Preparing Surface Anionic Species-imprinted Material Based On Cationic Monomer Surface-initiated Graft-polymerization And Study On Recognizing And Binding Characters For Anion(molecule)

With the development of the world economy, the water pollution problems becomesmore and more seriously. The main sources of water pollution are sewage, agriculturalsewage, industrial wastewater emissions and so on. The using of washing powder,detergent and agricultural nitrogen phosphorus fertilizer causing eutrophication, causedalgae and other plankton reproduce rapidly, dissolved oxygen decreased, thedeterioration of water quality, fish and other creatures of death phenomenon. Human andanimals long-term drinking also can cause poisoning. Pollution of heavy metal ions inindustrial wastewater, toxic oxyacid anion and acid dye wastewater caused serious harmto human health and the ecological balance of the water body. Therefore, it is veryurgent to develop new technologies and materials actively for removing pollutants fromwater.In this work, a novel surface-ion （molecule） imprinting method-“graftpolymerization of molecularly imprinted simultaneously” is put forward and found. Theanionic surface imprinted material can remove the oxyacid anion and acid dye moleculesin the water with high efficiency. The results have potential applications in the protectionof water environment.Firstly，the coupling agent γ-aminopropyltrimethoxysilane （AMPS） was bond ontothe surface of silica gel particles, and amino groups were introduced onto the surfaces ofsilica gel particles, obtaining the modified particles AMPS-SiO₂. In aqueous solution, themolecules of the cationic monomer methacryloxyethyltrimethyl ammonium chloride（DMC） were first combined around the template ion, phosphate ion, by right of ionexchange action. A surface-initiated graft-polymerization system was constructed by the amino groups on AMPS-SiO₂and ammonium persulphate in the solution, and freeradicals were produced on the surfaces of silica gel particles. These free radicals initiatedthe monomer DMC and the crosslinker N,N’-methylene bisacrylamide （MBA） to begraft-copolymerized and crosslinked, and the surface-imprinting of phosphate ion wasrealized. After removing the template ions, PO₄^3-ion surface-imprinted materialIIP-PDMC/SiO₂was obtained. Both static and dynamic methods were adopted to studythe binding properties and ion recognition character of IIP-PDMC/SiO₂for PO₄^3-ion.The experiment results show that IIP-PDMC/SiO₂have specific recognition selectivityand excellent binding affinity for PO₄^3-ion, and static and dynamic binding capacity arerespectively0.65mmol/g and0.76mmol/g. Its selectivity selectivity coefficients forPO₄^3-ion with respect of MnO₄^-ion is9.58. IIP-PDMC/SiO₂has excellent elutionproperty, with NaCl solution as eluent, the desorption ratio of PO₄^3-ion reach99.53％in20BV.Then, via “ion exchange” and “surface-initiated graft-polymerization”, thesurface-imprinting of arsenate anion was conducted, and after removing the templateions, arsenate anion surface-imprinted material IIP-PDMC/SiO₂was obtained. Theimprinted material IIP-PDMC/SiO₂was fully characterized by infrared spectrum （FTIR）,scanning electron microscope （SEM） and thermogravimetric analysis （TGA）. By usingchromate and nitrate anions as contrast anions, both static and dynamic methods wereadopted to study the binding properties and ion recognition character of IIP-PDMC/SiO₂for arsenate anion. The experiment results show that at pH=5, H₂AsO₄^-is the main formof existence for arsenate anion, and the prepared imprinted material IIP-PDMC/SiO₂prepared under this condition has excellent recognition selectivity and binding affinityfor H₂AsO₄^-ion, and static and dynamic binding capacity are respectively0.174mmol/gand0.185mmol/g. Its selectivity selectivity coefficients for H₂AsO₄^-ion with respect ofHCrO₄^-and NO3-anions are8.814and7.898, respectively. IIP-PDMC/SiO₂hasexcellent elution property, with NaCl solution as eluent, the desorption ratio of AsO₄^3-ion reach99.63％in25BV. Last, via “surface-initiated graft-polymerization” and the electrostatic interactionbetween subject and object, the surface-imprinting of sunset yellow was conducted. Aredox initiating system was constructed by the amino groups on AMPS-SiO₂andammonium persulphate in the solution, and free radicals were produced on the surfacesof silica gel particles. The cationic monomer acryloxyethyltrimethyl ammonium chloride（DAC） was used as functional monomer, and N,N’-methylene bisacrylamide （MBA） wasused as crosslinker, the surface-imprinting of sunset yellow was realized. And afterremoving the template molecule, sunset yellow surface-imprinted materialMIP-PDAC/SiO₂was obtained. By using acid red-18and acid red-14as contrast, bothstatic and dynamic methods were adopted to study the binding properties and moleculerecognition character of MIP-PDAC/SiO₂for sunset yellow. The experiment resultsshow that the molecule-imprinted material MIP-PDAC/SiO₂has specific recognitionselectivity and excellent binding affinity for sunset yellow, and static and dynamicbinding capacity are respectively0.928mmol/g and0.1048mmol/g. Its selectivityselectivity coefficients for sunset yellow with respect of acid red-18and acid red-14are8.36and7.63, respectively. MIP-PDMC/SiO₂has excellent elution property, withNaCO3solution as eluent, the desorption ratio of sunset yellow reach96.5％in20BV.