Surface Modification And Adsorption Property Of PGMA Copolymer Microspheres

Environmental pollution is everywhere.With the improvement of people's environmental protection and health awareness,the problem of environmental pollution has been alleviated to a certain extent.However,the fundamental problem of governance has become a major problem that plagues human beings.A lot of metal ions are released into rivers and discharged into drinking-water environments without effective removal,triggering a series of heavy metal poisoning incidents.Therefore,the treatment of metal ions in the water environment deserves attention.In a variety of metal ion treatment methods,due to the adsorption resin's strong affinity for heavy metal ions and high load capacity,it has been widely studied.PGMA microspheres with controlled particle size and narrow size distribution were prepared by suspension polymerization using glycidyl methacrylate?GMA?as the main monomer and divinylbenzene?DVB?as the crosslinking agent in the presence of initiator,porogen,dispersant and dispersion medium,in this paper.And the experimental synthesis conditions were optimized.Then PGMA was grafted with ethylenediamine?EDA?,diethylenetriamine?DETA?,triethylenetetramine?TETE?and tetraethylenepentamine?TEPA?to obtain chelating resins PGMA-g-EDA,PGMA-g-DETA,PGMA-g-TETE and PGMA-g-TEPA.Finally,PGMA-g-EDA was further graft-modified with sodium chloroacetate?SC?to obtain chelating resin PGMA-g-EDA-SC.The structure of polymer was determined by FT-IR.The surface morphology and composition of the obtained PGMA derivative chelating resins were tested by scanning electron microscope?SEM?,specific surface area analyzer?BET?,elemental analyzer?EA?and laser particle size analyzer.And the thermal stability of the chelating resins was tested by a thermogravimetric analyzer?TGA?.The static adsorption properties of PGMA-g-EDA-SC chelating resin were explored.The effects of adsorption time,resin dosage,solution pH value,stirring speed and initial concentration on the static adsorption properties of the PGMA-g-EDA-SC chelating resin to Co²⁺,Ni²⁺,Pb²⁺and Hg²⁺were studied and optimized.The adsorption data were fitted linearly by the kinetic models and isothermal adsorption models,respectively.The results showed that the adsorption of resin was dominated by chemisorption,and it belongs to monolayer adsorption.The dynamic adsorption properties of PGMA-g-EDA-SC chelate resin were explored.And effects of flow rate,height of fixed bed adsorption column and initial concentration of metal ions on the adsorption properties of Co²⁺,Ni²⁺,Pb²⁺and Hg²⁺on PGMA-g-EDA-SC chelating resin were investigated.The dynamic breakthrough curve was drawn and the data were fitted by Thomas model.The results show that there is no axial diffusion in the dynamic adsorption processes of the resin to four ions.Finally,the thermodynamic,desorption-regeneration properties and swelling behavior of PGMA-g-EDA-SC chelating resin were investigated.