Preparation Of Magnetic Nanocomposites And Study On The Adsorption Behavior Of Thorium(?)

With the continuous development of nuclear energy,a large amount of radioactive Th(?)waste water is inevitably produced.The discharge of radioactive Th(?)wastewater not only pollutes the natural environment but also harms human health.There are many methods for the purification and treatment of radioactive Th(?)in wastewater.Among them,the adsorption method has become the most common treatment method due to its low cost,simple process and high efficiency.Hexachlorocyclotriphosphazene(HCCP)is a type of polymer material.Due to the active nature of the P-Cl bond,it is prone to nucleophilic substitution reactions,thereby generating a series of phosphazene compounds.Due to its large specific surface area,small size effect,good adsorption performance,easy separation and recovery,Fe₃O₄magnetic nanomaterials have potential applications in sewage purification,magnetic resonance,biomedicine,and other fields.This topic is the first step is to synthesize poly(cyclotriphosphazene-co-3,3'-sulfonyl dianilide)microspheres(PSD)and poly(cyclotriphosphazene-co-4,4'-dihy-droxydiphenyl)by precipitation polymerization.Sulfide)(PTP)materials,and then synthesized magnetic polyphosphazene nanomaterials(MPSD and MPTP)by co-precipitation method,and then applied to the radioactive Th(?)in the waste liquid and further explore its adsorption performance,mainly including the following aspects:1.The treatment methods of waste liquid containing radioactive elements in recent years are briefly introduced.At the same time,a brief summary of polyphosphazene materials and magnetic Fe₃O₄nanocomposite materials was made,and the feasibility analysis of this topic was carried out.2.Polyphosphazene nanomaterials(PSD,PTP)were prepared by precipitation polymerization of hexachlorocyclotriphosphazene(HCCP)and organic monomer under ultrasonic conditions,with triethylamine as acid-binding agent and acetonitrile as the solvent,and then pass the original In-situ growth method grows Fe₃O₄on the surface of PSD and PTP materials,and successfully synthesizes magnetic nanocomposites(MPSD and MPTP)and uses VSM,FTIR,XRD,SEM,and other means to characterize and analyze them.The VSM characterization results show this the two materials have good magnetic properties,XRD analysis shows that the two materials maintain the spinel structure of Fe₃O₄,BET analysis shows that the material is a typical mesoporous material.3.The optimal conditions for the magnetic MPSD to adsorb thorium(?)solution were investigated by the single factor method.The experimental results show that:pH=4.0,the solid-liquid ratio is 0.2g/L,t=20min,MPSD has the best Th(?)removal effect,and its adsorption capacity was 286.7mg/g,the removal rate is 95.6%.according to the adsorption isotherm and the kinetic model,the adsorption process is a monolayer chemical adsorption and conforms to the Langmuir model(R²=0.9991)and the pseudo-secondary kinetic model(R²=0.9997);At the same time,the thermodynamic data indicated that the removal of thorium(?)by MPSD microspheres was an endothermic spontaneous process.4.The synthesized magnetic nanocomposite MPTP was used for the static adsorption experiments.The results show that:pH=4.0,the solid-liquid ratio is 1.0g/L,t=20min,MPTP has the best Th(?)removal effect,and its adsorption capacity was 28.74mg/g,the removal rate is91.7%,the adsorption process of MPTP on Th(?)conforms to the Langmuir model and the pseudo-second-order kinetic model.Simultaneously,the thermodynamic data indicated that the removal of Th(?)by MPTP was an endothermic spontaneous process.