The Adsorption Behaviors Of Polyphosphazene Microspheres With Active Amino Groups On Radioactive Elements

Hexachlorocyclotriphosphazene(HCCP)has a unique structure.It has multiple P-Cl bonds and is susceptible to nucleophilic substitution reactions to synthesize novel organic-inorganic hybrid materials or react with polyfunctional groups organic monomers to synthesize organic polymers material,these synthetic materials often show excellent physical and chemical properties.It is widely used in the fields of electrochemistry,catalysis,fluorescence,flame retardant,dye adsorption and other applications,but there are few reports on the treatment of radioactive elements with materials containing phosphazene.In this work,polyphosphazene microspheres with active amino groups on the surface were synthesized by organic monomers with polyfunctional groups and HCCP,and then were used to adsorb and removal radioactive elements uranium(VI)and thorium(IV)from aqueous solutions and explore Its adsorption properties.The mainly study contents and results are as follows:1.The treatment methods of radioactive element-containing waste liquid in recent years and the related applications of amino polyphosphazene microspheres were briefly summarized,and the feasibility analysis of the project is carried out.2.Hexachlorocyclotriphosphazene(HCCP)and polyfunctional groups organic monomers as comonomers,triethylamine(TEA)as acid binding agent,nitrogen as protective gas,and then Poly(cyclotriphosphazene-co-4,4'-diaminodiphenyl-ether)(PZA)microspheres and poly(cyclotriphosphazene-co-melamine)microspheres(PZM)with active amino groups on the surface are synthesized by one-step precipitation polymerization,using FTIR,XPS,XRD,EDS,SEM and other methods were used to characterize the prepared materials.3.The adsorption behavior of radioactive elements uranium(VI)and thorium(IV)in wastewater by these amino polyphosphazene microspheres were studied,and the influence of related factors on the adsorption performance was explored by single factor when PZA and PZM microspheresadsorb uranium(VI)and thorium(IV),respectively.The experimental results show that under optimized adsorption conditions,the removal rate of uranium(VI)by PZA microspheres reaches 97.03%.By comparing the correlation coefficient(R~2),the adsorption process conforms to the Langmuir isotherm model and the pseudo-second-order kinetic model;the thermodynamic data indicates that the adsorption behavior was spontaneous and exothermic.PZM,Another amino polyphosphazene microsphere,the experimental data were well-imitated via the pseudo-second-order kinetic model and its adsorption processes also conformed to the Langmuir isotherm model;adsorption thermodynamics studies show that the adsorption process was essentially a spontaneous endothermic process.Under optimized adsorption conditions,the adsorption removal rate reached at 98.6%.At the same time,according to the change trend of Th(IV)removal rate at different pH values,it was found that PZM microspheres can also was used in peracid environments..