Research On The Ammonia Nitrogen Online Monitoring Technology Based On The Electrodialysis Ion Transition

Environmental problems have become an increasing concern in recent years. As an important indicator of water pollution, ammonia nitrogen become the most commonly detected variable of environmental monitoring. The principle methods of detecting the ammonia nitrogen are ammonia-gas-sensing electrode method and Nessler’s reagent colorimetric method among the market detection machine. The Nessler’s reagent colorimetric method is widely used in the majority of online water quality monitoring devices. However, it is easy to be affected by chromaticity and turbidity in the solution. We should process pretreatment of water samples, and that leads to more maintenance work. What’s more, the added chemical oxidant is highly toxic and causes secondary pollution. Therefore, it is particularly important to develop a new online water quality monitoring device with simple structure, which is no secondary pollution, fast and efficient and have a high accuracy. The main research content can be divided into four parts:(1) On the basis of the ammonia-gas-sensing electrode method, design a method which adopts electrodialysis electrolysis of deionized water, then it can generate strong alkaline electrolytic water. This liquid can replace the traditional ammonia-sensitive electrode method of sodium hydroxide solution. The method with the results of the national standard method comparison results show that this method can meet the needs of on-line monitoring of ammonia.(2) Because ammonia-gas-sensing electrode is susceptible to temperature easily, a three-dimensional relationship model of ammonia-gas-sensing electrode potential and the solution concentration with temperature is established by nonlinear regression analysis method based on the Nernst equation. The experimental results shows that the compensation model is feasible and accurate.(3) Further research shows that the ammonia-gas-sensing electrode is susceptible to temperature and the speed of stirring. A compensation model of ammonia-gas-sensing electrode with temperature and the speed of stirring is established by nonlinear regression analysis method based on the Nernst equation. The experimental results show that the compensation model is feasible and accurate.(4) Do some optimized designs with the ammonia water quality online automatic monitoring device. By optimizing the electrodialysis module, the detection module, PLC control module, greatly improving the measurement accuracy of the device. Extend the life of the device. Optimize the interface of the device by Lab VIEW.