Study On The Construction Of Indole Hyper-cross-linked Microporous Polymer And Its Iodine Adsorption Performance

Microporous organic polymer?MOPs?is a new kind of solid adsorption material with permanent pore structure.It has the unique properties of high specific surface area?Brunauer-Emmett Teller,BET?,low skeleton density,acid-base resistance,high physical and chemical stability and so on).It is often used in gas separation,electrochemistry,gas storage,catalysis and other fields.Because MOPs are synthesized in a variety of ways and have adjustable pore sizes and are easily modified by functional groups,they often have advantages over other solid adsorption materials in their applications.Although MOPs has a series of characteristics,its industrialization and application in life need to be further improved.The reason is that the synthesis of MOPs mostly requires expensive metal catalysts or harsh experimental conditions such as high temperature and high pressure,which is not conducive to industrial mass production,so it has been greatly restricted in practical application.Radioactive iodine ¹²⁹I and ¹³¹I,derived from nuclear waste and radioactive medical diagnostic waste,are highly volatile and have a long half-life.Once ingested,they are at risk of teratogenesis and carcinogenesis.Adsorption and separation of such high-risk substances has been a challenge for the scientific community.It has been proved that the affinity of porous materials to iodine can be increased by the introduction of electron-rich groups in polymer networks.Therefore,a series of electron-rich porous organic polymers have been prepared in this thesis.The capture of volatile iodine and its adsorption in organic and aqueous solutions are expected to provide favorable methods and data for solving the problem of radioactive waste in the nuclear industry in this century.The main results are as follows:1)Indole microporous organic polymers?IMOPs?were synthesized by two kinds of monomers through using two different preparation ways.Synthesis method 1:Tri-indole monomer?TIBB?/di-indole monomer?BIPA?takes place intermolecular oxidative coupling reaction at room temperature with ferric chloride as catalyst to form hyper-cross-linked networks?PTIBB and PBIPA?;Synthesis method 2:in the presence of ferric chloride,TIBB/BIPA reacted with di-methoxy methane?FDA?at 80 ^oC to form hyper-cross-linked networks?PTIBBL and PBIPAL?.During the whole reaction procedure,there is no need for expensive catalyst or harsh experimental conditions.The synthesis process is simple and mild,which provides conditions for industrialization.Then a series of characterization of IMOPs,such as IR,NMR,thermogravimetry,SEM,TEM,BET measurements were carried out.2)By using four kinds of IMOPs as adsorbents,the capture properties of volatile iodine in porous materials with different morphologies and BET were studied,and the recycling properties of the materials were also studied.The results show that although the specific surface product value of PTIBB is only 233.707?m²/g?,the adsorption value of PTIBB is as high as 254 wt%.It was found that the morphology was the main factor affecting iodine capture in gas.The iodine capture of PTIBB and PBIPA with hollow nanotube structure was higher than that of PTIBBL and PBIPAL nanoparticles,which was independent of the specific surface area.The recycling experiments exhibit that after five cycles,these polymers still keep about 80%of the initial iodine capture capacity.3)Four kinds of IMOPs were used as absorbents to capture iodine in the solution of clohexane and water,respectively.The adsorption kinetics and thermodynamics of indole microporous materials on iodine uptake were studied.Between the two adsorption kinetic models,quasi-second order kinetics is the best one in the fitting curve.Between the two thermodynamic models,the Langmuir isotherm model is more suitable for the thermodynamic process of iodine adsorption in the solution.The fitting data of Gibbs free energy equation for iodine adsorption of indole-based porous materials suggest that increasing the temperature can promote the adsorption of iodine,and the process is spontaneous and irreversible.