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Cheng W.,South China Normal University | Cheng W.,Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System | Cheng W.,Key Laboratory of Theoretical Chemistry of Environment Ministry of Education | Yang M.,South China Normal University | And 9 more authors.
Chemical Engineering Journal | Year: 2013

We compared the degradation behavior of metronidazole (MNZ) under advanced oxidation processes with the aim of enhancing the mineralization of MNZ. Among the advanced processes used, that is, Ce/SnO2-Sb/Ti electrochemical/anode oxidation (EC/AO), the Fenton and the electro-Fenton (EF) processes, the EF process was the most effective. Different input variables, including catalyst concentration, [H2O2]/[Fe2+] molar ratio, and pH level were evaluated to find the optimum condition for mineralization by EF treatment. The total organic carbon was optimally diminished by up to 37% by applying a Fe2+ concentration of 2.0mM, a [H2O2]/[Fe2+] molar ratio of 10:1, and a pH of 2.0. The change in biodegradation was investigated on the basis of the BOD5/CODcr ratio. The ratio of BOD5/CODcr of raw MNZ aqueous (0.227) was increased to 0.252 and 0.345 by the EC and EF systems, respectively. The general toxicity resulting from the different treatments for MNZ aqueous solution was assessed by the Photobacterium bioassay. The toxicity of the EF-treated solution decreased 63%, falling to an effectively non-toxic level, indicating that the EF process can decontaminate and mineralize MNZ into a non-toxic product. According to the BOD5/CODcr ratio, the EF process is a sufficiently powerful pretreatment technology that can increase the biodegradability and decrease the toxicity of wastewater containing MNZ, providing a favorable condition for subsequent biochemical treatment. © 2013 Elsevier B.V..

Huang R.,South China Normal University | Huang R.,Key Laboratory of Theoretical Chemistry of Environment Ministry of Education | Fang Z.,South China Normal University | Fang Z.,Key Laboratory of Theoretical Chemistry of Environment Ministry of Education | And 4 more authors.
Chemical Engineering Journal | Year: 2012

In this study, the Fe3O4 magnetic nanoparticles (MNPs) were synthesized as heterogeneous catalysts to effectively degrade bisphenol A (BPA). The properties of the synthesized catalysts were characterized by Brunnaer-Emmett-Teller (BET), X-ray powder diffraction (XRD), X-ray photoelectron spectrometry (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The results indicated that the Fe3O4 MNPs appeared to be roughly spherical shapes and their average size was 10-20nm. The catalytic capacity of MNPs in US+Fe3O4+H2O2 system with different pH conditions, H2O2 concentrations and MNPs doses was investigated. It was found that the OH radicals were promptly generated due to the catalysis of the Fe3O4 MNPs. BPA could be degraded within a wide pH range from 3 to 9, and the degradation efficiencies were remarkably enhanced by ultrasound. The apparent rate constants were 8.31×10-3, 7.96×10-3 and 5.64×10-3min-1, respectively, when the pH values were 3, 7 and 9, respectively. The removal efficiencies of BPA were all over 95%. About half total organic carbon (TOC) in solution was eliminated under neutral condition by sono-Fenton process. Furthermore, the results of stability and reusability demonstrated that the Fe3O4 MNPS were promising in the treatment of wastewater with refractory organics. © 2012 Elsevier B.V.

Li X.,South China Normal University | Yin Y.,South China Normal University | Deng J.,South China Normal University | Zhong H.,South China Normal University | And 6 more authors.
Talanta | Year: 2016

A new rhodamine B-benzofurazan based fluorescent probe (1) for Fe3+ and Hg2+ was synthesized. In aqueous solution containing 30% (v/v) ethanol, probe 1 shows a high selective fluorescent enhancement recognition to Fe3+ with a binding ratio of 1:1 (probe 1: Fe3+), when the concentration of Fe3+ is less than that of the probe. When the concentration of Fe3+ is higher than that of the probe, it shows fluorescent "turn-on" response to Fe3+ by opening the rhodamine spirolactam with a binding ratio of 1:2 (probe 1: Fe3+). Furthermore, probe 1 displays a high selectivity and a hypersensitivity (detection limit is 4.4 nM) to Hg2+ with a binding ratio of 1:1 in ethanol. NMR and UV-vis experiments indicate that the different fluorescent recognition signals to Fe3+ and Hg2+ are derived from different binding modes of 1-Fe3+ and 1-Hg2+. © 2016 Elsevier B.V. All rights reserved.

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