Study On Functional Polymer Materials For Selective Recognition And Separation Of Dye Compounds

With the continuous development of technology in textile dying,dyes are also constantly enriched,which not only brings the color variety to the world,but also becomes an important source of water pollution,which is one of the challenges faced by human beings.Water pollution will take a huge threat to the survival and safety of animals and plants,and will also produce destruction to the social economy,human health and the sustainable development.Most dyes contain many aromatic groups and hydrophilic or lipophilic substituents in textile dying.In addition,dyes are difficult to be separated efficiently because of the molecular size with properties of easy to dissolve and difficult to degrade.Therefore,separation of dyes is challenging in the treatment of water pollution.Porous material is a kind of 3D network structure material with perforating pores,which has the characteristics of low relative density,high specific surface area,high specific strength and good permeability.As an important membrane material,polyvinylidene fluoride(PVDF)has excellent thermal stability,mechanical properties and chemical corrosion resistance.It can be used as the support structure of porous materials.And surface hydrophilicity of PVDF is needed to be modified in practical application.Hydrogel has controllable physical and chemical properties and strong plasticity with hydrophilic 3D network structure.Physical crosslinking was formed in hydrogels such as hydrogen bonding,electrostatic,host-guest and ionic interaction.After dehydration,hydrogel is also a porous material,which has the characteristics of large specific surface area and strong water absorption.To develop functional polymer materials with selective adsorption to the hydrophilic dyes can realize the separation of dyes in polluted water,might provide an alternative approach for water treatment.In this paper,the amphiphilic hyperbranched polyether amine(hPEA-GMA)with multifunction was synthesized firstly.We prepared PVDF@hPEA-GMA membrane through crystallization and diffusion(CCD)method.After that,a layer of polydopamine(PDA)was modified on the surface of the hybrid membrane.We characterized and tested the structures and properties of the two hybrid membranes,and explored the adsorption and filtration properties of 12 dyes.The results show that the modified hybrid membrane has the functions of selective recognition,adsorption and filtration.In addition,in the reusability test of hybrid membrane,the hybrid membrane showed excellent stability,the filtration and separation efficiency still reached more than 90% after 5 cycles.Therefore,the hybrid membrane has potential application value in dye pollution.Subsequently,the hPEA-GMA was introduced into the hydrogel system.Chitosan(CS),acrylic acid(AA)and acrylamide(AM)were selected as the support structure of the hydrogel,and the hybrid hydrogels were obtained by thermal initiating copolymerization,The adsorption and separation properties of 12 dyes by the obtained hydrogels were explored..The results show that a small amount of hPEA-GMA can improve the mechanical properties of hybrid hydrogels,and hPEA-GMA is used as a crosslinking agent and an adsorbent in the hydrogel system.The ability of selective recognition and separation to dyes was proved by saturated adsorption and mixed dyes static separation.Due to the cheap raw materials,simple preparation process and the performance,these hybrid hydrogel lays a foundation for the field of dye wastewater treatment.