TiO2/PPY/Fe3O4的水热法制备及其光催化与磁回收性能

以化学氧化法制备的聚吡咯(PPY)包覆Fe3O4复合材料为磁核,用水热反应法(170℃, pH=7±0.2)在其表面负载了纳米Ti02,制成壳/壳/核结构的磁载二氧化钛光催化剂.并用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)、Zeta电位仪对催化剂的物相组成、形貌、表面性质、磁学性质以及磁核的表面电位进行了表征分析.以初始浓度为25mg/L的苯酚溶液为模拟污染物, 对其进行光催化降解以考察其催化活性;并以自制的磁回收装置考察其磁回收率.结果表明,所制备的Ti02粒径在4~7nm,具有混晶结构,其中锐钛矿占95.2%,金红石占4.8%;PPY对Ti02在磁核表面的负载具有促进作用,TiO2在PPY/Fe3O4表面负载牢固;催化剂TPF(nTiO2:n PPY:nFe3O4 =30:2.1:1)具有良好的壳/壳/核结构,其磁感应强度为40emu/g,具有超顺磁性;所制备的催化剂光催化降解苯酚符合假一级反应动力学方程,其中纯TiO2、P25、TPF反应速率常数K值分别为0.0279、0.0264、0.0252,TPF循环使用5次后K值为0.020,催化活性略有降低,循环使用平均回收率可达到90.35%. 该法制备的磁载Ti02光催化剂具有优良的催化活性和磁回收性能,具有良好的应用前景.

Hydrothermal synthesis of TiO2/PPY/Fe3O4 and its photocatalytic activity and magnetic recovery

Hard magnetic composite photocatalytic particles—titania(photoactive shell)/polypyrole(intermediate layer)/ ferroferric oxide(magnetic core)(TiO2/PPY/Fe3O4TPF) were prepared by hydrothermal methods.The prepared composite particles were characterized with X-ray diffraction(XRD),transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FT-IR),vibrating sample magnetometer(VSM) and Zetasizer.The photocatalytic activity of the catalysts were evaluated by photocatalytic degradation of phenol,and the magnetic recovery rate were studied by self-made recovery equipment.The results indicated that the samples were mix-crystal TiO2with anatase phase(95.2%) and rutile phase(4.8%),and its particle size was 4~7nm;PPY could promote TiO2loading on the surface of the magnetic core,as a result,TiO2was strongly loaded on the surface of PPY/ Fe3O4.The catalyst TPF with the mass ratio of TiO2:PPY:Fe3O4of 30:2.1:1exhibited good shell/shell/core structure and superparamagnetism,and its magnetic induction intensity was 40emu/g.The degradation of phenol followed psudo-first-order reaction kinetics and the reaction rate constants(K) of pure TiO2,P25,TPF were 0.0279,0.0264,0.0252,respectively,after recycling for 5times,the activity of TPF reduced a little(K=0.020),and the average recovery was 90.35%.The magnetic composite photocatalyst had high activity and magnetic recyclability,which showed good application foreground.