| Endocrine disrupting chemicals(EDCs), also called environmental hormone, known as a class of chemicals which have xenobiotic and exogenous origins. After entering the organism, it can simulate the role of physiological hormones and interfere the normal biological hormone secretion by combined with hormone receptors or affecting cell signaling pathways, etc., increasing the risk of reproductive disorders, developmental abnormalities and cancer. In recent years, it appears in tersex fish and other anomalies in some rivers and lakes which are taken as drinking water sources, and a variety of endocrine disruptors are often detected in the water environment, especially drinking water sources, which has been paid more and more attention. Therefore, it is very important to prevent the pollution of EDCs for water quality safety and human health.Anthracite is a cheap filter media with good property of physical, chemical, corrosion resistance and hydraulic. At the same time, it also has high mechanical strength and certain specific surface area. Although anthracite is inferior to charcoal in the removal efficiency of organic matter, color and turbidity, anthracite can effectively remove the organic matter and avoid the problem of filter media excessive wear and debris filter leakage and other issues at the same time.The paper studied on the extraction/enrichment method and optimized HPLC method for three EDCs,17α-Ethynylestradiol, bisphenol A, sulfamethoxazole. The solid phase extraction for extraction and enrichment of EDCs showed good recoveries. The high performance liquid chromatography(HPLC) method for EDCs determination was studied with 100% methanol. The proposed HPLC metod provides a simple, rapid, precise quantitative analysis of EDCs in aqueous phase.In order to increase the adsorption capacity of anthracite, five inorganic modifier(Na Cl,Fe Cl3,Fe(NO)3,KMn O4,KOH) were used for modified anthracites preparation. And seven kind of modified anthracites were made. The experiment concluded that the adsorption of KOH modified anthracite was better than the other ways.The optimum making process condition of the KOH modification was studied by orthogonal test.Therefore, the concentration of KOH is 4mol/L, modification time and temperature is 24 h and 25℃, respectively.Original or modified anthracites were characterized by X-ray Photoelectron SPectroscopy(XPS), Fourier Transform Infra-Red SPectroscopy(FTIR),Boehm method, Specifiv Surface Area System(BET), Scanning Electron Microscope(SEM) and isoelectric point analysis. KOH could not only optimize the structure of carbon, destroy the carbon matrix of anthracite, increase the specific surface area of anthracite, but also change the surface chemical properties of anthracite, reduce the content of acidic group, increase the content of basic groups, and raise the isoelectric point.And the surface polarity of anthracite was weaken that improved the adsorption capacity of non-polar compounds.After trying with the two simplified kinetic model,the first-order equation and the pseudo-second-order equation for the the adsorption processes, the results showed that the three EDCs onto original and modified anthracites follows a pseudo-second-order kinetic model. The correlation coefficient of the fitting curve(R2) was more than 0.99. Besides, the adsorption process of original and modified anthracites on the EDCs has been found much closer to the Langmuir isotherm model than with that of Freundlich isotherm. The adsorption isotherm results of the modified anthracite demonstrate that the adsorption of EDCs is by nature the monomolecular adsorption on the surface of modified anthracite, chemical adsorption is the main control steps of adsorption. Meanwhile, the adsorption capacity of EE2 on original and modified anthracites was the highest, with equilibrium adsorption amount(qe) 0.2147 μg/mg and 0.6229 μg/mg, respectively, followed by bisphenol A. The adsorption capacity of sulfamethoxazole was the lowest, which was 0.0959 μg/mg and 0.1242 μg/mg on original and modified anthracites, respectively. The mechanism of removing EDCs with modified anthracites is analyzed in this paper,which are showed in the following three facts:(1)Increasing the surface area will enhance the adsorption of EDCs;(2) the p H value at zero point of charge on anthracite is enhanced from 6.29 to 7.41, positively charged anthracite in the neutral water environment can play a more important role in electrostatic adsorption in neutral water environment;(3) The enhancement of non polarity of suface is helpful to adsorpt the non-polar substances. Furthermore, the hydrophobic properties and molecular structure of target compounds can affect their adsorption capacity on anthracites. Moreover, the anthracite adsorption capacities for target compounds have a positive correlation with their octanol /water distribution coefficients. Natural anthracites and modified anthracites can respectively be regenerated with Na Cl solution on neutral p H.More than 70 percent of adsorption capacity can be retained after 3 times of regeneration that anthracite can be reused well. |
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