低温种子聚合法制备磁载纳米TiO2光催化剂及其对苯酚的光催化降解  

PREPARATION OF NANO TiO_2/Fe_3O_4 PHOTOCATALYST VIA SEED POLYMERIZATION AT LOW TEMPERATURE AND ITS PHOTOCATALYTIC DEGRADATION OF PHENOL

作　　者：任学昌[1] 于学华[1] 刘宏飞[1] 常青[1] 张国珍[1] 武福平[1] 孙三祥[1] 何春生[1] 

机构地区：[1]兰州交通大学环境与市政工程学院,寒旱地区水资源综合利用教育部工程研究中心,兰州730070

出　　处：《环境化学》2011年第3期609-615,共7页Environmental Chemistry

基　　金：国家自然科学基金资助项目(51068016);长江学者和创新团队发展计划资助(IRT0966);兰州交通大学第四批“青蓝”人才基金资助项目(QL-06-04-A);国家科技支撑项目(2006BAJ08B08-3);国家水体污染控制与治理科技重大专项(2008ZX07425-005)

摘　　要：通过种子聚合法,以聚乙烯亚胺(PEI)处理过的纳米Fe3O4为磁核,在低温(95℃)、中性(pH=7左右)条件下,制备了一种磁载TiO2光催化剂.利用Zeta电位仪、透射电子显微镜(TEM)、X射线衍射仪(XRD)、傅里叶红外分光光度计(FT-IR)、振动样品磁强计(VSM)测试方法对磁核的表面电位、催化剂的形貌、物相组成、表面性质、磁学性质进行了表征.用初始浓度为25mg.L-1的苯酚溶液为模拟污染物,以其90min的光催化降解率评价催化剂的活性.结果表明,PEI对TiO2在磁核表面的结晶有非常明显的促进作用,通过PEI改性后催化剂具有较厚致密的TiO2外壳层;所制催化剂具有超顺磁性,平均回收率可达到90%以上;催化剂TiO2/PEI/Fe3O4(nFe3O4∶nTiO2=1∶64)降解率最高可达95.4%,与P25的活性接近(降解率为96.7%),在循环使用5次后,催化活性仅降低3.1%,该法制备的磁载TiO2光催化剂具有良好的应用前景.A composite photocatalyst with an anatase titania shell and a magnetite core was prepared at low temperature（95℃）and in neutral pH by a seeded polymerization technique.The Fe3O4 core nanoparticles were synthesized by the co-precipitation method,with a size of about 15nm.The surface of Fe3O4 was modified by polyethyleneimine（PEI）,and was characterized by Zeta potential measurement.The morphology,phase composition,surface properity and the magnetic properties of the composite nanoparticles were characterized by transmission electron microscopy（TEM）,X-ray diffraction（XRD）,fourier infrared photometer（FT-IR）and vibrating sample magnetometer（VSM）.The photocatalytic activity and durability of the samples was determined by degradation of 25mg·L-1 for 90 min.The results illustrated that PEI promoted TiO2 crystallization to form a thick TiO2 shell layer after.The composite catalyst is a superparamagnetic and can be recovered with a recovery rate above 90%.The degradation rate of catalyst TiO2/PEI/Fe3O4（n Fe3O4∶ n TiO2=1∶64） is high as 95.4%,which is nearly equal to that of P25（degradation rate is 96.7%）,The photocatalyst can be recycled with a slight loss of photocatalytic activity,and the catalytic activity was reduced only by 3.1% after five cycles.The composite catalyst prepared in this work has good prospects in environmental application.

关 键 词：磁载二氧化钛 低温 光催化活性 包覆 

分 类 号：X13[环境科学与工程—环境科学] X50