Research On Solution Cathode Glow Discharge Spectral Detection System Based On Hollow Anode Structure

In recent years,the excessive discharge of domestic sewage and industrial wastewater has made the problem of water pollution more serious.At the same time,higher requirements for water resources health indicators are proposed.Therefore,a method that can quickly and accurately Technologies for detecting metals in water bodies are crucial.Solution cathode glow discharge(SCGD)technology has attracted wide attention by domestic and foreign scholars due to its high accuracy,good precision and simple operation.It has broad development prospects in the field of water environment analysis.In order to further improve the stability and performance of the detection system,in this thesis,the SCGD system is improved.A hollow anode-solution cathode glow discharge system is established.The system combines the gas blowing and optimization of experimental parameters to research the detection performance of the system,the main contents are as follows:1.In this thesis,the experimental device was improved firstly,a hollow anodesolution cathode glow discharge(HA-SCGD)system was established,Ar microjet was used as the discharge anode of this system.Then,the experimental parameters of titanium tube inner diameter,discharge current,solution flow rate and gas flow rate were optimized.The detection limits of Na,Li,K,Ca,Mg,Pb,Sr,Mn,Rb and Cs were 0.21,0.69,1.33,240.37,21.55,529,619.43,209.51,2.93 and 7.13 μg/L,respectively.The relative standard deviation is between 0.53-2.12%.Finally,the standard solution(GNMM051149-2013)was quantitatively analyzed.The results showed that the relative error was within-5.44-2.00%,the precision was within1.14-1.52%,and the recovery was within 95-102%.2.The plasma characteristics of the HA-SCGD system were studied in the experiment.The results show that the excitation temperature of the plasma was within 3450-6700 K,the vibrational temperature was within 12900-18100 K,the rotational temperature was within 1050-1239 K,and the electron number density was(1.41-8.19)× 10-14 cm-3.The electron number density in the near cathode region is 4-6 times that of the near anode.3.In order to further improve the detection performance of the system for heavy metal ions,the effects of organic reagents such as formic acid,acetic acid and ethanol on atomic emission spectra of Pb and Mn were investigated,and the added quality ratio was optimized.Formic acid,acetic acid,and ethanol had the best improvement when the mass ratios were 7%,3%,and 2%,respectively.Among them,formic acid has the best improvement effect.With 7% formic acid solution,the detection limits of Pb,Mn,and Zn were 122.64,170.24 and 165.17 μg/L,respectively.Then,the quantitative detection of Pb in natural water(GBW08607)and(GBW(E)080398)were analyzed.The results showed that the precision was 2.50% and 1.19%,and the recovery rates were 105% and 103%,respectively,indicating that the HA-SCGD system has good accuracy and stability.