Heng-Feng Miao

Jiangnan University, Wu-hsi, Jiangsu Sheng, China

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Publications (8)7.88 Total impact

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    ABSTRACT: Oxidation kinetics and degradation pathways of phenazone (an analgesic and antipyretic drug) upon reaction with O3 were investigated. Kinetic studies on degradation of phenazone were carried out under different operating conditions such as temperature, pH, anions and H2O2 addition. Results showed that the degradation followed the pseudo-first-order kinetic model. The reaction rate constant (kobs) of phenazone reached the maximum at 20°C (9.653×10(-3)s(-1)). The presence of NO3(-) could enhance the degradation rate, while the addition of HCO3(-), SO4(2)(-), Cl(-) and the rise of pH showed negative effects on the ozonation of phenazone. H2O2 addition increased the phenazone degradation efficiency by 45.9% with the optimal concentration of 0.135mM. Reaction by-products were evaluated by UPLC-Q-TOF-MS, which allowed the identification of a total of 10 by-products. The transformation pathways of phenazone ozonation consisted mainly of electrophilic addition and substitution, pyrazole ring opening, hydroxylation, dephenylization and coupling. The toxicity of these intermediate products showed that they are expected not to be more toxic than phenazone, with the exception of P7 (aniline) and P10 (1,5-dimethyl-4-((1-methyl-2-phenylhydrazinyl)methoxy)-2-phenyl-1H-pyrazol-3(2H)-one).
    Chemosphere 07/2014; 119C:326-333. · 3.14 Impact Factor
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    ABSTRACT: Kinetics on degradation efficiency of medroxyprogesterone (MPA) by ozonation was investigated in this paper. And the operating parameters such as MPA initial concentration, ozone dosage, pH and radicals scavenger (HCO3-) were further discussed. Results showed that MPA could be degraded effectively by ozonation, with a first-order kinetics in continuous ozone aeration system and a second-order kinetics in semibatch ozone aeration system, when the initial concentrations of MPA were 3, 5, 10 mg x L(-1). The increases of pH and the addition of HCO3- would bring negative effects to the degradation of MPA. The degradation efficiency of MPA decreased from 89.8% to 54.8% with pH increase from 3.10 to 9.02, and the rate constant k decreased from 0.1463 L x (mg x min)(-1) to 0.049 5 L x (mg x min)(-1) and the degradation efficiency decreased 22.2 percentage points with the addition of HCO3-, in semibatch aeration system.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 04/2012; 33(4):1227-33.
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    ABSTRACT: A runoff retention and filtration pilot system was designed and the long-term purification effect of the runoff was monitored. Runoff pollution characters in 2 typical events and treatment effect of the pilot system were analyzed. The results showed that the runoff was severely polluted. Event mean concentrations (EMCs) of SS, COD, TN and TP in the runoff were 361, 135, 7.88 and 0.62 mg/L respectively. The runoff formed by long rain presented an obvious first flush effect. The first 25% flow contributed more than 50% of the total pollutants loading of SS, TP, DTP and PO4(3-). The pilot system could reduce 100% of the non-point source pollution if the volume of the runoff was less than the retention tank. Otherwise the overflow will be purification by the filtration pilot system and the removal rates of SS, COD, TN, TP, DTP and PO4(3-) reached 97.4% , 61.8%, 22.6%, 85.1%, 72.1%, and 85.2% respectively. The system was stable and the removal rate of SS, COD, TN, and TP were 98.6%, 65.4%, 55.1% and 92.6%. The whole system could effectively remove the non-point source pollution caused by runoff.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 09/2011; 32(9):2562-8.
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    ABSTRACT: Pretreatment at different pHs was adopted in this study to enhance the substance solubilization and hydrogen production from kitchen wastes through anaerobic digestion. After a pretreatment set at pH = 13, solubilization of kitchen wastes improved substantially as the concentration of soluble carbohydrate, soluble protein, lipids and soluble chemical oxygen demand increased by 283.1%, 203.2%, 259.1% and 108.2%, respectively, as compared with those of the control. The maximum hydrogen production potential reached 105.38 mL/g VS after the pretreatment, which was 2.66 times that of the control. Furthermore, butyric acid and acetic acid were the major components in the total metabolites after fermentation, while propionic acid had a relatively low concentration. Finally, the concentration of exoprotein and exopolysaccharide within extracellular polymeric substances (EPS) kept increasing during the initial 14 and 9 hours, respectively, then decreased afterwards. However, the concentration of DNA increased throughout the whole stage. The total EPS might indirectly indicate the anaerobic digestion process. These findings may represent a feasible method for high-quality treatment of kitchen wastes.
    Environmental Technology 01/2011; 32(1-2):119-25. · 1.61 Impact Factor
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    ABSTRACT: Degradation of algal toxin Microcystin-RR (MC-RR) by ozonation processes was investigated. The degradation rate of MC-RR reached 83.0% at ozone/MC-RR dosage of 6, and the degradation efficiency was decreased with increase of pH or NOM contents. Ozonation byproducts of MC-RR under different ozone dosages were detected by HPLC-MS to elucidate degradation mechanisms and pathways. The results showed that MC-RR degradation by attacking of ozone and hydrogen radicals mainly involved in substitution and cleavage of the Adda conjugated diene structure, cleavage of the peptide bond between Mdha and Ala. And Adda degradation pathway exerted a dominant position during the process.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 05/2010; 31(5):1239-45.
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    ABSTRACT: In the present study, two Microsystins (MCs) of Microcystin-LR and Microcystin-RR were degraded with different dosages of ozone (O(3)). The possible degradation pathways were elucidated by analyzing their intermediates and end-products with liquid chromatography-mass spectrometry (LC-MS) method. The toxicity of the MCs ozonation products was also evaluated by assaying the protein phosphatase inhibition in vitro and acute toxicity in vivo. Results demonstrated that ozonation was a promising technology for removal and detoxification of the cyanotoxins. The MCs destruction was mainly involved in the attack of ozone on Adda side chain. First, the conjugated diene structure of Adda moiety was attacked by hydroxyl radical (OH()) to produce dihydroxylated products, then the hydroxylated 4-5 and/or 6-7 bond of Adda was cleaved into aldehyde or ketone peptide residues, and finally the residues were oxidized into the corresponding carboxylic acids. The fragmentation of the Mdha-Ala peptide bond of MCs also contributed positively to the oxidation process. Additionally, the attack on the benzene ring of Adda side chain was exclusively observed during MC-RR degradation. The toxicity evaluation of MCs ozonation products revealed that those end-products had no adverse effects in vivo and in vitro ozonation that could completely remove the MCs' toxicity.
    Chemosphere 03/2010; 79(4):355-61. · 3.14 Impact Factor
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    ABSTRACT: Degradation and byproducts of microcystin-LR (MC-LR) under different ozone dosages were investigated, and, the pathway and mechanism for the degradation of MC-LR were also elucidated according to the molecular weight of 8 degradation byproducts during ozonation process in this paper. The results showed that there were two pathways for the degradation of MC-LR by ozone. The first one is that the diene structure in Adda side chain was attacked and cleaved, which was named as Adda degradation pathway. The second one is that the pathway of Mdha and Ala degradation, which was that the peptide bond between Mdha and Ala was attacked and cleaved. Adda degradation pathway was dominant and mainly responsible for the degradation of MC-LR byozone. The removal of MC-LR by ozone could reach 92% when O3:MC is 6.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 11/2009; 30(11):3288-92.
  • Heng-feng Miao, Wen-yi Tao
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    ABSTRACT: Ozonation was applied to investigate the removal efficiency of 6 odorous organic compounds in eutrophic water from Taihu Lake (Wuxi). The results showed that the ozonation process could be described by first order kinetic model and the overall kinetic rates of the odorous compounds were determined by their chemical characteristic and structure, which could be ranked: beta-Ionone (3.3 x 10(-3) s(-1)) > beta-Cyclocitral (2.8 x 10(-3) s(-1)) > 2,4-Decadienal (2.7 x 10(-3) s(-1)) > Neryl Acetone (2.2 x 10(-3) s(-1)) > Geosmin (1.4 x 10(-3) s(-1)) > 2-Methylisoborneol (5.6 x 10(-4) s(-1)). Ozonation of eutrophic water led to the formation of a series of aldehydes, ketones, alcohols and esters. The influence of bicarbonate and natural organic carbon on odorous compounds ozonation were further investigated, results showed that the bicarbonate could restrain the effect of ozonation by cutting down the radical pathway and natural organic carbon in the water by competition with target compounds.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 01/2009; 29(12):3439-44.