| In recent years,due to the rapid development of China’s economy,the situation of water pollution is becoming increasingly serious.Local governments and relevant departments have strengthened the detection and treatment of all kinds of water bodies.In all kinds of water quality detection,ammonia nitrogen is one of the most important detection substances,and it is an important indicator for the detection of various water pollution conditions,such as oceans,rivers,drinking water,groundwater and so on.Seawater resources are important resources for human survival and development.Seawater pollution will have an important impact on the stability of marine ecology,lead to the destruction of marine biodiversity,and have a significant impact on marine fisheries,mariculture and coastal environment.Therefore,it is particularly important to strengthen the detection of ammonia nitrogen in coastal seawater and river water quality.There are many kinds of detection methods for ammonia nitrogen content in China,and national standards have been formed,such as Nessler’s reagent spectrophotometry,hypobromic acid oxidation,gas phase molecular absorption spectrometry,indophenol blue method,salicylic acid hypochlorite oxidation method.These detection methods are based on the traditional chemical principle of ammonia nitrogen detection,the detection speed is slow,the use of reagents and toxic,the operation is complex,vulnerable to the interference of colored substances and particles in water,which seriously affects the efficiency and accuracy of ammonia nitrogen detection.At present,in the field of water quality ammonia nitrogen detection,there is a device that uses ultraviolet absorption spectroscopy to detect ammonia nitrogen.This detection device converts ammonia nitrogen in water into gaseous ammonia（NH3）,obtains ammonia concentration by measuring the absorbance of ammonia,and then obtains ammonia concentration[2].This method can be applied to many kinds of water quality,such as ocean,river and groundwater.It has the advantages of simple operation,less use of chemical reagents,no need for pretreatment of water quality,non-toxic and harmless water quality after detection,no secondary pollution to the environment,fast detection speed,accurate and reliable detection results,wide detection range and strong anti-interference ability.It is a green environmental protection,efficient and reliable detection technology.In the domestic water quality detection equipment market,this kind of ammonia nitrogen detection equipment using ultraviolet absorption spectrometry completely depends on imports,and there is no domestic company that can produce it.Therefore,we need to break the foreign monopoly on this technology and realize the localization of the equipment.This topic introduces the research of ammonia nitrogen content detection equipment based on UV absorption spectrometry,and introduces the detection principle,equipment structure design,control circuit design and control program design of UV absorption spectrometry in detail.Through our own design and construction of ammonia nitrogen detection equipment based on UV absorption spectroscopy,we get the UV spectrum of ammonia,and use Fourier filtering,wavelet transform,Fourier transform and other data processing methods to process the absorbance signal.Finally,the least square method was used to fit the data to obtain the relationship between the signal and ammonia nitrogen concentration.The results show that UV absorption spectrometry is a simple method,which can achieve real-time,fast and accurate detection of ammonia nitrogen,and provides a new technology for the detection of ammonia nitrogen content. |
