Removal of pharmaceutical in a biogenic/chemical manganese oxide system driven by manganese-oxidizing bacteria with humic acids as sole carbon source
Jiuhui Qu , Tingming Ye , Huijuan Liu , Weixiao Qi
DOI:10.1016/j.jes.2022.05.035
Received March 18, 2022,Revised , Accepted May 18, 2022, Available online May 29, 2022
Volume 35,2023,Pages 734-741
Bioaugmented sand filtration has attracted considerable attention because it can effectively remove contaminants in drinking water without additional chemical reagent addition. In this study, a synthesized chemical manganese dioxide (MnO2)-coated quartz sand (MnQS) and biogenic manganese oxide (BioMnOx) composite system was proposed to simultaneously remove typical pharmaceutical contaminants and Mn2+. We demonstrated a manganese-oxidizing bacterium, Pseudomonas sp. QJX-1, could oxidize Mn2+ to generate BioMnOx using humic acids (HA) as sole carbon source. The coaction of MnQS, QJX-1, and the generated BioMnOx in simultaneously removing caffeine and Mn2+ in the presence of HA was evaluated. We found a synergistic effect between them. MnQS and BioMnOx together significantly increased the caffeine removal efficiency from 32.8% (MnQS alone) and 21.5% (BioMnOx alone) to 61.2%. Meanwhile, Mn2+ leaked from MnQS was rapidly oxidized by QJX-1 to regenerate reactive BioMnOx, which was beneficial for continuous contaminant removal and system stability. Different degradation intermediates of caffeine oxidized by MnQS and BioMnOx were detected by LC-QTOF-MS analysis, which implied that caffeine was oxidized by a different pathway. Overall, this work promotes the potential application of bioaugmented sand filtration in pharmaceutical removal in the presence of natural organic matter in drinking water.
