δ-Bi2O3微纳结构对水体硒污染物的吸附行为及机理研究

Selenium (Se) contamination is attracting wide attention and more in numerous contaminant sources. As an indispensable trace element for human being, animals and plants, Se is the key to form antioxidant enzyme which can protect the cell membranes from oxidation damage . However, the toxicological characteristic like arsenic poisoning will appear if the slightly excessive intake of Se takes place, which is seriously harmful for human beings. The Se concentration limitation in drinking water is as low as 10 ppb according to regulation of the World Health Organization (WHO) and European Union (EU). In most cases, Se exists in water as the forms of selenate and selenite. In this project, we aims to synthesize δ-Bi2O3 micro/nanostructures assembled by nanosheets by using hydrothermal method, and investigate the influence on density of the oxygen-vacancy and exposed crystal plane in δ-Bi2O3 micro/nanostructures from the synthesis conditions. We will also study the adsorption of selenate and selenite on the as-prepared δ-Bi2O3 micro/nanostructures with different oxygen-vacancy densities and exposed crystal planes, and determine the relationship between the adsorption properties and the oxygen-vacancy density and exposed crystal plane of the δ-Bi2O3 micro/nanostructures. The first-priciples calculation and synchrotron radiation will be used to analyze the complexation adsorption behavior of selenate and selenite on the δ-Bi2O3 micro/nanostructures. This project will provide theoretical support for the development of efficient and selective adsorbents for highly toxic Se contaminated water.

在众多的水体污染源中，硒污染越来越受到人们的关注。硒是是人体和动植物所必需的微量元素之一，它能组成体内的抗氧化酶，能保护细胞膜免受氧化损害。然而，硒的摄入量稍微过高，就会产生与砷类似的毒理特性，对人体造成极大的危害。因此，世界卫生组织和欧盟把饮用水中硒浓度上限设为10 ppb。在大多数情况下，硒是以硒酸根和亚硒酸根的形式存在于水体中。在本课题中，我们拟利用水热法合成纳米片组装的δ-Bi2O3微纳结构，探讨反应条件对δ-Bi2O3的氧空位密度以及暴露晶面的影响。研究各种具有不同氧空位密度和暴露晶面的δ-Bi2O3微纳结构对水体硒酸根和亚硒酸根的吸附性能，确定δ-Bi2O3微纳结构的氧空位密度与晶面特征与吸附性能间的关系。利用第一性原理和同步辐射技术，分析硒酸根和亚硒酸根在δ-Bi2O3微纳结构表面的络合吸附机理。该项目的开展将为水体剧毒硒污染物的选择性高效吸附材料的开发提供理论支持。

*硒是人体和动植物所必需的微量元素之一，它能组成体内的抗氧化酶，能保护细胞膜免受氧化损害，保持细胞的通透性。然而，硒的摄入量稍微过高，就会产生与砷类似的毒理特性，对人体造成极大的危害。在大多数情况下，硒是以硒酸根和亚硒酸根的形式存在于水体中。本课题以纳米片组装的δ-Bi2O3微球为吸附剂去除水体中的硒酸根和亚硒酸根，探讨反应条件对δ-Bi2O3的氧空位密度以及暴露晶面的影响，研究各种具有不同氧空位密度和暴露晶面的δ-Bi2O3微球与吸附性能间的关系。利用第一性原理和同步辐射技术，分析硒酸根和亚硒酸根在δ-Bi2O3微球表面的络合吸附机理。本项目为去除水体剧毒硒污染物的高效吸附材料开发提供理论支持。申请人在对δ-Bi2O3微纳结构中氧空位对SeO32-吸附进行系统研究的基础上，利用MOFs材料的大比表面及丰富孔道优势进而合成Bi-MOFs，实现对污水中的SeO32-高效捕获，并揭示相关吸附机理。在此基础上，提出强的化学配位键作用可以避免脱附引起的二次污染，且不饱和金属位点有利于配位键的形成并提高吸附量，进而设计合成用于去除SeO32-污染物的其他金属中心MOFs材料。这些工作不仅有利于理解吸附剂和污染物之间吸附过程及机制，还为以后设计新型、高性能吸附剂提供理论支撑和新的思路。