Preparation Of Metal-organic Coordination Polymers And Iodine Adsorption Properties

Nowadays,world energy demand is increasing,and the development of nuclear energy can also bring serious hidden dangers.Nuclear leakage accidents,whether caused by accident or human factors,will cause a serious impact to us.So it is very necessary to take effective measures to handle them.Radioactive iodine is one of product of nuclear fission.The iodine isotopes ¹²⁹I and ¹³¹I have the greatest influence,which destroy the natural environment due to long half-life.In this paper,We prepared MOFs and bismuth and zinc based coordination polymers,SEM,XRD,XPS and FT-IR were used to detect the property of CoZn-ZIF/MgAl-LDHs,Bi-na,Zn(tr)(OAC)and Zn(ttr)(OAC).Then we explored their iodine adsorption behavior at different intervals time,co-existing ions and several temperatures in n-hexane solution and water.1.CoZn-ZIF/MgAl-LDHs was prepared through in-situ growth and CoZn-ZIF materials were directly immobilized on layered double hydroxides MgAl-LDHs.We also explored the adsorption mechanism of CoZn-ZIF/MgAl-LDHs on iodine in n-hexane solution.We could know that adsorption at 225 min arrived dynamic equilibrium and CoZn-ZIF/MgAl-LDHs has capacity of 344.33 mg·g^-1.Adsorption kinetics showed CoZn-ZIF/MgAl-LDHs iodine adsorption was mainly controlled by chemisorption.CoZn-ZIF/MgAl-LDHs adsorption process fitted the Freundlich isothermal equation better.So we can summarize the iodine on multi-layer CoZn-ZIF/MgAl-LDHs was scattered adsorption.CoZn-ZIF/Mgal-LDHs was a spontaneous exothermic reaction.2.Bi-na,a coordination polymer with bismuth as the central ion and niacin as the organic ligand,was prepared by hydrothermal method.We used Bi-na to adsorb iodide ion in aqueous solution.We could know that adsorption at 300 min arrived dynamic equilibrium.Chemical adsorption dominated Bi-na iodine adsorption through analysing dynamic fitting data.The XPS characterization result showed that bismuth combined with iodide ion,so that the material has a high adsorption capacity on iodine.Langmuir isothermal model can illustrate that Bi-na iodine adsorption was monolayer adsorption,and 644.85 mg·g^-1 was model fitted maximum capacity.the adsorption of iodine by Bi-na was an endothermic reaction.3.3D columnar zinc triazole coordination polymer Zn(tr)(OAC)and 2D sheet-shaped material Zn(ttr)(OAC)were prepared in reflux at 60?using methanol and ethanol as solvents.XRD characterization of the materials after immersion in water for seven days showed that two materials had good water stability.The thermal stability temperature of Zn(tr)(OAC)and Zn(ttr)(OAC)can reach 300?.Langmuir isothermal model can illustrate that Zn(tr)(OAC)and Zn(ttr)(OAC)iodine adsorption was monolayer adsorption,and 714.50 mg·g^-1 was model fitted maximum capacity of Zn(tr)(OAC)at 25?,and the adsorption capacity of Zn(ttr)(OAC)was slightly higher than that of Zn(tr)(OAC)due to the presence of electron donating group amino in the ligand.The maximum adsorption capacity of Zn(ttr)(OAC)was 846.11 mg·g^-1.