Study On Detection Of Heavy Metal Ions Applied Electrochemical Analysis

With the continuous expansion of cities and the rapid development of industry,more and more cities and domestic sewage are discharged,and the heavy metals in water bodies are easily enriched and difficult to be degraded,which causes great disruption and seriousness to the ecological environment and human health.Therefore,exploring a convenient,fast and sensitive detection method of heavy metal ions to accurately detect the content of many heavy metal ions has become an urgent task to protect human health and protect the environment.Electrochemical analysis?SWASV?is widely used in the field of heavy metal detection,In this paper,three kinds of metal nanocomposites were prepared from the aspects of improving the sensitivity and selectivity of heavy metal ion detection and lowering the detection limit,and the four heavy metal ions were individually and simultaneously detected by electrochemical square wave stripping voltammetry.The main contents of this paper's research are as follows:Firstly,the nanocomposite materials?Ag NPs/RGO?were prepared by hydrothermal method,and the morphology and electrochemical performance of the materials were characterized.Experiments show that the graphene oxide has a wrinkle structure,and silver nanoparticles dispersed on the surface.The synthesized composites were modified to the surface of glassy carbon electrode and the four heavy metal ions?Cd?II?,Cu?II?,Hg?II?,Pb?II??were detected individually and simultaneously.The detection sensitivity and detection limit?LOD?of AgNPs/RGO modified electrode to Pb?II?were 48.69?A/?M and0.141?M,while the sensitivity to Cu?II?,Cd?II?,and Hg?II?were relatively low.The existence of Cd?II?,Hg?II?,Cu?II?has some interference to the detection of Pb?II?.The presence of Cu?II?causes the peak of Pb?II?to appear and shoulder peak phenomenon.In addition,the AgNPs/RGO modified electrodes show good cyclic stability and durability.Secondly,the composite materials of copper nanoparticles and reduced graphene oxide were prepared by hydrothermal method.The morphology and electrical properties of CuNPs/RGO nanocomposites were investigated.The experimental results show that there are a large number of copper nanoparticles on the surface of the reduced graphene oxide.Not only increase the specific surface area of the material,but also accelerate the electron transfer rate in the electrode material,which makes the electrical properties of the Cu NPs/RGO nanocomposite modified glassy carbon electrode improved.It was subsequently applied to the simultaneous and separate detection of inorganic heavy metal ions Cd?II?,Cu?II?,Hg?II?and Pb?II?,CuNPs/RGO modified glassy carbon electrode has higher selectivity and detection sensitivity to Cd?II?and Pb?II??66.3?A/?M,50.15?A/?M?,there is a certain interference between the two ions at the same time.The detection and recovery rate of Pb?II?in the actual water sample reached 92.24%,indicating that the CuNPs/RGO modified glassy carbon electrode has potential practical value.Finally,the composite materials of TiO₂NTs/Au NPs were prepared by hydrothermal method.The morphology of the TiO₂NTs/AuNP scomposites was characterized and electrical properties were tested.Surface scanning revealed that the gold nanoparticles were uniformly distributed on the independent titanium dioxide nanotubes.This unique spatial structure makes it high specific surface area,strong adsorption capacity,high-speed charged particle diffusion channels.The results show that TiO₂NTs/AuNPs modified electrode has higher selectivity and detection sensitivity to Cd?II?and Hg?II??213.19?A/?M,287.86?A/?M?.The interferences of Cd?II?,Cu?II?and Hg?II?on Pb?II?were studied separately.Finally,the Ti O₂NTs/AuNPs modified electrode exhibited good cycle performance and stability through multiple detections of Hg?II?.It shows that the composite of TiO₂NTs/AuNPs has better electrochemical sensing performance.