PMID- 35151701
OWN - NLM
STAT- MEDLINE
DCOM- 20220315
LR  - 20220315
IS  - 1879-1298 (Electronic)
IS  - 0045-6535 (Linking)
VI  - 295
DP  - 2022 May
TI  - Photochemical transformation of hexachlorobenzene (HCB) in solid-water system: 
      Kinetics, mechanism and toxicity evaluation.
PG  - 133907
LID - S0045-6535(22)00400-3 [pii]
LID - 10.1016/j.chemosphere.2022.133907 [doi]
AB  - As one of the first batch of persistent organic pollutants (POPs) included in 
      Stockholm Convention, hexachlorobenzene (HCB) has attracted great attention 
      because of its wide occurrence and great environmental risks. Considering the 
      easy adsorption of HCB on solids and the complexity of natural particles, we 
      systematically investigated the photodegradation of HCB on the surface of silica 
      gel (SG) in aqueous solution in this work to reveal its fate in natural waters. 
      Under mercury lamp irradiation, more than 90% of HCB loaded on SG could be 
      removed after 240 min. Moreover, the effects of solution pH and water 
      constituents were examined, and results showed that the presence of NO(2)(-), 
      NO(3)(-), Fe(3+) and humic acid (HA) significantly inhibited the reaction due to 
      the scavenging of ROS and/or competitive absorption of light. According to 
      radical quenching experiments and electron paramagnetic resonance (EPR) spectra, 
      hydroxyl radicals and singlet oxygen generated on the surface of SG could 
      participate in the transformation of HCB, but *OH played a dominant role. Based 
      on products identified by high performance liquid chromatography-mass 
      spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS), two main 
      pathways were proposed for the removal of HCB, including dechlorination and 
      hydroxylation which represent direct and indirect photodegradation, respectively, 
      and the occurrence of these two reactions was further supported by density 
      functional theory (DFT) calculations. From the quantitative analysis of 
      penta-chlorobenzene, it was estimated that dechlorination and hydroxylation 
      contributed to approximately 44.4% and 55.6% of initial HCB degradation, 
      respectively. Furthermore, toxicity predictions by the ecological 
      structure-activity relationship model (ECOSAR) suggested that the toxicity of HCB 
      was decreased in the photodegradation process. This study would provide important 
      information for understanding the photochemical transformation mechanism of HCB 
      at the solid/water interface.
CI  - Copyright (c) 2022 Elsevier Ltd. All rights reserved.
FAU - Tu, Zhengnan
AU  - Tu Z
AD  - State Key Laboratory of Pollution Control and Resources Reuse, School of the 
      Environment, Nanjing University, Jiangsu, Nanjing, 210023, PR China.
FAU - Qi, Yumeng
AU  - Qi Y
AD  - State Key Laboratory of Pollution Control and Resources Reuse, School of the 
      Environment, Nanjing University, Jiangsu, Nanjing, 210023, PR China.
FAU - Qu, Ruijuan
AU  - Qu R
AD  - State Key Laboratory of Pollution Control and Resources Reuse, School of the 
      Environment, Nanjing University, Jiangsu, Nanjing, 210023, PR China. Electronic 
      address: quruijuan0404@nju.edu.cn.
FAU - Tang, Xiaosheng
AU  - Tang X
AD  - Jiangsu Yangtze River Delta Environmental Science and Technology Research 
      Institute Co., Ltd., Jiangsu, Changzhou, 213100, PR China.
FAU - Wang, Zunyao
AU  - Wang Z
AD  - State Key Laboratory of Pollution Control and Resources Reuse, School of the 
      Environment, Nanjing University, Jiangsu, Nanjing, 210023, PR China.
FAU - Huo, Zongli
AU  - Huo Z
AD  - Jiangsu Provincial Center for Disease Control and Prevention, No.172 Jiangsu 
      Road, Jiangsu, Nanjing, 210009, PR China.
LA  - eng
PT  - Journal Article
DEP - 20220210
PL  - England
TA  - Chemosphere
JT  - Chemosphere
JID - 0320657
RN  - 0 (Humic Substances)
RN  - 059QF0KO0R (Water)
RN  - 4Z87H0LKUY (Hexachlorobenzene)
SB  - IM
MH  - *Hexachlorobenzene/chemistry
MH  - Humic Substances/analysis
MH  - Kinetics
MH  - Photolysis
MH  - *Water/chemistry
OTO - NOTNLM
OT  - Density functional theory
OT  - Hexachlorobenzene
OT  - Photodegradation
OT  - Reaction pathways
OT  - Reactive oxygen species
OT  - Silica gel
EDAT- 2022/02/14 06:00
MHDA- 2022/03/16 06:00
CRDT- 2022/02/13 20:28
PHST- 2021/12/07 00:00 [received]
PHST- 2022/01/19 00:00 [revised]
PHST- 2022/02/04 00:00 [accepted]
PHST- 2022/02/14 06:00 [pubmed]
PHST- 2022/03/16 06:00 [medline]
PHST- 2022/02/13 20:28 [entrez]
AID - S0045-6535(22)00400-3 [pii]
AID - 10.1016/j.chemosphere.2022.133907 [doi]
PST - ppublish
SO  - Chemosphere. 2022 May;295:133907. doi: 10.1016/j.chemosphere.2022.133907. Epub 
      2022 Feb 10.