摘要
采用纳米Fe3O4催化H2O2氧化降解水环境中的诺氟沙星.考察了溶液酸度、温度、催化剂和H2O2浓度对诺氟沙星降解的影响,对比不同底物在Fe3O4/H2O2体系中的降解情况,并进一步探讨了其反应机制.结果表明,溶液酸度显著影响诺氟沙星的降解率,在酸性条件下(pH=3.5)诺氟沙星的降解效率最高.诺氟沙星的降解率随纳米Fe3O4的用量、H2O2浓度和反应温度的增加而提高.Fe3O4/H2O2体系对诺氟沙星的降解效率远高于其对磺胺噻唑、苯酚和苯胺等污染物的降解效率.当H2O2浓度为4.4 mmol.L-1,纳米Fe3O4用量为0.80 g.L-1,T=303 K时,5 min内诺氟沙星的降解率可达到100%,同时诺氟沙星中的氟元素完全矿化成氟离子;反应1 h后,诺氟沙星的矿化率为57%.在Fe3O4/H2O2体系中检测到强的羟基自由基(.OH)信号,当反应溶液中加入.OH清除剂叔丁醇后,.OH的信号降低了约95%,1 h内诺氟沙星的降解率仅为10%.该结果证实了纳米Fe3O4催化H2O2氧化降解诺氟沙星的反应为类Fenton反应,降解过程中.OH起主要作用.
The degradation of norfloxacin in aquatic environment was studied in the presence of Fe3O4 nanoparticles and H2O2.The effects of solution pH,temperature,dose of catalysts and concentration of H2O2 on norfloxacin degradation were surveyed.The degradation behaviors of different substrates by nano-Fe3O4/H2O2 were investigated and the reaction mechanism of norfloxacin was discussed.The results showed that the reaction was strongly pH-dependent and favored in acidic solution（pH=3.5）.The removal efficiency of norfloxacin was enhanced with the increase of temperature,catalysts dosage and H2O2 concentration.The degradation efficiency of norfloxacin by nano-Fe3O4/H2O2 was significantly higher than those of sulfathiazole,phenolic and aniline compounds.In the presence of 4.4 mmol·L-1 of H2O2,0.80 g·L-1 of Fe3O4 and T=303 K,norfloxacin was degraded completely in 5 min.The F element in norfloxacin molecule existed totally as F-in solution within 5 min,and the removal efficiency of total organic carbon was 57% in 1 h.In the ESR spectrum of nano-Fe3O4/H2O2 system,the characteristic peaks of BMPO-·OH adduct was detected,however,the intensity of the peaks was reduced to 5% with the addition of tert-butanol,a strong ·OH scavenger,and the degradation efficiency of norfloxacin was correspondingly decreased to 10% in 1 h.These results indicated that ·OH played an important role on norfloxacin degradation,and the reaction proceeded based on a heterogeneous Fenton-like system.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2011年第10期2943-2948,共6页
Environmental Science
基金
国家自然科学基金重点项目(20837003)
国家自然科学基金重大项目(20890111)
国家重点基础研究发展规划(973)项目(2011CB936001)
