| Environmental endocrine disruptors(EDCs) is a kind of exogenous chemicals which can influence endocrine and reproductive systems of the human or animal body, cause abnormal effect, even including carcinogenic, teratogenic, mutagenic effects. Hexestrol(HEX) is a synthetic nonsteroidal estrogen substances, can produce identical pharmacological and therapeutic effect like natural estradiol, therefore in wastewater treatment and water purification process it is necessary to remove or reduce the concentration of HEX. Although there are a lot of analysis researches of HEX in water environment, but the oxidation degradation studies about HEX have not been reported. Heterogeneous catalysis of Fenton as a kind of advanced oxidation technology is being widely studied for the catalytic degradation of organic pollutants.Compared with the traditional Fenton, heterogeneous Fenton can reduce second pollution of iron ion, improve the catalytic power and light utilization rate, extend pH range. Therefore, to develop a kind of heterogeneous Fenton catalyst which can be separate and recycle easily, have small iron loss, stable catalytic performance and better ability to degrade the water environmental hormones is an important research direction of Fenton catalysis.The supported catalyst α-FeOOH/Resin was prepared through α-FeOOH being loaded on Amberlite200resin and the influence factors of preparation were investigated. The artificial endocrine disruptors hexestrol (HEX) was chosen as the target compound. The affecting factors and oxidative pathway in the heterogeneous UV-Fenton system degradation formed by α-FeOOH/Resin was studied. The main contents are summarized as follows:(1) The supported catalyst α-FeOOH/Resin was synthesized using the Amberlite200resin as support through the hydrolysis of Fe3+adsorbed on the surface of the resin in Fe(NO3)3-HNO3solution. The characterization results show that α-FeOOH loaded on the resin had good crystal type, was tightly wrapped in the surface of the resin, iron loaded in resin had different oxidation states. The suitable preparation conditions of the catalyst: resin concentration=20g/L, Fe(NO3)3concentration=200mM, T=60℃, pH=2.0,t=12h.(2) The degradation affecting factors of HEX and the stability of the catalyst were studied. The synergetic action of UV light and H2O2remarkably promoted thedegradation of HEX, the degradation rate increased with the decrease of pH and the increase of initial H2O2concentration or the dosage of catalyst. Degradation reaction mainly occurs in the surface of the catalyst, the heterogeneous reaction was dominant in the degradation of HEX, the dissolved Fe in aqueous phase leaking from the catalyst made a small contribution to the degradation of HEX. The catalyst has good catalytic stability, low iron loss, and stable mechanical strength.(3) The variation of TOC and estrogenic activity in degradation process of HEX was discessed. The decline rate of TOC is slower than HEX in first half, but significantly faster than the HEX in the second half, which indicated lots of organic intermediates were generated in earlier stage of degradation, further to be mineralized. The variation of estrogenic activity accorded with concentration variation of HEX, which indicated most intermediates didn’t have estrogenic activity or had lower estrogenic activity than HEX.(4) The production regularity of·OH in the degradation process of HEX was studied, lower pH value was good for the generation of·OH, but when pH is less than3, the catalyst stability will be affected. The increase of catalyst will promote the generation of·OH. With the concentration of H2O2increase, generation amount of ·OH increased first and then decreased. Intermediates structure was deduced and oxidative pathway of HEX was discussed on the basis of a few relevant literature reports. |
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