Degradation mechanism, intermediates and toxicology assessment of tris-(2-chloroisopropyl) phosphate using ultraviolet activated hydrogen peroxide

Xiaolong Yu; Hua Yin; Hui Peng; Guining Lu; Zehua Liu; Huanyong Li; Zhi Dang

doi:10.1016/j.chemosphere.2019.124991

Degradation mechanism, intermediates and toxicology assessment of tris-(2-chloroisopropyl) phosphate using ultraviolet activated hydrogen peroxide

Chemosphere. 2020 Feb:241:124991. doi: 10.1016/j.chemosphere.2019.124991. Epub 2019 Sep 28.

Authors

Xiaolong Yu¹, Hua Yin², Hui Peng³, Guining Lu¹, Zehua Liu¹, Huanyong Li⁴, Zhi Dang¹

Affiliations

¹ Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, China.
² Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, China. Electronic address: huayin@scut.edu.cn.
³ Department of Chemistry, Jinan University, Guangzhou, 510632, Guangdong, China.
⁴ Analytical and Testing Center, Jinan University, Guangzhou, 510632, Guangdong, China.

PMID: 31590022
DOI: 10.1016/j.chemosphere.2019.124991

Abstract

Organophosphate flame retardants (OPFRs), one kind of emerging flame retardants, have received prevalent attention owing to their ubiquity in aquatic matrices and their characteristics of being refractory to biodegradation. In current research, the degradation mechanism of tris-(2-chloroisopropyl) phosphate (TCPP), one of OPFRs, and its toxicological evaluation using UV-driven hydroxyl radical oxidation were investigated. A pseudo-first order reaction was fitted with an apparent rate constant (K_obs) of 0.1328 min^-1 on transformation of TCPP in the case of CH₂O₂ 0.1 mM, pH 6.6-7.1 and 4.7 mW cm^-2 UV irradiation. High resolution mass spectroscopy analyses identified nine degradation products (eg., C₆H₁₃Cl₂O₄P (m/z 251.0002), C₉H₁₇Cl₂O₅P (m/z 307.0266), C₉H₁₇Cl₂O₆P (m/z 323.0217), C₉H₁₈Cl₃O₅P (m/z 343.0033)) during transformation of TCPP. The removal efficiency dropped by inhibitory effect of natural organic matters and anions, implying that the complete mineralization of TCPP may be difficult in actual water treatment process. The toxicity assessment has shown an decrease in reactive oxygen species (ROS) and apoptosis, membrane potential (MP) elevation of Escherichia coli, and biological molecular function revision (eg., metabolism and DNA biosynthesis), indicating that toxicity of degradation products were conspicuously decreased in comparison with intact TCPP. To sum up, effective detoxification of TCPP can be realized by a UV driving radical-based oxidation, which will provide an alternative safe treatment method to control TCPP in water matrix.

Keywords: Flow cytometry; Hydroxyl radical oxidation; Intermediates toxicity; Photocatalysis; Tris-(2-chloroisopropyl) phosphate.

MeSH terms

Flame Retardants* / analysis
Flame Retardants* / radiation effects
Hydrogen Peroxide / chemistry*
Hydroxyl Radical / chemistry
Organophosphates / chemistry*
Organophosphates / toxicity
Oxidation-Reduction
Phosphates
Reactive Oxygen Species
Ultraviolet Rays*
Water Purification / methods

Substances

Flame Retardants
Organophosphates
Phosphates
Reactive Oxygen Species
Hydroxyl Radical
Hydrogen Peroxide