Boron-doped diamond (BDD) electro-oxidation coupled with nanofiltration for secondary wastewater treatment: antibiotics degradation and biofouling

Xing Du*, Zhuoyu Mo, Ziyang Li, Wenxiang Zhang, Yunlong Luo, Jinxu Nie, Zhihong Wang, Heng Liang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)
14 Downloads (Pure)

Abstract

In this study, a boron-doped diamond (BDD) electro-oxidation technology coupled with nanofiltration membrane (EO-NF) technology was investigated for its effectiveness in removing antibiotics (i.e., sulfamethazine:SMZ) and mitigating biofouling during secondary wastewater treatment. The result showed that EO obtained an effective SMZ removal, owing to the ·OH generation observed by Electron paramagnetic resonance (EPR) analysis; complete elimination of SMZ was found under the high current density (30 mA/cm2) and long Electrolysis Time (ET = 60 min). Meanwhile, EO-NF process enabled to reduce COD content from 60 mg/L to nearly 5 mg/L. Furthermore, regardless of the effect of EO process, NF could retain most NH3-N because of the excellent performance of NF for ions rejection, and its permeate concentration was below 0.5 mg/L. EO was able to reduce membrane fouling notably, increasing the final flux (15 L/(m2·h)) of NF by 25.1% during long-term operation (240 h). Scanning electron microscopy-Energy dispersive spectrometry (SEM-EDS) showed that a porous layer formed on the vicinity of NF membrane in the case of filtrating EO effluent, in contrast to a uniform and dense biofouling layer generated during the direct NF. Besides, the content of adenosine triphosphate (ATP) and the number of bacterial colonies in the retentate of the EO-NF process were greater than those of the direct NF process. This resulted in a smaller amount of extracellular polymeric substances (EPS) attaching to the membrane surface, decreasing the tightness and hardness of the fouling layer in the case of EO, as indicated by CLSM analysis. Overall, considering its ability to effectively eliminate persistent contaminants and reduce membrane fouling, BDD-based EO is considered a promising pre-treatment option for future NF applications.
Original languageEnglish
Article number106291
Pages (from-to)1-13
Number of pages13
JournalEnvironment International
Volume146
Early online date11 Dec 2020
DOIs
Publication statusPublished - Jan 2021
Externally publishedYes

Bibliographical note

Copyright the Author(s) 2020. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • Electro-oxidation
  • Nanofiltration
  • Antibiotics
  • Biofouling
  • Wastewater reuse

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