In-situ detection method for ammonia and nitrogen

Abstract

The method for on-line monitoring ammonia nitrogen includes following steps: Ammonia nitrogen escaped from the sample is blown in the absorption liquid. With ammonia nitrogen being leaded in the absorption liquid, testing the conductance value of the absorption liquid and comparing the said conductance value with the calibrated conductance value of the absorption liquid calculates out the contentof ammonia nitrogen in the sample. In the invention, ammonia is separated from the sample so as to prevent the irrespective elements (such as suspended matter) in the sample from disturbing the measurement. The traditional distillation method spends more time and gets low measuring accuracy and sensitivity since the absorption liquid is diluted by the vapor. Comparing with prior art, the invention provides the features of high accuracy (0.01 ml / L), and high efficiency.

Description

Field of invention: [0001] The invention relates to a method for monitoring ammonia nitrogen, in particular to a method for monitoring ammonia nitrogen content in surface water, such as rivers and lakes. Background technique: [0002] At present, there is a certain degree of pollution in most of the various water systems. The ammonia nitrogen content in water is an important technical indicator of water system pollution. There are many methods for measuring the ammonia nitrogen content in surface water. The existing methods for measuring ammonia nitrogen mainly include; Titration method, Nessler's reagent photometry, salicylic acid hypochlorite photometry, ion electrode method and gas sensitive electrode method, these methods are all used in automatic monitoring instruments. The special method in the automatic monitoring instrument is Fourier transform spectroscopy. The above-mentioned method and the instrument have some shortcomings respectively. The problem of the titratio...

AI Technical Summary

Problems solved by technology

The special method in the automatic monitoring instrument is Fourier transform spectroscopy. The above-mentioned method and the instrument have some shortcomings respectively. The problem of the titration method is that the sensitivity is not high enough. The maintenance workload is heavy. The ion electrode method is interfered by other positive particles, especially potassium ions, which will affect its scope of use. The gas-sensing electrode is the most used method at present, but its gas-sensing membrane is easily damaged by water. Ineffective due to the contamination of suspended matter, while Fourier transform spectroscopy is difficult to popularize due to the complexity of the instrument

In addition, the minimum concentration that can be measured by all the above instruments is 0.05mg / L, while the minimum standard of ammonia nitrogen in surface water and groundwater has reached 0.02mg / L, so the existing methods have the problem that the sensitivity cannot meet the requirements for use. And there are inconvenient or complicated problems to use