检索结果-南通市图书馆

Journal of environmental sciences 2013年第5期25卷 916-924页

作者： Xiaodong Ruan Lin Li Junxin Liu Research Center for Eco-environmental Science Chinese Academy of Sciences

Aluminum flocculant can enhance the flocculating performance of activated sludge.However,the binding mechanism of aluminum ion（Al 3＋） and extracellular polymeric substances（EPS） in activated sludge is unclear due to the complexity of EPS.In this work,threedimensional excitation emission matrix fluorescence spectroscopy（3DEEM）,fluorescence quenching titration and Fourier transform infrared spectroscopy（FT-IR） were used to explore the binding behavior and mechanism between Al 3＋ and EPS.The results showed that two fluorescence peaks of tyrosineand tryptophan-like substances were identified in the loosely bound-extracellular polymeric substances（LB-EPS）,and three peaks of tyrosine-,tryptophanand humic-like substances were identified in the tightly boundextracellular polymeric substances（TB-EPS）.It was found that these fluorescence peaks could be quenched with Al 3＋ at the dosage of 3.0 mg/L,which demonstrated that strong interactions took place between the EPS and Al 3＋.The conditional stability constants for Al 3＋ and EPS were determined by the Stern-Volmer equation.As to the binding mechanism,the-OH,N-H,C=O,C-N groups and the sulfurand phosphorus-containing groups showed complexation action,although the groups in the LB-EPS and TB-EPS showed different behavior.The TB-EPS have stronger binding ability to Al 3＋ than the LB-EPS,and TB-EPS play an important role in the interaction with Al 3＋.

关键词： extracellular polymeric substances activated sludge aluminum ion three-dimensional excitation emission matrix fluorescence quenching Fourier transform infrared spectroscopy

Characterization and reactivity of biogenic manganese oxides for ciprofloxacin oxidation

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 2014年第5期26卷 1154-1161页

作者： Jinjun Tu Zhendong Yang Chun Hu Jiuhui Qu State Key Laboratory of environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesResearch Center for Eco-Environmental Sciences

Biogenic manganese oxides （BioMnOx） were synthesized by the oxidation of Mn（II） with Mn- oxidizing bacteria Pseudomonas sp. G7 under different initial pH values and Mn（II） dosages, and were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and UV-Vis absorption spectroscopy. The crystal structure and Mn oxidation states of BioMnOx depended on the initial pH and Mn（lI） dosages of the medium. The superoxide radical （O2） was observed in Mn-containing （III/IV） BioMnOx suspensions by electron spin resonance measurements. BioMnOx（0.4）-7, with mixed valence of Mn（II/III/IV） and the strongest O^- signals, was prepared in the initial pH 7 and Mn（II） dosage of 0.4 mmol/L condition, and exhibited the highest activity for ciproftoxacin degradation and no Mn（II） release. During the degradation of ciprofloxacin, the oxidation of the Mn（II） formed came from biotic and abiotic reactions in BioMnOx suspensions on the basis of the Mn（II） release and O2- formation from different BioMnOx. The degradation process of ciprofloxacin was shown to involve the cleavage of the hexatomic ring having a secondary amine and carbon-carbon double bond connected to a carboxyl group, producing several compounds containing amine groups as well as small organic acids.

关键词： Mn oxidation state Mn-oxidizing bacteria superoxide radicals ciprofloxacin degradation

Hollow TiO_2 spheres with improved visible light photocatalytic activity synergistically enhanced by multi-stimulative: Morphology advantage,carbonate-doping and the induced Ti^(3+)

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 2018年第10期30卷 153-165页

作者： Guoliang Li Chunyang Liao Guibin Jiang State Key Laboratory of environmental Chemistry and eco-toxicology Research Center for Eco-Environmental SciencesChinese Academy of Sciences

Great efforts have been devoted to improve the photocatalytic activity of TiO2 in the visible light region. Rational design of the external structure and adjustment of intrinsic electronic status by impurity doping are two main effective ways to achieve this purpose. A facile onepot synthetic approach was developed to prepare C-doped hollow TiO2 spheres, which simultaneously realized these advantages. The synthesized TiO2 exhibits a mesoporous hollow spherical structure composed of fine nanocrystals, leading to high specific surface area（~180 m^2/g） and versatile porous texture. Carbonate-doping was achieved by a postthermal treatment at a relatively low temperature（200°C）, which makes the absorption edge red-shifted to the visible region of the solar spectrum. Concomitantly, Ti^（3＋） induced by C-doping also functions in improving the visible-light photocatalytic activity by reducing the band gap. There exists a synergistic effect from multiple stimulatives to enhance the photocatalytic effect of the prepared TiO2 catalyst. It is not out of expectation that the asprepared C-doped hollow TiO2 spheres exhibits an improved photocatalytic activity under visible light irradiation in organic pollutant degradation.

关键词： Hollow TiO2 sphere Carbonate Ti^3＋ Visible light Photo-degradation Synergistic enhancement

在线全文

学校读者我要写书评

暂无评论

Haze and health

National science Review 2016年第4期3卷 412-413页

作者： Liang-Hong Guo Research Center for Eco-environmental Science Chinese Academy of Sciences

As a general term,haze is defined as an aggregation in the atmosphere of very fine,widely dispersed,solid or liquid particles,or both,giving the air an opalescent appearance that subdues colors[1].While natural haze such as that in the forestcovered mountains and valleys has long existed,hazardous haze derived primarily from the combustion of fossil-fuel products has evolved with human activities.

关键词： PM Haze and health very

Advanced molecular-fingerprinting analysis of dissolved organic sulfur by electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry using optimal spray solvent

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of environmental sciences 2020年第11期32卷 67-74页

作者： Dong Cao Ziyu Rao Fanglan Geng Hongyun Niu Yali Shi Yaqi Cai Yuehui Kang State Key Laboratory of environmental Chemistry and ecotoxicology Research Center for Eco-Environmental ScienceChinese Academy of SciencesBeijing 100085China

Molecular level characterization of dissolved organic sulfur(DOS)by electrospray ionizationFourier transform ion cyclotron resonance mass spectrometry(ESI-FTICR MS)is necessary for further understanding of the role of DOS in the environment.Here,ESI spray solvent,a key parameter for ion production during ESI process,was investigated for its effect on the molecular characterization of DOS by ESI-FTICR MS.100%MeOH as spray solvent was found for the first time to remarkably enhance the ionization efficiency of the majority of CHOS-molecules in NOM,which facilitated a total of 1473 CHOS-molecular formulas with one sulfur atom to be detected.The number of CHOS-molecular formulas obtained using 100%MeOH as spray solvent increased notably over 740 in comparison with those using 50%MeOH aqueous solution(731)or 50%ACN aqueous solution(653).Moreover,due to the enhancement of ionization efficiency of DOS during ESI processes,the tandem mass spectra of the NOM CHOS-molecules could be easily obtained using 100%MeOH as spray solvent,which were hardly obtained using 50%MeOH aqueous solution as spray solvent.The results of the tandem mass spectra suggested the first discovery of organosulfates or sulfonic acids in Suwannee River NOM sample.A simple method based on 100%MeOH as ESI spray solvent for advanced molecular characterization of DOS by ESI-FTICR MS was proposed and applied,and the results revealed more molecular information of DOS in sea DOM samples.

关键词： Natural organic matter Fourier transform ion cyclotron resonance mass spectrometry Spray solvent Dissolved organic sulfur

Floc structure and membrane fouling affected by sodium alginate interaction with Al species as model organic pollutants

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 2019年第8期31卷 1-13页

作者： Xuejun Xiong Hui Xu Beiping Zhang Xiaohui Wu Hongyan Sun Dongsheng Wang Zhengyang Wang School of environmental science and Engineering Huazhong University of Science and Technology Key Laboratory of Drinking Water science and Technology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences State Key Laboratory of environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Department of Civil and environmental Engineering University of Missouri

Membrane filtration combined with pre-coagulation has advantages in advanced wastewater treatment. As a model of a microbial polysaccharide, research on the effect of sodium alginate(SA) on alum hydrolysis has been rare; therefore, it is necessary to gain insight into the interface interaction between SA molecules and Al species, and the role SA plays during floc formation. In this study, the interaction mechanism between SA and Al species has been investigated, by evaluating the effect of SA on floc characteristics and membrane fouling during coagulation–ultrafiltration with different Al species coagulants(AlCl3 and preformed Al13). Al 2 p X-ray photoelectron spectroscopy(XPS) confirmed that the complexation of ligands and Al species strongly affects the reaction pathways for Al hydrolysis and the final nature of the flocs, as Al13 can be decomposed into octahedral precipitates when SA is added. The presence of SA can affect floc properties, which have important impacts on the characteristics of the cake layer and membrane fouling. Due to the bridging ability of SA, the floc strength increased by about 50% using Ala, which was much better than preformed Al13, with a percentage increase of only about 6%. Moreover,the recovery factor of HA-flocs was decreased from 96% to 43% with SA addition of 0.5 mg/L.It was concluded that SA can affect the characteristics of the cake layer and membrane fouling through participating in the formation of primary flocs and altering the Al hydrolysis pathway.

关键词： Coagulation–ultrafiltration process Al species Interface interaction X-ray photoelectron spectroscopy Floc properties Membrane fouling

Identification of unknown disinfection byproducts in drinking water produced from Taihu Lake source water

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 2022年第3期34卷 1-11页

作者： Jiabao Li Haifeng Zhang Juan Wang Zhiyong Yu Hongyan Li Min Yang Key Laboratory of Drinking Water science and Technology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China State Key Laboratory of environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesUniversity of Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of sciences Beijing 100049China

Although disinfection byproducts(DBPs) in drinking water have been suggested as a cancer causing factor, the causative compounds have not yet been clarified. In this study, we used liquid chromatography quadrupole-time-of-flight spectrometry(LC-QTOF MS) to identify the unknown disinfection byproducts(DBPs) in drinking water produced from Taihu Lake source water, which is known as a convergence point for the anthropogenic pollutants discharged from intensive industrial activities in the surrounding regions. In total, 91 formulas of DBPs were discovered through LC-QTOF MS nontarget screen, 81 of which have not yet been reported. Among the 91 molecules, 56 only contain bromine, 15 only contain chlorine and 20 DBPs have both bromine and chlorine atoms. Finally, five DBPs including 2,4,6-tribromophenol, 2,6-dibromo-4-chlorophenol, 2,6-dichloro-4-bromophenol, 4-bromo-2,6-di-tert-butylphenol and 3,6-dibromocarbazole were confirmed using standards. The former three compounds mainly formed in the predisinfection step(maximum concentration, 0.2-2.6 μg/L), while the latter two formed in the disinfection step(maximum concentration, 18.2-33.6 ng/L). In addition, 19 possible precursors of the discovered DBPs were detected, with the aromatic compounds being a major group. 2,6-di-tert-butylphenol as the precursor of 4-bromo-2,6-di-tert-butylphenol was confirmed with standard, with a concentration of 20.3 μg/L in raw water. The results of this study show that brominated DBPs which are possibly formed from industrial pollutants are relevant DBP species in drinking water produced form Taihu source water, suggesting protection of Taihu Lake source water is important to control the DBP risks.

关键词： Source water Disinfection byproducts Brominated disinfection byproducts Nontarget analysis Precursors Source water pollution

A sustained-release microcarrier effectively prolongs and enhances the antibacterial activity of lysozyme

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 2023年第7期129卷 128-138页

作者： Mei Du Jingzhang Liu Fengbang Wang Lei Bi Chunyan Ma Maoyong Song Guibin Jiang State Key Laboratory of environmental Chemistry and ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of ScienceBeijing 100085China University of Chinese Academy of sciences Beijing 100049China

Bacterial infections have become a great threat to public health in recent years.A primary lysozyme is a natural antimicrobial protein;however,its widespread application is limited by its instability.Here,we present a poly(N-isopropylacrylamide)hydrogel inverse opal particle(PHIOP)as a microcarrier of lysozyme to prolong and enhance the efficiency against bacteria.This PHIOP-based lysozyme(PHIOP-Lys)formulation is temperature-responsive and exhibits long-term sustained release of lysozyme for up to 16 days.It shows a potent antibacterial effect toward both Escherichia coli and Staphylococcus aureus,which is even higher than that of free lysozyme in solution at the same concentration.PHIOPs-Lys were demonstrated to effectively inhibit bacterial infections and enhance wound healing in a full-thickness skin wound rat model.This study provides a novel pathway for prolonging the enzymatic activity and antibacterial effects of lysozyme.

关键词： Bacterial infection Lysozyme Temperature-responsive Inverse opal particle Wound healing

The influence of particle size and concentration combined with pH on coagulation mechanisms

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 2019年第8期31卷 39-46页

作者： Hongyan Sun Ruyuan Jiao Hui Xu Guangyu An Dongsheng Wang State Key Laboratory of environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Key Laboratory of Drinking Water science and Technology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences University of Chinese Academy of sciences

In order to evaluate the influence of particle size and particle concentration on the coagulation process, two kinds of particle suspensions, nanoparticles and microparticles,were employed to investigate the effect of particle size on coagulation mechanisms with varying coagulation parameters. Results showed that it is easier for nanoparticles to cause self-aggregation because of Brownian motion, while interception and sedimentation are the mainly physical processes affecting particle transport for microparticles, so they are more stable and disperse more easily. The particle size distribution and particle concentration had distinct influence on the coagulation mechanisms. Under neutral conditions, as the amount of coagulant increased, the coagulation mechanism for nanoparticles changed from charge neutralization to sweep flocculation and the nanoparticles became destabilized, re-stabilized and again destabilized. For microparticles, although the coagulation mechanism was the same as that of nanoparticles, the increased rate of aluminum hydroxide precipitation exceeded the adsorption of incipiently formed soluble alum species, resulting in the disappearance of the re-stabilization zone. Under acidic conditions, Brownian motion dominates for nanoparticles at low particle concentrations, while sweep flocculation is predominant at high particle concentrations. As for microparticles, charge neutralization and sweep flocculation are the mechanisms for low and high particle concentrations respectively.Under alkaline condition, although the mechanisms for both nano-and microparticles are the same, the morphology of flocs and the kinetics of floc formation are different. At low particle concentrations, nanoparticles have larger growth rate and final size of flocs, while at high particle concentrations, nanoparticles have higher fractal dimension and recovery factors.

关键词： Nanoparticles Microparticles Particle size distribution Coagulation mechanisms Alum

Degradation of kanamycin from production wastewater with high-concentration organic matrices by hydrothermal treatment

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 2020年第11期32卷 11-18页

作者： Mei Tang Fan Li Min Yang Yu Zhang State Key Laboratory of environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesUniversity of Chinese Academy of SciencesChinese Academy of ScienceBeijing 100085China Key Laboratory of Drinking Water science and Technology Research Center for Eco-Environmental SciencesUniversity of Chinese Academy of SciencesChinese Academy of ScienceBeijing 100085China National Engineering Laboratory for Industrial Wastewater Treatment Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

It is known that many kinds of fermentative antibiotics can be removed by temperatureenhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics.However,a few aminoglycosides are hard to hydrolyze below 100℃ because of their stability expressed by high molecular energy gap(E).Herein,removal of hard-to-hydrolyze kanamycin residue from production wastewater by hydrothermal treatment at subcritical temperatures was investigated.The results showed the reaction temperature had a significant impact on kanamycin degradation.The degradation half-life(t1/2)was shortened by 87.17-fold when the hydrothermal treatment temperature was increased from 100℃ to 180℃.The t1/2 of kanamycin in the N2 process was extended by 1.08-1.34-fold compared to that of the corresponding air process at reaction temperatures of 140-180℃,indicating that the reactions during hydrothermal treatment process mainly include oxidation and hydrolysis.However,the contribution of hydrolysis was calculated as 75%-98%,which showed hydrolysis played a major role during the process,providing possibilities for the removal of kanamycin from production wastewaters with high-concentration organic matrices.Five transformation products with lower antibacterial activity than kanamycin were identified using UPLC-QTOF-MS analysis.More importantly,hydrothermal treatment could remove 97.9%of antibacterial activity(kanamycin EQ,1,109 mg/L)from actual production wastewater with CODCr around 100,000 mg/L.Furthermore,the methane production yield in anaerobic inhibition tests could be increased about 2.3 times by adopting the hydrothermal pretreatment.Therefore,it is concluded that hydrothermal treatment as a pretreatment technology is an efficient method for removing high-concentration hard-to-hydrolyze antibiotic residues from wastewater with high-concentration organic matrices.

关键词： Pharmaceutical wastewater Hydrothermal process Antibiotic antibacterial activity Hydrolysis Refractory organic wastewater