零价铁与厌氧微生物协同还原地下水中的硝基苯

通过间歇式实验,考察了零价铁与厌氧微生物协同还原地下水中硝基苯的效果。实验结果表明,由零价铁腐蚀为厌氧微生物提供H2电子供体还原硝基苯的效果明显优于零价铁和微生物单独作用,硝基苯去除率分别提高21.8%和57.0%。弱酸性条件有利于协同反应进行,当初始pH为5.0和6.0时,4 d后硝基苯去除率比初始pH为7.0时的提高74.4%和35.2%。增加零价铁投加量可提高协同还原的效果,零价铁最佳投加量为250 mg/L。零价铁腐蚀产生的Fe2+无法作为电子供体被微生物利用,但可作为无机营养元素促进协同过程。由于零价铁产H2速率受表面覆盖物影响不明显,在地下水修复过程中可保证协同效果并延长零价铁的使用寿命。

Reduction of nitrobenzene in ground water by the combination of zero valent iron and anaerobic microorganism

Batch tests were conducted to investigate the reduction of nitrobenzene(NB) in groundwater by the combination of zero valent iron(ZVI) and anaerobic microorganism.The results showed that the ZVI/anaerobic microorganism system was better than ZVI or anaerobic microorganism alone,and the removal of NB increased by 21.8% and 57.0%,respectively.Acid condition was favorable for NB reduction in the synergy system.When solution pH decreased from 7.0 to 6.0 and 5.0,NB removal increased by 74.4% and 35.2% after 4 d,respectively.NB removal increased with iron dosage and the optimal iron dosage was 250 mg/L.The released Fe2+ during ZVI corrosion could not be used as an electron donor,but it was beneficial to anaerobic microorganism as an inorganic nutrient element.Since the production of H2 was not significantly affected by the precipitates on iron surface,NB removal efficiency could be maintained and the life span of ZVI could also be prolonged in contaminated groundwater remediation.