Fabrication And Characterization Of Bi₂O₃ Photocatalysts With Enhanced Photocatalytic Activity Towards 17?-ethynylestradiol

As a typical synthetic estrogen,EE2 is more stable and have greater estrogenic potency than the natural estrogens.It has been widely detected in the environment,which can cause great threat to animals and human beings.It's very urgent for us to develop a effective method to remove EE2 in water.The photocatalysis method has attracted a lot of attention.Bi2O3 has a relatively small band gap energy and good visible-light response,so that it has promising application prospects in the field of photocatalysis.In this paper,?-Bi2O3 and ?/?-Bi2O3 photocatalysts were fabricated via the novel hydrothermal-calcination method and solvothermal-calcination method,respectively.The physical and chemical properties of photocatalysts were characterized based on XRD,XPS,SEM,TEM,EDS,BET,UV-vis DRS and PL techniques.Photocatalatytic activity of the fabricated ?-Bi2O3 and ?/?-Bi2O3 photocatalysts were investigated through the degradation of EE2 under visible-light,and the effect of photocatalyst dosage and pH value was investigated.The possible photocatalytic mechanisms were discussed.The details are as follows:1.A porous flake-like ?-Bi2O3 catalyst was fabricated via a novel hydrothermal-calcination method.According to the characteristic analysis and the experimental results,the optimal preparation conditions were established to be that the dosage of ethylenediamine was 10mL,the dosage of PVP was 0.2g,the hydrothermal temperature was 120?,the hydrothermal time was 12h,the calcination temperature was 500? and calcination time was 2h.EE2(3mg/L)was degraded under visible-light irrdiation over a-Bi2O3 photocatalyst,and the optimal experimental conditions were catalyst dosage of 0.5g/L and pH of 5.8.97.8%of EE2 was degraded over ?-Bi2O3 potocatalyst after 75min of visible-light irrdiation,and 99.1%of EE2 was degraded after 100min of visible-light irrdiation at the optimal experimental conditions.The photocatalytic activity of the fabricated ?-Bi2O3 photocatalyst was 11.6 and 50.6 times of that of traditional rod-like ?-Bi2O3 from hydrothermal method and P25,respectively.The ?-Bi2O3 photocatalyst has good photocatalytic activity and stability.2.A phase junction catalyst of ?/?-Bi2O3 was fabricated via solvothermal-calcination method.The optimal preparation conditions were established to be that the dosage of aniline was 1.0mL,the solvothermal temperature was 180?,the solvothermal time was 12h,the calcination temperature was 300? and calcination time was 1.0h.EE2(3mg/L)was degraded under visible-light irrdiation over ?/?-Bi2O3 photocatalyst,and the optimal experimental conditions were catalyst dosage of 0.5g/L and pH of 5.8.96.9%of EE2 was degraded over ?-Bi2O3 potocatalyst after 24min of visible-light irrdiation,and 98.3%of EE2 was degraded after 40min of visible-light irrdiation at the optimal experimental conditions.The reaction rate constant over the fabricated ?/?-Bi2O3 photocatalyst was 1.42,9.22 and 54.1 times of that of pure?-Bi2O3,?-Bi2O3 and P25,respectively.A phase junction between ?-Bi2O3 and ?-Bi2O3 was obtained,and this could help the reduction of the recombination probability of generated elections and holes,and thus the enhanced photocatalytic activity could be achieved.