不同pH下纳米铁镍颗粒对生物降解苯酚的影响

研究不同pH(8.0、6.0和3.0)下金属纳米颗粒(Fe和Fe/Ni)对纺锤芽孢杆菌(BFN)降解苯酚的影响.实验结果发现pH在8.0和6.0时投加2种金属纳米颗粒(Fe和Fe/Ni)对BFN降解苯酚有促进作用,其原因主要是纳米颗粒在水中持续腐蚀产生H2,为BFN降解苯酚提供电子,促进BFN的生长.但在pH=3.0时,只有BFN-纳米Fe耦合体系才使苯酚得到部分降解,主要是因为纳米Fe颗粒与水反应产生OH-,使pH值有所升高,更适宜BFN的生长,同时提供电子供体H2促进BFN对苯酚的利用.扫描电镜(SEM)和能谱分析(EDS)数据证实金属纳米颗粒(Fe和Fe/Ni)在反应后附着在微生物表面,但微生物的表面形态并未发生显著改变.因此,纳米金属颗粒虽然通过附着影响微生物的活性,但其在腐蚀过程中产生的H2将作为电子供体而被BFN所利用,综合作用的结果是有利于BFN的生长进而提高苯酚的降解速率.

Effect of Fe and Fe/Ni Nanoparticles on the Biodegradation of Phenol by BFN at Different pH Values

Effect of nanoparticles (Fe and Fe/Ni) on the biodegradation of phenol by BFN at different pH values (8.0, 6.0 and 3.0) was investigated. The results showed that the degradation of phenol was promoted in the presence of the Fe and Fe/Ni nanopracticles at pH=8.0 and pH=6.0, whereas only Fe nanoparticles improved the biodegradation of phenol at pH=3.0. The former could be ascribed to the H₂ generated from iron corrosion, which can contribute to the degradation of phenol by BFN and the growth of BFN by providing electrons, while the latter could be attributed to that the increasing pH value resulted from the generation of OH^- from iron corrosion was beneficial to the growth of BFN. The improved growth of BFN in the presence of the metallic nanopracticles was observed in medium with various pH values. The results obtained from SEM and EDS demonstrated that the nanoparticles were adhered to the surface of BFN, but there was no significant change in the morphology of the microbes. Overall, nanoparticles (Fe and Fe/Ni) can facilitate the growth of BFN and thus the degradation of phenol.