Research On The Analysis And Detection Of Heavy Metal Ions Based On The Electrochemical Sensing Interface Constructed By Metal Oxide-based Nanomaterials

The fast-growing modernization and industrialization have greatly improved the economy and brought many problems to the environment.The most typical one is that the discharge of industrial wastewater containing heavy metal ions（HMIs）has caused heavy metal pollution.Because HMIs are difficult to degrade in the water environment and can be enriched in the human body through the food chain,they cause long-term health hazards.Therefore,in order to realize rapid,accurate and highly sensitive detection of heavy metal ions in water environment,it is necessary to design a detection technology with good performance.Compared with traditional determination means,electrochemical means are widely used in the determination of heavy metal ions due to their simplicity,convenience,high sensitivity,and ease of miniaturization.With the innovation of nanotechnology,the unique properties of nanomaterials make it commonly used in electrochemical detection.The highly sensitive detection of heavy metal ions using the electrochemical sensing interface designed by nanomaterials is the core goal of electrochemical analysis,and the exploration of the response mechanism of the sensing interface is the key to further optimizing the electrochemical sensing interface.This thesis takes metal oxide-based nanomaterials as the research object,and explores the influence mechanism of the electrochemical detection and analysis of HMIs on their physical properties,specifically from the following aspects:（1）Successfully prepared gold nanoparticles（AuNPs）uniformly supported on porous Co₃O₄（Co₃O₄）microsheets（AuNPs/Co₃O₄）,and modified them on the screen-printed carbon electrode to construct an electrochemical sensing interface to ultra-sensitive detection of trivalent arsenic（As（III））,with a sensitivity of 12.1±0.2μA ppb-1 and a limit of detection（LOD）of 0.09 ppb.This study showed that the ultra-high sensitivity of As（III）determination is attributed to the strong adsorption capacity of Co₃O₄ on As（III）and the excellent electrocatalytic effect of AuNPs on As（III）.At the same time,the constructed electrochemical sensing interface has been successfully applied to the detection of As（III）in water and human serum.This work provides a good new idea for the construction of a stable electrochemical sensing interface to realize the practical application of accurate determination of trace As（III）.（2）Synthesize the heterostructure nanocomposite material（α-Fe₂O₃/NiO）of iron trioxide（α-Fe₂O₃）and nickel oxide（NiO）,and modify the glass carbon electrode（GCE）to construct the electrochemical sensing interface.Highly sensitive and selective detection of Pb（II）,with a sensitivity of 59.8±0.9μAμM^-1 and an LOD of 0.02μM.The density functional theory（DFT）calculation reveals the fundamental reason for the high sensitivity and selectivity of electrochemical analysis of Pb（II）.This work is also well used to detect Pb（II）in water and serum,proving that this analytical method has great potential value in the analysis of environmental and biological samples.