Synthesis Of Di - Tert - Butyl Dicyclohexyl - 18 - Crown - 6 Coated Polystyrene Magnetic Particles And Their Adsorption Properties For Strontium

⁹⁰Sr is a fission product of 235U and 239Pu in nuclear materials, which is commonly used as a signal radionuclide to be monitored in the incident involving the nuclear issue.⁹⁰Sr in the environment usually enter into human body mostly by ingestion with contaminated food or drinking water. As the biochemical behavior of ⁹⁰Sr is similar to calcium, which deposited in bones and bone marrow. The high energy beta rays generated by ⁹⁰Sr produce radiation damage to bone tissue and hematopoietic system, it is considered one of the key radionuclides to evaluate the health effects, the monitoring or decontamination of ⁹⁰Sr under emergency or normal situationis mainly achieved by radiochemical separation. Traditional separation of strontium are co-precipitation, solvent extraction, extraction chromatography, etc. and all of these methods have their advantages, however, all the process are complex and time-consuming. With the rapid development of new materials and new techniques, the establishment of efficient and rapid separation of radionuclides is of great significance in the field of radiation hygiene.Magnetically assisted chemical separation （MACS） combines the fast and simple operation of magnetic separation with specific selectivity of functional solid extractant. Applied to the separation of radionuclides, MACS has the obvious advantage such as high selectivity, simple and fast operation, etc.In this work, magnetic Fe₃O₄ nanoparticles and polymer microspheres were synthesized, then coated with extractant 4’,4"（5"）-di-tert-butyldicyclohexano-18-crown-6 （DtBuCH18C6）. the separating performence of functional magnetic particles was investigated. The main research includes the following:（1） DtBuCH18C6-coated magnetic poly（styrene-divinylbenzene） microparticles （DtBuCH18C6@Pst-DVB@Fe₃O₄, D-Pst@MNPs for short） were successfully prepared by co-precipitation method and emulsion polymerization. Finally, DtBuCH18C6 was physically coated on the surface of magnetic poly（styrene-divinylbenzene） microparticles （Pst-DVB-Fe₃O₄, Pst@MNPs for short）（2） Synthesis influence factor of D-Pst@MNPs was optimized and magnetic Fe₃O₄ nanoparticles, Pst@MNPs and D-Pst@MNPs were characterized. Optimizing the carriers、the diluents、the amount of DtBuCH18C6 and heating time during Pst@MNPs were coated with DtBuCH18C6. TEM and SEM results indicate that Pst@MNPs particles were spherical and the average size of D-Pst@MNPs was about 22μm. The functional extractant on the surface of D-Pst@MNPs was analyzed by FT-IR and XPS, The results showed that DtBuCH18C6 was successfully coated on the particle’s surface by the chemical bond （C-O-C）. TGA results showed that The Fe₃O₄ content of the D-Pst@MNPs particle is 10%.VSM indicated that the saturation magnetization of the D-Pst@MNPs particles is 10.08 emu/g with a superparamagnetic behavior.（3） Influence factor of magnetic separation process was optimized and It’s adsorption model was established. Optimizing some influence factors during magnetic separation process. For example, pH value, contact time, initial strontium concentration, temperature and so on. In pH=13 solution medium, it takes D-Pst@MNPs particles 2h to reach equilibrium while separated by 400 μg/L strontium standard solution. The adsorption model was studied by D-Pst@MNPs particles, and the Langmiur model was in accordance with the adsorption process of D-Pst@MNPs during the initial strontium concentration range from 0.01mg/L～10 mg/L. The Langmiur equation are as follows:Finally, Batch desorption experiments with different desorption agents showed result that 1% of HCl solution was the best desorption solution, and the total recovery rate was 78.4%.