Degradation of bisphenol A by UV/persulfate process in the presence of bromide: Role of reactive bromine

Anhong Cai, Jing Deng, Xiao Ling, Cheng Ye, Huihong Sun, Yang Deng, Shiqing Zhou, Xueyan Li

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1 Scopus citations

Abstract

Bromide (Br), a ubiquitous species in natural water, is capable of reacting with sulfate radical (SO4) and hydroxyl radical (∙OH) to form secondary reactive bromine species (RBS). The reaction routes can influence the degradation mechanisms and performance of these radicals for removal of target pollutants and may also form harmful bromine-containing disinfection by-products (Br-DBPs) during subsequent chlorination. In the present research, the UV-activated persulfate (PS) degradation of bisphenol A (BPA) was systematically examined in the presence of Br. Results indicated that the presence of Brenhanced the BPA degradation and both UV/PS and UV/PS/Br processes followed the pseudo-first-order kinetics. At 0–0.8 mM Br, 0.2 mM Br exerted the best enhanced effect on BPA degradation, while RBS functioned as the major contributor in the presence of 0.05–0.5 mM Br. Solution pH (6.0–8.0) barely affected the BPA degradation in the UV/PS system, but the introduction of Br augmented the pH dependence. In the UV/PS/Brsystem, the reaction rate constant of BPA increased/decreased with increasing PS/HA dosage, and was affected slightly in the presence of bicarbonate and chloride. According to the quantum chemical calculation, the second-order rate constants of BPA with ∙OH, SO4, Br∙ and Br2 were calculated as 7.65 × 1010, 1.67 × 109, 1.77 × 108 and 2.83 × 102 M−1 s−1, respectively. Additionally, three degradation pathways of BPA were proposed based on DFT calculation and HPLC/MS analysis, and the formed bromine-containing products exhibited higher toxicity than BPA. Br-DBPs, particularly tribromomethane and tribromoacetic acid, generated from UV/PS/Brpre-oxidation during BPA chlorination significantly increased the toxicity of total DBPs.

Original languageEnglish
Article number118288
JournalWater Research
Volume215
DOIs
StatePublished - 15 May 2022

Keywords

  • Advanced oxidation processes
  • Bromide
  • Disinfection by-products
  • Quantum chemical calculation
  • Reaction mechanism

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