纳米银对水体中硝化细菌活性的影响

Effect of nano-silver on the activity of nitrifying bacteria in water

研究了不同质量浓度的纳米银在不同pH值和腐殖酸存在的条件下对水体中硝化细菌的影响.结果表明:纳米银质量浓度在0~20μg/mL范围内均对硝化细菌有抑制作用,且浓度越高抑制率越高;纳米银浓度为20μg/mL时,第10天抑制率就达到了98%.低pH值条件下,纳米银易于金属离子释放,对硝化细菌的抑制率较高,在pH=3时,第6天抑制率达到最大,为96.97%;在高pH值条件下纳米银容易发生团聚作用,导致硝化细菌的毒性作用减弱,pH=11时在第10天抑制率为54.83%.腐殖酸也能够使水体中的纳米银发生团聚作用,并且能够包覆纳米银降低对硝化细菌的毒性作用.

Due to the widespread use of nano silver,it inevitably discharged into the environment,causing a negative impact on the environment,nitrifying bacteria is an important participant in the nitrogen cycle of water,its activity reflects the disturbance of water ecosystem changes.The effect of nano silver on nitrifying bacteria in water was studied under the conditions of different nano silver concentration,different pH value and presence of humic acid.The results showed that the inhibition rate of nitrifying bacteria was within the range of 0-20μg/mL,and the higher the concentration,the higher the inhibition rate.When the concentration of nano silver was 20μg/mL,the inhibition rate reached 98%.Under low pH value of nano silver to metal ion release,inhibition of nitrifying bacteria was higher in pH=3 in sixth days to reach a maximum of 96.97%;in the condition of high pH value under the silver nanoparticles prone to aggregation,weaken the toxicity of nitrifying bacteria,i.e.pH=11 in tenth days for the inhibition rate 54.83%.Humic acid can also induce the aggregation of silver nanoparticles in water,and can be coated with nano silver to reduce the toxicity of nitrifying bacteria.