Study On The Removal Of 17β-estradiol In Water By Magnetic Activated Carbon

Natural steroid estrogen,for example,estrone(E1),17α-estradiol(17α-E2),17β-estradiol(17β-E2),estriol(E3),and artificial synthesize steroid estrogens,such as 17α-ethynylestradiol(EE2),which have female effect,are detected in the sewage treatment plant water,secondary effluent water,surface water,river water and even drinking water.Extreme Minimal estrogen can show a strong genetic and ecological toxicity and do harmful for the health of human and animal body when they existence in the environment,so the research on the removal of environmental estrogens in water has been widely concerned.17β-estradiol was used as the target compound in this study,magnetic activated carbon was prepared by co-precipitation method,studying on the adsorption characteristics of activated carbon powder and magnetic activity of 17β-estradiol in pure water,absorption factors,effects of magnetic activated carbon in two removal water17β-estradiol,evaluating the regeneration effect of magnetic activated carbon;Using automatic surface area and pore analyzer,scanning electron microscope,X-ray diffraction,thermogravimetric analysis,vibrating sample magnetometer,surface properties of magnetic composite materials were characterized in this way;The main conclusions of experiment are as follows:The experimental results show that the 17β-estradiol adsorption kinetics on powdered activated carbon and magnetic activated carbon were well described by the pseudo second order kinetics model,reached the adsorption equilibrium at about90 min,5 minutes before the fast adsorption stage,the removal rate of 17β-estradiol is about 90%,the 17β-estradiol adsorption by powdered activated carbon and magnetic activated carbon were consist with the Freundlich isotherm model.The saturated adsorption capacity of 17β-estradiol on the magnetic activated carbon was 430 mg/g,while the saturated adsorption capacity was 471 mg/g.Glassware has no effect on adsorption of 17β-estradiol,anionic surfactants has no obvious influence on the magnetic activated carbon adsorption of 17β-estradiol;iron oxide has a certain effect on the removal of 17β-estradiol;adsorption of 17β-estradiol on powder activated carbon is not affected by pH,while magnetic activated carbon is affected by pH and has the best adsorption effect when the vaule of pH is 6;The dosage of adsorbent has no significant effect on the final removal rate of 17β-estradiol,but in the initial stage of adsorption,the adsorbent dosage is more,the concentration of 17β-estradiol decreased faster.Regeneration eluent was prepared by methyl alcohol and ethyl acetate at different volume ratio,the recovery rates of 17β-estradiol is 84.74%,87.68%,78.84%,87.03%,97.18%,82.77%,71.96%,the optimum volume of regeneration eluent ratio was 50:50.Experiment results of regeneration times of magnetic activated carbon show that the removal rate of 17β-estradiol in the secondary effluent water by magnetic activated carbon was followed: 96.3%,88.5%,79.4%,69.3% and 61.2%.It can be seen that the removal rate of 17β-estradiol,in the secondary effluent water by magnetic activated carbon which is regenerated,is decreased.In general,the magnetic activated carbon has good potential for reuse.The results of surface area analysis show that,compared with powdered activated carbon,the specific surface area and pore volume of magnetic activated carbon decreased.Scanning electron microscopy results show that the surface morphology of the magnetic activated carbon is changed due to the presence of iron oxides,a large number of iron oxide particles are attached to the surface.The results of X-ray diffraction show that the crystal structure of the activated carbon powder is changed after the loading of iron oxide.The magnetic properties of iron oxides and magnetic activated carbons showed that the saturation magnetization of iron oxides and magnetic activated carbon was23.5 emu/g and 16.5 emu/g,all of them have some remanent magnetization and coercive force.In the course of the experiment,there is no phenomenon of agglomeration of magnetic particles.It can be seen that the magnetic activated carbon can be easily separated from the solution under the condition of appropriate external magnetic field intensity.