Study On The Determination Of Lead Ion By Electrospinning Nanofiber Modified Glassy Carbon Electrode

Heavy metal pollution is seriously related to human health,and have toxic effects on human organs.When a small amount of heavy metal is into human body for a long time accumulation,it will cause human disease.In 2011,the World Health Organization?WHO?has reduced the safety standards of drinking water from50nmol/L to 10nmol/L.Therefore,it is crucial to realize the sensitive detection of Lead Ion in water.Due to low cost and fast detection speed,electrochemical detection is widely used in detection fields.And for the electrochemical detection,firstly,people need to pay attention to improvement and modification of electrode material,in order to heighten the diffusion of heavy metal ions at the electrode.Due to its high surface area and electronic conductivity,Nanometer-materials has been concerned widely in the field of electrode modification.Electro spinning technology is a general and efficient method to product the filament fiber whose diameter is from several microns to several nanometers.The extraordinary surface area,high porosity and good structure control of electro spinning nanometer fibers have great attraction to ultra-sensitive electrochemical sensors.In this thesis,electro spinning Nanometer material to modify glassy carbon electrode is used to the detection of the heavy metal-Lead Ion.The whole thesis is divided into fives parts:?1?The first part elaborates research progress of nanometer material modified electrode,expounds the advantages of electro spinning materials in electrode modification fields,and then puts forward the suppose of this thesis.?2?In the second part,electro spinning silver/copper oxide nanometer materials are used on the surface of glassy carbon electrode to make the modified electrode,realizing the detection of heavy metal-Lead Ion;Scanning electron microscopy,infrared testing,X-ray diffraction and thermo gravimetric analysis are used to characterized heavy metal-Lead Ion.?3?Thirdly,the single factor process is used to optimize of preparation processing of electro spinning nanometer fibers,which includes the amount of polyvinyl pyrrolidone PVP,adding the mass fraction of copper nitrate,the distance from the nozzle of electro spinning to the collection board,the voltage applied by electro spinning,the speed of electro spinning,the mass ratio of silver nitrate and copper nitrate and etc.?4?Then,the Ag/CuO modified glassy carbon electrode was applied to research the electrochemical activity of the modified electrode by using differential pulse voltammetry,and to research the detection limit,repeatability and stability of the modified electrode by using stripping voltammetry to detect the Lead-Ion with different concentrations.The experimental results indicated:when the Pb²⁺is in the concentration from 0.10nmol/L to 40nmol/L,the concentration is linear with peak current size,the correlation coefficient is 0.99333,the linear equation is y=-15.574x+1.07252(x:the concentration of Pb²⁺,nmol/L;y:peak current,uA),the detection limits is 0.1nmol/L?S/N=3?.Meanwhile,the repeatability and stability of the modified electrode was tested,the results show that this modified electrode is applicable to the detection of lead ions due to its high testing stability and good the repeatability.?5?Lastly,the nanometer Ag/CuO modified glassy carbon electrode was used to test the concentration of lead ions in daily water.The experimental results indicated:the stripping peak is not found in the testing stripping voltammetry graph,which shows that the lead ions in daily water is less than 0.1 nmol/L,meeting the healthy and safety standards(the World Health Organization has made the safety standards of lead ions in drinking water as 10nmol/L,,and is safe to drink.