used as the carrier,combined with covalent organic framework（COFs）with high specific surface area,excellent mesoporous structure and versatile adsorption of ionic liquids（ILs）,a new porous magnetic enrichment material Fe₃O₄@COFs@ApMeIm⁺PF₆^-for the adsorption of heavy metal ions has been successfully prepared by combining various techniques such as chemical derivation,mesoporous enhancement and functionalization,and the morphology,structure and magnetic properties were systematically characterized by Tem,SEM and XPS.The porosity,large specific surface area and superparamagnetism are well maintained,and the introduction of COFs improved the loading amount of thiol behaving as adsorption sites for heavy metal ions capture,where P content was as high as 12.7%（atomic conc%）.The resultant adsorbent exhibited a powerful absorption for Mn²⁺,Pb²⁺and Cu²⁺capture from water with maximum adsorption capacities as high as 278 mg/g,192 mg/g,208mg/g,respectively,where the adsorption equilibrium could be achieved within 30 min.The prepared adsorbents were further employed to capture Mn²⁺,Pb²⁺and Cu²⁺in water showing high removal efficiency and selectivity even among coexisting metal ions(K^+,Ca²⁺,Na⁺,Mg²⁺,Fe³⁺,Hg²⁺,Cd²⁺,Zn²⁺,Cr³⁺).After 7 cycles of adsorption-desorption experiments,the removal efficiency of target ions can be reduced by no more than 10%.These results show that the prepared adsorbents have high practical value.