• 硫化纳米零价铁对PCB153的降解研究
  • Degradation of PCB153 by sulfidated nanoscale zero-valent iron
  • 基金项目:国家自然科学基金(4137144);水体污染控制与治理科技重大专项(2017ZX07206-003)
  • 作者
  • 单位
  • 楼轶玲
  • 浙江大学环境与资源学院
  • 蔡雨宸
  • 浙江大学环境与资源学院
  • 童彦宁
  • 浙江大学环境与资源学院
  • 谢理淳
  • 浙江大学环境与资源学院
  • 沈超峰
  • 浙江大学环境与资源学院
  • 徐新华
  • 浙江大学环境与资源学院
  • 楼莉萍
  • 浙江大学环境与资源学院
  • 摘要:硫化纳米零价铁(S-nZVI)是近年来最新的纳米零价铁改性技术,已有研究发现其在重金属等污染物去除方面具有较好的效果,而对多氯联苯(PCBs)的反应活性目前尚未有报道。本研究对比了运用低亚硫酸钠为硫化试剂制备的S-nZVI、纳米零价铁(nZVI)和羧甲基纤维素稳定纳米零价铁(CMC-nZVI)三种纳米零价铁材料降解六氯联苯PCB153的反应动力学。研究了pH值、阴离子、腐殖酸(HA)等因素对该反应的影响,分析了反应前后材料表面性质的变化,探讨了脱氯路径和反应机理。结果表明,三种纳米零价铁材料对PCB153的降解反应符合准一级动力学,降解机理相似,降解效果依次为CMC-nZVI>nZVI>S-nZVI。硫化改性降低了nZVI去除PCB153的反应活性,S-nZVI表面的硫铁化物并未直接参与PCB153降解反应,S-nZVI反应活性低的原因可能是硫铁化物的形成损耗了一部分的Fe0的还原能力。此外,与CMC-nZVI、nZVI不同,高pH更有利于S-nZVI对PCB153的降解,阴离子和HA对三种纳米零价铁活性的影响规律相似。研究结果可为S-nZVI在持久性有机污染物降解中的应用提供理论依据和技术支持。
  • Abstract:Sulfidated nanoscale zero-valent iron (S-nZVI) is the latest modification technology in recent years. Many studies showed that S-nZVI has a good effect on the removal of pollutants such as heavy metals, however, its reactivity with polychlorinated biphenyls (PCBs) has not been reported yet. In this study, the reduction reaction kinetics of PCB153 by S-nZVI prepared by using dithionite as a sulfidation agent, nanoscale zero-valent iron (nZVI) and carboxymethylcellulose stabilized nanoscale zero-valent iron (CMC-nZVI) were compared, the effects of pH, anion and humic acid (HA) on the degradation of PCB153 were studied. The surface properties of three materials before and after the reaction were analyzed, and the dechlorination pathway and reaction mechanism were investigated. The results showed that the degradation of PCB153 by three materials was well described by a pseudo-first-order kinetics model and the degradation mechanism was similar. The degradation efficiency decreased in the order of CMC-nZVI>nZVI>S-nZVI. The sulfidation suppressed the reactivity of nZVI to degrade PCB153. The iron sulfide on the surface of S-nZVI was not directly involved in the degradation reaction of PCB153. The low reactivity of S-nZVI may be attributed to the formation of iron sulfide, which decrease the reductive ability of Fe0. In addition, different from CMC-nZVI and nZVI, high pH will help the degradation of PCB153 by S-nZVI, and the effects of anion and HA on three nZVI were similar. The results can provide theoretical basis and technical support for the application of S-nZVI on the degradation of persistent organic pollutants.

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