Effect of Plastics on the Photodegradation Behavior of Chlorophenols

Abstract

In this study, we compared the photodegradation behavior of pentachlorophenol (PCP) and 2,3,4,6-tetrachloro phenol (TeCP) sorbed on polyethylene (PE), polyethylene tereph thalate (PET), and polyvinyl chloride (PVC) to investigate the plastic e ect. PE accelerated photodegradation of PCP and TeCP, and the photodegradation rate constants on the PE surface were approximately 1.50 times higher than that on a glass surface. In contrast, photodegradation of these organochlorine pollutants on PET was slower than on the glass surface. Furthermore, photodegradation of PCP on the PVC surface was suspended after approximately 60 min of ultraviolet irradiation. These results con rmed that plastics a ected the photodegradation behavior of organochlorine pollutants. Lower chlorinated phenols were detected as degradation products, such as di-, tri-and tetra-chlorophenols, thereby con rming occurrence of dechlorination. Fourier transform infrared analysis showed that C C bonds were produced on PE after UV irradiation, suggesting that PE might act as a hydrogen donor to accelerate photodegradation of PCP and TeCP. For PVC, an increase of the absorbance of the C-Cl bond after photodegradation indicated occurrence of chlorine migration, resulting in rechlorination of the intermediate chlorophenols. This study suggests that the characteristics of plastics should be considered for assessment of the fate of organic pollutants sorbed on plastics through phototransformation.

Non-Negligible Effects of UV Irradiation on Transformation and Environmental Risks of Microplastics in the Water Environment

“…The concentration of heavy metals in the leachate of PVC exposed to UV-C radiation was higher than that of unweathered PVC [ 88 ]. The increase in the absorbance of the C–Cl bond in PVC after degradation indicated the occurrence of Cl migration, which brought about the rechlorination of the intermediate chlorophenol produced [ 89 ]. A series of molecular degradation products (sulfur compounds, terephthalic acid, 4-acetylbenzoic acid, etc.)…”