Simultaneous determination of chlorinated aromatic hydrocarbons in fly ashes discharged from industrial thermal processes

Chlorinated aromatic hydrocarbons (CAHs) have received increasing attention because of their environmental persistence, bioaccumulation potential and high toxicity. In this study, an analytical methodology based on high-resolution gas chromatography/high-resolution mass spectrometry for the simultaneous determination of four typical kinds of CAHs including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and chlorinated polycyclic aromatic hydrocarbons (ClPAHs) in fly ash was developed. Highly effective cleanup and separation procedures combined with optimum instrumental conditions provided a reliable method for the detection and quantification of CAHs. Meanwhile, the spike of C-13-labeled standards and deuterated phenanthrene achieved more accurate measurement. The method detection limits were determined to be in the ranges of 0.1-13.4 pg g(-1) for tetra-to octa-CDD/F congeners, 0.04-11.1 pg g(-1) for tri-to hepta-CB congeners, 0.2-48.5 pg g(-1) for mono-to octa-CN congeners and 3.5-9.5 pg g(-1) for mono-and di-chlorinated aromatic hydrocarbons. Good recoveries of CAHs (62-136%) were achieved, except for PCN-2 and PCN-6. The developed analytical methodology was validated and then used to determine the levels of CAHs in fly ashes collected from industrial thermal processes. All the target compounds were detected and the CAH congener concentrations showed a wide variation in different fly ashes

Electrophilic Chlorination of Naphthalene in Combustion Flue Gas

Naphthalene chlorination is an important formation mechanism of polychlorinated naphthalenes (PCNs) in combustion flue gas. In this study, a total of 21 metal chlorides and oxides were screened for their activities in the electrophilic chlorination of naphthalene. Copper(II) chloride exhibited the highest activity at 200-350 degrees C, followed by copper(I) chloride. Copper(II) chloride primarily acted as a strong chlorinating agent to facilitate chlorine substitution on naphthalene. Iron (II and III) chlorides were only highly active at 200-250 degrees C. At 250 degrees C, the average naphthalene chlorination efficiency over CuCl2 center dot 2H(2)O was 7.5-fold, 30.2-fold and 34.7-fold higher than those over CuCl, FeCl3 center dot 6H(2)O and FeCl2 center dot 4H(2)O, respectively. The other metal chlorides were less active. Under heated conditions, copper(II) and iron(III) chlorides were transformed to copper (I) and iron(II) chlorides via dechlorination, and then transformed to oxychlorides and oxides, thereby forming dechlorination-oxychlorination cycles of copper and iron species, respectively. The results obtained suggest that electrophilic chlorination of naphthalene in combustion flue gas is primarily driven by dechlorination-oxychlorination cycles of copper and iron species, and the reaction produces a selective chlorination pattern at 1 and 4 positions of naphthalene

Levels and fingerprints of chlorinated aromatic hydrocarbons in fly ashes from the typical industrial thermal processes: Implication for the co-formation mechanism

Municipal solid waste incineration (MSWI) and iron and steel making plants are two of important sources of chlorinated aromatic hydrocarbons (CAHs). In this study, the typical CAHs including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) in fly ash samples collected from MSWI, iron ore sintering (LOS) and steel smelting (SS) plants were simultaneously identified and quantified. The total concentrations of quantified CAHs in different fly ashes showed a large variation (5.88-4255 ng/g). Cl-PAHs were found to be predominant CAH species in most of fly ash samples, and the concentrations of mono-chlorinated PAHs in all fly ashes were obviously higher than those of di-chlorinated PAHs. The fingerprints of CAHs in MSWI fly ashes were mainly characterized by the high content of PCDDs, especially the hexa-CDD homologue. However, in IOS and SS fly ashes, tetra-to hexa-CDF homologues showed the higher abundance, and tetra-to octa-CDFs predominated over tetra- to octa-CDDs by factors of 3-26. The strong concentration correlations were observed between tetra- to octa-CDF homologues, middle-chlorinated PCN and PCB homologues, between tetra- to octa-CDD homologues, between low-chlorinated PCB and PCN homologues, between di-chlorinated PAH homologues, and between deca-CB and highly chlorinated PCN homologues. These results implied that the main formation mechanism of CAHs might be significantly varied with the change of chlorination degree and aromatic ring structure. (C) 2019 Elsevier Ltd. All rights reserved

Means, standard deviations, reliability coefficients, average variance extracted, standardised factor loadings, item residual variances, and factor correlations for the Chinese versions of the Music Ear Test (MET).

Means, standard deviations, reliability coefficients, average variance extracted, standardised factor loadings, item residual variances, and factor correlations for the Chinese versions of the Music Ear Test (MET).</p

Anticipated internal consistency reliability statistics (Cronbach’s alpha) for scores on the MET and anticipated sample size.

For comparison purposes, values from four previous reports are provided.</p

Overview of the music ability test.

In the context of extensive disciplinary integration, researchers worldwide have increasingly focused on musical ability. However, despite the wide range of available music ability tests, there remains a dearth of validated tests applicable to China. The Music Ear Test (MET) is a validated scale that has been reported to be potentially suitable for cross-cultural distribution in a Chinese sample. However, no formal translation and cross-cultural reliability/validity tests have been conducted for the Chinese population in any of the studies using the Music Ear Test. This study aims to assess the factor structure, convergence, predictiveness, and validity of the Chinese version of the MET, based on a large sample of Chinese participants (n≥1235). Furthermore, we seek to determine whether variables such as music training level, response pattern, and demographic data such as gender and age have intervening effects on the results. In doing so, we aim to provide clear indications of musical aptitude and expertise by validating an existing instrument, the Music Ear Test, and provide a valid method for further understanding the musical abilities of the Chinese sample.</div

Fit indices for confirmatory factor analysis models of the Music Ear Test (MET).

Fit indices for confirmatory factor analysis models of the Music Ear Test (MET).</p

Timeline.

In the context of extensive disciplinary integration, researchers worldwide have increasingly focused on musical ability. However, despite the wide range of available music ability tests, there remains a dearth of validated tests applicable to China. The Music Ear Test (MET) is a validated scale that has been reported to be potentially suitable for cross-cultural distribution in a Chinese sample. However, no formal translation and cross-cultural reliability/validity tests have been conducted for the Chinese population in any of the studies using the Music Ear Test. This study aims to assess the factor structure, convergence, predictiveness, and validity of the Chinese version of the MET, based on a large sample of Chinese participants (n≥1235). Furthermore, we seek to determine whether variables such as music training level, response pattern, and demographic data such as gender and age have intervening effects on the results. In doing so, we aim to provide clear indications of musical aptitude and expertise by validating an existing instrument, the Music Ear Test, and provide a valid method for further understanding the musical abilities of the Chinese sample.</div

The demographics of the pre-experimental participants and the grouping of the participants.

The demographics of the pre-experimental participants and the grouping of the participants.</p

The MET index scores situation (pre-test data n = 82).

The MET index scores situation (pre-test data n = 82).</p