Wang Guanlong, Zhao Ya, Ma Huanran, Zhang Chenjing, Dong Xiaoli, Zhang Xiufang
School of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian 116034, China.
School of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian 116034, China.
Sci Total Environ. 2021 Feb 20;756:144139. doi: 10.1016/j.scitotenv.2020.144139. Epub 2020 Nov 27.
Constructing highly efficient metal-free material towards peroxymonosulfate (PMS) activation under photocatalytic assistance is a promising strategy for water decontamination. Herein, N vacancy modified g-CN nanotube (VCN) was prepared to build a novel photo-assisted PMS activation system (PPAS), in which the unique electronic structure created by N vacancy could favor the PMS activation on VCN under visible-light irradiation. The role of N vacancy in PPAS was firstly studied through tuning its content in VCN. The results showed that the N vacancy greatly improved PMS activation on VCN PPAS towards organic pollutants removal. The VCN PPAS with moderate N vacancy modification performed best, whose kinetic constant for Rhodamine B degradation was 9.6 and 2.6 times higher than that of VCN/PMS system and pristine g-CN PPAS, respectively. Moreover, the VCN PPAS performed well in wide pH range (3-12) and real water background. Selective removal of different organic pollutants was found on VCN PPAS, owing to the different interaction between pollutant and the catalyst surface with surface-bound radicals. The O and OH were major oxidants for pollutant removal in VCN PPAS, which were produced on dual active sites of VCN via two pathways: The N vacancy enhanced PMS adsorption and trapped photogenerated electrons for PMS reduction into OH, while the electron-deficient C atoms created by N loss promoted the PMS oxidation into O.
构建高效的无金属材料以在光催化辅助下实现过一硫酸盐（PMS）活化是一种很有前景的水净化策略。在此，制备了N空位修饰的g-CN纳米管（VCN）以构建一种新型的光辅助PMS活化系统（PPAS），其中由N空位产生的独特电子结构有利于在可见光照射下VCN上的PMS活化。首先通过调节其在VCN中的含量研究了N空位在PPAS中的作用。结果表明，N空位极大地改善了VCN PPAS上PMS对有机污染物去除的活化效果。具有适度N空位修饰的VCN PPAS表现最佳，其罗丹明B降解的动力学常数分别比VCN/PMS系统和原始g-CN PPAS高9.6倍和2.6倍。此外，VCN PPAS在较宽的pH范围（3-12）和实际水背景下表现良好。在VCN PPAS上发现了对不同有机污染物的选择性去除，这是由于污染物与具有表面结合自由基的催化剂表面之间的相互作用不同。O和OH是VCN PPAS中去除污染物的主要氧化剂，它们通过两条途径在VCN的双活性位点上产生：N空位增强了PMS吸附并捕获光生电子将PMS还原为OH，而N损失产生的缺电子C原子促进了PMS氧化为O。
