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Complexation of iron by salicylic acid and its effect on atrazine photodegradation in aqueous solution

Xiaoxia OU, Chong WANG, Fengjie ZHANG, Yan MA, He LIU, Xie QUAN,

《环境科学与工程前沿(英文)》 2010年 第4卷 第2期   页码 157-163 doi: 10.1007/s11783-010-0018-3

摘要: The photodegradation of atrazine and the photochemical formation of Fe(II) and HO in aqueous solutions containing salicylic acid and Fe(III) were studied under simulated sunlight irradiation. Atrazine photolysis followed first-order reaction kinetics, and the rate constant () corresponding to the solution of Fe(III)-salicylic acid complex (Fe(III)-SA) was only 0.0153 h, roughly one eighth of the observed in the Fe(III) alone solution (0.115 h). Compared with Fe(III) solution, the presence of€ salicylic€ acid€ significantly€ enhanced€ the€ formation€ of Fe(II) but greatly decreased HO generation, and their subsequent product, hydroxyl radical (OH), was much less, accounting for the low rate of atrazine photodegradation in Fe(III)-SA solution. The interaction of Fe(III) with salicylic acid was analyzed using Fourier-transform infrared (FTIR) spectroscopy and UV-visible absorption, indicating that Fe(III)-salicylic acid complex could be formed by ligand exchange between the hydrogen ions in salicylic acid and Fe(III) ions.

关键词: salicylic acid     iron     atrazine     photodegradation    

Enhanced atrazine removal using membrane bioreactor bioaugmented with genetically engineered microorganism

LIU Chun, HUANG Xia

《环境科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 452-460 doi: 10.1007/s11783-008-0050-8

摘要: Bioaugmentation with genetically engineered microorganisms (GEMs) in a membrane bioreactor (MBR) for enhanced removal of recalcitrant pollutants was explored. An atrazine-degrading genetically engineered microorganism (GEM) with green fluorescent protein was inoculated into an MBR and the effects of such a bioaugmentation strategy on atrazine removal were investigated. The results show that atrazine removal was improved greatly in the bioaugmented MBR compared with a control system. After a start-up period of 6 days, average 94.7% of atrazine was removed in bioaugmented MBR when atrazine concentration of influent was 14.5 mg/L. The volumetric removal rates increased linearly followed by atrazine loading increase and the maximum was 65.5 mg/(L·d). No negative effects were found on COD removal although carbon oxidation activity of bioaugmented sludge was lower than that of common sludge. After inoculation, adsorption to sludge flocs was favorable for GEM survival. The GEM population size initially decreased shortly and then was kept constant at about 10–10 CFU/mL. Predation of micro-organisms played an important role in the decay of the GEM population. GEM leakage from MBR was less than 10 CFU/mL initially and was then undetectable. In contrast, in a conventionally activated sludge bioreactor (CAS), sludge bulking occurred possibly due to atrazine exposure, resulting in bioaugmentation failure and serious GEM leakage. So MBR was superior to CAS in atrazine bioaugmentation treatment using GEM.

Effect of short-term atrazine addition on the performance of an anaerobic/anoxic/oxic process

Changyong WU, Xiaoling LI, Zhiqiang CHEN, Yongzhen PENG,

《环境科学与工程前沿(英文)》 2010年 第4卷 第2期   页码 150-156 doi: 10.1007/s11783-010-0020-9

摘要: In this study, an anaerobic/anoxic/oxic (AO) wastewater treatment process was implemented to treat domestic wastewater with short-term atrazine addition. The results provided an evaluation on the effects of an accidental pollution on the operation of a wastewater treatment plant (WWTP) in relation to Chemical Oxygen Demand (COD) and biological nutrient removal. Domestic wastewater with atrazine addition in 3 continuous days was treated when steady biological nutrient removal was achieved in the AO process. The concentrations of atrazine were 15, 10, and 5mg·L on days 1, 2 and 3, respectively. The results showed that atrazine addition did not affect the removal of COD. The specific NH NO reduction rate decreased slightly due to the short-term atrazine addition. However, it did not affect the nitrogen removal due to the high nitrification and denitrification capacity of the system. Total nitrogen (TN) removal was steady, and more than 70% was removed during the period studied. The phosphorus removal rate was not affected by the short-term addition of atrazine under the applied experimental conditions. However, more poly-hydroxy-alkanoate (PHA) was generated and utilized during atrazine addition. The results of the oxygen uptake rate (OUR) showed that the respiration of nitrifiers decreased significantly, while the activity of carbon utilizers had no obvious change with the atrazine addition. Atrazine was not removed with the AO process, even via absorption by the activated sludge in the process of the short-term addition of atrazine.

关键词: biological nutrient removal     atrazine     anaerobic/anoxic/oxic (A2O) process     oxygen demand removal     oxygen uptake rate (OUR)    

Investigation of the effects of humic acid and H 2 O 2 on the photocatalytic degradation of atrazine

Chao QIN, Shaogui YANG, Cheng SUN, Jia ZHOU, Manjun ZHAN, Rongjun WANG, Huanxing CAI,

《环境科学与工程前沿(英文)》 2010年 第4卷 第3期   页码 321-328 doi: 10.1007/s11783-010-0238-6

摘要: A solution of atrazine in a TiO suspension, an endocrine disruptor in natural water, was tentatively treated by microwave-assisted photocatalytic technique. The effects of mannitol, oxygen, humic acid, and hydrogen dioxide on the photodegradation rate were explored. The results could be deduced as follows: the photocatalytic degradation of atrazine fits the pseudo-first-order kinetic well with = 0.0328 s, and ·OH was identified as the dominant reactant. Photodegradation of atrazine was hindered in the presence of humic acid, and the retardation effect increased as the concentration of humic acid increased. HO displayed a significant negative influence on atrazine photocatalysis efficiency. Based on intermediates identified with gas chromatography-mass spectrometry (GC-MS) and Liquid chromatography-mass spectrometry (LC-MS/MS) techniques, the main degradation routes of atrazine are proposed.

关键词: atrazine     retardation effect     photocatalysis     TiO2    

标题 作者 时间 类型 操作

Complexation of iron by salicylic acid and its effect on atrazine photodegradation in aqueous solution

Xiaoxia OU, Chong WANG, Fengjie ZHANG, Yan MA, He LIU, Xie QUAN,

期刊论文

Enhanced atrazine removal using membrane bioreactor bioaugmented with genetically engineered microorganism

LIU Chun, HUANG Xia

期刊论文

Effect of short-term atrazine addition on the performance of an anaerobic/anoxic/oxic process

Changyong WU, Xiaoling LI, Zhiqiang CHEN, Yongzhen PENG,

期刊论文

Investigation of the effects of humic acid and H 2 O 2 on the photocatalytic degradation of atrazine

Chao QIN, Shaogui YANG, Cheng SUN, Jia ZHOU, Manjun ZHAN, Rongjun WANG, Huanxing CAI,

期刊论文