Removal of tetracycline by denitrifying Mn(II)-oxidizing bacterium Pseudomonas sp. H117 and biomaterials (BMO and MBMO): Efficiency and mechanisms

Coexistence of multiple pollutants such as antibiotic, nitrate and heavy metal has received increasing attention resently. In this study, the functions of Pseudomonas sp.H117 on the removal of tetracycline(TC), nitrate and Mn (II), and biological materials (BMO(biogenic manganese oxides), MBMO(magnetic BMO)) on the removal of TC were investigated. Strain H117 showed higher TC removal efficiency of 68.86% (0.071 mg.L-1.h(-1)) within 96 h. Meanwhile, NO3-N and Mn(II) achieved high removal efficiency of 100% (0.211 mg.L-1.h(-1)) and 64.64% (0.265 mg.L-1.h(-1)), respectively. Furthermore, trapping experiments testified that Mn(III) intermediate formed during the biological manganese oxidation process, which contribute to the TC degradation. 91.29% and 96.63% of TC removal efficiency within 12 h were achieved by BMO and MBMO. Moreover, XPS, FTIR spectra, kinetics analysis and adsorption isotherms elucidated Mn(III) oxidation, chemical adsorption and ligand exchange reactions contribute to the removal of TC by biomaterials.