CHEMOSPHERE
·
2021
·
IF 7.086
Zongping Wang,Lisan Cao,Ying Wan,Jingwen Wang,Fan Bai,Pengchao Xie
Degradation of tetrabromobisphenol A (TBBPA), an emerging micropollutant, by photo/Fe 3+ /sulfite process was investigated under different operational conditions and water matrices. 91% of TBBPA was efficiently degraded within 30 min in the Fe 3+ /sulfite system under sunlight irradiation when the initial pH was 6.0, which is much higher than that of TBBPA without irradiation (52%). The acceleration of radical generation and direct photolysis by photo irradiation were responsible for the enhanced TBBPA degradation. Although this process showed better performance on TBBPA degradation in weak acid conditions, the high removal efficiency was also achieved at near-neutral pH. HO , SO 4 − and direct photolysis contributed to TBBPA degradation. Direct photolysis and SO 4 − presented the dominant contribution. The degradation rate increased with elevating the Fe 3+ dose (10–40 μM), but slightly decreased when the Fe 3+ dose was further raised to 100 μM. Similarly, the degradation efficiency initially increased with increasing the sulfite dose (100–400 μM), but decreased when the sulfite concentration reached 1000 μM. Dissolved oxygen played a crucial role in TBBPA degradation, the presence of water matrices such as humic acid (0.8–4.0 mg/L), bicarbonate (0.5–10 mM) and chloride (0.5–10 mM) retarded TBBPA degradation. This study proposed a new efficient strategy to enhance TBBPA degradation in the Fe 3+ /sulfite process.
研究领域:
环境科学
·
水处理
·
光化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2023
·
IF 13.6
Chenguang Li,Yanlei Zhang,Shiqi Yin,Qin Wang,Yuanyuan Li,Qiang Liu,Liuqingqing Liu,Xianxiang Luo,Lingyun Chen,Hao Zheng,Fengmin Li
p -Phenylenediamines (PPDs), an important type of rubber antioxidants, have received little study on their environmental fate , particularly for their vital photodegradation process in water environment. Accordingly, N -(1,3-dimethylbutyl)- N′ -phenyl-1,4-phenylenediamine (6PPD), as a representative of PPDs, was investigated experimentally and theoretically for its photodegradation in water. Rapid photodegradation occurred when 6PPD was exposed to illumination especially UV region irradiation. Under acidic conditions, the photodegradation of 6PPD accelerated mainly due to the increased absorption of long wavelength irradiation by ionized 6PPD. Nine photodegradation products (e.g., 6PPD - quinone (6PPDQ)) of 6PPD were identified by an ultra-performance liquid chromatography QTOF mass spectrometry . Molar yields of photoproducts such as 6PPDQ, aniline, 4-aminodiphenylamine, and 4-hydroxydiphenylamine were 0.03 ± 0.00, 0.10 ± 0.01, 0.03 ± 0.02, and 0.08 ± 0.01, respectively. Mechanisms involved in 6PPD photodegradation include photoexcitation , direct photolysis, self-sensitized photodegradation, and 1 O 2 oxidation , as demonstrated by electron paramagnetic resonance (EPR) analysis, scavenging experiments, and the time-dependent density functional theory (TD-DFT). Notably, the toxicity of the reaction solution formed during the photodegradation of 6PPD was increased by the formation of highly toxic products (e.g., 6PPDQ). This study provides the first explanation for photodegradation mechanisms of 6PPD and confirms the pathway of 6PPDQ produced by the photoreaction in water environment.
研究领域:
环境科学
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化学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
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2020
·
IF 6.793
Yi Liu,Majda Mekic,Luca Carena,Davide Vione,Sasho Gligorovski,Gan Zhang,Biao Jin
Triclosan (TCS) is an antimicrobial compound ubiquitously found in surface waters throughout the world. Although several studies have focused on the photochemical degradation of TCS, there is still limited knowledge about its environmental fate . In this study, we got molecular-level insights into the photochemical degradation of TCS. Significant stable carbon isotope fractionation was observed during photodegradation ; different bond-cleavage reaction pathways under different photolytic conditions were characterized, using compound specific isotope analysis (CSIA). Photochemical modeling of TCS photodegradation showed that direct photolysis would be the main transformation pathway if pH > 7, even in presence of dissolved organic matter . Moreover, by use of ultrahigh resolution mass spectrometry, FT-ICR-MS, a broad and complex spectrum of organic by-products (some of which potentially toxic, as assessed by a quantitative structure-activity relationship approach) were identified. A detailed reaction mechanism was developed on the basis of the detected compounds. A possible sequence of steps leading to some of the detected product compounds in aqueous solution is suggested.
研究领域:
环境科学
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分析化学
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质谱学
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同位素分析
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光化学
✓ 已验证
DOI
PubMed
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2021
·Vol. 223
·期 3
·2100340
·
IF 2.527
Jianxiong Zhang,Junjin Duan,Dong Chen,Yuhong Ma,Wantai Yang
A direct photolysis reversible addition-fragmentation chain transfer (RAFT) polymerization of (meth)acrylates is developed with 2-cyano-2-propyldodecyl trithiocarbonate (TTP), which plays the dual role as photoinitiator and chain transfer agent. The polymerizations can be efficiently activated by blue light while maintaining a linear increase in M n versus conversion. With poly(methyl methacrylate)-TTP (PMMA-TTP, M n = 6700 g mol –1 , Ð = 1.29) as precursor, a higher molecular weight PMMA ( M n = 14 600 g mol –1 , Ð = 1.67) by chain extension, and a series of block copolymers, including poly(methyl methacryalte)- b -poly(glycidyl methacrylate), poly(methyl methacrylate)- b -poly(tert-butyl methacrylate), and poly(methyl methacrylate)- b -poly(benzyl meacrylate)(PMMA- b -PBnMA), are prepared. The M n,NMR = 14 900 g mol –1 of PMMA- b -PBnMA measured by NMR is very close to M n,GPC = 14 200 g mol –1 determined by gel permeation chromatography. Furthermore, the polymerization of acrylates exhibits higher controllability in regarding to dispersity ( Ð < 1.20) compared to those of polymethacrylates ( Ð = 1.10–1.80). With poly(methyl acrylate) (PMA-TTP, M n = 11 900 g mol –1 , Ð = 1.09) as macro-RAFT agent, a higher molecular weight PMA ( M n = 23 500 g mol –1 , Ð = 1.28) by chain extension, and PMA- b -PBnA ( M n = 26 500 g mol –1 , Ð = 1.19) are also prepared. A positive synergic effect is demonstrated by enhanced apparent polymerization rates at elevated temperature. For example, the apparent polymerization rates of MA increases from 0.0860 to 0.115 h –1 with temperature rising from 32 to 50 °C.
研究领域:
高分子化学
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材料科学
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光化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）