Preparation And Adsorption Properties Of Thionine Molecular Imprinting Polymers

Thionin is a purple dye,easily soluble in water,acetonitrile and other polar solvents,widely used in printing and dyeing industry,biological staining and some other fields.However,it could cause a lot of damage to water resources,and the chemical structure of thionin is relatively stable,so there are some difficulties in the traditional treatment of its treatment.Molecular imprinting is an interdisciplinary technology based on polymer chemistry,materials science and environmental science.The main content of this technology is to synthesize molecularly imprinted polymers that can specifically adsorb the target substance under the guidance of the target substance,which can be used for the separation and detection of the target substance.Molecularly imprinted polymer has the advantages of high selectivity,large adsorption capacity,high efficiency,no secondary pollution,simple operation and so on,so it is widely used in the fields of biology,medicine,environment,medicine and so on.Based on the above reasons,the problem of using molecular imprinting technology to treat thionin in water was explored in this paper,and mainly carries out research and discussion from the following aspects:In the first chapter,the main methods of dyeing wastewater treatment were reviewed,and the advantages and disadvantages of several methods were compared.After that,the characteristics,development history,research hotspot and research status of molecular imprinting technology were reviewed,and the feasibility of the treatment of thionin wastewater by molecular imprinting technology was discussed.In Chapter 2,thionin-molecularly imprinted polymer（MIP）was synthesized by bulk polymerization,and non-molecularly imprinted polymer（NIP）was synthesized without template thionin for control experiment.Scanning electron microscopy（SEM）,Fourier transform infrared spectroscopy（FT-IR）,thermogravimetric analysis（TGA）and specific surface area test（BET）were used to characterize the synthesized MIP,and relevant adsorption properties were tested,including kinetic adsorption experiments.Isothermal adsorption experiment,selective adsorption experiment and repeatability test.The experimental results show that MIP has better overall performance than MIP and can achieve specific adsorption of thionin.However,MIP has the problem of deep embedding of adsorption sites,so the adsorption capacity of MIP is not improved much compared with NIP.In order to solve the above problems,the third chapter introduced the surface imprinting method on the basis of the synthesis method in the second chapter.Chitosan was used as the carrier to synthesize chitosan-thionin surface imprinting polymer（MIP-CTs）,and the above method was used to study MIP-CTs.The results show that the overall performance of MIP-CTs was greatly improved compared with MIP,which indicates that surface imprinting is an excellent method to synthesize molecularly imprinted polymers,it can solve the problem of too deep embedding of adsorption sites,and chitosan is a suitable carrier.On the basis of the third chapter,the fourth chapter continued to use the surface imprinting method,using titanium dioxide as the carrier to synthesize the Ti O₂-thionin surface imprinting polymer（MIP-Ti O₂）,and the above method was used to study it.The results showed that the overall performance of MIP-Ti O₂ was slightly lower than that of MIP-CTs,but it was still significantly improved compared with MIP.It is proved that surface imprinting is an effective method.In Chapter 5,Si O₂-thionin surface imprinted polymer（MIP-Si O₂）was synthesized using silicon dioxide as the carrier and studied by the same method.The results show that the overall performance of MIP-Si O₂ is weaker than MIP-CTs and MIP-Si O₂,but still much stronger than MIP.It is proved that surface imprinting is a practical and reliable method.In summary,a total of four kinds of thionin-molecularly imprinted polymers were synthesized in this paper.Although the MIP synthesized by bulk polymerization could achieve specific adsorption of thionin,the adsorption capacity was not high.Therefore,surface imprinting was introduced in the subsequent research and three kinds of surface imprinted polymers were synthesized:MIP-CTs,MIP-Si O₂ and MIP-Si O₂.The overall performance of these three polymers is significantly improved compared with MIP,and the three polymers have their own characteristics,which can be used in different treatment situations to treat thionin.