| With the rapid development of social economy, science and technology, the application of pharmaceuticals and personal care products(PPCPs) are increasing sharply, which makes PPCPs an emerging environmental pollutants and attracts great public attention. Among numerous PPCPs treatment technologies, visible-light photocatalysis is highly appreciated because of its distinguished merits such as full utilization of solar energy, no secondary pollution, broad-spectrum property, strong oxidization capacity and long service life. At present, although most of the well-studied photocatalysts can exhibit favorable photocatalytic performance towards organic pollutants, they are difficult to recover because of their small paticle size, which undoubtedly increases the processing cost. The addition of magnetic material can solve this problem, however, it is the key to find the best way to combine magnetic material with photocatalyst, and to make the composite to retain not only photocatalytic performance but also magnetic performance. Therefore, it is of great importance to exploit and study the visible-lightresponsive magnetic photocatalysts.Based on the above ideas, in this work, a magnetic visible-light-responsive Bi4VO8 Cl composite photocatalyst was fabricated via hydrothermal method with Fe3O4 as support and characterized by XRD, UV-Vis DRS, TEM and HRTEM. The photocatalytic activity of the photocatalysts with different contents of Fe3O4 was evaluated by the removal of degradation-resistant dye methyl orange in aqueous solution under visible light irradiation. It was found that the photocatalyst containing 15 wt% Fe3O4 exhibited the best magnetism and photocatalytic performance, and 85% methyl orange could be removed by such a photocatalyst at initial MO concentration of 5 mg/L. Then the degradation of four antibiotics in water was investigated,and pefloxacin mesylate was selected as a representative antibiotic to study the factors affecting the degradation of antibiotic by the magnetic Bi4VO8 Cl photocatalyst. It was shown that the magnetic Bi4VO8 Cl photocatalyst(15% Fe3O4) also exhibited excellent photocatalytic and mineralization performance(>77.1%) for the antibiotics mentioned above. Under optimized conditions, 93.5% degradation efficiency was achieved for pefloxacin mesylate, and the photocatalyst could be easily recovered by using an external magnet. It was also noted that after five recycles, 88.1% degradation efficiency for the antibiotic and 94.2% recovery rate for the photocatalyst were remained, respectively. Therefore, it is expected that magnetic Bi4VO8 Cl would be a promising photocatalyst for the removal of PPCPs under solar irradiation.Furthermore, another magnetic visible-light-responsive BiOBr photocatalyst was synthesized by water bath method with Fe3O4 as support and characterized by XRD, UV-Vis DRS, TEM and HRTEM. Photocatalytic degradation for methyl orange under visible light irradiation was used to evaluate the photocatalytic activity of the photocatalysts with different content of Fe3O4. The results revealed that the photocatalyst containing 25 wt% Fe3O4 showed the best magnetism and photocatalytic performance, and 93.0% methyl orange could be removed(initial MO concentration of 10 mg/L). Then the degradation of four drugs in water by the photocatalyst was investigated, and 4-hydroxyl coumarin was selected as a representative drug to study the factors affecting the degradation of drug by the magnetic BiOBr photocatalyst. It was found that the magnetic BiOBr photocatalyst with 25% Fe3O4 also manifested favorable photocatalytic and mineralization performance for the drugs mentioned above. For example, the mineralization of 4-hydroxyl coumarin was as high as 92.3%. The recycling degradation experiment of 4-hydroxyl coumarinresults showed that after five times reuse, 87.2% degradation efficiency for pefloxacin mesylate and 92.6% recovery rate were maintained by the photocatalyst. The above findings suggest that magnetic BiOBr would be a kind of promising photocatalysts. |
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