催化学报 ›› 2017, Vol. 38 ›› Issue (10): 1726-1735.DOI: 10.1016/S1872-2067(17)62902-4

• 论文 • 上一篇    下一篇

Ag/AgCl/铁-海泡石异相可见光Fenton催化降解双酚A

刘云, 毛妍彦, 唐宵宵, 许银, 李程程, 李峰   

  1. 湘潭大学环境与资源学院环境科学与工程系, 湖南湘潭 411105
  • 收稿日期:2017-05-18 修回日期:2017-08-05 出版日期:2017-10-18 发布日期:2017-10-28
  • 通讯作者: 刘云
  • 基金资助:

    国家自然科学基金(41573118);湖南省教育厅优秀青年项目(14B177);湘潭大学专项基金。

Synthesis of Ag/AgCl/Fe-S plasmonic catalyst for bisphenol A degradation in heterogeneous photo-Fenton system under visible light irradiation

Yun Liu, Yanyan Mao, Xiaoxiao Tang, Yin Xu, Chengcheng Li, Feng Li   

  1. Department of Environmental Science and Engineering, College of Environment and Resources, Xiangtan University, Xiangtan 411105, Hunan, China
  • Received:2017-05-18 Revised:2017-08-05 Online:2017-10-18 Published:2017-10-28
  • Contact: 10.1016/S1872-2067(17)62902-4
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (41573118), Research Foundation of Education Bureau of Hunan Province, China (14B177), and Special Project of Xiangtan University.

摘要:

光-Fenton技术是高级氧化技术中的一种,常用于难降解废水处理,由于其反应速度快、毒性低、反应条件温和而受到广泛关注.然而,传统的光-Fenton体系具有可见光利用率低、回收困难等缺点.为了解决这些问题,本文采用廉价易得、无污染、吸附能力强的天然矿物海泡石作为催化剂载体,并利用Ag/AgCl能够吸收可见光的表面等离子响应这一光学性质,合成了一种有潜力的非均相等离子体光催化剂Ag/AgCl/铁-海泡石催化剂(Ag/AgCl/Fe-S),并对该催化剂的形貌结构、性能和机理等进行了系统研究.
通过XRD,SEM,XPS,BET,UV-vis等表征手段对催化剂形貌、结构和可见光性能进行了分析.其中,XRD和SEM结果显示,Ag/AgCl粒子已经成功负载在Fe-海泡石上;XPS结果显示,铁氧化物的组成主要为FeOOH和Fe2O3;UV-vis结果显示,催化剂有较好的可见光吸收性能.
以双酚A为目标污染物,分别考察了Ag/AgCl/Fe-S,Ag/AgCl和Fe-海泡石的光-Fenton催化性能.结果显示,Ag/AgCl/Fe-S降解双酚A的效果明显优于另外两种催化剂,在H2O2浓度为6 mmol/L,pH为4,光照强度500 W,Ag/AgCl/Fe-S催化剂量为1.0 g/L,双酚A初始浓度为10 mg/L的条件下,1 h时,双酚A基本被完全降解,且3 h时,其矿化率达到61.2%;而Ag/AgCl和Fe-海泡石催化剂在同样的条件下完全降解双酚A至少要3 h,且其矿化率分别只有46.61%和28.85%.另外,还分别探讨了H2O2浓度、pH值、光照强度和催化剂剂量对双酚A降解的影响.
最后,通过活性物种捕获、ESR、电化学和PL实验对该体系的反应机理进行了探讨.活性物种捕获实验和ESR实验结果表明,羟基自由基(·OH)和空穴(h+)是该体系中的主要活性物种,且Ag/AgCl/Fe-S+H2O2+vis体系产生的·OH明显多于Fe-S+H2O2+vis体系.为了探讨·OH增多的原因,我们进行了电化学实验和PL实验.电化学实验结果显示,Ag/AgCl/Fe-S催化剂具有更低的阻抗,因此有利于电子-空穴分离.PL结果显示,Ag/AgCl/Fe-S催化剂的电子-空穴复合率更低.结合以上实验,我们提出了Ag/AgCl/Fe-S+H2O2+vis体系对双酚A的降解机理,即一方面催化剂能够发生Fenton反应而产生·OH,另一方面,催化剂中的Ag/AgCl在可见光下由于表面等离子响应而产生电子-空穴,空穴本身可作为活性物种降解双酚A.同时,产生的电子被体系中的Fe3+捕获生成Fe2+,从而促进了铁循环,有利于体系中产生更多的·OH.最后,空穴和羟基自由基发生协同作用共同促进污染物降解.

关键词: 可见光, 光-Fenton, 等离子催化剂, Ag/AgCl/Fe-S, 海泡石

Abstract:

A novel plasmonic photo-Fenton catalyst of Ag/AgCl/Fe-S was synthesized by ion exchange and photoreduction methods. The obtained catalyst was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope imaging, and Brunauer-Emmett-Teller measurements. Moreover, the photocatalytic activity of Ag/AgCl/Fe-S was investigated for its degradation activity towards bisphenol A (BPA) as target pollutant under visible light irradiation. The effects of H2O2 concentration, pH value, illumination intensity, and catalyst dosage on BPA degradation were examined. Our results indicated that the Ag/AgCl material was successfully loaded onto Fe-sepiolite and showed a high photocatalytic activity under illumination by visible light. Furthermore, active species capture experiments were performed to explore the photocatalytic mechanism of the Ag/AgCl/Fe-S in this heterogeneous photo-Fenton process, where the major active species included hydroxyl radicals (·OH) and holes (h+).

Key words: Visible light, Photo-Fenton, Plasmonic catalyst, Ag/AgCl/Fe-S, Sepiolite