Research On On-line Automatic Digestive Equipment For Total Phosphorus And Total Nitrogen In Seawater

Phosphorus and nitrogen are not only the important lives' sourse elements in seawater. but also indicative elements of marine eutrophication. When a great quantity of nutrient matters such as phosphorus and nitrogen flow into the waters, it will bring about eutrophication, which leads to plankton and algaess' death and deteriorates waters quality. Monitoring total phosphorus and total nitrogen in seawater real-timely is especially important. The traditional determination measures of total phosphorus and total nitrogen are divided. There are also different digestion measures which have relatively long measurement cycle, complicated procedure and can achieve only in the aboratory but can no longer meet the spot testing needs using shipborne methods. With the advancement of the technology, the environmental monitoring technology is turning to the orientation of automation, intelligent and network. In order to test total phosphorus and total nitrogens' content synchronously and fleetly in seawater, we are in dire need of developing a instrument which can achieve continuous, online and fast determination for total phosphorus and total nitrogen of marine water, it will play more important role in preventing marine red tide and other damage.This paper's main destination is to manufacture a combined and automatic digestive equipment for total phosphorus and total nitrogen. The digestive equipment of combining ultraviolet and microwave based on prophase experimentation is improved. So that it can meet spot need more ideally. The paper improves experimental condition on the basis of actual need. The ultraviolet lamp is changed from 1 m long to 29 cm,40 W to 8 W. By means of a series of single-factor experiments and orthogonal experiment, the optimum condition of ultraviolet oxidation for total phosphorus and total nitrogen is obtained: Irradiation distance:5 cm; Irradiation time:20 min; UV Lamp power:40 W.In the experiment, ultraviolet oxidation and microwave digestion are united and optimized which is based upon optimum condition of ultraviolet oxidation and microwave digestion. This meathod gives priority to microwave digestion and that ultraviolet oxidation plays a assistant part. The joint digestion optimal experimental parameters: Irradiation distance:5 cm; Irradiation time:20 min; UV Lamp power:40 W; Microwave heating time:200 s; Holding temperature:120℃; Holding time:720 s.On the base of the determinated experiment parameter, several phosphorus and nitrogen compounds are selected which are the representational matters in seawater. After digested, the digestive rate of most of the phosphorus and nitrogen compounds is up to 90%. the digestive effect turned up trumps.According to the basic data, digestive equipment and software are designed. The digestive equipment contains three sections:hardware's function, associated form of ultraviolet and microwave, way of digestive pot designed. The digestive equipment is able to supply simultaneously three kinds of energy form, such as ultraviolet oxidation, microwave digestion, ultraviolet associating with microwave digestion. Additionally, a water cooled digestive pot is designed. System software is also developed and designed based on Microsoft Visual C++6.0, its function is to enacting flow path and digestion procedure parameter. At last, we gave a test to software by means of curve proofreading, the fitting effect is good.