Preparation And Performance Study Of Surface Imprinted Adsorption Materials For Lead (II) Ions And Cobalt (II) Ion

Lead（Ⅱ）ions and cobalt（Ⅱ）ions are two common toxic heavy metals,which are difficult to degrade and have bioaccumulation.If industrial activities produce lead-containing wastewater or cobalt-containing wastewater,it will not only pose a threat to the health of organisms,but also cause a waste of resources.Functional polymer materials prepared by metal ion imprinting technology（IIT）have abundant coordination groups and sufficient active sites,and have a high degree of specific recognition and chemical stability for target ions,which have been widely used in the field of metal ion adsorption and separation.However,there are still some shortcomings in the study of IIT.For example,the types of functional monomers are limited,and the adsorption capacity of metal ion imprinted materials prepared needs to be improved,which cannot well meet the requirements of metal ion adsorption and identification.Based on the above factors,a new compound was designed and synthesized in this academic paper,and the carrier material was introduced.Using IIT,Pb（Ⅱ）ion imprinted composite membrane and Co（Ⅱ）ion imprinted polymer were prepared by combining the surface imprinting polymerization method with Pb（Ⅱ）ion imprinted composite membrane and Co（Ⅱ）ion imprinted polymer.The specific research contents are as follows:（1）The self-synthesized compound N,N’-（Ethane-1,2-diyl）bis（2-methylacrylamide）（EBMA）was used as functional monomer,Pb（Ⅱ）ion was used as imprinting ion,and ethylene glycol dimethacrylate（EGDMA）was used as crosslinking agent.A series of Pb（Ⅱ）ion-imprinted composite membranes(Pb（Ⅱ）@EBMA-IICM_1-13)and corresponding non-imprinted composite membranes(Pb（Ⅱ）@EBMA-NICM_1-13)were prepared by combining the single factor method with U₆（6⁴）uniform design experiment and by optimizing the preparation conditions of imprinting system.The structure and properties of the imprinted composite membranes were characterized by FT-IR,SEM-EDS,BET,TGA,ICP-OES and DCA.The results showed that when the mole ratio of imprinted ions Pb（Ⅱ）ions,functional monomer EBMA and crosslinking agent EGDMA was 1:6:50.Nylon-6 composite membrane was used as the base membrane,methanol-water（2:3,v/v）as the pore-forming solvent,the base membrane soaked for 1 min,polymerization for 12 h at 55℃,the composite membrane performance was better.The adsorption capacity of Pb（Ⅱ）@EBMA-IICM was 138.067mg·g^-1,the membrane flux was 2.10 m L·cm^-2·min^-1,and the blotting factor was 2.545.The adsorption process of Pb（Ⅱ）@EBMA-IICM for Pb（Ⅱ）ions was more consistent with Langmuir adsorption model and quasi-first-order kinetic model,which belongs to the physical adsorption of single molecular layer.After 6 h adsorption,Pb（Ⅱ）@EBMA-IICM can support more than 90%Pb（Ⅱ）in the solution.After five adsorption/desorption cycles,the adsorption capacity was still 84%of the initial adsorption capacity,which shows good reusability and regeneration performance.In the system where Cd（Ⅱ）,Cu（Ⅱ）,Ni（Ⅱ）,Zn（Ⅱ）and other competitive ions coexist,the permeability of Pb（Ⅱ）@EBMA-IICM to Pb（Ⅱ）ions was 0.1393 mg·cm^-2·h^-1,which accords with the Piletsky gate model.（2）Vinyl multiwalled carbon nanotubes（VMWCN）were prepared by bromo-propylene modification.Co（Ⅱ）ion was used as imprinting ion,4-vinylpyridine（4-VP）as functional monomer,EGDMA as crosslinking agent,and ethanol-water as pore-forming solvent were used as surface imprinting polymerization method.A series of Co（Ⅱ）ion-imprinted polymers(Co（Ⅱ）@VMWCN-IIP_1-13)and corresponding non-imprinted polymers(Co（Ⅱ）@VMWCN-NIP_1-13)were prepared by using single factor method and U₅（5³）uniform design experiment.The structure and properties of the imprinted polymers were characterized by FT-IR,SEM-EDS,BET and TGA.The results showed that when the imprinted ion Co（Ⅱ）ion:4-VP:When the molar ratio of crosslinking agent EGDMA was 1:3:40,the adsorption capacity of Co（Ⅱ）@VMWCN-IIP was 70.58 mg·g^-1,using ethanol-water（1:1,v/v）as pore-forming solvent and 70.00mg ethylenated multi-walled carbon nanotubes as carrier at 70℃for 12 h.The imprinting factor was 1.857.When the p H of the adsorption solution was about 5,the adsorption time was 180 min,and the Co（Ⅱ）ions in the solution could reach the equilibrium state.The adsorption behavior of Co（Ⅱ）ions of the imprinted polymer was consistent with the Freundlich adsorption model and the quasi-first-order kinetic model,which belonged to the multi-molecular layer physical adsorption behavior.