Preparation Of Magnetic Functionalized Calix[4]arene Phosphate Derivatives And Their Separation And Enrichment Properties Towards Uranium

With the development of economy and society,the problem of energy shortage becomes more and more obvious.As a kind of efficient and clean energy,nuclear energy has attracted more and more attention.Uranium is both the main fuel of nuclear energy and an important strategic resource.During the development and utilization of uranium resources,a large amount of uranium-containing wastewater will be produced.If not properly handled,it will cause great harm to the ecological environment and human health,as well as waste of uranium resources.Therefore,it is of great significance to study new methods and technologies for the treatment of uranium-containing wastewater.Calixarene is a kind of third generation supramolecular cyclic oligomers with unique hole structure.Calixarene and its derivatives have attracted increasingly attention because of their simple synthesis steps and easy modification.Magnetic Fe₃O₄ nanoparticles have many unique properties,such as good biocompatibility,excellent magnetism,huge specific surface area,etc.,showing broad application prospects in many fields.?1?Diphenyl chlorophosphate as the substituent react with the calix[4]arene to synthesis a novel calix[4]arene phosphate derivative.The calix[4]arene phosphate derivative was characterized by FT-IR and ¹H-NMR.The effects of pH value,concentration of extractant,extraction time and temperature on the extraction of U???by calix[4]arene phosphate derivatives were investigated.The results of the investigation show that the optimum conditions for the extraction of uranium by calix[4]arene phosphate derivative are as follows.The pH value is 4.0,the temperature is 25?,the concentration of extractant is 0.20 g/L and the extraction balance time is 2 h when the initial concentration of uranium is 5 mg/L.The extraction process of uranium by calix[4]arene phosphate derivative conforms to the pseudo-second-order reaction kinetic model.Besides,in the presence of multiple coexisting ions,the calix[4]arene phosphate derivative exhibit good selectivity to uranium???.?2?P-carboxyphenyl azo calix[4]arene phosphate derivative?CPD?was successfully synthesized using calix[4]arene as raw material.The CPD was characterized by FT-IR and ¹H-NMR.The effects of pH,extraction time and temperature on the extraction of U???by CPD were investigated.The results show that pH value,extraction time and temperature have an effect on the extraction of U???by CPD.When the initial pH is 5,temperature is 25?,extraction time is 2 h,the extraction rate of U???by CPD reaches the maximum.Both kinetics parameters and thermodynamic parameters of the extraction process were calculated.The calculated data indicate that the extraction process of uranium by CPD is an exothermic spontaneous process,which well fits with the pseudo-second-order kinetic model.?3?A magnetic functionalized calix[4]arene composite consisting of Fe₃O₄and calix[4]arene phosphonate derivative?CPD?was prepared through a facile self-assembly method.It was characterized by scanning electron microscopy?SEM?,powder X-ray diffraction?PXRD?,and Fourier transformed infrared?FTIR?techniques.The as-synthesized Fe₃O₄/CPD composite was used to remove U?VI?from aqueous solutions under different conditions.Meanwhile,the adsorption isotherm,kinetics and thermodynamics were fitted and analyzed.The results show that the Fe₃O₄/CPD composite may be a promising adsorption material for the separation and enrichment of U?VI?from aqueous solutions in environmental pollution cleanup.