Test study of the degradation ability of the coated sludge microbe-nanometer iron system on perchlorate

摘要

In biological degradation, perchlorate is the ultimate electron receptor of the electron transport chain and is reduced to chloride. Microbe-Nanometer Zero-Valent Iron (NZVI) is oxidized and H_2O reacts to give hydrogen as an electron donor to perchlorate. In order to preserve NZVI, agar is used as a medium to make coated microbe-nanometer zero-valent iron and dried to be a composite. The test studied the composite's degradation ability on perchlorate, and also the factors, including preservation period, activation, and adding trehalose. The contrast group includes NZVI and activated sludge. Perchlorate measuring 50.0 mg/L declines to detection limits in 12 days. When trehalose is added to activated composite preserved for 7 days, 50.0 mg/L perchlorate declines to detection limits in 18 days. The dried composite's degradation ability is lower than the activated sludge. When the preservation period is 30 days, the composite has about the same degradation ability as that preserved for 7 days. It suggests that the dried composite can be preserved effectively, which provides a basis for its industrial production and practical application. If trehalose is not added to NZVI, the composite is slightly different from that added with trehalose. The reflection point is delayed to 12 days, which proves that trehalose can protect microbial activity of the composite to a certain degree. If the composite is not activated, perchlorate only declines by 8% in 18 days. It can be concluded that activation plays an important role in the degradation on perchlorate.