Study On Degradation And Denitrification Of O-chloroaniline In Hot Compressed Water

In the industrial production process of human beings,various organic wastes are inevitably generated.If these highly toxic and difficult-to-degrade organic wastes are not properly disposed of,they will cause huge damage to the ecological environment.Nitrogen-containing aniline is one of the organic substances that are difficult to degrade,and it is difficult for the traditional pollutant treatment methods to treat it thoroughly and harmlessly.The hot-pressed water oxidation technology is widely researched and applied in the oxidative degradation of organic pollutants due to its high efficiency,thoroughness and cleanliness.In this paper,the fused silica tube reactor was used to study the catalytic oxidation and nitrogen transfer of o-chloroaniline?o-Cl A?in hot compressed water.The effects of catalyst,temperature,oxygen stoichiometric ratio?OSR?and reaction time on the o-Cl A mineralization,total nitrogen removal,and degradation product nitrogen distribution during hot-pressed water oxidation were investigated.The degradation products were analyzed by GC-MS,and the degradation path of o-Cl A was deduced.The main contents and results of the research are as follows:?1?The effects of temperature,oxygen stoichiometric ratio and reaction time on the oxidation and nitrogen transfer of o-chloroaniline in hot-pressed water were investigated.First,the feasibility of using Raman spectroscopy to quantitatively analyze the oxygen and CO₂ concentration levels in the fused quartz tube reactor was verified.The results show that the intensity of the Raman peaks of O₂ and CO₂ is proportional to the gas concentration in this experiment.The hydrolysis experiment of o-Cl A in hot compressed water showed that its hydrolysis in hot compressed water was very slow.After reacting with o-chloroaniline in hot compressed water at 400°C and 27MPa for 150 min,its conversion rate was only 16.0%.The higher the oxygen stoichiometric ratio,the faster the mineralization of o-chloroaniline and the removal rate of total nitrogen,the faster the removal of amino groups from the benzene ring,the higher the conversion rate of ammonia nitrogen,and under the condition of high stoichiometric ratio Ammonia nitrogen is oxidized to nitrate nitrogen.The increase in temperature is beneficial to increase the mineralization rate of o-chloroaniline and the removal rate of total nitrogen.The temperature has a certain effect on the migration and transformation of nitrogen elements.The increase in temperature can promote the conversion of organic nitrogen and ammonia nitrogen.When the temperature is higher than 400°C,the denitrogenation rate of o-chloroaniline increases significantly.Through GC-MS analysis,the main degradation intermediate of o-chloroaniline hot-pressed water oxidation was o-chlorophenol.?2?The Mn₂O₃ catalyst was prepared by hydrothermal method and the effect of the catalyst to the mineralization of o-chloroaniline and the migration and transformation of nitrogen was studied under different reaction conditions.Under different temperature and stoichiometric ratio conditions,Mn₂O₃ has a weak promotion effect on the mineralization of o-chloroaniline.When OSR=1.5,T=350°C,the mineralization rate increased from 53.26%to 60.71%after 7 minutes of reaction;OSR=1.5,T=400°C,the mineralization rate increased from 69.49%to 71.76%;OSR=2.5,T=400°C,the mineralization rate increased from 77.83%to 82.23%.The catalytic effect of Mn₂O₃ on denitrification is not obvious in the low temperature region,but when the reaction temperature rises to 400°C,the addition of Mn₂O₃ significantly improves the removal rate of total nitrogen,OSR=1.5,after 150 min of reaction,the removal rate of total nitrogen Increased from 30.89%to 89.54%;the morphological analysis of the product nitrogen element found that the catalyst Mn₂O₃ had a certain effect on the migration and transformation of nitrogen element in the degradation process of o-chloroaniline,and slightly promoted the production of nitrate nitrogen in the early stage of the reaction In the case of high peroxygen multiples,the presence of a catalyst at the late stage of the reaction will inhibit the production of nitrate nitrogen.