Span/Tween混合表面活性剂微乳液制备纳米铁及脱硝研究  

Synthesis of Iron Nanoparticles by Microemulsion with Span/Tween as Mixed-surfactants for Denitrification of Nitrate in Water

作　　者：李铁龙[1] 金朝晖[1] 刘海水[1] 王薇[1] 李海莹[1] 韩璐[1] 

机构地区：[1]南开大学环境科学与工程学院,天津300071

出　　处：《高等学校化学学报》2006年第4期672-675,共4页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20477019);教育部南开大学/天津大学科技基金资助

摘　　要：研究了以Span 80和Tween 60为混合表面活性剂的微乳液的形成.以电导率及目测法为表征手段,利用正交试验,分析了多因素对W/O型微乳液最大增溶水量的影响,探明了该微乳液形成的较适宜条件,以此微乳液为反应介质合成了粒径为80 nm的铁粒子,用透射电镜(TEM)、X射线衍射(XRD)等分析技术对纳米微粒的特性进行了表征,用纳米铁与硝酸盐的反应验证其具有很强的活性.Recent studies have shown that zero-valent iron （Fe^0） may potentially be used as a chemical medium in permeable reactive barriers（PRBs） for groundwater nitrate remediation, and due to the extremely high reactivity, denitrification of nitrate in groundwater using nanoparticles has received increasing interest in recent years. In order to fabricate iron nanoparticles with homogeneous spherical shape and narrow size distribution, we developed a simple and green approach for synthesizing iron nanoparticles. We modified the conventional methods by applying the microemulsion with Span 80 and Tween 60 as mixed surfactants. Water was then titrated into the octane-surfactant mixture and changes were observed by visual inspection and conductivity measurement and the information was used in developing a phase diagram. The maximum content of water in the W/O microemulsion and its appropriate forming condition of the microemulsion were found. And then the microemulsion system consisting of saturated Fe^2＋ solution was used to synthesize α-Fe uhrafine particles by reduction reaction. The nanoparticles were characterized by using the powder X-ray diffraction （XRD）, transmission electron microscopy（TEM）. The results show that the average diameter of the particle is about 80 nm. The reductive activity of the obtained iron nanoparticles were studied by the denitrification experiment of nitrate. And the results show that under the experimental conditions iron removed mostly 120 mg/L of nitrate within a period of 30 min. And the mass balance of nitrate reduction with nanoscale Fe indicates that endproducts mainly are ammonia and the probable formation of nitrogen gas species during reaction with the new prepared nanoscale iron without pH control.

关 键 词：混合表面活性剂 微乳液 纳米铁 硝酸盐 

分 类 号：O62[理学—有机化学] X131.2[理学—化学]