Preparation And Selective Properties Of Surface Molecular Imprinted Materials Based On The Graft Polymerization Of 2-D Montmorillonite

Montmorillonite is an natural mineral material,which has abundant storage in our country and has great potential in the treatment of water pollution.It has many advantages,such as large specific surface area,excellent adsorption property and friendly environment.The effective use of montmorillonite resources is important to solve the problems of shortage of resources and environmental pollution.In this paper,the surface of montmorillonite was modified by the means of surface molecular imprinted andcontrolled/activefreeradicalpolymerizationtechnique,using micrometer montmorillonite as matrix.This modification not only make the montmorillonite has the selectivity,but also solve the shortcomings of the traditional imprinted complex,such as the heterogeneous organic molecular polymerization,theuncontrollablegraftoforganicmolecules,the unsatisfactory graft,which result in the large mass transfer resistance,low adsorption efficiency,slow adsorption rate,poor stability and low reuse rate and so on.1.Usingelectrontransferactivatedatomtransferfreeradical polymerization?AGET-ATRP?technologyandpoly?hydroxyethyl methacrylate??HEMA?monomer,the montmorillonite is synthesized to poly?hydroxyethyl methacrylate?composite.Then the hydroxamic acid group is grafted on the surface of montmorillonite by nucleophilic substitution,and Pb²⁺ions as the template,glycol diglycidyl ether as cross-linkingagentissynthesizedtoPb²⁺-ionimprintedpolymer?IIP-MMT?.The ion imprinted polymers are characterized by FTIR,SEM,TEM,XPS,EDS.It is proved that the imprinted polymer is successfully synthesized on the surface of montmorillonite,and the imprinted polymer show a flaky structure,and the surface of the imprinted polymer form with obvious imprinted holes.Moreover,the effect of cross-linking density of IIP-MMT,kinetics of adsorption,isothermal adsorption and adsorption properties are studied.The results show that IIP2-MMT has the best adsorptionpropertiesandhighselectiveadsorptionproperties;The adsorption of IIP-MMT can reach equilibrium within 30 min and the adsorption capacity can reach 158.68 mg/g,where the maximum saturated adsorption capacity can reach 201.84 mg/g;Under the presence of Cu²⁺,Cd²⁺,Zn²⁺,Sn²⁺,Mn²⁺ions,the IIP2-MMT selection coefficient are 21.195,29.191,23.694,24.743,35.328;IIP-MMT can reach more than 95%after 6times and has a very good stability.On this basis,IIP-MMT has high efficiency,high selective adsorption and easy regeneration.And it apply to the practical smelting waste water,smelting slag and contaminated soil.The results show that IIP-MMT can well recycle Pb²⁺ions in the smelting waste water,smelting slag and contaminated soil,and it has good regenerative property and stability.2.The Pb²⁺-ion imprinted polymer?IIP-MMT?and RhB molecular imprintedpolymer?MIPs?weresuccessfullysynthesizedbyusing suspension controlled/free polymerization technology,methyl acrylic acid?MMA?and acrylamide?AM?as monomers,ethylene glycol dimethacrylate as cross-linker,Pb²⁺ions or RhB as imprinted template.The effect of dosage of two monomers and dosage of cross-linker were studied.The adsorption capacity and selectivity of Pb²⁺-ion imprinted polymer to Pb²⁺ions and the adsorption capacity and selectivity of RhB molecular imprinted polymer to RhB were systematically studied.The results show that the Pb²⁺-ion imprinted polymer has the maximum capacity when the molar ratio of MMA,AM,cross-linker is 1:2:10;the RhB molecular imprinted polymer has the maximum capacity to RhB when the molar ratio of MMA,AM,cross-linker is 12:3:50.The adsorption process of Pb²⁺ionsreach equilibrium within 50 min and the adsorption capacity is 57.32 mg/g;the adsorption process of RhB reach equilibrium within 30 min and the adsorption amount was 115.2 mg/g.On this basis,the imprinted polymer prepared has established a new method as a solid extraction agent for the adsorption and separation of Pb²⁺ions and RhB.This method was convenient,fast,selective and reproducible,and provided a new way to treat Pb²⁺ions and RhB in waste water.