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Photocatalytic removal of thallium(I) ions from aqueous media using ultraviolet light and titanium dioxide.

机译：使用紫外线和二氧化钛光催化去除水性介质中的（离子。

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摘要

Heterogeneous photocatalysis using titanium dioxide as the catalyst under ultraviolet (UV) irradiation was investigated for Tl(I) removal from aqueous media. In this dissertation, photocatalytic reactions under various conditions (e.g., pH, light intensity, and organic and inorganic co-additives) were studied. The direct photocatalytic reduction process was first explored. Due to its fairly negative reduction potential, the direct photocatalytic reduction of Tl(I) species using photogenerated electrons in UV-irradiated titania suspensions was unfavorable. However, the photocatalytic reactivity is drastically modified when co-additives were present. The extent of Tl(I) removal from water was dependent on the type and concentration of additives. It was found that Tl(I) was successfully removed from water by photocatalytic reduction in the presence of organic co-additives (e.g., formate, oxalate, and acetate ions). The photoconversion of Tl(I) was enhanced by nitrite and nitrate, while chloride inhibited the process.; In addition to the photocatalysis-related experiments, the dark adsorption of Tl(I) on the titania surface using different types of additives in aqueous media, was investigated. It was found that oxalate, formate, acetate and phosphate (at low levels) had a positive influence on Tl(I) adsorption, while phosphate (at high levels), chloride and nitrate exerted a negative effect. Finally, point of zero charge of the titania surface in the presence of different types of additives in Tl(I) aqueous solution, was also measured to provide supportive data for Tl(I) interfacial adsorption.
机译：研究了使用二氧化钛作为催化剂在紫外线（UV）照射下进行的非均相光催化从水性介质中去除Tl（I）的过程。本文研究了在各种条件下（例如pH，光强度以及有机和无机助添加剂）的光催化反应。首先探索了直接光催化还原过程。由于其相当大的负还原电位，在紫外线照射的二氧化钛悬浮液中使用光生电子直接光催化还原Tl（I）物种是不利的。但是，当存在共添加剂时，光催化反应性会大大改变。从水中去除Tl（I）的程度取决于添加剂的类型和浓度。发现在有机共添加剂（例如甲酸根，草酸根和乙酸根离子）的存在下，通过光催化还原成功地从水中除去了T1（I）。亚硝酸盐和硝酸盐增强了Tl（I）的光转化，而氯化物则抑制了该过程。除了与光催化有关的实验以外，还研究了在水性介质中使用不同类型的添加剂对Tl（I）在二氧化钛表面的暗吸附。发现草酸盐，甲酸盐，乙酸盐和磷酸盐（低含量）对Tl（I）的吸附有积极影响，而磷酸盐（高含量），氯化物和硝酸盐则有不利影响。最后，还测量了在Tl（I）水溶液中存在不同类型添加剂的情况下二氧化钛表面的零电荷点，从而为Tl（I）界面吸附提供了支持性数据。

著录项

  • 作者

    Kajitvichyanukul, Puangrat.;

  • 作者单位

    The University of Texas at Arlington.;

  • 授予单位 The University of Texas at Arlington.;
  • 学科 Engineering Environmental.; Chemistry Analytical.; Engineering Civil.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 122 p.
  • 总页数 122
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境污染及其防治;化学;建筑科学;
  • 关键词

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