催化学报

催化学报 ›› 2017, Vol. 38 ›› Issue (2): 227-239.DOI: 10.1016/S1872-2067(16)62566-4

• 论文 • 上一篇    下一篇

亚微米级Cu0/Fe3O4复合物多相催化过一硫酸盐降解有机污染物

聂刚, 黄佳, 胡冶州, 丁耀彬, 韩小彦, 唐和清   

  1. 中南民族大学资源与环境学院, 国家民委-教育部共建催化材料重点实验室, 湖北武汉 430074
  • 收稿日期:2016-09-14 修回日期:2016-10-28 出版日期:2017-02-18 发布日期:2017-03-14
  • 通讯作者: Yaobin Ding,Tel/Fax:+86-27-87543632;E-mail:yaobinding@mail.scuec.edu.cn;Heqing Tang,Tel/Fax:+86-27-87543632;E-mail:tangheqing@mail.scuec.edu.cn
  • 基金资助:

    国家自然科学基金（21377169，21507168）；湖北省自然科学基金（2014CFC1119，2015CFB505）；中央高校基本科研基金（CZW15078）.

Heterogeneous catalytic activation of peroxymonosulfate for efficient degradation of organic pollutants by magnetic Cu0/Fe3O4 submicron composites

Gang Nie, Jia Huang, Yezhou Hu, Yaobin Ding, Xiaoyan Ha, Heqing Tan   

  1. Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074, Hubei, China
  • Received:2016-09-14 Revised:2016-10-28 Online:2017-02-18 Published:2017-03-14
  • Contact: 10.1016/S1872-2067(16)62566-4
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21377169, 21507168), the Fundamental Research Funds for the Central Universities (CZW15078), and the Natural Science Foundation of Hubei Province of China (2014CFC1119, 2015CFB505).

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摘要：

过一硫酸盐催化活化技术因其可产生强氧化性活性氧化物种，可快速氧化降解并矿化有机污染物的优异性能而备受关注.本文成功制备了亚微米级Cu0/Fe3O4复合物，发现其能多相催化过一硫酸盐产生单线态氧降解有机污染物.首先，以CuCl2·2H2O，FeCl2·4H2O和FeCl3·6H2O为铜源和铁源，水合肼为还原剂，采用水热法在180℃反应24 h制备了亚微米级磁性Cu0/Fe3O4复合物.表征结果显示，所制材料为Cu0和Fe3O4的复合物，颗粒大小约为220 nm；单一相Cu0和Fe3O4晶体粒径分别为33.8和106.2 nm，而Cu0/Fe3O4复合物中Cu0和Fe3O4晶体粒径分别减为20.8和31.9 nm.这表明Cu0和Fe3O4复合降低了Cu0和Fe3O4晶体粒径，有利于Cu0和Fe3O4的分散.BET测试结果表明，Cu0/Fe3O4复合物比表面积为4.6 m2/g，与Cu0颗粒的（4.2 m2/g）相当，但远小于Fe3O4的（15.6 m2/g）.制备的Cu0/Fe3O4复合物可有效催化过一硫酸盐产生单线态氧降解罗丹明B、亚甲基蓝、金橙II、苯酚和对氯酚.当Cu0/Fe3O4复合物的用量为0.1 g/L，过一硫酸盐浓度为0.5 mmol/L和初始pH为7时，Cu0/Fe3O4复合物可在30 min内完全降解20 μmol/L的罗丹明B、亚甲基蓝、金橙II以及0.1 mmol/L的苯酚和对氯酚.对比试验显示，在相同条件下，Cu0和Fe3O4颗粒分别可以降解28%和20%的罗丹明B.这表明Cu0/Fe3O4复合物中的Cu0和Fe3O4晶体在催化过一硫酸盐降解污染物的反应中具有协同作用，这主要来源于Cu0/Fe3O4复合物中Cu0和Fe3O4的晶体粒径变小和更好的分散.采用分光光度法测定了降解反应液中铜和铁离子的溶出量.当Cu0/Fe3O4复合物的用量为0.1 g/L，过一硫酸盐浓度为0.5 mmol/L和初始pH为7时，反应60 min后，降解液中铜和铁离子的浓度分别为0.22和0.1 mg/L，仅占复合物中总铜和总铁量的1.1%和0.2%，表明Cu0/Fe3O4复合物具有较强的化学稳定性.所制Cu0/Fe3O4复合物具有超顺磁性，借助磁场实现快速分离回收，可循环利用五次，表明其优越的催化稳定性.通过加入乙醇和叠氮化钠，考察了Cu0/Fe3O4复合物催化活化过一硫酸盐体系中的活性氧化物种.发现100 mmol/L乙醇的加入对污染物的降解无明显影响，而加入同等量的叠氮化钠可完全抑制污染物的降解，表明Cu0/Fe3O4复合物催化活化过一硫酸盐产生的主要活性氧物种为单线态氧.采用电子顺磁共振谱进一步证实了单线态氧的生成.
基于以上研究，Cu0/Fe3O4复合物催化活化过一硫酸盐的机理为Cu0/Fe3O4作为一个电子媒介加速过一硫酸盐和污染物之间的电子转移，从而导致污染物被快速降解.该反应机理不同于常见的金属催化过一硫酸盐产生硫酸根和羟自由基的反应机理.我们推测，电导性优良的Cu0在此催化反应中起着关键性作用.本催化方法可作为一种绿色的氧化技术用于环境污染物的氧化降解处理.

关键词: 多相催化, Cu0/Fe3O4磁性复合物, 过一硫酸盐, 单线态氧, 氧化降解

Abstract:

Magnetic Cu0/Fe3O4 submicron composites were prepared using a hydrothermal method and used as heterogeneous catalysts for the activation of peroxymonosulfate (PMS) and the degradation of organic pollutants. The as-prepared magnetic Cu0/Fe3O4 submicron composites were composed of Cu0 and Fe3O4 crystals and had an average size of approximately 220 nm. The Cu0/Fe3O4 composites could efficiently catalyze the activation of PMS to generate singlet oxygen, and thus induced the rapid degradation of rhodamine B, methylene blue, orange II, phenol and 4-chlorophenol. The use of 0.1 g/L of the Cu0/Fe3O4 composites induced the complete removal of rhodamine B (20 μmol/L) in 15 min, methylene blue (20 μmol/L) in 5 min, orange II (20 μmol/L) in 10 min, phenol (0.1 mmol/L) in 30 min and 4-chlorophenol (0.1 mmol/L) in 15 min with an initial pH value of 7.0 and a PMS concentration of 0.5 mmol/L. The total organic carbon (TOC) removal higher than 85% for all of these five pollutants was obtained in 30 min when the PMS concentration was 2.5 mmol/L. The rate of degradation was considerably higher than that obtained with Cu0 or Fe3O4 particles alone. The enhanced catalytic activity of the Cu0/Fe3O4 composites in the activation of PMS was attributed to the synergistic effect of the Cu0 and Fe3O4 crystals in the composites. Singlet oxygen was identified as the primary reactive oxygen species responsible for pollutant degradation by electron spin resonance and radical quenching experiments. A possible mechanism for the activation of PMS by Cu0/Fe3O4 composites is proposed as electron transfer from the organic pollutants to PMS induces the activation of PMS to generate 1O2, which induces the degradation of the organic pollutants. As a magnetic catalyst, the Cu0/Fe3O4 composites were easily recovered by magnetic separation, and exhibited excellent stability over five successive degradation cycles. The present study provides a facile and green heterogeneous catalysis method for the oxidative removal of organic pollutants.

Key words: Heterogeneous catalysis, Magnetic Cu0/Fe3O4 composite, Peroxymonosulfate, Singlet oxygen, Oxidative degradation