Photodegradation of 17α-Ethynylestradiol in Aqueous Solution with Nitzschia hantzschiana or Chlorella vulgaris and Fe^3＋

0　IntroductionTherehasbeenincreasingconcernabouttheenvironmentaleffectsofoestrogensandxenoestrogens[1 ] .17α ethynylestradiol(EE2 ) (Fig .1)isasyntheticestrogenicsteroidthathastherapeuticuses (e.g .Oralcontraception) .Syntheticestrogensaregenerallymorestableinwaterthannaturalestrogensandhavegreaterpotency.Theyaredifficulttobeabsolutelyremovedfromwastewatersbyprimaryandsecondarytreatment.Thedegradationchemistryofthiscom poundhasnotbeenextensivelystudied .Therearefewpublishedarticlesstudying…     

Photodegradation of bisphenol a induced by metal ions in aqueous solution in the presence of ascorbic acid

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.     

Relationship between climatic conditions and the relative abundance of modern C3 and C4 plants in three regions around the North Pacific

Using −24‰ and −14‰ as the endpoints of stable carbon isotopic composition of total organic carbon (δ¹³C_TOC) of surface soil under pure C₃ and C₄ vegetation, and surface soil δ¹³C_TOC 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.     

Preparation and photocatalytic properties of ilmenite NiTiO<Subscript>3</Subscript> powders for degradation of humic acid in water

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.     

Layered Fe（Ⅲ） doped TiO2 thin-film electrodes for the photoelectrocatalytic oxidation of glucose and potassium hydrogen phthalate

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.     

Microstructure and electrical conductivity of 10% Yb-doped SrCeO3 ceramics

As a candidate material for hydrogen separation, Yb-doped SrCeO₃ has attracted increasing attention in recent decades. In the present study, Yb-doped SrCe_0.9Yb_0.1O_3-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 SrCe_0.9Yb_0.1O_3-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.     

Degradation of the antibiotic sulfamonomethoxine sodium in aqueous solution by photo-Fenton oxidation

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.     

Stable isotopes of modern herbivore tooth enamel in the Tibetan Plateau: Implications for paleoelevation reconstructions

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‰...     

Magnetic properties of Fe3(1−x)Cr3xC alloys

The magnetic properties of Fe_3(1−x)Cr_3xC 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 (T_c) 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 T_c =360 K for x = 0.05 in a magnetic field change from 0 to 1 T and 0 to 5 T, respectively.     

Photocatalytic degradation pathways and adsorption modes of H-acid in TiO2 suspensions

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.     

Amphiphilic dextran/magnetite nanocomposites as magnetic resonance imaging probes

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.     

Fabrication and Photocatalytic Characteristics of TiO2 Films on Silicon Substrates

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.     

Pu(H2O)53+和Pu(H2O)54+ 团簇的相对论密度泛函研究

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.     

Preparation and characterization of LiAlxMn2-xO4 for a supercapacitor in aqueous electrolyte

LiAl_xMn_2—xO₄ (0≤x≤0.5) was synthesized by high temperature solid-state reaction. The structure and morphology of LiAl_xMn_2—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 LiAl_xMn_2—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 LiAl_xMn_2—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 LiAl_xMn_2—xO₄ with x=0.1 is only about 14% after 100 cycles.     

Structure and electrochemical properties of LiLaxMn2-xO4 cathode material by the ultrasonic-assisted sol-gel method

Powders of spinel LiLa_xMn_2—xO₄ were successfully synthesized by the ultrasonic-assisted sol-gel (UASG) method. The structure and properties of LiLa_xMn_2—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 LiLa_xMn_2—xO₄, respectively. The charge-discharge test exhibits that the initial discharge capacity of LiLa_xMn_2—xO₄ drops off, and the capacity retention increases gradually at C/5 discharge rate with the increase of doping lanthanum, and LiLa_0.01Mn_1.99O₄ 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.     

非金属离子对S31603不锈钢表面锈蚀的影响

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。     

A novel bimetallic RuFe nanocluster to enable highly efficient oxygen reduction in zinc-air batteries

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 (E_1/2) 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 mg_Ru 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.     

Bioleaching of zinc from gold ores using Acidithiobacillus ferrooxidans

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.     

Investigation of the interfacial water structure on poly[2-（dimethylamino）ethyl methacrylate] at the air/water interface by sum frequency generation vibrational spectroscopy

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.     

Synthesis, crystal structure and thermal behavior of Rb(NTO) · H2O

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, D_c = 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 .