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Research Of Surface Acoustic Wave Sensor Based On Mesoporous Structural TiO2 For Detecting Heavy Metal Ion

Posted on:2017-02-13Degree:MasterType:Thesis
Country:ChinaCandidate:X L SunFull Text:PDF
GTID:2348330485473695Subject:Optics
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There are large amounts of heavy metal ions in waste water,waste liquor discharged by modern industry production,which cause increasingly serious pollution and harm to biological systems,crops and the health of human beings.Heavy metal ions cannot be degraded,it can be recycled to the human body with food cycle,tiny content can show very large toxicity,and so the detection of heavy metal ion is very important.The existing heavy metal detection techniques have high cost,low sensitivity,difficult integration and other problems,so to look for a simple,rapid heavy metal sensor with high sensitivity is very important.In this paper,the surface acoustic wave?SAW?technology and TiO2 sensitive film with biology hierarchy configuration are combined and used in the detection of heavy metal ions.At first,a layer of TiO2 sensitive film is decorated on surface acoustic wave sensor,which is used to adsorb heavy metal ions;and the quality change caused by the incorporation of adsorbed heavy metal ions and TiO2 sensitive film makes the resonant frequency of sound surface wave resonator decrease,and the detection for heavy metal ion concentration is realized by detecting variable quantity of SAW frequency.In this paper,specific research work can be divided into the following sections:1.Preparation of ZnO surface acoustic wave resonator.The magnetron sputtering method is used to prepare SAW resonator which regards ZnO as piezoelectric film,the influences of different sputtering process parameters on microstructure and performance of ZnO thin film are researched,under the conditions that sputtering power is 150 W,working air pressure is 0.25 Pa,substrate temperature is 300?,ZnO thin film with C axis preferred orientation,flat surface,compact structure is prepared by optimal process parameters.The delay line ZnO SAW resonator is designed,interdigital electrode is prepared on the surface of ZnO thin film by using Lift-off Negative Optical Photoresist stripping technology,the SAW resonator with a resonant frequency of 140 MHz is made,and the test results are consistent with the design values.2.Preparation of the biological hierarchy TiO2 sensitive film.Regard rape pollen in the nature as model,regard titanous sulfate as titanium source,and use two-step impregnation method to obtain powdery titanium dioxide with rape pollen mesoporous structure.Use X-ray diffraction?XRD?and scanning electron microscope?SEM?and other methods to do representation for titanium dioxide,test results show that TiO2 maintains mesoporous structure of rape pollen,has larger specific surface area.Use self-assembly method to assemble TiO2 with biology mesoporous structure on surface acoustic wave sensor.3.Detection of heavy metal ions Pb2+.Drop Pb2+ solution on sensitive film of surface of acoustic wave transducer,stew,and then wash with deionized water,let it dry,use network analyzer to detect the change of resonant frequency of surface of acoustic wave transducer.The test detects Pb2+ions of 100?1300 nM,and variation of resonant frequency of SAW sensor after absorbing Pb2+ions with different concentration,and it is gained that the sensitivity of sensor for Pb2+ ions is 165 Hz/nM.At the same time,detect Cd2+,Cu2+,Cr3+ ions with a concentration of 500 nM,it is found that their frequencies decrease 98 kHz,49 kHz,45 kHz respectively,frequency variation is smaller than the frequency after Pb2+ ion.SAW sensor of TiO2 sensitive layer of biology hierarchical structure detects that the reason that Pb2+ has larger frequency shift distance is connected to the larger atomic mass of Pb.
Keywords/Search Tags:Surface Acoustic Wave Sensors, Mesoporous Structural of TiO2, Heavy Metal Ions
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