Simultaneous removal of nitrate, tetracycline, and Pb(II) by iron oxidizing strain Zoogloea sp. FY6: Performance and mechanism.

Based on the prevalence of combined antibiotics and heavy metals contamination in the aquatic environment, this study utilized a microbial approach to achieve simultaneous removal of nitrate (NO3--N), tetracycline (TTC), and Pb(II). Zoogloea sp. FY6 could achieve an optimal NO3--N removal efficiency of 91.5% under C/N ratio of 2.0, at a pH of 6.3, and Fe(II) concentration of 20.23 mg L-1 based on response surface methodology. Additionally, strain FY6 was further found to achieve 89.9 and 81.7% removal of TTC and Pb(II) at 6 h under the optimal conditions. Finally, the results of Fluorescence excitation-emission matrix, X-ray diffraction, Fourier transform infrared spectrometer, and X-ray photoelectron spectroscopy further proved that the biologically formed nanoscale iron oxides and biological action jointly led to the removal of TTC and Pb(II). This study provided a theoretical basis for the application of microbially driven process to remove multi-pollutants in micro-polluted water bodies.