ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2018
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IF 6.653
Qingcai Chen,Haoyao Sun,Mamin Wang,Zhen Mu,Yuqin Wang,Yanguang Li,Yansong Wang,Lixin Zhang,Zimeng Zhang
To understand the nature and possible sources of environmentally persistent free radicals (EPFRs) in atmospheric aerosols, the present study used a solvent extraction method to fractionate aerosol components with different polarities and solvent resistance in fine particulate matter (PM2.5) from Xi’an, China. The characteristics of EPFRs, that is., their concentration, type and lifetime, were obtained based on their electron paramagnetic resonance spectra. The results showed that the EPFRs in the PM2.5 samples were carbon-centered with a nearby heteroatom (g = 2.0031) and had a long half-life of more than 3 years. Nearly all of the extractable EPFRs were detected in the water-insoluble organic fraction and showed characteristics indicating that may contain oxygen-centered radical (g = 2.0038). Most of the total EPFRs in the PM2.5 were derived from solvent-resistant organic matter (88%), which likely consisted of graphene oxide analogues. The results suggest that previous studies may have missed the major proportion of EPFRs in atmospheric particulates if they only focused on solvent-extractable or metallic oxide-formed EPFRs. Our results showed that the EPFR concentration was significantly and positively correlated with the elemental carbon and NO2 concentrations, suggesting that traffic emissions may be an important source of EPFRs in PM2.5 over Xi’an.
研究领域:
环境科学
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大气化学
✓ 已验证
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2021
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IF 7.963
Ziyu Zhao,Meixuan Wu,Dandan Zhou,Quan Chen,Hao Li,Di Lang,Bo Pan,Baoshan Xing
Environmentally persistent free radicals (EFPRs) have recently attracted a great deal of research attention because of their significant toxicity and ubiquitous occurrence in the environment. The information is still very limited on how to estimate the intensity of EPFRs under ambient circumstances. This study is designed to specifically compare EPFRs generation during catechol degradation in dark and UV light irradiation. CuO and TiO 2 were selected as model metal oxides to coat on silica at 1% CuO has a large electron exchange capacity, which may mediate catechol degradation in dark, while TiO 2 possesses strong photocatalytic property and could accelerate catechol degradation under UV light. Under UV light irradiation, EPFRs were generated very quickly and reached the maximum value in 4 d, which was related to the photocatalytic property of the particle. However, these EPFRs dissipated quickly in 14 d. On the contrary, the intensities of EPFRs generated in dark were 2 times higher, and stabled for over 2 months. Therefore, the environmental impacts of EPFRs in dark may be widespread and long-lasting, which should be monitored more carefully. It should be noted that for CuO-coated silica, a significant amount of EPFRs (20% of the maximum) survived the UV-light irradiation and stabled during the experimental period (45 d). Stronger EPFRs were associated with more abundant dimer structures, suggesting the dimer structures were related to EPFRs formation during catechol degradation. Monitoring the generation of dimer structures in the degradation of organic chemicals may provide useful information to estimate EPFRs generation and risks.
研究领域:
环境科学
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毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2021
·
IF 7.963
Dongmei Bi,Fupeng Huang,Mei Jiang,Zhisen He,Xiaona Lin
Biochar derived from nitrogen-rich pyrolysis of biomass can be used as a soil conditioner, but it contains a large amount of environmental persistent free radicals (EPFRs). EPFRs are a newly identified environmentally harmful substance, and the detection and research on EPFRs in nitrogen-rich pyrolyzed char is lacking. Biochars prepared from cellulose-urea mixtures at different temperatures, residence times, and urea ratios were analyzed in this study. EPFRs in biochar prepared at 500 °C had the highest spin concentrations. Substituted aromatic compounds were the precursors to the EPFRs. The types of EPFRs in biochars shifted from oxygen-centered at 400 °C to carbon- and oxygen-centered in the 450–600 °C range due to a reduction in oxygen-containing functional groups. Residence time experiments showed that most EPFRs formed in the first 5 min of pyrolysis. C was the main element used for the formation of EPFRs, while N content was negatively correlated with the concentration of EPFRs. Pyrolysis temperature was the key factor determining the types of EPFRs produced, while proportion of urea only affected the concentrations of EPFRs and not type. The results of this study are of great significance for understanding the environmental behavior of common EPFRs in nitrogen-rich biochar.
研究领域:
环境科学
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土壤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
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2023
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IF 11.4
Yanzhuo Zhang,Rui He,Jing Zhao,Xiaozhuan Zhang,Alexandr V. Bildyukevich
For the first time, biochar was prepared by changing the polystyrene (PS) content in sludge, and the efficiency of antibiotics removal by biochar was evaluated after fermentation aging. Fermentation aging affects the efficiency of antibiotics removal by reducing the specific surface area and active sites of biochar. The antibiotics removal efficiency of different types of biochar after aging decreased by 5.95%–13.59%. Owing to the biotoxicity of biochar, the relative abundance of most communities decreased during fermentation, whereas Anaerolineae still increased (14.29% to 33.05% or 33.02%). However, controlled experiments confirmed that biochar was much less toxic to Scenedesmus obliquus than to antibiotics, with concentrations of 11.09 × 10 5 cells/mL and 0.188 × 10 5 cells/mL, respectively. With the positive effect of environmentally persistent free radicals (EPFRs) considered, increasing the PS content in sludge facilitated the removal of antibiotics by biochar. This study assesses the stability of biochar in removing antibiotics after long-term microbial aging.
研究领域:
环境科学
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生物技术
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微生物学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2019
·
IF 7.149
Peng Yi,Quan Chen,Hao Li,Di Lang,Qing Zhao,Bo Pan,Baoshan Xing
The formation and occurrence of environmentally persistent free radicals (EPFRs) have recently attracted increasing research attention. The interactions between organics and transition metals and the crystalline forms of the transition metals are essential for EPFR formation. This study is thus designed to investigate catechol degradation and compare the characteristics of EPFRs on α-Fe2O3 (hematite, HM) and α-FeOOH (goethite, GT). Catechol degradation was inhibited in the dark in the presence of iron oxides. The inhibition was stronger on GT-silica, but the electron paramagnetic resonance (EPR) signals of the two systems were comparable. The enhanced degradation under UV light irradiation was comparable between HM-silica and GT-silica, but the EPR signals were stronger on GT-silica. Catechol was adsorbed on HM in a mononuclear bidentate (M-B) configuration, but it was adsorbed in both mononuclear monodentate (M-M) and binuclear bidentate (B-B) configurations on GT. After series analysis, we proposed that the dimer-type radical (2,2′,3,3′-tetrahydroxy-1,1′-biphenylene) was responsible for the more stable EPR signals for the HM system, while the M-M structure was more favorable for the catechol stabilization. Note that in the analysis of EPFR formation mechanisms, it is important to consider (1) different crystalline lattices and (2) the contribution of the degradation byproducts of the parent organics.
研究领域:
环境科学
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化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
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2024
·
IF 7.6
Jiawen Zhang,Shanjian Liu,Fupeng Huang,Dongmei Bi,Jie Song,Santao Chou
To investigate the impact of different H 2 O 2 concentrations on the Fenton-like systems of H 2 O 2 /biochar, this study examined the mechanism of the physical structure and environmental persistent free radicals (EPFRs) of biochar during diethyl phthalate (DEP) removal by the Fenton-like system. The peak-splitting method was utilized to differentiate EPFRs types in cotton stalk biochar produced at different temperatures. High-temperature environments promote π-electron delocalization, which facilitates phenyl π free radicals and σ-π oxygen-containing free radicals. By analyzing relationships between the removal rate K 1 and removal constant K obs of DEP with the structural properties of biochar, it was discovered that EPFRs concentrations in biochar had a significant positive correlation with K 1 (r = 0.92) and K obs (r = 0.97). Different H 2 O 2 concentrations added to the biochar removal system resulted in varied DEP removal efficiency. Among them, CS 500 , CS 550 , and CS 600 exhibited superior DEP removal efficiency when H 2 O 2 concentration was 5 mM.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）