NanoFe3O4 accelerates anoxic biodegradation of 3, 5, 6-trichloro-2-pyridinol

3, 5, 6-trichloro-2-pyridinol (TCP) is a widespread organic pollutant with persistent, mobile and high antimicrobial effects. Here, nanoFe3O4 was firstly introduced into the anoxic biodegradation of TCP. It was found that nanoFe3O4 significantly accelerated TCP biodegradation. The removal rate of TCP (100 mg L−1) increased from 83.03% to 98.74% within 12 h in the presence of nanoFe3O4, and the addition of nanoFe3O4 also promoted the accumulation of CO2. Reductive dechlorination mechanism was involved in anoxic biodegradation of TCP. Molecular approaches further revealed that nanoFe3O4 distinctly induced the shifts of bacterial community. The dominant genus Ochrobactrum was converted to genus Delftia in nanoFe3O4 treatment, and the relative abundance of Delftia increased from 10.26% to 44.62%. Meanwhile, the total relative abundance of bacteria related to TCP dechlorination and degradation significantly increased in the presence of nanoFe3O4. These results indicated that nanoFe3O4 induced the enrichment of TCP-degrading bacteria to promote the anoxic biodegradation of TCP.