催化学报 ›› 2021, Vol. 42 ›› Issue (6): 953-962.DOI: 10.1016/S1872-2067(20)63719-6

• 论文 • 上一篇    下一篇

基于N-掺杂碳包覆Fe3N复合材料的高效异相电芬顿降解有机物

肖娟, 陈军伟, 欧祖翘, 赖俊杭, 俞同文, 王毅*()   

  1. 中山大学化学工程与技术学院, 材料科学与工程学院, 广东省低碳化学与过程节能重点实验室, 广东广州510275
  • 收稿日期:2020-07-30 接受日期:2020-09-09 出版日期:2021-06-18 发布日期:2021-01-30
  • 通讯作者: 王毅
  • 基金资助:
    国家自然科学基金(21975292);国家自然科学基金(21978331);国家自然科学基金(21905311);催化基础国家重点实验室开放基金(N-20-02);广东省基础与应用基础研究基金(2020A1515010343);广州科技计划项目(2017A050501009);高校基本科研业务费青年教师重点培育项目(19lgpy116);中山大学百人计划启动基金.(76110-18841219)

N-doped carbon-coated Fe3N composite as heterogeneous electro-Fenton catalyst for efficient degradation of organics

Juan Xiao, Junwei Chen, Zuqiao Ou, Junhang Lai, Tongwen Yu, Yi Wang*()   

  1. The Key Laboratory of Low-Carbon Chemistry & Energy Conservation of Guangdong Province, School of Chemical Engineering and Technology, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
  • Received:2020-07-30 Accepted:2020-09-09 Online:2021-06-18 Published:2021-01-30
  • Contact: Yi Wang
  • About author:*Tel/Fax: +86-20-84113253; E-mail: wangyi76@mail.sysu.edu.cn
  • Supported by:
    National Natural Science Foundation of China(21975292);National Natural Science Foundation of China(21978331);National Natural Science Foundation of China(21905311);Open Fund of State Key Laboratory of Catalytic Foundation(N-20-02);Guangdong Fundamental and Applied Basic Research Foundation(2020A1515010343);Guangzhou Science and Technology Project(2017A050501009);Fundamental Science Research Fundation of Sun Yat-Sen University(19lgpy116);Hundred Talents Program Startup Grant of Sun Yat-sen University(76110-18841219)

摘要:

水污染导致的缺水危机、水质恶化和生态环境破坏等问题, 严重影响人的健康及社会的和谐可持续发展. 异相电芬顿技术因催化剂可循环利用、宽pH适用范围等优点而广受关注. 常见的催化剂以铁、铁氧化物等铁基材料为主, 存在金属颗粒分布不均匀、铁元素易溶出、铁循环易受阻和H2O2选择性和转化效率低等问题, 严重制约该技术的发展. 尽管可以通过变价金属和非金属掺杂提高H2O2转化效率和选择性等, 但铁基催化剂的异相电芬顿性能仍有待提升. 因此, 亟待开发一种具有合金性质且宽pH响应的高H2O2选择性及转化效率、高稳定性的铁基催化剂. 本文利用具有高分散的金属位点和丰富碳源的铁基金属有机骨架材料, 采用同步高温煅烧和氨气刻蚀等手段, 制备N-掺杂碳包覆Fe3N复合材料(Fe3N@NG/NC), 并探究了该材料在异相电芬顿降解有机污染物体系中的应用前景.
XRD, SEM和TEM测试结果表明, Fe3N@NG/NC催化剂是由N-掺杂的石墨化碳包覆的Fe3N纳米颗粒(大小约为70 nm)均匀分散在N-掺杂碳骨架材料中组成的, 这一特殊结构有利于电荷的快速传输, 有助于电催化氧还原产H2O2及其转化至·OH反应的发生. 电化学测试结果表明, 该催化剂具有良好的两电子氧还原性能, 在电压范围为-0.3~0.1 V内的H2O2选择性为82.2%~74.5%, 电子转移数为2.35~2.50. 电子顺磁共振光谱结果表明, 该催化剂在异相电芬顿体系中主要的活性物质为·OH. XPS结果表明, 该催化剂中高含量的石墨N和吡啶N、Fe(II)有利于电催化合成H2O2和活化H2O2至·OH, 使其具有高效的异相电芬顿性能. 异相电芬顿降解评估结果表明, 该催化剂在pH 5.0体系中120 min内能高效去除罗丹明(RhB)、邻苯二甲酸二甲酯、亚甲基蓝和橙黄II等多种有机污染物(有机物去除率为97%~100%, TOC去除率为49%~65%), 不同RhB降解体对其去除率贡献程度依次为异相电芬顿 > 电催化 > 电生成H2O2氧化 > O2氧化 > 吸附; 能实现宽pH范围内RhB的高效去除(在pH为3.0, 5.0, 7.0和9.0条件下, 在60 min内的RhB去除率分别为100%, 96%, 92%和81%); 在宽pH范围内呈现出高稳定性, 铁溶出量为0~0.03 mg/L; 经过6次循环使用后, 仍具有高的异相电芬顿性能(去除率达90%以上). 综上所述, Fe3N@NG/NC复合材料能作为良好的异相电芬顿催化剂, 应用于污水处理领域.

关键词: Fe3N@NG/NC复合材料, 异相电芬顿, 金属有机骨架, 降解, 有机污染物

Abstract:

Herein, the application of a N-doped graphitic-carbon-coated iron nitride composite dispersed in a N-doped carbon framework (Fe3N@NG/NC) is investigated as a heterogeneous electro-Fenton ( HE-EF) catalyst for the efficient removal of organics. The simultaneous carbonization and ammonia etching of iron-based metal organic framework (Fe-MOF) materials yielded well-dispersed N-doped carbon-coated Fe3N nanoparticles with a diameter of ~70 nm. The Fe3N and pyridinic N endowed the composite with high HE-EF activity for decomposing the electrogenerated H2O2 toOH. The Fe3N@NG/NC exhibited outstanding HE-EF performance in removing various organic pollutants with low iron leaching. A removal rate of 97-100% could be obtained for rhodamine B (RhB), dimethyl phthalate, methylene blue, and orange II in 120 min at a pH of 5.0. When the solution pH was set to 3.0, 5.0, 7.0, and 9.0, the removal rate of RhB reached 100%, 96%, 92%, and 81%, respectively, in 60 min at an optimum voltage of 0.0 V (vs. reversible hydrogen electrode (RHE)). Moreover, the concentration of leached iron was expected to be below 0.03 mg/L in a wide pH range of 3.0-9.0. In addition, the RhB removal efficiency remained as high as 90% after six cycles in the reusability experiments. This work highlights the MOF-derived Fe3N composite as an efficient HE-EF catalyst and the corresponding catalytic mechanism, which facilitates its application in wastewater treatment.

Key words: Fe3N@NG/NC composite, Heterogeneous electro-Fenton, Metal-organic frameworks, Degradation, Organic pollutants