The Study Of Hexabromocyclododecane Distribution In The Tian Jin Haihe River And Its Disposal

HBCD(Hexabromocyclododecanes HBCDs)is a new type of persistent organic pollutants,although there have been banned from production and use,as one of the most widely used brominated flame retardants,the storage capacity of HBCDs in the environment is still relatively huge which will cause great potential harm for the natural environment and human health.Due to the limitation from current economic conditions and technical means,there were less research for the disposal of HBCDs.so there is an urgent need to establish a qualitative and quantitative analysis method for reasonable and effective HBCDs detection methods and therefore to accurately measure the HBCDs pollution levels in the environmental media.More importantly,to explore the possibility for low energy consumption and economical disposal method.In this thesis,a method for analyzing environmental of HBCDs were established and samples from Haihe were evaluated for their environmental and ecological risk;Fe304 micro and nano metal oxide material were prepared by the method of polyol-mediated,at the meanwhile the thermal rearrangement,degradation and reaction mechanisms of HBCDs were studied;thermal desorption experiments.were performed by own prepared mini-reactors containing HBCDs soil.The main results of this research are the following:1.By optimizing the parameters a method using HPLC-MS/MS were established for the determination of HBCD in environmental samples.This method were not only high sensitive,but also were efficient for separation of the three HBCD monomers,while enhancing the strength of the response signal,each parameter after optimizing is as follows:spray voltage 4000 v;probe temperature 260 ?;cone temperature 300?;buffer concentration 1 mM;mobile phase was methanol:acetonitrile(v/v = I:1)and water.2.Seven sediment samples were collected along the Haihe River in Tianjin and T6,T7 were located in upstream of the Haihe River near steel plant.The results show that the highest HBCD concentration was the sample from T6,?HBCD range from T1 to T7 is 0.4-58.82 ng/g,an average concentration of all sample is 15.71 ng/g.The ratio of a-HBCD,P-HBCD and ?-HBCD accounting ?HBCD are repectively 7.91-88.6%,0-91.47%,0.62-42.83%.except T5,a-HBCD are dominated in other samples which is contrary to the proportion in the product HBCD.That may be due to the different degradation rates among mutual transformation.Three different monomers RQs value of T6 were highest among Seven samples(RQs = 0.0012),therefore in this study HBCD concentration of ecological risk assessment were no risk.3.In this paper,the degrading activity of HBCDs by Fe3O4 prepared by a glycol-mediated method were tested,and HBCDs degradation products were detected by the use of ion chromatography and GC-MS mass spectrometer.The studies have shown that the degradation efficiency are more than 90%when r reaction temperature were at 200 ? for 20 min;the degradation behavior of three monomers accord with the first-order kinetics;formic acid,acetic acid,propionic acid,butyric acid,naphthalene,pBCD and other degradation products were determines and a HBCDs degradation route were speculated.4.the effects of different temperature and time in the thermal desorption experiments performed by HBCDs soil(concentration of 62.4 ng/g)were explored and the thermal desorption results show it were most effective at 300 ? for the desorption of HBCDs,the desorption efficiency of 74.7%;with the increase of the desorption rate of time gradually increased,but decreased at 40 min after desorption amount.