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Xiao H.,South China Normal University | Song H.,South China Normal University | Xie H.,Dongguan Environmental Monitoring Station | Huang W.,South China Normal University | And 2 more authors.
Journal of Hazardous Materials

This study investigates the oxidative transformation kinetics of acetaminophen (APAP) by δ-MnO2 under different conditions. APAP was rapidly oxidized by δ-MnO2 with the generation of Mn2+. The measured APAP reaction rate considerably increased with an increase in initial δ-MnO2 and APAP concentration, but decreased as pH increased. The APAP reaction rate also increased with an increase in temperature. The addition of inorganic ions (Mn2+, Ca2+, and Fe3+) and substituted phenols (guaiacol, caffeic acid, and p-coumaric acid) as co-solutes remarkably decreased the transformation rate of APAP. The UV-Vis absorption spectra exhibited the π→π* transition, typical for aromatic rings. In addition, the intensity of the absorption peak gradually improved with increasing reaction time, suggesting that APAP can polymerize to form oligomers. Moreover, the secondary mass spectra of the dimers elucidated that the dimers were formed by the covalent bonding of phenol aromatic rings. Moreover, the higher-degree oligomers were formed by the coupling polymerization of phenolic and anilidic groups of dimers. These results are useful in understanding the fate of APAP in natural systems. © 2013 Elsevier B.V. Source

Huang W.,South China Normal University | Song H.,South China Normal University | Xie H.,South China Normal University | Yin Y.,South China Normal University | And 4 more authors.
Water, Air, and Soil Pollution

The impacts of dissolved organic matter (DOM) on the removal of 17β-estradiol (E2) in horseradish peroxidase (HRP)-mediated oxidative coupling systems were investigated in this study. The results showed that the removal rate of E2 and the affinity of HRP to E2 had been significantly decreased in the presence of DOM. Compared with urban sludge DOM (USDOM), river sediment DOM (RSDOM), which features relatively low aromaticity and molecular weight and a large number of O-containing groups, more strongly inhibited the E2-HRP-H2O2 reactions than USDOM. The products were analyzed with electrospray ionization mass spectrometry. The results suggested that the self-coupling of E2 was suppressed in the presence of DOM, likely resulting from cross-coupling between DOM and E2 or self-coupling of DOM in the HRP system. The results are useful in understanding the fate of estrogens in natural systems. © 2012 Springer Science+Business Media Dordrecht. Source

Liu L.,Huazhong University of Science and Technology | Hu H.,Huazhong University of Science and Technology | Li X.,Dongguan Environmental Protection Agency | Cai X.,Dongguan Environmental Monitoring Station | Zhang G.,Dongguan Environmental Monitoring Station
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae

PM1, PM1~2.5, PM2.5~10 samples were collected simultaneously using medium-volume samplers at commercial/residential area (A site) and industrial area (B site) in Dongguan city from August 2011 to July 2012. With respect to the analysis of nine kinds of water-soluble inorganic ions (i. e. F-, Cl-, NO3 -, SO4 2-, NH4 +, Na+, K+, Mg2+ and Ca2+), it was concluded that the pollution of fine particle at B site was more serious than that at A site. An annual average mass concentration of PM1 at B site was 48 μg · m-3, which was 1.2 times the value of A. The difference in mass contributions of PM1 to PM2.5 and PM10 at A and B site was not obvious, with values of 69% and 45%, respectively. Secondary ions of NO3 -, SO4 2- and NH4 +, and K+ and Cl-, indicators of combustion, were all concentrated in submicron particle PM1, with contribution ratios to PM1 mass of 18.82%~19.76%, 4.98%~5.47%, 3.98%~4.12%, 2.03%~2.27% and 3.39%~3.78%, respectively. Moreover, the other four ions, i. e. Ca2+, Mg2+, F- and Na+, were concentrated in coarse particle PM2.5~10. With respect to the three particles PM10, PM2.5 and PM1, the values of AE/CE ratios, SOR and NOR of PM1 were the highest. Source

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