高等学校化学学报 ›› 2024, Vol. 45 ›› Issue (3): 20230422.doi: 10.7503/cjcu20230422

• 物理化学 • 上一篇    下一篇

黏土矿物表面羟基介导的分子氧活化机理

杜晴1, 牛慧斌2, 徐艳1, 张静1, 兰星1, 黄应平2, 谈云志3, 陈晓婷1, 方艳芬1()   

  1. 1.三峡大学材料与化工学院
    2.水利与环境学院
    3.土木与建筑学院, 宜昌 443002
  • 收稿日期:2023-09-25 出版日期:2024-03-10 发布日期:2024-01-02
  • 通讯作者: 方艳芬 E-mail:fangyf@ctgu.edu.cn
  • 基金资助:
    国家自然科学基金(22076098);湖北省自然科学基金(2023AFA054);高等学校学科创新引智计划项目(D20015)

Mechanism of Molecular Oxygen Activation Mediated by Hydroxyl Groups on the Surface of Red Clay

DU Qing1, NIU Huibin2, XU Yan1, ZHANG Jing1, LAN Xing1, HUANG Yingping2, TAN Yunzhi3, CHEN Xiaoting1, FANG Yanfen1()   

  1. 1.School of Materials and Chemical Engineering
    2.School of Water Resources and Environment
    3.College of Civil Engineering & Architecture,China Three Gorges University,Yichang 443002,China
  • Received:2023-09-25 Online:2024-03-10 Published:2024-01-02
  • Contact: FANG Yanfen E-mail:fangyf@ctgu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22076098);the Natural Science Foundation of Hubei Province, China(2023AFA054);the 111 Project of China(D20015)

摘要:

天然黏土矿物表面羟基(Me-OH, Me=Al, Si, Fe)对分子氧(O2)活化机制目前尚不明晰. 本文通过在N2气氛中对红黏土(R-Clay)进行不同温度热处理, 调控其表面MeOH位点数及形态, 使其不同程度地活化O2, 进而降解水中四环素(TC). 研究结果表明, 随着温度的升高, R-Clay内高岭土结构逐渐被破坏, Fe2O3结构更加突显. 其中, 红黏土R-Clay400表面Me-OH以Al-Al-OH和Al-Si-OH形态存在, 可高效降解(86.36%)和矿化TC(40%, 6 h). 在可见光照射下, R-Clay400 Si-O-Al上氧原子和TC分子均可作为电子供体, 它们将光生电子(e-)转移给 吸附在R-Clay400表面的O2生成超氧自由基(O2- )及单线态氧(1O2), 实现对TC的高效降解. 机理研究表明, 表面Me-OH可作为Brönsted酸位点, 通过氢键吸附O2, 促进了电子转移, 而非传统认为的电子供体.

关键词: 热处理, 红黏土, 表面羟基, 分子氧活化机理, 降解

Abstract:

The activation mechanism of molecular oxygen(O2) by surface hydroxyl groups(Me-OH, Me=Al, Si, Fe) of natural clay minerals is still unclear. In this study, red clay(R-Clay) was heat-treated at varying temperatures in N2 to adjust the number and shape of Me-OH sites on its surface, thus activating O2 to different degrees for tetracycline(TC) degradation in water. As the temperature increased, the kaolin structure in R-Clay was gradually destroyed, and the Fe2O3 structure became more prominent. Among them, Me-OH on the surface of red clay (R-Clay400) exists in the form of Al-Al-OH and Al-Si-OH, which efficiently degraded(86.36%) and mineralized TC(40%, 6 h). Under visible light irradiation, both oxygen atoms and TC molecules on R-Clay400 Si-O-Al can be used as electron donors to transfer photogenerated electrons(e-) to O2 adsorbed on the surface of R-Clay400 to form superoxide radical(O2-) and singlet oxygen(1O2), thus achieving efficient degradation of TC. Here, the surface Me-OH, used as the Brönsted site, adsorbs O2 by hydrogen bond, which promotes electron transfer rather than traditional electron donor. This study further clarified the activation mechanism of clay minerals to O2 and promoted the development of related research fields of mineral-based materials.

Key words: Heat treatment, Red clay, Surface hydroxyl group, Molecular oxygen activation mechanism, Degradation

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