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1.
Liu Xian-li Wu Feng Liao Zhen-huan Li Shun-xing Deng Nan-sheng . School of Resource Environmental Science Wuhan University Wuhan Hubei China . Huangshi Polytechnic College Huangshi Hubei China . College of Chemistry Molecular Sciences Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2004,9(1):109-114
0 IntroductionTherehasbeenincreasingconcernabouttheenvironmentaleffectsofoestrogensandxenoestrogens[1 ] .17α ethynylestradiol(EE2 ) (Fig .1)isasyntheticestrogenicsteroidthathastherapeuticuses (e.g .Oralcontraception) .Syntheticestrogensaregenerallymorestableinwaterthannaturalestrogensandhavegreaterpotency.Theyaredifficulttobeabsolutelyremovedfromwastewatersbyprimaryandsecondarytreatment.Thedegradationchemistryofthiscom poundhasnotbeenextensivelystudied .Therearefewpublishedarticlesstudying… 相似文献
2.
The photodegradation of bisphenol A (BPA) in aqueous solution containing metal ions and ascorbic acid (AsA) was investigated.
After strong irradiation, the aqueous solution containing AsA and Cu2+ could produce hydroxyl radicals that induced the photodegradation of BPA. The photodegradation efficiency of BPA in the solution
containing 70 μmol·L−1 Cu2+ and 15 mg·L−1 AsA reached 59% at pH 6.0 after 4 hours irradiation with high pressure mercury lamp. The photodegradation efficiency of BPA
reached 10% after 4 hours irradiation with daylight lamp in the presence of 70 μmol·L−1 Cu2+ and 15 mg·L−1 ascorbic acid. BPA was not degraded in the aqueous solution only containing AsA or Cu2+. The BPA photodegradation in aqueous solution containing AsA and Fe3+ was weaker than in aqueous solution that containing AsA and Cu2+ at the same concentration. This work showed a new route of the BPA photodegradation in aqueous environment.
Biography: PENG Zhang’e (1970–), female, Ph. D. candidate, research direction: aquatic environmental chemistry. 相似文献
3.
Rao ZhiGuo Zhu ZhaoYu Jia GuoDong Chen FaHu Barton Loukas Zhang JiaWu Qiang MingRui 《科学通报(英文版)》2010,55(18):1931-1936
Using −24‰ and −14‰ as the endpoints of stable carbon isotopic composition of total organic carbon (δ13CTOC) of surface soil under pure C3 and C4 vegetation, and surface soil δ13CTOC data from eastern China, Australia and the Great Plains of North Amer- ica, we estimate the relative abundance of C3/C4 plants (i.e., the ratio of C3 or C4 biomass to local primary production) in modern vegetation for each region. The relative abundance of modern C3/C4 vegetation from each region is compared to the corresponding climatic parameters (mean annual temperature and precipitation) to explore the relationship between relative C4 abundance and climate. The results indicate that temperature controls the growth of C4 plants. However, even where temperature is high enough for the growth of C4 plants, they will only dominate the landscape when precipitation declines as temperatures increase. Our results are consistent with those of other investigations of the geographic distribution of modern C4 plant species. Therefore, our results provide an important reference for interpretation of past C3/C4 relative abundance records in these three regions. 相似文献
4.
Pei-hong Yuan Cai-mei Fan Guang-yue Ding Yun-fang Wang Xiao-chao Zhang 《矿物冶金与材料学报》2012,19(4):372-376
The powders of ilmenite structure NiTiO3 were prepared by a modified Pechini process using tetrabutyl titanate and nickel acetate as raw materials, and using citric
acid and ethanol as a chelating agent and a solvent respectively. The powder samples were characterized by thermogravimetric
and differential thermal analysis (TG-DTA) and X-ray diffraction (XRD). The photocatalytic activity of NiTiO3 under the irradiation of ultraviolet rays (UV) light was evaluated by degrading humic acid (HA) in water as a probe reaction.
The possible photodegradation mechanism was studied by the examination of active species ·OH, ·O2−, and holes (h+) through adding scavengers. The TG-DTA and XRD results indicated that the good crystal structure of ilmenite phase NiTiO3 could be obtained when the Ni-Ti citrate complex was calcined at 600°C. The photocatalytic activity experiments indicated
that NiTiO3 had favourable photocatalytic activity under the irradiation of UV light, and the photocatalytic degradation rate of HA reached
95.3% after a 2.5 h reaction with the photocatalyst calcined at 600°C and a photocatalyst dosage of 0.4 g/L. The possible
photocatalytic mechanism was deduced that holes (h+) and ·OH radicals are the major reactive active species in the photocatalytic reaction, and dissolved oxygen plays a weak
role in the degradation of HA. 相似文献
5.
Four types of TiO 2 thin-film electrodes were fabricated from TiO 2 and Fe(III) doped TiO 2 sols using a layer-by-layer dip-coating technique. Electrodes fabricated were TF (pure TiO 2 surface, Fe(III)-TiO 2 bottom layer), FT (Fe(III)-TiO 2 surface, pure TiO 2 bottom layer), TT (both layers pure TiO 2 ) and FF (both layers Fe(III)-TiO 2 ). The photoelectrochemical behavior of these electrodes was characterized using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and steady-state photocurrent measurements in aqueous 0.1 mol L –1 NaNO 3 containing varying concentrations of glucose or potassium hydrogen phthalate (KHP). EIS and LSV results revealed that exciton separation efficiency followed the sequence of TF﹥TT﹥FT > FF. Under a constant potential of +0.3 V, steady-state photocurrent profiles were recorded with varying organic compound concentrations. The TF electrode possessed the greatest photocatalytic capacity for oxidizing glucose and KHP, and possessed a KHP anti-poisoning effect. Enhanced photoelectrochemical performance of the TF electrode was attributed to effective exciton separation because of the layered TF structure. 相似文献
6.
《自然科学进展(英文版)》2021,31(5):672-678
As a candidate material for hydrogen separation, Yb-doped SrCeO3 has attracted increasing attention in recent decades. In the present study, Yb-doped SrCe0.9Yb0.1O3-α ceramics were prepared by the dry pressing and sintering approach, with the microstructure evolution and the micro morphology investigated. It was indicated that the ceramics sintered in air were of a pure perovskite structure, and that the sintering temperature had a significant effect on the growth of ceramic grains. The average grain size increased from 1 μm to 10 μm with an increase in sintering temperature from 1300 to 1500 °C. Further investigation of the thermodynamics and kinetics of grain growth revealed that the grain boundary diffusion was the main driving force of grain growth during solid phase sintering, with a grain growth index of 4 and an activation energy of approximately 61.23 kJ mol−1. These results illustrate an obvious tendency of grain size growth. By electrochemical workstation with different atmospheres the effects of sintering temperature on the conductivity were characterized in the temperature range of 700–900 °C. The electrical conductivities σ of SrCe0.9Yb0.1O3-α ceramics in different atmospheres were as follows: σ(wet hydrogen) > σ(dry hydrogen) > σ(dry air) > σ(wet air). In the test atmosphere containing water and hydrogen the conductivity of protons increased with increasing temperature because of the protons jump between lattices in the form of interstitial hydrogen ions or bare protons. 相似文献
7.
In this study, photo-Fenton oxidation was applied to degradation of sulfamonomethoxine sodium (SMMS) in aqueous solution. The operation parameters of pH, temperature, and concentrations of H2O2, Fe2+ and SMMS were investigated. The optimum conditions for the photo-Fenton process were determined as follows: [SMMS]=4.53 mg/L, pH 4.0, [H2O2]=0.49 mmol/L, [Fe2+]= 19.51 μmol/L and T=25°C. Under these conditions 98.5% of the SMMS degraded. The kinetics were also studied, and degradation of SMMS by the photo-Fenton process could be described by first-order kinetics. The apparent activation energy was calculated as 23.95 kJ/mol. Mineralization of the process was investigated by measuring the chemical oxygen demand (COD), and the COD decreased by 99% after 120 min. This process could be used as a pretreatment method for wastewater containing sulfamonomethoxine sodium. 相似文献
8.
Qiang Xu Lin Ding LiYun Zhang Di Yang FuLong Cai QingZhou Lai Jing Liu RenDeng Shi 《科学通报(英文版)》2010,55(1):45-54
Fossil tooth enamel from herbivores is considered one of the best proxies for paleoclimate and paleoelevation reconstructions, due to its low susceptibility to diagenetic alteration. A synthesis of oxygen and carbon isotope analyses of modern tooth enamel from herbivores such as Tibetan yaks, asses and antelopes is assessed. The average δ 13C(PDB) value of herbivore tooth enamel in the Lhasa and south Qiangtang terrains is-11.3‰± 1.1‰, whereas in the north Qiangtang and Hoh Xil terrains value is-10.2‰± 1.4‰... 相似文献
9.
The magnetic properties of Fe3(1−x)Cr3xC alloys with x=0.05, 0.1, 0.15, and 0.2, which crystallize in the cementite Fe3C-type structure with space group Pnma, were investigated by means of magnetization measurements. These alloys show temperature-induced second-order magnetic phase transitions. The Curie temperature (Tc) of these alloys decreases with increasing x. The isothermal magnetic-entropy changes of these alloys were derived from the magnetic isotherms measured with increasing temperature and increasing field. The maximum values of the magnetic-entropy change are about 0.9 and 3.6 J·kg−1·K−1 at Tc =360 K for x = 0.05 in a magnetic field change from 0 to 1 T and 0 to 5 T, respectively. 相似文献
10.
Effect of adsorption mode on photodegradation of H-acid in TiO2 suspension was studied using DFT calculation,UV-Vis spec-troscopy,FTIR,and ionic chromatography.At pH 2.5,H-acid was adsorbed on TiO2 surfaces by one dissociated sulfonic group.The adsorbed sulfonic group was attacked by surface ·OH,resulting in the production of SO42-and the cleavage of the naphtha-lene ring.At pH 5.0,H-acid was adsorbed on TiO2 surfaces by two sulfonic groups.The two adsorbed sulfonic groups were sim-ultaneously attacked by surface ·OH,leading to a faster initial production of SO42-and initial degradation rate of H-acid than those under pH 2.5.Microscopic adsorption structures may be more important than adsorption amount in controlling the photo-degradation pathways of organic pollutants. 相似文献
11.
QiaoYing Wang HongYing Su ChunChao Xia JiaYu Sun Chen Liu ZhiYong Wang QiYong Gong Bin Song FaBao Gao Hua Ai ZhongWei Gu 《科学通报(英文版)》2009,54(17):2925-2933
Superparamagnetic iron oxide (SPIO) nanoparticles are effective contrast agents for enhancement of magnetic resonance imaging at the tissue, cellular or even molecular levels. High quality SPIO nanoparticles can be synthesized in the organic phase but need to be transferred into water before any biomedical applications. In this study, amphiphilic poly(ε-caprolactone) grafted dextran (Dex-g-PCL) was used as carriers for particle encapsulation and stabilization in the aqueous phase. Multiple SPIO nanoparticles were self-assembled together with the help of Dex-g-PCL during phase transfer from chloroform to water, and diameters of Dex-g-PCL/SPIO nanocomposites were (64 ± 22) nm through dynamic light scattering measurement. These nanocomposites were superparamagnetic at 300 K with saturated magnetization of 88 emu/g Fe. In the magnetic field of 1.5 T, Dex-g-PCL/SPIO nanocomposites had a T2 relaxivity of 363 Fe mL·mol-1·s-1. This unique nanocomposite brought significant mouse liver contrast with signal intensity changes of -60% at 5 min after intravenous administration. However, uptake of Dex-g-PCL/SPIO nanocomposites in liver reticuloendothelial cells (Kupffer cells) did not immediately happen at shorter time points (〈4 h) as verified by histology studies, and it was evident that more iron staining would be located in Kupffer cells 24 h after contrast agent administration. After 24 h and 10 d, the signal intensities (SI) gradually recovered, and SI changes were -44% and -31%, respectively. From our observation, the time window for enhanced-MRI could last at least 12 days and totally recovered after 16 days. This novel sensitive MRI contrast agent may find potential applications in discovering small liver lesions such as early tumor diagnosis. 相似文献
12.
YANGJia-long WANGFu ZUOLiang YIGu-chul CHOIWong-yong 《武汉大学学报:自然科学英文版》2005,10(3):581-586
Silicon ( 111 ) and Silicon (100) have been employed for fabrication of TiO2 films by metal organic chemical vapor deposition (MOCVD). Titanium (Ⅳ) isopropoxide (Ti[O (C3H7)4 ])was used as a precursor. The as-deposited TiO2 films have been characterized with Field emission scanning electron microscopy (FE-SEM), X ray diffraction (XRD) and atomic force microscopy (AFM). The photocatalytic properties were investigated by decomposition of aqueous orange Ⅱ. The crystalline and structural properties of TiO2 film had crucial influences on the photodegradation efficiency. For MOCVD in-situ deposited films on Si substrates, thephotoactivities varied following a shape of “M”: At lower (350 ℃ ) middle (500 ℃) and higher (800 ℃) temperature of deposition, relative lower photodegradation activities have been observed. At 400 ℃ and 700 ℃ of deposition, relative higher efficiencies of degradation have been obtained, because one predominant crystallite orientation could be obtained as deposition at those two temperatures, especially a single anatase crystalline TiO2 film could be obtained at 700 ℃ growth. 相似文献
13.
用TPSSTPSS密度泛函方法, Pu离子和H2O分子分别采用相对论有效原子实势(RECP)和6-31g基组, 研究了Pu(H2O)53+和Pu(H2O)54+ 团簇溶剂化和非溶剂化效应中的几何结构及紫外可见吸收光谱. 计算结果表明: 水溶剂环境对Pu(H2O)53+及Pu(H2O)54+ 团簇的几何结构影响都比较明显. NBO电荷分析表明水分子与钚离子之间没有直接的电荷转移. 所研究团簇的未配对电子都占据5f轨道. 在气相及水溶剂环境下, 所研究团簇的紫外可见吸收光谱存在较大差距. 主要的吸收峰大都源于f电子之间的跃迁. 相似文献
14.
Preparation and characterization of LiAlxMn2-xO4 for a supercapacitor in aqueous electrolyte
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LiAlxMn2—xO4 (0≤x≤0.5) was synthesized by high temperature solid-state reaction. The structure and morphology of LiAlxMn2—xO4 were investigated by X-ray diffraction and scanning electron microscopy (SEM). The results indicate that all samples show spinel phase. The polyhedral particles turn to club-shaped, then change to small spherical, and finally become agglomerates with increasing Al content. The supercapacitive performances of LiAlxMn2—xO4 were studied by means of galvanostatic charge-discharge, cyclic voltammetry, and alternating current (AC) impedance in 2 mol·L−1 (NH4)2SO4 aqueous solution. The results show that LiAlxMn2—xO4 represents rectangular shape performance in the potential range of 0-1 V. The capacity and cycle performance can be improved by doping Al. The composition of x=0.1 has the maximum special capacitance of 160 F·g−1, which is 1.37 times that of LiMn2O4 electrode. The capacitance loss of LiAlxMn2—xO4 with x=0.1 is only about 14% after 100 cycles. 相似文献
15.
Structure and electrochemical properties of LiLaxMn2-xO4 cathode material by the ultrasonic-assisted sol-gel method
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Powders of spinel LiLaxMn2—xO4 were successfully synthesized by the ultrasonic-assisted sol-gel (UASG) method. The structure and properties of LiLaxMn2—xO4 were examined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electronic microscopy (SEM), galvanostatic charge-discharge test, and cyclic voltammetry (CV). XRD results show that the La3+ can partially replace Mn3+ in the spinel and the doped materials with La3+ have a larger lattice constant compared with pristine LiMn2O4. FT-IR indicates that the absorption peak of Mn3+−O and Mn4+− O bonds has a red and blue shift with the increase of doping lanthanum in LiLaxMn2—xO4, respectively. The charge-discharge test exhibits that the initial discharge capacity of LiLaxMn2—xO4 drops off, and the capacity retention increases gradually at C/5 discharge rate with the increase of doping lanthanum, and LiLa0.01Mn1.99O4 has a higher discharge capacity and a better cycling performance at 1C discharge rate. CV reveals that the doping La3+ is beneficial to the reversible extraction and intercalation of Li+ ions. 相似文献
16.
S31603不锈钢具有优异的耐腐蚀性能,广泛应用于化工、沿海设施等领域。在使用过程中,长期经历内部应力、苛刻环境的腐蚀作用。其中,水溶液中的离子对S31603不锈钢的耐腐蚀性能有着重要影响。通过分析锈蚀S31603不锈钢的微观形貌、元素组成及化学状态等,研究非金属离子对其表面锈蚀的影响。结果表明,NO3−、NO2−、SO42−对S31603不锈钢锈蚀起关键作用,Cl-起辅助作用,且锈蚀主要发生在S31603不锈钢与水溶液长期接触的界面。通过对锈蚀表面进行物质鉴定,发现锈蚀表面含有Fe2(SO4)3、FeSO4、CrO2等多种化合物。 相似文献
17.
《自然科学进展(英文版)》2022,32(6):769-775
Zinc-air batteries (ZABs) have the advantages of high energy density and safety but their large-scale application is hindered by sluggish kinetics of four-electron aqueous O2 redox reactions. Widely used Ruthenium (Ru)-based catalysts possess intrinsic oxygen evolution catalytic activity but suffer from insufficient oxygen reduction reaction (ORR) performance. Herein, to optimize the ORR activity of Ru-based catalyst, an iron (Fe)-coordinated, bimetallic RuFe cluster is constructed and homogeneously dispersed within nitrogen (N)-doped carbon layers (denoted as RuFe@NC). Benefitting from the optimized ORR activity and more active site exposure, the RuFe@NC exhibits superior ORR activity with a half wave potential (E1/2) of 0.88 ?V higher than that of Pt/C (0.82 ?V). Accordingly, the RuFe@NC-based ZAB outperforms the Pt/C ?+ ?IrO2-based device, presenting a reduced polarization of 0.7 ?V and an enhanced cycling lifetime of 50 ?h at 10 ?mA ?cm?2. Moreover, the optimized structural design ultralow Ru loading (0.013 mgRu cm?2) overcomes the cost barriers and demonstrates its high practicality. This bimetallic RuFe nanocluster opens a new way for future design of more efficient and stable catalytic systems. 相似文献
18.
The present work investigated microbial leaching of zinc from ore using Acidithiobacillus ferrooxidans (ATCC 14859). The ore samples, consisted of 13wt% zinc, were obtained from a gold mine in north-eastern Thailand. A shake flask study was performed on the ore samples using a rotary shaker under the following fixed conditions (250 r·min−1, 30°C for 16 d). The influence of various conditions, namely medium type (with and without iron), particle ore size (<20, 20-40, 40-60, 60-100, and >100 mesh), ore density (20 kg·m−3, 50 kg·m−3, and 100 kg·m−3), and pH of the medium (2, 2.5, 2.8, and 3), were investigated. The microbial leaching was assessed by determining the concentration of zinc in the medium and compared with the initial sample concentration. The results show that Acidithiobacillus ferrooxidans can successfully leach zinc by as much as 6 times compared with the control experiment (without Acidithiobacillus ferrooxidans ferrooxidans). The maximum efficiency (92.3%) for microbial leaching is obtained in iron-containing medium, 20-40 mesh ore sizes, 20 kg·m−3 ore density at pH 2.8, and the zinc content is found in the medium at about 120 mg·L−1. 相似文献
19.
The effect of pH on the conformation of surface alkyl groups and the structure of interfacial water molecules on poly[2-(dime-thylamino)ethyl methacrylate](PDEM) at the air/water interface were investigated with sum frequency generation vibrational spectroscopy(SFG-VS).At pH 4.1,the hydrogen bonding SFG spectra were similar to that of the air/pure water interface.As the pH increased from 5.4 to 9.6,the SFG intensities of both highly ordered hydrogen bonding(3200 cm-1 band) and less-ordered hydrogen bonding(3400 cm-1 band) were enhanced because of the charge-induced effect of deprotonated PDEM.The free OH peak disappeared completely because it was replaced by interfacial PDEM molecules.At pH 11.5,a new spectral band appeared at about 3580 cm-1 in the ppp and sps spectra,and this could be assigned to the C2v asymmetric stretching mode of the water molecules through molecular symmetry simulation.These hydrogen bonding structures are fully consistent with the conformational change of PDEM alkyl groups,and PDEM molecules act as a Hofmeister solvent.PDEM molecules are kosmotropic when they are charged and become more chaotropic as the pH increases. 相似文献
20.
The Rb(NTO)·H2O crystal has been synthesized by reaction of 3-nitro-1,2,4-triazole-5-one (NTO) with Rb2CO3 in aqueous solution. Its crystal structure has been determined. The crystal belongs to monoclinic system. Crystal structure data: space group P21 / n; a = 0.633 0(1), b = 0.824 1(2), c =1.296 4(3) nm; β= 97.90(1)°; V = 0.669 9 (2) nm3 , Z = 4, Dc = 2.306 g/cm3, μ= 7.365 nm-1, F (000) = 448. An eight coordinated compound is formed between Rb+ with oxygen atoms and nitrogen atoms. A layer structure is formed by coordination bonds and hydrogen bonds. The thermal decomposition mechanism of this coordination compound is discussed . 相似文献