| This thesis is mainly based on the new nanomaterials of graphene oxide(GO).By modifying the surface functional groups of GO by non-covalent and covalent methods,composites with specific functional groups are prepared.On the one hand,the adsorption property of the functionalized material is utilized to adsorb the noble metal,and on the other hand,the electrochemical ion sensor is used to determine the metal ion content.main tasks as follows:1.The excellent adsorption properties of three-dimensional graphene(3DG)can be further enhanced by triethylenetetramine modification to increase its adsorption capacity for precious metal ions.Herein,we successfully synthesized an amino-modified 3DG(N-3DG)adsorbent with improved adsorption conditions with regards to pH value,dosage,and adsorption time.Adsorption equilibrium was reached at pH 3 over 120 min.In addition,the theoretical basis for the adsorption of N-3DG is provided by fitting the adsorption model.The synthesized material was tested in seawater and lake water samples for the adsorption of precious metals,namely Au(III)and Pd(II),achieving a recovery rate of 87%to 106%as assessed by inductively coupled plasma mass spectrometry.Thus,N-3DG showed good adsorptivity.The present results indicate that N-3DG materials could have a viable application in environmental and sewage treatment in the near future.2.In this experiment,an electrochemical sensor for selective detection of Fe(III)in the presence of the real water samples was prepared by Au/Bi bimetallic nanoparticles decorated L-cysteine functionalized graphene oxide nanocomposites(Au-BiNPs/GO-SH)modified glassy carbon electrode(GCE).Bimetallic nanoparticles not only have various excellent properties of nanomaterials,but also have better catalytic properties than single metals because of the unique synergistic effect between metals.The modified electrode was characterized using scanning electron microscopy(SEM),X-ray energy spectrum(EDX),X-ray photoelectron spectra(XPS),Fourier-transform infrared spectroscopy(FT-IR),Raman spectra,and X-ray diffraction(XRD).A pair of well-defined redox peaks of Au-BiNPs/GO-SH nanocomposites with a formal potential of-0.2 V in 0.1 M hydrochloric acid buffer solution by square wave voltammetry.Under optimized conditions,there was a good linear relationship between the dissolution peak current of Fe(III),The concentration range of 0.2-50?M(R~2=0.993)and the limit of detection was0.07?M(S/N=3).Finally,the Au-BiNPs/GO-SH/GCE was used for the determination of real lake and sea water samples with recoveries ranged from 90%to 103%.Those satisfactory results revealed potential application of the Au-BiNPs/GO-SH electrochemical sensor for heavy metal detection in the environmental monitoring.3.In this experiment,o-phenylenediamine was first functionalized on graphene oxide,andthenbismuthnanoparticleswereloadedontothesurfaceof o-phenylenediamine-modified graphene oxide material to obtain a composite material of bismuth nanoparticles and poly(o-phenylenediamine).The composite was characterized by SEM,XPS,XRD and cyclic voltammetry(CV).Poly-o-phenylenediamine has excellent photoelectric properties and can improve the selective permeability of ions.The presence of cerium nanoparticles can improve the catalytic performance of materials in detection.The composite has better conductivity and can improve Pb(II)Sensitivity of the assay.Based on this,the sensor was applied to the determination of Pb(II)content.The results showed that Pb(II)was in the range of 0.1-50?M(R~2=0.996)and the detection limit was 0.04?M(S/N=3).The recovery rate is 93%~99%,which can be successfully applied to the determination of Pb(II). |
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