Dynamic monitoring and regulation of pentachlorophenol photodegradation process by chemiluminescence and TiO2/PDA

• Published in: Journal of hazardous materials Vol. 399; p. 123073
• Main Authors: Chen, Fengjie, Zhao, Lixia, Yu, Wanchao, Wang, Yarui, Zhang, Hui, Guo, Liang-Hong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2020
• Subjects: Chemiluminescence; PCP photodegradation process; PDA modified TiO2; TCBQ and OH-TrCBQ; Toxic intermediates; PDA modified TiO2; PCP photodegradation process; Chemiluminescence; TCBQ and OH-TrCBQ; Toxic intermediates
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.123073

[Display omitted] •The degradation of PCP may produce toxic intermediates and cause secondary pollution.•P25/PDA was synthesized to dynamic regulating the generation of toxic intermediates.•The inhibition of toxic intermediates was achieved through the regulation of ROS.•It is suggestive for the control of toxic intermediate during pollutants degradation. Pentachlorophenol (PCP), a highly toxic halogenated aromatic compound, and its direct photolysis or TiO2 photocatalysis may generate toxic intermediates and induce secondary pollution in the environment. It is urgently needed to design a strategy to inhibit the toxic intermediates in the photodegradation of PCP. To achieve this, polydopamine (PDA), a non-toxic substance, modified TiO2 (P25/PDA) nanoparticles were synthesized and used to improve the PCP photodegradation process. The dynamic tracking of toxic intermediates tetrachloro-1,4-benzoquinone (TCBQ) and trichlorohydroxy-1,4-benzoquinone (OH-TrCBQ) produced in the PCP photodegradation process were obtained by continuous flow chemiluminescence. Combined with reactive oxygen species (ROS) measurements, P25/PDA could approximatively depress 70 % TCBQ and 40 % OH-TrCBQ generation through the regulation of ROS especially the generation of a fairly large amount of H2O2 (about 30 μM) and O2− (about 20 μM) on the surface of the P25/PDA. The toxicity evaluation showed that the photodegradation of PCP by P25/PDA was a safer and green approach. Therefore, it was instructive to inhibit the formation of highly toxic intermediates in the photodegradation of environmental contaminants by regulating the ROS generated on the surface of the photocatalysts.