SCIENCE OF THE TOTAL ENVIRONMENT
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2023
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IF 9.8
Xiaoxue Pan,Junyan Wei,Min Wang,Jie Zhang,Zhiming Xu,Haojie Wei,Nami Lai,Kainan Nian,Rui Zhang,Xuesheng Zhang
Due to wide applications, halophenols (HPs), especially bromophenols, chlorophenols, and fluorophenols, are commonly detected but resistant to biological removal in wastewater treatment plants (WWTPs). This study investigated the overall transformation behaviors of three representative HPs (2,4-dichlorophenol: 24-DCP, 2,4-dibromophenol: 24-DBP, 2,4-difluorophenol: 24-DFP) in six chemical oxidative systems (KMnO 4 , K 2 FeO 4 , NaClO, O 3 , UV, and persulfate (PS)). The results revealed fast removal of selected HPs by O 3 , PS and K 2 FeO 4 , while a large discrepancy in their removal efficiencies occurred under UV irradiation, KMnO 4 oxidation and particularly chlorination. Based on the analysis of the identified intermediates and products, coupling among the five routes was the general route, and dimers were the main intermediates for HP oxidation. The effect of the halogen atom on the transformation pathways of HPs was highly reaction type dependent. Among the six chemical treatments, PS could induce HPs to yield relatively low-molecular-weight polymers and obtain the highest coupling degree. Transition state (TS) calculations showed that the H atom linked to the phenoxy group of HPs was the most easily abstracted by hydroxyl radicals to form the coupling precursor, i.e., phenoxy radicals. This high coupling behavior further resulted in the increased toxicity to green algae. Characterization revealed that HP reaction solutions treated with PS had a severely negative effect on algae growth, photosynthetic pigment synthesis, and the antioxidant enzyme system. These findings can shed light on the reaction mechanisms of advanced oxidation technologies and some risk management and control of PS technique may be considered when treating phenolic pollutants.
研究领域:
环境科学
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化学
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生物学
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高影响因子
Environmental Science-Processes & Impacts
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2020
·Vol. 22
·期 9
·1842-1851
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IF 3.238
Xintong Li,Chen Shen,Hongxia Zhao,Jingqiu Jiang,Zixin Ban,Zhenyu Chen,Baocheng Qu
This study investigates the formation of persistent free radicals (PFRs) on particulate organic matter (POM) under irradiation in water. A montmorillonite–humic acid complex (Mnt–HA complex) was prepared to simulate POM, and the generated PFRs were detected by the electron paramagnetic resonance (EPR) technique. EPR signals with the trend of an initial increase and then a decrease were observed under irradiation for 8 days, and the g factors were in the range of 2.0034–2.0039, which indicated the generation of carbon-centered radicals with electrophilic moieties. Different concentrations and types of halophenols and transition-metal ions were respectively adsorbed on the Mnt–HA complex to probe their influence on the formation of PFRs. The amount of PFRs generated in the Mnt–HA complexes was in the order: 2-bromophenol (2-BP) > 2,4-dibromophenol (2,4-DBP) > 2,4-dichlorophenol (2,4-DCP), which implied that halogen substitution and the number of substituents in the halophenols could affect the generation of PFRs. The effects of transition-metal ions that resulted in the reduction of PFRs when adsorbed on the Mnt–HA complex were as follows: Fe3+ > Zn2+ > Cu2+ > Mn2+, and this is in agreement with their redox capacity. Analyzing the induced generation of reactive oxygen species (ROS) and electrons on POM, it is found that halophenols and transition metal ions also affected this process under irradiation. These findings indicate that the photoformation of PFRs on POM could be a source of PFRs in aqueous environments and requires further attention.
研究领域:
环境科学
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化学
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高影响因子
WATER RESEARCH
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2024
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IF 11.4
Jie Chen,Peizeng Yang,Jing Chen,Bin Gao,Junhe Lu
This study investigated the expediated transformation of halophenols in the presence of nitrite (NO 2 − ) under slightly acidic conditions in ice, whereas such transformation was negligible in liquid water at 4 °C. We proposed that this phenomenon was attributed to the freeze-concentration effect, incurring a pH drop and the aggregation of NO 2 − and halophenols within the liquid-like grain boundary layer amid ice crystals. Within this micro-environment, NO 2 − underwent protonation to generate reactive nitrous acid (HNO 2 ) and nitrosonium ions (NO + ) that facilitate the nitration and oxidation of halophenols. When 10 μМ halophenol was treated by freezing in the presence of 5 μМ NO 2 − , the total yields of nitrated products reached 2.4 μМ and 1.4 μМ within 12 h for 2-chlorophenol (2CP) and 2-bromophenol (2BP), respectively. NO + drove oxidative coupling reactions, generating hydroxyl polyhalogenated diphenyl ethers (OH-PBDEs) and hydroxyl polyhalogenated diphenyls via C-O or C-C coupling. These two pathways were intricately intertwined. The presence of natural organic matter (NOM) mitigated the formation of nitrated products and completely suppressed the coupling products. This study offers valuable insights into the fate of halophenols in ice and suggests potential pathways for the formation of nitrophenolic compounds and OH-PBDEs in natural cold environments. These findings also open up a new avenue in environmental chemistry research.
研究领域:
环境化学
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低温环境化学
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水处理
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高影响因子
JOURNAL OF CHROMATOGRAPHY A
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2022
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IF 4.601
Aimin Li,Xiaolan Huang,Ling Yan,Jing Cheng
2,4,6-trihalorophenol disinfection by-products (DBPs) have strong toxicity to be needed for monitoring. In this study, two kind of molecularly imprinted polymeric fibers were prepared using 2,4,6-trichlorophenol as template and tricuronic phloroglucinol (MOP) as pseudo-template, respectively. The two fibers were assembled as solid phase microextraction (SPME) fiber to extract 2,4,6-trihalophenol DBPs from water and detect them by gas chromatography coupled to electron capture detector (GC-ECD). The results of F-test and t-test stated that there are significant difference in the analytical results of 2,4,6-trichlorophenol between using the fiber based on 2, 4, 6-trichlorophenol as template and MOP as pseudo-template. It was found that the carry-over of template (2,4,6-trichlorophenol) leaked from the fiber in GC thermal desorption, resulting in the wrong quantitative analytical result for 2,4,6-trichlorophenol in water. Hence, molecularly imprinted polymeric fibers based on MOP as pseudo-template was applied for the determination of 2,4,6-trihalophenol DBPs in water combined with GC-ECD. The selectivity of the fiber for 2,4,6-trihalophenol DBPs was investigated and demonstrated. Under the optimized condition, the method has much lower limit of detection (0.5–1.1 pg mL −1 ) than most reported methods. The method was applied for the determination of 2,4,6-trihalophenol DBPs in environmental water and the relative recoveries were found to be in the range from 77.1% to 105.6% and the relative standard deviation was 0.5–9.4%. 2,4,6-tribromophenol was found at concentration of 0.054 ng mL −1 in a swimming pool.
研究领域:
分析化学
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环境科学
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水质监测
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高影响因子
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