Nitrate is the leading cause of eutrophication worldwide and is one of the most challenging pollutants for restoration of polluted surface waters such as lakes, rivers and reservoirs. We report herein a new architectu...Nitrate is the leading cause of eutrophication worldwide and is one of the most challenging pollutants for restoration of polluted surface waters such as lakes, rivers and reservoirs. We report herein a new architecture of iron nanoparticles for high-efficiency denitrification by selective reduction of nitrate (NO3-) to dinitrogen (N2). The iron nanoparticles are doped with nitrogen (FeN) and encapsulated within a thin layer of nitride-carbon (NC). The nanoparticles have high pyrrolic N content (17.4 at.%) and large specific surface area (2040 m2/g). Laboratory experiments demonstrated high N2selectivity (91%) and nitrate removal capacity (6004 mg N/g Fe) for treatment of nitrate-containing water. This iron-based nanomaterial overcomes shortcomings of conventional catalysts by eliminating the use of precious and toxic heavy metals (e.g., Pd, Pt, Cu, Ni) and minimizing the generation of undesirable byproducts (e.g., ammonia) from the reactions with nanoscale zero-valent iron (n ZVI). The multiple electron transfers process from NO3- to N2can be fine-tuned by adjusting the NC shell thickness. Superior electrocatalytic perfor- mance, low cost and minimal environmental impact of the iron-derived nanocatalyst offer promising prospects for water purification, waste treatment and environmental remediation.展开更多
利用电化学氧化技术在泡沫铜基底上生长出纳米线,再进行退火氧化处理,使其具备高催化还原硝酸盐的性能。实验结果表明,该三维铜电极的比表面积高、传质效果好;用适度氧化后的电极以15 m A/cm^(2)的电流密度,在120 min内基本上可将pH=7...利用电化学氧化技术在泡沫铜基底上生长出纳米线,再进行退火氧化处理,使其具备高催化还原硝酸盐的性能。实验结果表明,该三维铜电极的比表面积高、传质效果好;用适度氧化后的电极以15 m A/cm^(2)的电流密度,在120 min内基本上可将pH=7的水体中存在的30 mg N/L硝酸盐去除(去除率为99%);为了将生成的氨氮副产物去除,加入NaCl还原120 min,硝酸盐的去除率达91%,氮气选择性高于95%。5次循环实验后硝酸盐的去除率保持在91%~95%,氮气选择性为93%~95%。该材料与工艺的结合解决了水体中硝酸盐的污染问题,为实际水体污染提供了新的解决方案。展开更多
基金This work was financially supported by the National Natural Science Foundation of China(51978488,41772243 and 41673096).
文摘Nitrate is the leading cause of eutrophication worldwide and is one of the most challenging pollutants for restoration of polluted surface waters such as lakes, rivers and reservoirs. We report herein a new architecture of iron nanoparticles for high-efficiency denitrification by selective reduction of nitrate (NO3-) to dinitrogen (N2). The iron nanoparticles are doped with nitrogen (FeN) and encapsulated within a thin layer of nitride-carbon (NC). The nanoparticles have high pyrrolic N content (17.4 at.%) and large specific surface area (2040 m2/g). Laboratory experiments demonstrated high N2selectivity (91%) and nitrate removal capacity (6004 mg N/g Fe) for treatment of nitrate-containing water. This iron-based nanomaterial overcomes shortcomings of conventional catalysts by eliminating the use of precious and toxic heavy metals (e.g., Pd, Pt, Cu, Ni) and minimizing the generation of undesirable byproducts (e.g., ammonia) from the reactions with nanoscale zero-valent iron (n ZVI). The multiple electron transfers process from NO3- to N2can be fine-tuned by adjusting the NC shell thickness. Superior electrocatalytic perfor- mance, low cost and minimal environmental impact of the iron-derived nanocatalyst offer promising prospects for water purification, waste treatment and environmental remediation.
