催化学报

催化学报 ›› 2020, Vol. 41 ›› Issue (2): 322-332.DOI: 10.1016/S1872-2067(19)63447-9

• 论文 • 上一篇    下一篇

石墨相氮化碳可见光下活化过一硫酸盐氧化降解光惰性邻苯二甲酸二甲酯的机理研究

徐立杰a, 戚蓝月a, 孙阳a, 公晗b, 陈一良a, 裴纯c, 甘露d   

  1. a 南京林业大学生物与环境学院, 江苏南京 210037;
    b 华南农业大学海洋学院, 广东广州 510642;
    c 深圳大学土木工程学院, 广东省滨海土木工程耐久性重点实验室, 广东深圳 518060;
    d 南京林业大学材料科学与工程学院, 江苏南京 210037
  • 收稿日期:2019-04-19 修回日期:2019-07-05 出版日期:2020-02-18 发布日期:2019-11-04
  • 通讯作者: 甘露
  • 基金资助:
    江苏省自然科学基金青年基金（BK20160936，BK20160938）；国家自然科学基金青年基金（51708297）；江苏省优势学科建设项目.

Mechanistic studies on peroxymonosulfate activation by g-C3N4 under visible light for enhanced oxidation of light-inert dimethyl phthalate

Lijie Xua, Lanyue Qia, Yang Suna, Han Gongb, Yiliang Chena, Chun Peic, Lu Gand   

  1. a College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, Jiangsu, China;
    b College of Marine Sciences, South China Agricultural University, Guangzhou 510642, Guangdong, China;
    c Guangdong Province Key Laboratory of Durability for Marine Civil Engineering, School of Civil Engineering, Shenzhen University, Shenzhen 518060, Guangdong, China;
    d College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, Jiangsu, China
  • Received:2019-04-19 Revised:2019-07-05 Online:2020-02-18 Published:2019-11-04
  • Supported by:
    This work was supported by the Natural Science Foundation of Jiangsu Province (BK20160936, BK20160938), the National Natural Science Foundation of China (51708297), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). The advanced analysis and testing center of Nanjing Forestry University is also acknowledged.

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摘要： 近几年过一硫酸盐（PMS）活化技术备受关注，其中利用太阳能活化PMS具有可持续和环保的优势，但PMS本身不吸收可见光.因此，本文提出利用具有可见光响应的石墨相氮化碳（g-C3N4）激发产生光电子进而活化PMS.首先利用三聚氰胺前驱体通过热缩聚法制备g-C3N4，通过X射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）、紫外-可见光漫反射（UV-Vis）、荧光光谱（PL）、透射电镜（TEM）、N2吸附脱附测试（BET）、电化学等一系列方法对g-C3N4进行表征，研究其表面性质及光学性能.结果显示，g-C3N4具有典型的片层结构和可见光活性，禁带宽度为2.7eV.本文选取光惰性的内分泌干扰物邻苯二甲酸二甲酯（DMP）为目标污染物，系统地研究了其降解动力学和降解机理.研究发现，在短波紫外光（254和300nm）照射下，直接光解和·OH参与的反应机理能实现DMP的光降解，而在可见光照射下g-C3N4介导的光催化过程不能使DMP分解；但当添加PMS时，体系主导自由基由·O2-转化为SO4·-和·OH，从而实现DMP的有效降解和矿化.研究还发现，高浓度的PMS和高剂量的g-C3N4均可以提高PMS的活化量和相应的DMP降解效率，但提高催化剂剂量的方式能更充分的利用PMS.尽管高浓度的DMP阻碍了PMS和光催化剂g-C3N4的有效接触，但可以提高PMS的利用率.当pH低于零电荷点（5.4）时，DMP的降解效率较高.此外，使用两种淬灭剂（乙醇和叔丁醇）与DMP进行竞争性实验，结合电子自旋共振检测，表明SO4·-和·OH都是体系主要的自由基.此外，还对g-C3N4的可持续性能进行考察，四次循环实验结果显示，该催化剂具有良好的可重复利用性.对DMP降解进行总有机碳测定，发现降低了19%.最后，利用液相色谱质谱联用对DMP降解产物进行定性定量分析，发现DMP主要通过SO4·-和·OH对苯环的攻击以及脂肪族链的氧化断键这两种途径进行降解.综上可见，利用可见光激发g-C3N4产生的光电子能有效活化PMS降解顽固型有机污染物，可为实现太阳能活化PMS技术提供有力的技术参考.

关键词: 石墨相氮化碳, 可见光, 过一硫酸盐, 邻苯二甲酸二甲酯, 活化, 降解

Abstract: Excitation of metal-free graphitic carbon nitride (g-C3N4) under visible light can successfully achieve efficient activation of peroxymonosulfate (PMS). Synergistic effects and involved mechanism were systematically investigated using a light-inert endocrine disrupting compound, dimethyl phthalate (DMP), as the target pollutant. Under visible light irradiation, DMP could not be degraded by direct g-C3N4-mediated photocatalysis, while in the presence of PMS, the dominant radicals were converted from ·O2 to SO4·- and ·OH, resulting in effective DMP degradation and mineralization. Results showed that higher dosage of PMS or g-C3N4 could increase the activation amount of PMS and corresponding DMP degradation efficiency, but the latter approach was more productive in terms of making the most of PMS. High DMP concentration hindered effective contact between PMS and g-C3N4, but could provide efficient use of PMS. Higher DMP degradation efficiency was achieved at pH lower than the point of zero charge (5.4). Based on intermediates identification, the DMP degradation was found mainly through radical attack (·OH and SO4·-) of the benzene ring and oxidation of the aliphatic chains.

Key words: Graphitic carbon nitride, Visible light, Peroxymonosulfate, Dimethyl phthalate, Activation, Degradation