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Insight into the distribution of metallic elements in membrane bioreactor: Influence of operational temperature and role of extracellular polymeric substances

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Journal of Environmental Sciences 2019年第2期31卷 111-120页

作者： He Wang Xiufen Li Xinhua Wang Yueping Ren Laboratory of Environmental Biotechnology School of Environmental and Civil EngineeringJiangnan University Jiangsu Key Laboratory of Anaerobic Biotechnology

The distribution of metallic elements in a submerged membrane bioreactor(MBR) was revealed at different temperatures using inductively coupled plasma-optical emission spectrometry(ICP-OES), and the role of extracellular polymeric substances(EPS) was probed by integrating scanning electron microscopy(SEM) with confocal laser scanning microscopy(CLSM) over long-term operation. More metallic elements in the influent were captured by suspended sludge and built up in the fouling layer at lower temperature. The concentration of metallic elements in the effluent was 5.60 mg/L at 10°C operational temperature, far lower than that in the influent(51.35 mg/L). The total contents of metallic elements in suspended sludge and the membrane fouling layer increased to 40.20 and 52.19 mg/g at 10°C compared to 35.14 and 32.45 mg/g at 30°C, and were dominated by the organically bound fraction. The EPS contents in suspended sludge and membrane fouling layer sharply increased to 37.88 and 101.51 mg/g at 10°C, compared to 16.87 and 30.03 mg/g at 30°C. The increase in EPS content at lower temperature was responsible for the deposition of more metallic ions. The strong bridging between EPS and metallic elements at lower temperature enhanced the compactness of the fouling layer and further decreased membrane flux. This was helpful for understanding the mechanism of membrane fouling at different operational temperatures and the role of EPS, and also of significance for the design of cleaning strategies for fouled membranes after long-term operation.

关键词： Membrane bioreactor Metallic elements Extracellular polymeric substances

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Evaluation of the secondary structures of protein in the extracellular polymeric substances extracted from activated sludge by different methods

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Journal of Environmental Sciences 2019年第6期31卷 128-136页

作者： Benyi Xiao Yu Liu Meng Luo Tang Yang Xuesong Guo Hao Yi Research Center for Eco-Environmental Sciences Chinese Academy of Sciences University of Chinese Academy of Sciences Beijing ZEHO Waterfront Ecological Environment Treatment Company South China Institute of Environmental Sciences Ministry of Environmental Protection

The changes of protein secondary structures in the extracellular polymeric substances(EPS) extracted from activated sludge by four different methods were studied by analyzing the amide I region(1700–1600 cm-1) of the Fourier transform infrared spectra and model protein test. The results showed the molecular weight distribution of organic matter extracted by centrifugation, heating and cation exchange resin(CER) was similar, while the EPS extracted by centrifugation(Control) and CER had similar fluorescent organic matter. The protein secondary structures of extracted EPS by the four methods were different. The similarities of protein secondary structures between the EPS extracted by CER with the Control were the highest among the four extracted EPS. Although the EPS yield extracted by formaldehyde + NaOH method were the highest, its protein secondary structures had the lowest similarity with those extracted by the Control. Additionally, the effects of centrifugation and CER extraction on the secondary structures of bovine serum albumin were also lower than that of other extraction processes. CER enables the second maximum extraction of EPS and maximum retention of the original secondary structure of proteins.

关键词： Activated sludge Different extraction methods Extracellular polymeric substances Protein secondary structure

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Molecular insight into electron transfer properties of extracellular polymeric substances of electroactive bacteria by surface-enhanced Raman spectroscopy

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Science China(Technological Sciences) 2019年第10期62卷 1679-1687页

作者： TAN Bin ZHOU ShaoFeng WANG Yi ZHANG BeiPing ZHOU LiHua YUAN Yong Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control Guangdong Key Laboratory of Environmental Catalysis and Health Risk ControlSchool of Environmental Science and EngineeringInstitute of Environmental Health and Pollution ControlGuangdongUniversity of TechnologyGuangzhou510006China Institute of Natural Medicine&Green Chemistry School of Chemical Engineering and Light IndustryGuangdong University of TechnologyGuangzhou510006China

Extracellular polymeric substances(EPS) extracted from electroactive bacteria show promising redox activity, but the electron transfer(ET) mechanism of the EPS has been rarely elucidated because of their structural complexity and lack of efficient methodologies. In this study, the charge transfer theory of surface-enhanced Raman spectroscopy(SERS) was applied to evaluate the redox properties of EPS adsorbed on Ni and Ag nanoparticles(NPs). These metal NPs were used to simultaneously magnify Raman signals and reduce/oxidize the redox moieties in EPS. As a result, the ET between EPS and metal NPs was evaluated through the changes in Raman signals. In this regard, we compared the redox activity of EPS extracted from two typical electroactive bacteria(Shewanella oneidensis and Geobacter sulfurreducens) and another two nonelectroactive strains(Escherichia coli and Bacillus subtilis). Electrochemical measurements show that the electroactive strains have higher redox capabilities than nonelectroactive strains. The SERS analysis shows that the porphyrin present in cytochrome c is the dominating redox moiety in the EPS of electroactive bacteria. The results of this study show that SERS with active metal substrates is a sensitive tool to probe the redox response of EPS, offering an opportunity to better understand the redox nature of biomolecules.

关键词： electroactive bacteria extracellular polymeric substances redox properties SERS

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Analysis of bacitracin and its related substances by liquid chromatography tandem mass spectrometry

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Journal of Pharmaceutical Analysis 2017年第1期7卷 48-55页

作者： Suleiman Ahmed Suleiman Fan Song Mengxiang Su Taijun Hang Min Song Department of Pharmaceutical Analysis China Pharmaceutical University Nanjing 210009 China

A suitable liquid chromatography quadrupole time-of-flight mass spectrometric(LC–Q-TOF–MS) method was developed for separation and characterization of related substances in bacitracin test drug. The separation was performed on Li Chrospher RP-18 column using methanol as mobile phase A and 0.2% ammonium acetate buffer solution as mobile phase B in gradient elution. A total of 12 related substances were detected through high resolution mass spectrometric determination in a positive electrospray ionization mode. They were identified as co-existing active components and degradation products of bacitracin through the analysis and elucidation of both the protonated parents and the product ions of all the related substances and their fragmentation pathways were also proposed.

关键词： Bacitracin Degradation products Fragmentation pathways Related substances LC–Q-TOF–MS

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Maternal exposure to specific perfluoroalkyl substances is associated with increasing blood glucose in pregnant women

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Journal of Environmental Sciences 2018年第7期30卷 1-2页

作者： Jagdeesh S.Uppal Qi Zheng X.Chris Le Division of Analytical and Environmental Toxicology Department of Laboratory Medicine and PathologyFaculty of Medicine and Dentistry University of Alberta Key Laboratory of Optoelectronic Chemical Materials and Devices Ministry of Education Institute of Environment and HealthJianghan University

Imagine if a group of toxic substances that increase oxidative stress and disrupt glucose and lipid metabolism have been broadly used worldwide for applications such as repellent,food packaging,and non-stick frying pa... 详细信息

关键词： perfluoroalkyl and polyfluoroalkyl substances PFAS PFOS gestational diabetes mellitus blood glucose

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Identification and characterization of related substances in EVT-401 by hyphenated LC–MS techniques

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Journal of Pharmaceutical Analysis 2017年第4期7卷 223-230页

作者： Binan Zhu Yuting Lu Leilin Chen Binbin Yu Yuexin Liu Min Song Taijun Hang Key Laboratory of Drug Quality Control and Pharmacovigilance Ministry of Education Department of Pharmaceutical Analysis China PharmaceuticalUniversity Nanjing 210009 China Department of Chemical Drug Control Hubei Institute for Food and Drug Control Wuhan 430074 China Department of Pharmacy Taizhou First People's Hospital Taizhou 318200 China

A sensitive and selective method was developed for the separation and characterization of related substances(RSs) in EVT-401 by hyphenated LC–MS techniques. Complete separation of the RSs was achieved with an Inertsil ODS-SP column(250 mm×4.6 mm, 5 μm) by linear gradient elution using a mobile phase consisting of 0.2% formic acid solution, methanol and acetonitrile. EVT-401 was found to be susceptible to acid, alkaline and oxidative stresses, while relatively stable under photolytic and thermal dry stress conditions. Fourteen RSs including six process-related substances and eight degradation products were detected and identified in EVT-401 with positive ESI high-resolution TOF-MS analysis of their parent ions and the corresponding product mass spectra elucidation, and some of them were further verified by chemical synthesis and NMR spectroscopy. The specific LC–MS method developed for separation, identification and characterization of RSs is valuable for EVT-401 manufacturing process optimization and quality control.

关键词： EVT-401 Related substances LC–MS Degradation products

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Contamination of Prohibited substances in Various Food Products in Guangzhou, China

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Biomedical and Environmental Sciences 2020年第1期33卷 68-71页

作者： MHUNGU Florence HU Ke Qi ZHANG Wei Wei ZHOU Zhi Feng SHI Ming LIU Yun Gang School of Public Health Southern Medical UniversityGuangzhou 510515GuangdongChina Guangzhou Centre for Disease Control and Prevention Guangzhou 510440GuangdongChina Department of Environmental and Occupational Health School of Public HealthGuangdong Medical UniversityDongguan 523808GuangdongChina

The use of antibiotics to maintain animal health has widely been practiced,for both therapeutic and prophylactic *** with the identification of serious adverse effects of some antibiotics on human and domestic animals... 详细信息

关键词： Contamination of Prohibited substances Various Food Products Guangzhou China

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Effects of pH value and coagulant dosage on contact filtration of humic substances

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Journal of Central South University 2009年第S1期16卷 384-390页

作者：蒋绍阶刘宗源梁建军 Key Laboratory of Three Gorges Reservoir Region's Eco-Environment Ministry of Education Shenzhen Institute of Building Research Co. Ltd.

Humic substances (especially fulvic acid (FA)) are the major components of natural organic matter (NOM) that widely exist in drinking water source. Due to their potential effects on public health,the removal of FA was one of the main concerns during the water treatment. Therefore,the contact filtration of FA by using aluminum sulfate as coagulant on the basis of jar tests was carried out. The effects of pH and coagulant dosage on the FA removal and the development of head loss were investigated. The results show that the range of pH value during the FA contact filtration can be effectively influenced by the dosage of aluminum sulfate,and the high aluminum sulfate dosage is an important factor that can result in early filter breakthrough. The FA filtration by deep-bed filtration or by membrane filtration is sometimes disparate under the same coagulation conditions. The choice of aluminum sulfate dosage by the method of membrane filtration,i.e. the "true color measurement",may result in inappropriate filter run,whereas it can be determined with simple jar tests by observing the formation of micro flocs. Considering the effects of pH on aluminum sulfate dosage and FA removal,the optimal pH range of 5.5?6.0 is suggested.

关键词： humic substances fulvic acid filtration coagulation

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Application of Coulometric Titration for the Certification of Primary Reference Materials of Pure substances

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American Journal of Analytical Chemistry 2014年第9期5卷 559-565页

作者： Gennady I. Terentiev Alena V. Sobina Alexandr J. Shimolin Veniamin M. Zyskin Ural Scientific and Research Institute for Metrology Ekaterinburg Russia

In this article, the block scheme and metrological characteristics of the State primary standard of the mass (molar) fraction and mass (molar) concentration of the component in the liquid and solid substances and materials based on coulometric titration GET 176-2010 are given. Primary reference materials certified by coulometric titration in the Ural Scientific and Research Institute for Metrology include eight certified reference materials (CRMs) of pure solid substances (mostly salts of sodium or potassium) and one hydrochloric acid solution CRM. The metrological characteristics of these reference materials and the scheme of their application in titrimetric analysis are shown. The expanded uncertainty of the certified value (mass fraction for the solid substances or molar concentration for the solution) is in the range from 0.018% to 0.05%. Information about two primary reference materials of high purity iron and lead nitrate certified by controlled-potential coulometry with expanded uncertainty from 0.04% to 0.07% is also given.

关键词： Coulometric Titration Controlled-Potential Coulometry Primary Reference Materials High Purity substances State Primary Standard

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Self and Foreign substances in Organic and Conventional Milk Produced in the Eastern Region of Mexico

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Food and Nutrition Sciences 2013年第5期4卷 586-593页

作者： Rey Gutiérrez P. Rosell S. Vega Jesús Pérez Acacia Ramírez Marta Coronado Departamento de Producción Agrícola y Animal Universidad Autónoma Metropolitana Unidad Xochimilco D.F. México México ma Metropolitana Unidad Xochimilco D.F. México México

The objective of the present study was to evaluate the physicochemical properties, presence of water and aflatoxin M1, as well as the effect of the time of year (dry or rainy season) to value the quality and safety of conventional and organic raw milk samples. Samples were collected of conventional (n = 12) and organic (n = 11) raw milk from Tizayuca, Hidalgo and from Tuxpan, Veracruz, respectively. Infrared spectrophotometry and other analytical techniques were employed, approved by the International Dairy Federation for the analysis of the physicochemical properties, the cryoscopy technique for the detection of water addition, and high performance liquid chromatography for the determination of aflatoxin M1. Results showed that there are no significant differences in the components of conventional milk in the season of the year, whereas in organic milk a significant difference (P 0.05) was observed in acidity during the seasons of the year (rainy and dry), as well as a decrease in the percentage of lactose in the dry season, with a significant difference (P 0.05). The means of the cryoscopic point of the milk samples complied with the limits established in the Mexican Official Norm (–0.530, –0.560°H) for milk and no effect was found of the time of year on this variable. Of the milk samples, 50% of the conventional milk and 54.55% of organic milk were above the maximum limits permitted for aflatoxin M1, established in Mexico (0.5 μg·Kg-1).

关键词： Self and Foreign substances Organic Milk Mexico

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