Effect of nano-scale zero-valent iron particles on the dechlorination and diversity of Dehalococcoides spp.

The effect of nano-scale zero-valent iron( NZVI) particles on the dechlorination and diversity of Dehalococcoides spp. was investigated in this study. The integrated NZVI-bacteria system was characterized using gas chromatography,PCR-DGGE,and TEM technology. Based on the results,less than 40% of increase in the dechloriantion rate was obtained when the concentration of NZVI was below 0. 50 g·L-1,and there was no significant change of bacterial species. A faster increment of the dechlorination rate from 0. 31 μmol·h-1to 0. 77 μmol·h-1was observed as the concentration of NZVI increased in the range of 0. 50 ~ 1. 00 g·L-1. In addition,the results of PCR-DGGE showed the decrease in band quantities,which indicated that the diversity of Dehalococcoides spp. was lowered. Also,the TEM images displayed the bacteria surface contacting with NZVI had a mild damage,while the cells were not broken completely. In summary,the obtained results indicated that higher concentration of NZVI led to larger dechlorination rate of the bacteria but smaller diversity of Dehalococcoides spp.