Research On UV Spectrophotometry Of Determination Of TN In Sewage

TN is main measure indicator of eutrophication, and UV spectrophotometry is one of most commonly used methods of TN's determination. However, the determination limit of spectrophotometry is not high, and it can not eliminate the interference of iodine ions and bromine ions effectively. This paper mainly studies how to improve the UV spectrophotometry, how to improve the determination limit of TN, how to eliminate interference of iodine ions and bromine ions and how to improve the efficiency of TN determination.In the process of study, found that the process of nitrogen's digestion in the sewage spends a lot of time, and that it is difficult to determine weather it has been digested completely. After analysis carefully, we found that dual-wavelength method can rapidly determinate the content of nitrate and nitrite in the water, and that in some cases you can use the dual-wavelength method to determine whether the process of digestion is completely quickly. The result of experimental shows the method is simple, determination has a higher accuracy, and that it can meet the requirements of accuracy in the test and analysis process. To eliminate the interference of iodine ions and bromine ions and improve the determination limit of TN, establish prediction model of TN based on BP neural network.The prediction model trained can eliminate the interference of iodine ion and bromine ion effectively and improve the determination limit of TN. When the range of error is limited within 2%, the determination limit of TN is 6mg/L, and when the range of error is limited within 8%, the determination limit of TN is 10mg/L. If the prediction model can be trained by more spectrum data, the prediction model will been more accurate, the performance of forecast will be better.There is a large number of data generated in the experiment. In order to manage and organize these data effectively, store data in Access database. To ensure data security, and to make it easy for user to modify the data and query the data, develop a program based on Microsoft's ADO technology. User can modify and query the data easily by the program. The program can draw spectral curve by spectrum data. And the program makes it easy to manage and organize data.