| Diphenylamine antioxidants(DPAs)as an emerging pollutant,widely used as antioxidants in industrial products such as lubricants,tires,rubber and plastics,it has the characteristics of difficult degradation,bioaccumulation and biotoxicity,their existence in the environment is mainly caused by human activities.This paper optimizes the method of gas chromatography-tandem triple quadrupole mass spectrometer for the detection of DPAs,and used in detecting the wastewater and activated sludge samples of nine sewage treatment plants in Heilongjiang Province,as well as the samples of river and sediment of Songhua river.The concentration level of DPAs in sewage and sludge are varied in sewage treatment processes,influencing factors of influent concentration and removal efficiency are analyzed,and the removal mechanisms are discussed in detail.The DPAs levels in the Songhua River basin and sediment samples were analyzed,and the influencing factors were discussed.Through comprehensive analysis and comparison,TO-DPA and SPA can be detected in all sewage and sludge samples,DPPD and DBA are the main components of the influent and effluent,and DTO-DPA and DMBPD are the main components of sludge.The concentration levels of DPAs are varied in sewage treatment plants.The highest concentrations of DPAs in the influent,effluent,and sludge are in W#01(110 μg/L),W#07(5.7 μg/L)and W#02(14 μg/g,d.w.)sewage treatment plants respectively.There was a significant correlation between DPAs in influent,and the concentration of DPAs in influent was positively correlation with the total suspended matter concentration.The concentration of DPAs in effluent and activated sludge is related to the octanol-water distribution coefficient(Log Kow)and treatment process.The higher the Log Kow,the higher the concentration of DPAs in sludge.The removal efficiency of SDPA by A/O,A2/O,CASS and SBR processes is 98%±3.7,96%±7.4,98%±2.5 and 95%±10,respectively.These four treatment processes all have good removal rates for SPA except ADPA with removal efficiency range from 45-71%.The main removal mechanisms of DPAs in sewage treatment plants is sludge adsorption.The concentration of DPAs in river water and sediment is low,with concentrations are 841±159 ng/L,746±61 ng/g,d.w.respectively.Except for TO-DPA,DBPDA and NPA,the concentration of DPAs in the downstream is higher than that in the upstream.At the same time,the concentration of DPAs in the river water is significantly lower than that in the effluent,so the influence of the effluent from the sewage treatment plant on the Songhua river basin cannot be ignored. |
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