中文摘要：

以聚苯乙烯（PS）包覆油酸修饰过的纳米Fe3O4为磁核,在低温（90℃）、中性（pH=7左右）条件下,制备了以PS为惰性隔离层的磁载TiO2光催化剂.用X射线衍射仪（XRD）、透射电子显微镜（TEM）、傅里叶红外分光光度计（FT-IR）、振动样品磁强计（VSM）对催化剂的物相组成、形貌、表面性质、磁学性质进行了表征.以苯酚为模拟污染物,考察了其光催化活性,以自制的磁回收装置,考察其回收特性.结果表明,低温制备的TiO2为锐钛矿结构,平均粒径为2～5 nm,催化剂TiO2/PS/Fe3O4[其中物质的量比为n（TiO2）∶n（St）∶n（Fe3O4）=60∶2.5∶1]具有结构完整的壳/壳/核结构,TiO2在PS/Fe3O4表面负载牢固;光催化降解苯酚遵循一级反应动力学方程,TiO2/PS/Fe3O4[n（TiO2）∶n（St）∶n（Fe3O4）=60∶2.5∶1]的反应速率常数K=0.025 8,与纯TiO2的活性接近（K=0.026 2）;循环使用5次后,反应速率常数仅降低0.003 4.所制催化剂具有较强的磁感应强度,平均回收率可达到92%以上.该低温水解法制备的磁载TiO2光催化剂具有良好的应用前景.

英文摘要：

This study reports the fabrication of magnetically responsive titania catalyst,which consisted of a magnetic core surrounded by a titania shell.The magnetic core（oleic acid-modified Fe3O4 nanoparticles） was modified with polystyrene as inert isolating layer.The magnetic photocatalyst was prepared at low temperature（90℃） and a neutral pH（about 7）.The phase composition,morphology,surface properties and magnetic properties of the composite particles were characterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM）,fourier infrared photometer（FT-IR） and vibrating sample magnetometer（VSM）.The photocatalytic activity of the samples were determined by degradation of phenol and their recovery characteristics were determined by a self-regulating magnetic recycling equipment.The results illustrated that the mean diameter of anatase titanium dioxide synthesized at low temperature was 2-5 nm,the catalyst TiO2/PS/Fe3O4[the molar ratio of the magnetic photocatalyst was n（TiO2）∶n（St）∶n（Fe3O4）=60∶2.5∶1] had the structural integrity of shell/shell/core,and titanium dioxide was loaded firmly on the PS/Fe3O4 surface.The photocatalytic degradation of phenol followed first-order reaction kinetics and the reaction rate constant K of the TiO2/PS/Fe3O4[n（TiO2）∶n（St）∶n（Fe3O4）=60∶2.5∶1] was 0.025 8,which was close to that of pure TiO2（K =0.026 2）.After 5 times recycling,the K value reduced only by 0.003 4.The catalyst had a strong magnetic induction,and the average recovery rate reached 92%.The magnetic TiO2 photocatalyst prepared by this low-temperature hydrolysis method has a good application prospect.