Fluorescent Polymer And Cadmium CdTe Dot For Detection Of Trace Uranyl Ion

Uranium,one of actinides,is a radioactive element,and it is also a major component of the main fuel and nuclear weapons in nuclear industry.With the development of the nuclear industry,the possibility of human exposure to trace uranium is increasing,especially those engaged in the nuclear industry or living around nuclear power plants.The radiotoxicity and chemical toxicity of uranium could bring great damages to the human body.US Environmental Protection Agency stipulates that the maximum concentration of uranyl ions in drinking water is 1.30×10^-7 mol L^-1.Therefore,high requirements for the detection of uranyl ions of low concentrations were proposed.Thus the development of simple and convenient methods to achieve rapid detection of uranium ion in situ in the environment has become one of the focus of current research.Based on the requirement of uranyl detection,the detection of uranyl ions by functional fluorescent polymer and CdTe quantum dots was studied.Specific studies of this paper are as follows:?1?Amidoximated fluorescent polymer based sensor for detection of trace uranyl ion in aqueous solutionIn this study,a fluorescent polymer sensor with amidoximated groups was prepared for detection of uranyl ions.First poly?diimine ketone?was synthesized by condensation reaction of 1,4-dibromo-benzophenone and p-phenylenediamine,followed by reacting with malononitrile to obtain the cyano groups.Finally polymeric sensor?P3?was obtained by the amidoximation of poly?diimino 2,2-dicyanoethylene?.P3 exhibited stable optical properties and good fluorescence intensity with emission wavelengths of 547 nm(?_ex=340 nm).The polymer sensor exhibited a linear responsive range of 10-150 nM and a fast response time of 200 s for uranyl ions through fluorescence“turn-off”response.Importantly,there was high selectivity for the sensor binding with UO₂²⁺in comparison with other ions,which could be used for detecting uranyl ion in lake water.The results indicated that the fluorescent polymer can be used as a promising sensor for effective detecting of UO₂²⁺in environmental solutions.?2?Highly selective and sensitive determination of uranyl ion by the probe of CdTe quantum dot with special sizeThis study reported a CdTe quantum dot with special size for efficient detection of uranyl ions.First,four different sizes of MPA-terminated CdTe quantum dots were prepared.These quantum dots showed green,yellow,light red,and magenta respectively under UV-lamp.It was found that when the size of the quantum dots increased to about 6.8 nm?magenta?,the detection exhibited high selectivity and high sensitivity to uranyl ions.The probe gave a linear response to uranium ion in the range of 1-500 nM and 500-1000 nM independently with two different slopes.The actual detection limit could be as low as to 1 nM.The detection mechanism might be as follows:the specific CdTe quantum dots react with Te?0?on the surface,which affects the composition of quantum dots,and finally result in the fluorescence quenching.The filter strip coated with the materials also provided a probe with simple performance for real-time and in-situ detection of uranyl ions.And the discovery also provides new materials and ideas for future designs for the detection of uranyl ion.