Preparation Of Novel Cyclodextrin Polymer Materials And Application In The Enrichment And Seperation Of Endocrine Disruptors

In recent years,endocrine disruptors have become the third-largest global pollution problem due to the frequent detection in surface water sources and effluent from municipal wastewater plants.Despite the low environmental concentration(ng/L)in the water environment,long-term exposure can also cause significant damage to ecosystems and human health.Steroid oestrogens are the main compounds that cause environmental endocrine disruptive toxicity,and their sources are mainly the emissions of the human and animal excretion and the use and release of synthetic steroidal estrogens.Among the major river basins in China,the Shaying River,the largest tributary of the Huaihe River,has a high endocrine-disruption toxicity risk because of passing through the two major aquaculture provinces,Henan and Anhui.However,the current research work on the endocrine disruptor system in the Shaying River Basin is still very scarce.It is very necessary to carry out basic research in this area to provide scientific assessment of the risk of endocrine disruption in the Shaying River Basin in order to work out scientific and effective control measures for endocrine disruptors.Endocrine disruption often occurs in natural water at low concentrations.In order to meet the requirements of detection techniques,extraction and enrichment methods before treatment are generally required.Solid phase extraction technology has the advantages of high recovery rate,high enrichment factor and good reproducibility,and is widely used in the pretreatment of trace organics in water.The most important factor influencing the efficiency of solid phase extraction is the selection of solid phase extraction materials.Currently,the materials used for solid phase extraction of endocrine disruptors in surface water are mainly HLB and C18,but both of them have the defects of slow extraction rate and poor specificity.The ?-cyclodextrin polymer can achieve specific adsorption of phenols or estrogens containing hydroxysteroids due to the hydrophobic cavity of the cyclodextrin and hydrogen bonding in the outer surface.However,the extraction and enrichment rate of currently studied ?-cyclodextrin polymer material for the target compunds is still very slow and needs further improvement.Based on the above background,this study developed a new type of ?-cyclodextrin polymer material with rapid extraction and enrichment capability for steroid estrogen endocrine disruptors,and applied it to the investigation of endocrine disruptors in the Shaying River Basin.The main research contents and conclusions are as follows:(1)The ?-cyclodextrin,tetrafluoroterephthalonitrile and epichlorohydrin were used as reaction substrates to synthesize a new ?-cyclodextrin polymer material NP-ECP.The internal cavity and he external hydroxyl group of ?-cyclodextrin is the main factor for the strong adsorption capacity of target compunds.The introduction of the rigid structure of tetrafluoroterephthalonitrile makes the adsorption site of NP-ECP easier to expose and enhance Adsorption speed.The optimum ratio of?-cyclodextrin,tetrafluoroterephthalonitrile and epichlorohydrin was 1:3:25(2)The adsorption properties of NP-ECP on seven different types of organics were studied and the adsorption mechanism was discussed.As a result,it was found that NP-ECP adsorbed phenols or steroid-containing estrogens rapidly and reached 90%of equilibrium adsorption capacity within 10 s.Further study found that the adsorption effect of NP-ECP on the target was positively correlated with the ability of forming hydrogen bonds of the target compunds.The stronger the hydrogen bonding ability has,the faster the adsorption rate has.The secondary kinetic model of adsorption kinetics of NP-ECP on the target compounds showed that the adsorption process was chemical adsorption.The adsorption thermodynamic process accords with the Freundlich model and the thermodynamic parameters ?G and ?H are all negative,indicating that the adsorption process is more prone to occur and the adsorption process is exothermic.Inorganic ions and humic acid had no obvious effect on the adsorption properties of NP-ECP,and the excellent reproducibility was obtained.(3)According to the above study,NP-ECP has better adsorption properties for steroidal estrogens,the feasibility of NP-ECP as a solid phase extraction material for enrichment of trace amounts of estrogen in water was further investigated.After optimizing the solid-phase extraction conditions,compared with the commonly used solid-phase extraction materials C18 and HLB,the recovery of six estrogens by NP-ECP was significantly higher than that of C18,and the difference between HLB and HLB was not significant.Under the extraction conditions,the NP-ECP enrichment rate is twice that of C18 and HLB.Finally,the established NP-ECP-GC-MS method was used to determine the six trace estrogens in the actual water.The recovery of the method was between 88%and 98%.The method detection limit was 0.67-1.1ng/L.The standard deviation was less than 3%.(4)The established NP-ECP-GC-MS technique was used to determine the six estrogens in the Shaying River Basin,except for ethinyl estradiol,and the remaining five estrogens were detected.The total concentration was 41.08-271.98 ng/L.Through risk assessment,estradiol(E2)presents a high risk in Shaying River Basin,and NP,BPA,El,and EE2 present a medium-to-low risk,indicating that estradiol is an endocrine-disrupting pollutant that needs to be primarily controlled in the Shaying River Basin.Through correlation studies with COD,TN,and TP,it has been speculated that industrial wastewater and urban sewage discharge are the main sources of exogenous estrogen in the Shaying River,and the surface runoff and untreated domestic wastewater are the main source of endogenous hormones in the Shaying River.