Reduction of byproduct formation and cytotoxicity to mammalian cells during post-chlorination by the combined pretreatment of ferrate(VI) and biochar

J Hazard Mater. 2023 Sep 15:458:131935. doi: 10.1016/j.jhazmat.2023.131935. Epub 2023 Jun 24.

Abstract

Ferrate [Fe(VI)] can efficiently degrade various pollutants in wastewater. Biochar application can reduce resource use and waste emission. This study investigated the performance of Fe(VI)/biochar pretreatment to reduce disinfection byproducts (DBPs) and cytotoxicity to mammalian cells of wastewater during post-chlorination. Fe(VI)/biochar was more effective at inhibiting the cytotoxicity formation than Fe(VI) alone, reducing the cytotoxicity from 12.7 to 7.6 mg-phenol/L. The concentrations of total organic chlorine and total organic bromine decreased from 277 to 130 μg/L and from 51 to 39 μg/L, compared to the samples without pretreatment. Orbitrap ultra-high resolution mass spectrometry revealed that the number of molecules of DBPs decreased substantially from 517 to 229 by Fe(VI)/biochar, with the greatest reduction for phenols and highly unsaturated aliphatic compounds. In combination with the substantial reduction of 1Cl-DBPs and 2Cl-DBPs, 1Br-DBPs and 2Br-DBPs were also reduced. Fluorescence excitation-emission matrix coupled with parallel factor analysis suggested that fulvic acid-like substances and aromatic amino acid was obviously reduce likely due to the enhanced oxidation of Fe(IV)/Fe(V) produced by Fe(VI)/biochar and adsorption of biochar. Furthermore, the DBPs generated by electrophilic addition and electrophilic substitution of precursors were reduced. This study shows that Fe(VI)/biochar pretreatment can effectively reduce cytotoxicity formation during post-chlorination by transforming DBPs and their precursors.

Keywords: Biochar; Chlorination; Cytotoxicity; Ferrate(VI); Wastewater.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Disinfectants* / chemistry
  • Disinfection / methods
  • Halogenation
  • Phenols / analysis
  • Wastewater
  • Water Pollutants, Chemical* / chemistry
  • Water Purification* / methods

Substances

  • ferrate ion
  • biochar
  • Wastewater
  • Phenols
  • Water Pollutants, Chemical
  • Disinfectants