Mechanism investigation and stable isotope change during photochemical degradation of tetrabromobisphenol A (TBBPA) in water under LED white light irradiation
Mechanism investigation and stable isotope change during photochemical degradation of tetrabromobisphenol A (TBBPA) in water under LED white light irradiation
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LED白光照射下水中四溴双酚A（TBBPA）光化学降解过程的机理研究和稳定同位素变化
DOI：
10.1016/j.chemosphere.2020.127378
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发表时间：
2020
期刊：
影响因子：
8.8
通讯作者：
Jukun Xiong
中科院分区：
文献类型：
--
作者：
Jukun Xiong
光驱动降解是一种非常有前途的污染物修复方法。研究了四溴双酚A（TBBPA）在LED白色光（λ > 400 nm）照射下的光化学反应，探讨了TBBPA的光化学降解途径和同位素分馏模式.结果表明，在鼓泡条件下，腐殖酸对TBBPA有光化学降解作用，而在N2鼓泡条件下则无光化学降解。对于TBBPA的光化学反应，单线态氧（1 O2）被发现是重要的活性氧物种的TBBPA的光化学降解。2，6-二溴-4-（2-亚丙基）环己-2，5-二烯酮和两种异丙基苯酚衍生物被确定为1 O2光化学降解的中间产物。通过氧化骨架重排、还原和O-甲基化反应确定2，6-二溴-4-（1-甲氧基乙基）苯酚为中间体。在还原脱溴过程中还观察到水解产物羟基-三溴双酚A。此外，为深入探讨TBBPA光化学降解的机理，采用气相色谱/燃烧/同位素比值质谱（GC/C/IRMS）和气相色谱-多接收器电感耦合等离子体质谱（GC/MC/ICPMS）对TBBPA光化学降解过程中的碳和溴同位素进行了分析。结果表明，光化学降解过程中没有明显的同位素分馏，表明C-C和C-Br键断裂不是光化学降解的速率控制过程。未分馏的碳稳定同位素将有助于区分TBBPA的途径和追踪TBBPA在水体中的归宿。这一工作为溴代有机污染物的光化学降解机理提供了理论依据。
Light driven degradation is very promising for pollutants remediation. In the present work, photochemical reaction of tetrabromobisphenol A (TBBPA) under LED white light (λ > 400 nm) irradiation system was investigated to figure out the TBBPA photochemical degradation pathways and isotope fractionation patterns associated with transformation mechanisms. Results indicated that photochemical degradation of TBBPA would happen only with addition to humic acid in air bubbling but not in N2bubbling. For photochemical reaction of TBBPA, singlet oxygen (1O2) was found to be important reactive oxygen species for the photochemical degradation of TBBPA. 2,6-Dibromo-4-(propan-2-ylidene)cyclohexa-2,5-dienone and two isopropyl phenol derivatives were identified as the photochemical degradation intermediates by1O2. 2,6-Dibromo-4-(1-methoxy-ethyl)-phenol was determined as an intermediate via oxidative skeletal rearrangement, reduction and O-methylation. Hydrolysis product hydroxyl-tribromobisphenol A was also observed in the reductive debromination process. In addition, to deeply explore the mechanism, carbon and bromine isotope analysis were performed using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) and gas chromatography-multicollector inductively coupled plasma mass spectrometry (GC/MC/ICPMS) during the photochemical degradation of TBBPA. The results showed that photochemical degradation could not result in statistically significant isotope fractionation, indicated that the bond cleavage of C-C and C-Br were not the rate controlling process. Stable isotope of carbon being not fractionated will be useful for distinguishing the pathways of TBBPA and tracing TBBPA fate in water systems. This work sheds light on photochemical degradation mechanisms of brominated organic contaminants.