TiO_2-Ag_2O复合纳米纤维烟气脱汞实验研究  

Removing elemental mercury by TiO_2-Ag_2O nanofiber

作　　者：袁媛[1] 张军营[1] 赵永椿[1] 郑楚光[1] 

机构地区：[1]华中科技大学煤燃烧国家重点实验室,湖北武汉430074

出　　处：《华中科技大学学报（自然科学版）》2012年第6期99-103,共5页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(41172140;51176060;51021065);国家重点基础研究发展计划资助项目(2011CB201500)

摘　　要：使用静电纺丝法制备TiO2及TiO2-Ag2O纳米纤维,脱除模拟烟气中的汞元素.对纳米纤维进行了XRD,SEM,EDX,UV-Vis及BET检测.研究了不同光照条件下Ag2O的掺杂比和循环次数对脱汞的影响,分析了TiO2-Ag2O的脱汞机理.结果表明:TiO2-Ag2O纳米纤维为锐钛矿相,纤维直径在200nm左右.与纯TiO2相比,TiO2-Ag2O的吸光范围增大,对可见光的利用率提高,并且随着Ag2O掺杂量的增加纤维对光的吸收也逐渐增强.TiO2-Ag2O纳米纤维在无光、可见光及紫外光下的脱汞率均达到95%以上.合成的复合纳米纤维脱汞性能稳定,到第8次循环时脱汞率仍保持在95%以上.TiO2-Ag2O脱汞的机理可为银与汞通过汞齐化作用形成银汞合金.TiO2 and TiOe-Ag20 nanofibers prepared by electrospinning method were used to remove elemental mercury from simulated coal combustion flue gas. The nanofibers were characterized by XRD （X-ray diffraction）, SEM （scanning electron microscope）, UV-Vis （ultraviolet-visible） spectra as well as BET （Brunauer-Emmett-Teller）. The mercury removal efficiency under different light conditions, the optimum doping content of Ag2 O as well as the capability to oxidize Hg^0 for 8 cycles were tested. The mechanism of Hg^0 removal over TiO2-Ag2O was deduced. The result shows that TiO2- Ag2O nanofibers exhibited an anatase phase structure with average diameter of 200 nm. Compared with pure TiO2, the absorption wavelength range of TiO2-Ag2O is expanded and the utilization ratio of visible light is improved. In addition, the UV-Vis absorption intensity of TiO2-Ag20 significantly increases with increasing Ag2O doping content. Hg^0 removal efficiencies of TiO2-Ag2 O are all around 95% whatever in the dark, under visible light or UV light. After the eighth cycle, its Hg^0 removal efficiency remained above 95%, which indicated it was stable with prolonged use of the catalyst. The mechanism of Hg^0 removal over TiO2-Ag2O is considered to form silver amalgam via amalgamation.

关 键 词：静电纺丝 TiO2-Ag2O 纳米纤维 模拟烟气 脱汞 

分 类 号：TQ51[化学工程]