Engineered digestate-derived biochar mediated peroxymonosulfate activation for oxytetracycline removal in sustainable wastewater remediation

Ifunanya R. Akaniro, Ruilong Zhang, Xuyang Chai, Christina H.M. Tsang, Peixin Wang, Shan He, Zhu Yang, Jun Zhao*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

Abstract

Nowadays, biochar is extensively used in wastewater remediation with the aim of achieving water security and circularity with minimal impacts on ecosystems and the environment. In this study, digestate biochar was prepared and modified using different methods and then employed as a peroxymonosulfate (PMS) activator to oxidize oxytetracycline, a model antibiotic pollutant in wastewater. The optimal biochar catalyst was characterized, spin trapping tests were carried out to confirm the dominant catalytic mechanism, and in silico toxicity prediction was conducted based on structure-activity relationships. Assessment of the catalytic performance of the pristine and engineered biochar showed that nitrogen doping increased oxytetracycline degradation efficiency by 1.92-fold (i.e., 100% oxytetracycline degradation with the engineered biochar compared to 52% with pristine biochar), while pyrrolic nitrogen was identified as a major PMS activation site. It was discovered that several parameters, such as catalyst dose, pH, PMS concentration, and competing ions, affected oxytetracycline degradation efficiencies. Additionally, the toxicity of the degradation intermediate was studied. Scavenger trapping tests showed that 1O2 and SO4- were the most prevalent species during oxytetracycline degradation in the system, with four possible degradation pathways proposed, including secondary alcohol oxidation, hydroxylation, dehydration, and deamidation. Overall, it is anticipated that this study would contribute to our understanding of metal-free biochar activation of PMS as an attractive treatment scheme for antibiotic-polluted water.

Original languageEnglish
Article number124640
Number of pages12
JournalEnvironmental Pollution
Volume360
DOIs
Publication statusPublished - 1 Nov 2024

Scopus Subject Areas

  • Toxicology
  • Pollution
  • Health, Toxicology and Mutagenesis

User-Defined Keywords

  • Catalytic PMS activation
  • Nitrogen-doped biochar
  • Oxytetracycline degradation
  • Sustainable wastewater treatment

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