Study On Electrochemical Detection Of Heavy Metal Ions In Water Based On Metal-organic Framework Derived Materials

The deterioration of the natural environment has always been a long-term problem.Among all kinds of environmental problems,water environmental pollution has become the top priority,and heavy metal pollution has always been paid attention to,especially the problem of excessive heavy metal ions in drinking water.Excessive levels of heavy metals in water have drawn close attention from the government and the public due to their excessive accumulation,biological amplification and toxicity.Heavy metals are mainly from natural and man-made sources,causing great harm to soil,water environment and plants.Heavy metal pollution in water causes long-term and lasting damage to human and other biological health,so it is urgent to find a fast,accurate,stable and efficient detection method for heavy metal ions in water.Electrochemical analysis is the most rapid,effective,simple and economical method for the detection of heavy metal ions in water.Metallic organic matrix materials(MOF)are relatively popular materials in recent years due to the outstanding pore structure diversity,high specific surface area,simple synthesis,environmental friendliness,thermal properties and chemical stability.Therefore,MOFs materials are frequently used in energy storage,biosensor catalysts,material separation and other fields.Zeolite imidazolate framework materials(ZIF)are part of the classification of metal organic framework materials.It has the advantages of simple synthesis,thermal stability and chemical stability.In recent years,MOFs materials have attracted more and more researchers’ attention,showing a strong potential and prospect in electrochemical sensors.However,because most MOF materials are poor or even non-conductive,their application in electrochemical sensors is limited.At present,the electrochemical sensor based on MOF,while preserving its special pore structure,and the preparation of electrochemical sensor with REDOX activity and good conductivity is a problem that we always need to solve.MOF materials can be combined with conductive materials or REDOX active substances to make electrochemical sensors.The electrode interface designed in this way has specific selectivity for trace substances,which makes the use of MOFs materials more extensive.Based on the excellent properties of ZIF,two different ZIF derived nanomaterials were prepared with Zn-ZIF,Co and Fe-ZIF as templates,and the electrochemical application was studied.The work of this paper mainly includes the following two contents:(1)The carbonized ZIF-8 has good conductivity,and still retains the rich porous structure of ZIF-8.Meanwhile,the ZIF-8 is calcined at high temperature to form a uniform nitrogen-doped carbon shell structure,with good adsorption and catalytic performance.Gold nanoparticles(AuNPs)were loaded onto ZIF-8 by amination.The electrochemical mechanism and performance of the constructed sensitive interface for the analysis and detection of As(Ⅲ)were studied by square wave anode stripping voltammetry(SWASV).The results show that AuNPs/1000-ZIF-8 modified glassy carbon electrode(GCE)can detect arsenic As(Ⅲ)sensitively,and is basically not affected by other heavy metal ions.It has good stability and reproducibility,and can be used to detect arsenic ions in actual water samples.(2)Co,Fe-ZIF for nitrogen doped carbon nano materials are derived from the template,core-shell Co,Fe-ZIF derived materials as an effective electrochemical catalyst,improvement on the glassy carbon electrode to common studies on the electrochemical properties of four kinds of heavy metal ions,lead ions.For example,to optimize the experimental conditions,using electrochemical analysis of square wave anodic stripping voltammetry.The results show that the constructed sensitive interface has good anti-interference ability,good stability and reproducibility.