...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Environmental Science & Technology >Tio_2 Photocatalytic Oxidation Mechanism Of As(Ⅲ)
【24h】

Tio_2 Photocatalytic Oxidation Mechanism Of As(Ⅲ)

机译：As（Ⅲ）的Tio_2光催化氧化机理

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

There has been a controversy over the TiO_2 photocatalytic oxidation (PCO) mechanism of As(Ⅲ) for the last several years. The key argument has been whether superoxide (HO2·/O_2-·) is the main oxidant of As(Ⅲ) in the UV/TiO_2 system. Previously we and other groups have refuted the claim that superoxide plays the main role in the TiO_2 PCO of As(Ⅲ). Nevertheless, thereafter, the superoxide-mediated As(Ⅲ) oxidation mechanism has been repeatedly claimed, making it difficult to draw a clear conclusion regarding this mechanism. The objective of this study is to draw a unanimous conclusion on the TiO_2 PCO mechanism of As(Ⅲ) and thus finish the controversy regarding this issue. To investigate the correlation between As(Ⅲ) oxidation and superoxide, both As(Ⅴ) and H_2O_2 were measured simultaneously. When excess formic acid (FA) was added as a scavenger of valence band (VB) hole (or·OH) in UV/TiO_2 or vacuum-UV lamp irradiation (λ= 185 + 254 nm), As(Ⅲ) oxidation was greatly inhibited while H_2O_2 generation was promoted. Since H_2O_2 is photochemically produced through the disproportionation of superoxide, this result definitely shows that superoxide has little role in the oxidation of As(Ⅲ) not only in UV/TiO_2 but also in other advanced oxidation processes (AOPs). Interestingly, not only FA (a scavenger of VB hole) but also methanol (a scavenger of adsorbed·OH) showed an inhibitory effect on the TiO_2 PCO of As(Ⅲ). Excess methanol retarded the TiO_2 PCO of As(Ⅲ) moderately but not completely, which indicates that adsorbed ·OH also plays a significant role along with VB hole in the TiO_2 PCO of As(Ⅲ). Although the conclusion is not based on the rate constant between As(Ⅲ) and superoxide but derived from indirect inference from the experimental data, this study provides convincing evidence to support that adsorbed ·OH and VB hole are the main oxidants in the TiO_2 PCO mechanism of As(Ⅲ).
机译：近年来，关于As（Ⅲ）的TiO_2光催化氧化（PCO）机理一直存在争议。关键论点是在UV / TiO_2系统中超氧化物（HO2·/ O_2-·）是否为As（Ⅲ）的主要氧化剂。以前，我们和其他研究小组驳斥了过氧化物在As（Ⅲ）的TiO_2 PCO中起主要作用的说法。然而，此后，人们反复提出了超氧化物介导的As（Ⅲ）氧化机理，因此很难对此机理作出明确的结论。本研究的目的是就As（Ⅲ）的TiO_2 PCO机理作出一致的结论，从而完成对该问题的争论。为了研究As（Ⅲ）氧化与超氧化物之间的关系，同时测定了As（Ⅴ）和H_2O_2。当在UV / TiO_2或真空-UV灯照射（λ= 185 + 254 nm）中加入过量的甲酸（FA）作为价带（VB）空穴（或·OH）的清除剂时，As（Ⅲ）的氧化作用很大。抑制H_2O_2的产生。由于H_2O_2是通过超氧化物的歧化而光化学生成的，因此该结果明确表明，超氧化物不仅在UV / TiO_2中而且在其他高级氧化过程（AOPs）中对As（Ⅲ）的氧化作用很小。有趣的是，不仅FA（VB空穴的清除剂）而且甲醇（吸附的·OH的清除剂）对As（Ⅲ）的TiO_2 PCO也有抑制作用。过量的甲醇对As（Ⅲ）的TiO_2 PCO有中等程度的抑制作用，但并不完全，这表明吸附的·OH和VB空穴在As（Ⅲ）的TiO_2 PCO中也起着重要的作用。尽管结论并非基于As（Ⅲ）与超氧化物之间的速率常数，而是根据实验数据的间接推论得出的，但本研究提供了令人信服的证据支持吸附的·OH和VB空穴是TiO_2 PCO机理中的主要氧化剂。的砷（Ⅲ）。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号