Changes in fluorescent dissolved organic matter upon interaction with anionic surfactant as revealed by EEM-PARAFAC and two dimensional correlation spectroscopy

Maqbool, Tahir; Hur, Jin

doi:10.1016/j.chemosphere.2016.07.016

Cited by 46 publications

(10 citation statements)

References 58 publications

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“…As illustrated in Figure a–f, three main components (component 1 at Ex/Em = 220/320 and 280/320 nm, component 2 at Ex/Em = 280/350 nm, and component 3 at Ex/Em = 250/460 and 300/460 nm) were identified by the EEM fluorescence with parallel factor analysis. Among them, two components (components 1 and 2) were related to aromatic amino acid-like components (tyrosine-like and tryptophan-like components, respectively). , These protein-like substances demonstrated a decreasing trend in all three EPS samples during illumination, confirming a strong photodegradation of such protein-like substances in EPS. It was not surprising that these highly aromatic substances could be oxidized due to their electron-rich moieties .…”

Section: Resultsmentioning

confidence: 74%

“…It was not surprising that these highly aromatic substances could be oxidized due to their electron-rich moieties . However, the component C was related to humic-like substances, and its peak intensities remained relatively stable. The slight increase of component 3 in M-EPS and S-EPS could be attributed to the formation of phenolic-like intermediates from the oxidation of the macro aromatic structure of other portions (e.g., aromatic proteins) in EPS .…”

Section: Resultsmentioning

confidence: 99%

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Photochemical Behavior of Microbial Extracellular Polymeric Substances in the Aquatic Environment

Zhou

Liao

Zhang

et al. 2021

Environ. Sci. Technol.

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Microbially derived extracellular polymeric substances (EPSs) occupy a large portion of dissolved organic matter (DOM) in surface waters, but the understanding of the photochemical behaviors of EPS is still very limited. In this study, the photochemical characteristics of EPS from different microbial sources (Shewanella oneidensis, Escherichia coli, and sewage sludge flocs) were investigated in terms of the production of reactive species (RS), such as triplet intermediates (3EPS*), hydroxyl radicals (•OH), and singlet oxygen (1O2). The steady-state concentrations of •OH, 3EPS*, and 1O2 varied in the ranges of 2.55–8.73 × 10–17, 3.01–4.56 × 10–15, and 2.08–2.66 × 10–13 M, respectively, which were within the range reported for DOM from other sources. The steady-state concentrations of RS varied among different EPS isolates due to the diversity of their composition. A strong photochemical degradation of the protein-like components in EPS isolates was identified by excitation emission matrix fluorescence with parallel factor analysis, but relatively, humic-like components remained stable. Fourier-transform ion cyclotron resonance mass spectrometry further revealed that the aliphatic portion of EPS was resistant to irradiation, while other portions with lower H/C ratios and higher O/C ratios were more susceptible to photolysis, leading to the phototransformation of EPS to higher saturation and lower aromaticity. With the phototransformation of EPS, the RS derived from EPS could effectively promote the degradation of antibiotic tetracycline. The findings of this study provide new insights into the photoinduced self-evolution of EPS and the interrelated photochemical fate of contaminants in the aquatic environment.

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Section: Resultsmentioning

confidence: 74%

Section: Resultsmentioning

confidence: 99%

Photochemical Behavior of Microbial Extracellular Polymeric Substances in the Aquatic Environment

Zhou

Liao

Zhang

et al. 2021

Environ. Sci. Technol.

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“…The split-half analysis, residual analysis, and visual inspection were all used to determine the correct number of final components (Stedmon and Bro, 2008;Wu et al, 2011;Zhang et al, 2020). The maximum fluorescence intensity (F max ) derived by the PARAFAC model represented the relative intensity or concentration of the PARAFAC components (Guo et al, 2015;Maqbool and Hur, 2016). The model loadings obtained from the PARAFAC analysis were uploaded into OpenFluor (https://openfluor.lablicate.com), in which a query was conducted to match the spectral properties from our loadings with existing data available from other studies.…”

Section: Parafac Analysismentioning

confidence: 99%

“…The spectra of individual components were successfully deconvoluted via the PARAFAC analysis of EEMs of all FA and HA samples during their irradiation. Using the PARAFAC models' residual analysis and split-half analysis (Maqbool and Hur, 2016;Song et al, 2017), the appropriate number of components was determined to be four (Figure 4).…”

Section: Parafac Analysis Of Hssmentioning

confidence: 99%

Photochemical Reactivity of Humic Substances in an Aquatic System Revealed by Excitation-Emission Matrix Fluorescence

et al. 2021

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The photochemical reactivity of humic substances plays a critical role in the global carbon cycle, and influences the toxicity, mobility, and bioavailability of contaminants by altering their molecular structure and the mineralization of organic carbon to CO2. Here, we examined the simulated irradiation process of Chinese standard fulvic acid (FA) and humic acid (HA) by using excitation-emission matrix fluorescence combined with fluorescence regional integration (FRI), parallel factor (PARAFAC) analysis, and kinetic models. Humic-like and fulvic-like materials were the main materials (constituting more than 90%) of both FA and HA, according to the FRI analysis. Four components were identified by the PARAFAC analysis: fulvic-like components composed of both carboxylic-like and phenolic-like chromophores (C1), terrestrial humic-like components primarily composed of carboxylic-like chromophores (C2), microbial humic-like overwhelming composed of phenolic-like fluorophores (C3), and protein-like components (C4). After irradiation for 72 h, the maximum fluorescence intensity (Fmax) of C1 and C2 of FA was reduced to 36.01–58.34%, while the Fmax of C3 of both FA and HA also decreased to 0–9.63%. By contrast, for HA, the Fmax of its C1 and C2 increased to 236.18–294.77% when irradiated for 72 h due to greater aromaticity and photorefractive tendencies. The first-order kinetic model (R2 = 0.908–0.990) fitted better than zero-order kinetic model (R2 = 0–0.754) for the C1, C2, and C3, of both FA and HA, during their photochemical reactivity. The photodegradation rate constant (k1) of C1 had values (0.105 for FA; 0.154 for HA) that surpassed those of C2 (0.059 for FA, 0.079 for HA) and C3 (0.079 for both FA and HA) based on the first-order kinetic model. The half-life times of C1, C2, and C3 ranged from 6.61–11.77 h to 4.50–8.81 h for FA and HA, respectively. Combining an excitation-emission matrix with FRI and PARAFAC analyses is a powerful approach for elucidating changes to humic substances during their irradiation, which is helpful for predicting the environmental toxicity of contaminants in natural ecosystems.

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“…At present, a wide range of techniques have been used to evaluate the interaction mechanism between DOM and organic pollutants, such as UV-vis, high-performance liquid chromatography (HPLC), molecular weight distribution, fluorescence spectroscopy and molecular modeling etc. [9,10]. Among all above techniques, fluorescence spectroscopy has been widely utilized as a feasible technique for molecular structure assessment of DOM because of its sensitivity and selectivity.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic characteristics of dissolved organic matter from aquaculture wastewater and its interaction mechanism to chlorinated phenol compound

Huang

Mei-lin

Ngo

et al. 2018

Journal of Molecular Liquids

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In present study, the characteristics of dissolved organic matter (DOM) from aquaculture wastewater and its interaction to 4-chlorophenol (4-CP) was evaluated via a spectroscopic approach. According to EEM-PARAFAC analysis, two components were derived from the interaction samples between DOM and 4-CP, including humic-like and fulvic-like substances for component 1 and protein-like substances for component 2, respectively. The fluorescence intensity scores of two PARAFAC-derived components decreased with increasing 4-CP concentration. Synchronous fluorescence coupled to two-dimensional correlation spectroscopy (2D-COS) implied that DOM fractions quenched different degrees and occurred in the order of fulvic-like and humic-like fractions > protein-like fraction. Moreover, the quenching mechanisms were mainly caused by static quenching process. It was also found from Fourier transform infrared spectroscopy that the main functional groups for interaction between 4-CP and DOM were OH stretching and C=O stretching vibration. The obtained results provided a spectroscopic approach for characterizing the interaction between organic pollutant and DOM from aquaculture wastewater.

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Changes in fluorescent dissolved organic matter upon interaction with anionic surfactant as revealed by EEM-PARAFAC and two dimensional correlation spectroscopy

Cited by 46 publications

References 58 publications

Photochemical Behavior of Microbial Extracellular Polymeric Substances in the Aquatic Environment

Photochemical Behavior of Microbial Extracellular Polymeric Substances in the Aquatic Environment

Photochemical Reactivity of Humic Substances in an Aquatic System Revealed by Excitation-Emission Matrix Fluorescence

Spectroscopic characteristics of dissolved organic matter from aquaculture wastewater and its interaction mechanism to chlorinated phenol compound

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