Water Environment In The Jialing River Of Chongqing And The Effects Of EOM/Fe³⁺/NO₃^-on The Indirect Photodegradation Of DBP In Water

Jialing River is one of the major source of Chongqing,more and more people pay attention to the change of the water quality.After Three Gorges stored water,the concentration of organic nitrogen and phosphate increases.This may be the main factor of the eutrophication in Jialing River,and due to the heightening of the water level,the water flow rate slows down which caused the accumulation of organic pollutants of Jialing River.Due to its perniciousness,dibutyl phthalate?DBP?is listed as one of the precedence-controlled pollutants in Jialing River.The extracellular secretions?EOM?,Fe³⁺,NO₃^-have photochemical properties which have important effects on the degradation of organic compounds.Based on it,the experiment monitored the water environment situation in Ci Qikou,Hua Longqiao,Da Xigou,Chao Tianmen first and then explore infuluence the EOM,Fe³⁺,NO₃^-and other factors on DBP's photolysis.The main research results are as follows:?1?The temperature is gradually rising from March to July,and the dissolved oxygen goes down as the temperature goes up.The water is alkaline and the COD_Mnn increases with the increase of the rainfall.The average concentration of COD_Mn is4.00mg·L^-1.The average concentrations of TN,TP,N/P were 2.78mg·L^-1,0.17mg·L^-1,16.8,and all reached the eutrophication level.Meanwhile,the average concentration of the DBP is 11.68?g·L^-1 which exceeded the limits of China's water environment standards.?2?The experiment explores the effect of different light sources,illumination intensities and different pH on the photolysis of the DBP.Photolysis reactions of DBP follows the first order reaction kinetics process,pseudo first order reaction.Compared with xenon lamp,mercury lamp light source is more conducive to the degradation of the DBP.And with the increase of the light intensity,the photolysis rate of DBP also increases.It is more favorable for DBP's photolysis in acidic environment.?3?The influence of EOM,Fe³⁺,NO₃^-and other factors on DBP's photolysis was investigated under the irradiation of high pressure mercury lamp with 500W.In general,the existence of EOM is not conducive to the photolysis of DBP,and the higher the concentration of EOM is,the more obvious the inhibiton of the DBP's photolysis is.The existence of Fe³⁺and NO₃^-is conducive to DBP's photolysis,and DBP's photolysis rate increases with the concentration of both.We also discovered when the Fe³⁺and EOM coexists,the reaction will produce the Fe³⁺-EOM complex,which leads the electronic transfer from the ligands to the Fe³⁺,and it will produce the·OH to degrade the DBP.And the photolysis rate is greater than that which the EOM or Fe³⁺exists alone.The existence of NO₃^-can alleviate the inhibiton of EOM to DBP's photolysis.Compared to when Fe³⁺or NO₃^-exists alone,it is more conducive to DBP's photolysis.But when high concentration of two ions co-exist,it will also inhibit DBP's photolysis.When NO₃^-,EOM and Fe³⁺co-exist,they have synergistic effect and can promote the further photolysis of DBP.