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China is a country with scarce water resources, the per capita possession of water resources for the 2500m 3 , only 1/4 of the world per capita consumption, long time, \serious threat to make the most of our city and the region's water resources damage suffered deterioration of water quality and aquatic ecosystems. . Without valid in more than 80% of China's sewage treatment directly into water bodies, resulting in the contamination of more than 1/3 of our reach serious pollution of the waters of more than 90% of the city, one of the largest contributors to organic pollutants, species target range, and a huge number of organic pollutants direct threat to human survival environment and health. The degree of contamination of permanganate index (COD Mn ) as indicators of surface water pollution a comprehensive reflection of the water column reducing substances (mainly organic) have implemented \Mainly adopt the national standard of the People's Republic of China (GB11892-89), or \GB method or standard method, there is the consumption of energy consumption was time-consuming, complicated operation, low sensitivity, accuracy and precision, as well as easy on the environment cause secondary pollution monitoring of water quality COD Mn and difficult to meet the demand for batch testing and other shortcomings. Shortcomings in the GB method, exploring two new methods for determination the surface water COD Mn spectrophotometry using a spectrophotometer and sealed digestion. Optimized through experiments on the method of measurement conditions, respectively, determined by spectrophotometry and sealed digestion method for the determination of the optimum analysis conditions of the surface water COD Mn , and through statistical analysis of the test results on the evaluation. Wherein the spectrophotometric measurement condition is: the total volume of the reaction solution 20mL potassium permanganate (1/5KMnO4) concentration of standard solution 0.0125mol · L-1, and sulfuric acid (13) is added in 5mL, heating temperature of 100 ° C, the heating time of 30 min. The method has high sensitivity detection limit 0.085μg · L-1, a good linear relationship, the correlation coefficient of 0.9993, less than 1.5% relative standard deviation of the experimental results, the relative error in 0.46% 1 < / sup> .25% between, with high precision and accuracy, the standard method to do the t-test, the 95% confidence level, in line with the requirements, the method with the standard method no significant difference in the method can be used in Ⅰ Ⅴ category of surface water as well as sewage COD Mn Analysis and Testing. Measurement conditions: sealed digestion method using the concentration of the solution of potassium permanganate standard 0.001000mol L -1 and sulfuric acid (13) is added in 1mL, sealed digestion temperature and time were 150 ℃, 15min. The method has good sensitivity and detection limit of 1.67mg L -1 , has a strong anti-jamming capability, the standard deviation of the relative standard deviation of the experimental results in 1.28% 1 < / sup> .61% relative error between 5% 6 % with good precision and accuracy, the standard method of doing t-test, 95% confidence Next, meet the requirements, with the standard method does not exist significant difference. Through experiments and with the technical and economic analysis of the other COD Mn test analysis methods show that the research spectrophotometry and sealed digestion has a simple, rapid, high sensitivity, high precision, strong anti-jamming capability environmental friendly, application and promotion in the country, capable of easy fast monitoring and analysis waters COD Mn , to fully understand and master the POPs monitoring environmental pollution, as provide timely, reliable data monitoring and control of surface water pollution.
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