Study Of The Detection Of Heavy Metals In Soils-sediment Based On Laser Induced Breakdown Spectroscopy Technology

The rivers exist around us,water sediment is an critical part of the ecological system of rivers and lakes,and it is the source food and habitats of Aquatic life.However,with random discharge of industrial waste water and unreasonable treatment of the garbage,the water body is damaged seriously,which brings great harm to human health and living environment.Because heavy metal elements in the sediment of the river is harmful to human health and ecological environment,so the detection requirements and technical requirements of heavy metal elements in the water sediments getting higher and urgent.This main work of this paper presents a new method that can detect and analysis the heavy metal elements in the sediment of the river,it is the laser induced breakdown spectroscopy technology.It is a type of atomic emission spectroscopy and detection technology of element analysis.Under analytical conditions,it is a fast and useful qualitative and semi-quantitative technique for the determination of elements composition of a wide range of material.Because of its unique features,like the absence of sample preparation,the ability to perform real-time,and in situ analysis as well as the quasi non-destruction and micro-analysis character of the measurements,which attracts people's attention,so that it is widely used in water pollution detection,industrial,soil and bio-medicine and other fields.The details are arrange as following:1.A new detection method is introduced,which is the laser induced breakdown spectroscopy.This paper mainly begins with a brief background introduction of this work,the research status of LIBS technology at home and abroad,the significance and content of the research and on-line detection methods of heavy metal elements in river sediments2.We mainly describes the LIBS experimental device system and its sample preparation process and methods.Filtering principle of characteristic spectrum and the optimization of the experimental parameters is described.the experimental parameters include number of laser shots to accumulate,pulse energy and delay time.Compared the variation of parameters with the intensity of characteristic spectral line,the signal to noise ratio and the relative standard deviation of the characteristic line,We can determine the optimal conditions for the experimental parameters.3.Finally we introduced the qualitative analysis and the quantitative analysis based on the experimental data of LIBS technology,the quantitative analysis method including the external standard method,the internal standard method and partial least squares method are discussed in this paper.according to the experimental data,the corresponding standard curve are established and calculate the content of the heavy metal in the measured sample.The experimental results show that(Cd,Cu and Pb)the outcome of PLS model is more accurately than the external standard method and the internal standard method.The quantitative analysis results compared with the state soil environment quality standard level,the elements of Cd,Cu and Pb slightly overweight,between the primary and secondary standard,the element of Ni and As is in the scope of the national standard.the technique of laser-induced breakdown spectroscopy can be used quickly to detect the heavy metal in soil,so as to verify the feasibility of LIBS application in soil.At last,conclusions of the whole paper were summarized,the directions for the further studies and suggestions were arranged.