N,F-Bi2O3-SBA15光催化剂降解Cr(VI)的研究.doc

PAGE PAGE 20 N,F-Bi2O3-SBA15光催化剂降解Cr(VI)的研究 摘要：现代工业技术的发展之迅速是前所未有的，各类工业产业排放大量的废水中，重金属离子造成的污染引起了人们越来越多的关注。Cr(VI)作为非常具有代表性的重金属污染物而受到重视，Cr(VI)排放量大，易溶解，易迁移。传统的Cr(VI)处理方法普遍存在去除率低，残留高，费用高，易产生二次污染的缺点。而新兴的光催化法作为高级氧化法的一种，能够利用太阳光能高效绿色地完成Cr(VI)的降解。而利用光催化法进行Cr(VI)的降解时，最需要的是开发一种高效并且稳定的可见光催化材料，使之能够利用占绝大部分太阳光能量的可见光来降解污染物。本研究首先通过各个Bi2O3与SBA-15负载比例的降解效果评价，筛选出最优比例，进一步依据诸多N-F共掺杂文献确定出N-F负载量。结果表明，通过将Bi2O3负载在SBA-15上能够有效提升其比表面积，在吸附性能上能够有一定提升，通过N-F共掺杂能够窄化带隙，提升其可见光响应，同时对于电子的传递也能起到促进作用，在可见光照条件下，光电流产生地十分明显。对于催化剂的可见光响应、带隙结构进行了一系列表征，并且以Cr(VI)为研究对象，进一步考察了光照、反应pH、EDTA加入量等对N,F-Bi2O3-SBA15降解动力学的影响规律，实验结果发现，在一定范围内，Cr(VI)的去除率随着光照的增强提高，随着EDTA的加入、pH的降低提高。 关键词：Bi2O3；SBA-15；N-F共掺杂；光催化；可见光；Cr(VI)。 Study on N,F-Bi2O3-SBA15 for Photocatalytic Degradation of Cr(VI) Abstract: With modern industrial development, heavy metal ions pollution in waste water attracts more and more attention. As a typical heavy metal pollutant, Cr(VI) is concerned by more and more people. The emission of Cr(VI) is enormous. On the other hand, Cr(VI) is easy-dissolved and easy migrated. The traditional methods of Cr(VI) removing have a lot of disadvantages, including high residual, high cost, easy to produce secondary pollution. as a kind of advanced oxidation process, photocatalytic method , is able to take full use of the solar energy efficiently, which is really a green way to solve the problem of Cr(VI) pollutant. At the same time, using the method of photocatalytic degradation also need to solve the low visible light response of photocatalyst . To develop a kind of of visible light catalytic material with high efficiency and stability , which can also use most of visible light of the sunlight energy to degrade pollutants. This study first load the Bi2O3 on SBA-15 ,and make an assessment of degradation performance of several proportion of Bi2O3 on SBA-15 ,then select the best proportion. Further, on the basis of a lot of literature about N-F doped ,we determined the doping ratio of NH4F. Results show that by loading Bi2O3 on S