葡萄糖酸钠和苯甲酸钠体系与锌盐、镧盐对Z30铸铁片的缓蚀协同研究

采用失重法研究了复配葡萄糖酸钠、苯甲酸钠与硫酸锌、硝酸镧可溶性盐在pH值为6.5的3.5%NaCl溶液中对Z30铸铁片的缓蚀效应.结果表明当葡萄糖酸钠、苯甲酸钠的浓度均为250 mg/L,Zn2+浓度分别为2 mmol/L与3 mmol/L时,缓蚀率高达92.5%与95.3%,而加入La3+浓度为0.5 mmol/L时,缓蚀率可达86.7%.     

糖基季铵盐双子表面活性剂的缓蚀性能

由葡萄糖和十四烷基二甲基叔胺合成的糖基季铵盐双子表面活性剂(C14-GDQ)作为缓蚀剂,用静态失重法研究了该表面活性剂在1 mol/L盐酸溶液中对Q235钢的缓蚀作用。结果表明,在1 mol/L盐酸溶液中C14-GDQ对Q235钢具有良好的缓蚀作用,缓蚀率随缓蚀剂浓度的增加而增大,当缓蚀剂质量浓度达到0.1mmol/L时缓蚀率趋于稳定。通过吸附理论、动力学和热力学公式得到相应的参数,并讨论了缓蚀作用机理。     

季铵盐双子表面活性剂的缓蚀性能研究

采用自制的季铵盐双子表面活性剂1,6-二(癸烷基吗啉)己烷(HDMB)作为缓蚀剂,用失重及极化曲线研究了该表面活性剂在1 mol/L盐酸溶液中对Q235钢的缓蚀效果.失重结果表明:在1 mol/L盐酸溶液中HDMB对Q235钢具有良好的缓蚀作用,缓蚀率随缓蚀剂浓度的增加而增大,当浓度达到0.1 mmol/L时,缓蚀率趋于稳定.通过吸附理论、动力学和热力学公式得到相应的参数,并讨论了缓蚀作用机理;极化曲线法表明:HDMB为混合抑制型缓蚀剂.     

反萃更新中空纤维液膜对四价铈的回收提取研究

研究了Ce4+在以2-(二乙基己基)磷酸(P204)为流动载体,煤油和P204的混合溶液作为膜溶液,膜溶液和解析剂H2SO4溶液组成更新相的反萃更新中空纤维液膜(SRHFLM)中的提取行为;考察了料液酸度、更新相H2SO4浓度、膜溶液与H2SO4溶液体积比、不同载体浓度对Ce4+提取的影响,得出了以下Ce4+最优提取条件:更新相H2SO4溶液浓度2.50mol/L,膜溶液与H2SO4溶液体积比2:1,载体浓度控制在0.200mol/L,料液相酸度为0.05mol/L。在最优分离条件下,当Ce4+的初始浓度为1.00?10-4mol/L时,Ce4+在45min时提取率达到92.2%。最后提出了Ce4+在SRHFLM中的学渗透系数动力学模型。     

一种苯胺类席夫碱对N80钢在盐酸介质中的缓蚀性能

合成了一种席夫碱:4-氯-N-[(吡啶-4基)-亚甲基]苯胺(CNP),并采用失重法、电化学阻抗谱和动电位极化曲线等,研究了CNP对N80钢在1mol/L HCl溶液中的缓蚀性能。结果表明,在1mol/L HCl溶液中,当缓蚀剂摩尔浓度为1.0mmol/L时,缓蚀率达到86.17%。其在N80钢表面吸附满足Langmuir吸附等温式,是一种混合型缓蚀剂。     

2-氨基苯并咪唑及其衍生物在0.5mol/L硫酸中对碳钢的缓蚀性能

采用静态失重法和电化学技术等研究了2-氨基苯并咪唑(ABT)及2-正己氨基-4-(3′-N,N-二甲氨基-丙基)氨基-6-(苯并咪唑-2-基)氨基-1,3,5-均三嗪(BACT)在0.5mol/L硫酸溶液中对45号碳钢的缓蚀性能。结果表明:在0.5mol/L硫酸溶液中,BACT比ABT具有更好的缓蚀作用。当缓蚀剂浓度为0.20mmol/L时,BACT对碳钢的缓蚀率可达86.07%,而ABT对碳钢的缓蚀率仅为42.13%。通过表面张力仪研究了BACT和ABT在0.5mol/L硫酸溶液中的表面活性。通过量子化学计算和分子动力学模拟方法研究了缓蚀剂在金属Fe界面上的吸附作用。结果表明:BACT的吸附作用明显高于ABT的;BACT分子结构中亲水基、疏水基和三嗪环的引入提高了其在碳钢表面的吸附成膜作用,从而提高了缓蚀剂的缓蚀性能。     

从低冰镍中高效浸提Ni、Cu、Co

以低冰镍为研究对象,采用FeCl_3-HCl溶液体系高效浸提目标金属Ni、Cu、Co,系统地研究FeCl_3溶液的浓度、盐酸溶液的浓度、浸出温度和时间对Ni、Cu、Co浸出率的影响,并对Ni的浸出动力学进行探讨。结果表明:在最优浸出条件下,即FeCl_3溶液的浓度为1.0 mol/L、盐酸溶液的浓度为0.5 mol/L、浸出温度90℃、浸出时间7 h时,Ni、Cu、Co浸出率分别达到98.4%、98.9%和97.3%。当温度为60~90℃时,Ni的浸出反应符合未反应核收缩模型,代入动力学方程分析后发现,Ni浸出反应过程是界面化学反应控速,表观活化能为38.4kJ/mol。     

2-吡啶甲醛缩4-苯基氨基硫脲席夫碱在盐酸溶液中对Q235钢的缓蚀作用

合成了一种吡啶席夫碱衍生物,2-吡啶甲醛缩4-苯基氨基硫脲席夫碱(PCPTC),并采用失重法、电化学阻抗谱法和极化曲线法研究了PCPTC对Q235钢在1 mol/L HCl溶液的缓蚀作用。结果表明:PCPTC对Q235钢在1mol/L HCl溶液中具有优良的缓蚀效果,是一种混合型缓蚀剂;当缓蚀剂浓度达到0.5 mmol/L时,缓蚀率达到93.6%;PCPTC在Q235钢表面的吸附符合Langmuir吸附等温式;扫描电镜(SEM)观察表明,PCPTC可以有效保护Q235钢。     

4-苯基氨基硫脲在盐酸介质中对Q235钢的缓蚀性能

目的研究4-苯基氨基硫脲(4-PTC)对Q235钢在1mol/L HCl中的缓蚀作用。方法采用异硫氰酸苯酯和水合肼为原料,合成4-PTC。采用熔点分析、核磁共振氢谱和红外光谱等方法确定合成物质为目标产物4-苯基氨基硫脲。采用静态失重法、电化学极化曲线法、电化学阻抗谱法和扫描电子显微镜法,分析研究4-PTC的缓蚀性能。结果静态失重实验表明,当4-PTC浓度增加到1.0 mmol/L时,缓蚀效率达到85.9%,在Q235钢表面吸附符合Langmuir吸附等温式,形成单分子吸附层。计算得到吉布斯自由能为?35.60 k J/mol,说明缓蚀剂分子在Q235钢表面吸附同时存在物理吸附和化学吸附过程。动电位极化曲线表明,该缓蚀剂是以阴极型为主的混合型缓蚀剂,当4-PTC浓度增加到1.0 mmol/L时,缓蚀效率达到83.6%。电化学阻抗谱表明,随4-PTC浓度的增加,电荷转移电阻值增大,双电层电容值减小,金属腐蚀速率降低,缓蚀作用增强。当4-PTC浓度增加到1.0 mmol/L时,缓蚀效率达到84.7%。扫描电子显微镜表明,缓蚀剂分子能有效保护金属表面,抑制腐蚀。结论在盐酸介质中,4-PTC对Q235钢具有优良的缓蚀性能。     

酸性介质中HR-2不锈钢表面活性的SECM三维图像表征研究

采用扫描电化学显微镜（SECM）,面扫描与线性扫描技术相结合,研究了HR-2不锈钢在0.5 mol/L H₂SO₄+0.1 mol/L NaCl溶液中的腐蚀行为。结果表明：HR-2不锈钢在该溶液中的开路电位、活化电位及钝化区电位分别为：-0.4 V、-0.23 V、0.0 V ~ 0.8 V,基底保持开路电位和活化电位时,探头最大电流为9.5 nA和35.2 nA,基底形成钝化膜后探头电流明显减小;当探头电位为-0.2 V时能有效氧化基底产生的H₂,0.6 V时能有效氧化基底反应产生的Fe₂₊,探头-基底间距为20 μm时,可较好地表征基底活性;当溶液中硫脲浓度为0.75 mmol/L时,有最佳的缓蚀作用。     

Impact of Ce ion on microstructure and luminescence character of Ho/Yb co-doped ZrO2 nanocrystal

By solid-state synthesis method, Ho³⁺/Yb³⁺ co-doped CeO₂-ZrO₂ nano-powders have been prepared. The concentration of Ce⁴⁺ ions has greater effect to the oxygen lattice structure. When the concentration of Ce⁴⁺ ions is 30 mol%, the oxygen lattice is a tetrahedral space group and the luminescence intensity of the sample is strongest. The results show that the lattice structure can be changed by inducting the Ce⁴⁺ ions into Ho³⁺/Yb³⁺ co-doped ZrO₂. And the emission character can be improved.     

Photoluminescence and energy transfer studies on Eu and Ce co-doped SrCaSiO4 for white light-emitting-diodes

The luminescence of SrCaSiO₄:Eu²⁺, Ce³⁺ is studied as a potential ultraviolet light-emitting diodes (UV-LEDs) phosphor that is capable of converting the ultraviolet emission of a UV-LED into green light with good luminosity. There are two emissions peaks peaking at 420 and 500 nm, respectively. The two emissions come from d-f transitions of Ce³⁺ and Eu²⁺, respectively. Effective energy transfer occurs in Ce³⁺/Eu²⁺ co-doped SrCaSiO₄ due to a part of spectral overlap between the emission of Ce³⁺ and excitation of Eu²⁺. Co-doping of Ce³⁺ enhances the emission intensity of Eu²⁺ greatly by transferring its excitation energy to Eu²⁺. The Ce³⁺/Eu²⁺ energy transfer, thoroughly investigated by the diffuse reflection emission and excitation spectra, photoluminescence decay curves, is demonstrated to be in the mechanism of electric dipole-dipole interaction.     

Photoluminescence and energy transfer of Ce and Tb doped oxyfluoride aluminosilicate glasses

The transmission and photoluminescence (PL) properties of Ce³⁺ or Tb³⁺ doped and Tb³⁺/Ce³⁺ codoped oxyfluoride aluminosilicate glasses were reported. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were applied to confirm the structure and thermal stability of samples. PL spectra revealed a bright and broad violet-blue emission derived from Ce³⁺ [5d (²D) → ²F_5/2,7/2] and an intense sharp green emission (543 nm) derived from Tb³⁺ (⁵D₄ → ⁷F₅) in the Ce³⁺ and Tb³⁺ doped glasses, respectively. Concentration quenching is not observed even the mole ratio of Tb³⁺ is up to 8% in Tb³⁺ doped glass. This indicates that the as-made host glass provides a good distribution of Tb³⁺ activators in glass matrix. For Tb³⁺/Ce³⁺ codoped glasses, a strong green emission corresponding to Tb³⁺ (⁵D₄ → ⁷F₅) and an energy transfer phenomenon from Ce³⁺ to Tb³⁺ were observed upon excitation with an UV wavelength (289 nm). It was also observed that their PL intensity depends on the concentration of Ce³⁺ when the concentration of Tb³⁺ is fixed. The mechanism involved in the energy transfer between Ce³⁺ and Tb³⁺ was explained with an energy level diagram.     

Combustion synthesis of CaSc2O4:Ce nano-phosphors in a closed system

The CaSc₂O₄:Ce³⁺ nano-phosphors were successfully prepared by a single-step combustion method at an ignition temperature as low as 200 °C in a closed autoclave using glycine as a fuel and PEG4000 as a dispersant. The samples were characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscope (TEM). The results revealed that CaSc₂O₄:Ce³⁺ nano-phosphors can be conveniently prepared at an ignition temperature as low as 200 °C, which was much lower than that in the ordinary combustion methods. The optimized ignition temperature was 220 °C. The CaSc₂O₄:Ce³⁺ nano-phosphors give a uniform particle size in the range of 15-20 nm. The low ignition temperature and the addition of PEG4000 dispersant play important roles in the formation of small sized nanoparticles. The as-prepared nano-phosphors were incompact aggregates, but highly dispersed nano-phosphors can be obtained after further ultrasonic treatment. The CaSc₂O₄:Ce³⁺ nano-phosphors give satisfactory luminescence characteristic benefiting from the closed circumstance, in which cerium atoms can be isolated from the oxidizing atmosphere and non-fluorescent Ce⁴⁺ ions can be ruled out. The present highly dispersed CaSc₂O₄:Ce³⁺ nano-phosphors with efficient fluorescence are promising in the field of biological labeling, and the present low temperature combustion method is facile and convenient and can be applied as a universal process for preparing non-aggregate oxide nano-phosphors, especially those being sensitive to air at high temperature.     

Effects of Ce<Superscript>3+</Superscript> doping on the structure and magnetic properties of Mn-Zn ferrite fibers

Ce³⁺-doped Mn-Zn ferrite fibers were successfully prepared by the organic gel-thermal decomposition method from metal salts and citric acid. The composition, structure, and magnetic properties of these ferrite fibers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). The results show that Mn_0.2Zn_0.8Fe_2−x Ce _x O₄ (x = 0–0.04) fibers are featured with an average grain size of 11.6–12.7 nm, with diameters ranging between 1.0 to 3.5 μm and a high aspect ratio (length/diameter). The Ce³⁺ ion doping has not resulted in crystal structural changes of the Mn-Zn ferrite phase and all the as-prepared ferrite fibers have a simple spinel phase structure, although this influences the morphologies of Mn_0.2Zn_0.8Fe_2−x Ce _x O₄ ferrite fibers possibly owing to the lattice distortion and internal-stress. Both the lattice constant and grain size increase slightly with the increase of the Ce³⁺ ion doping content. The soft magnetic properties of Mn-Zn ferrite fibers can be improved by a small amount of Ce³⁺ ion doping with an increase of the saturated magnetization and a decrease of the coercivity.     

Synergistic inhibition effect of rare earth cerium(IV) ion and sodium oleate on the corrosion of cold rolled steel in phosphoric acid solution

The synergistic inhibition effect of rare earth cerium(IV) ion (Ce⁴⁺) and sodium oleate (SO) on the corrosion of cold rolled steel (CRS) in 3.0 M phosphoric acid (H₃PO₄) has been investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) methods. The results reveal that SO has a moderate inhibitive effect and its adsorption obeys Temkin adsorption isotherm. Ce⁴⁺ has a poor effect. However, incorporation of Ce⁴⁺ with SO improves the inhibition performance significantly, and exhibits synergistic inhibition effect. SO acts as a cathodic inhibitor, while SO/Ce⁴⁺ mixture acts as a mixed-type inhibitor.     

Photoluminescence properties and energy-transfer of thermal-stable Ce, Mn-codoped barium strontium lithium silicate red phosphors

A series of thermal-stable Ce³⁺, Mn²⁺-codoped barium strontium lithium silicate (BSLS) phosphors was synthesized by a high-temperature solid-state reaction. The XRD patterns of this phosphor seem to be a new phase that has not been reported before. BSLS:Ce³⁺, Mn²⁺ showed two emission bands under 365 nm excitation: one observed at 421 nm was attributed to Ce³⁺ emission, and the other found in red region was assigned to Mn²⁺ emission through Ce³⁺-Mn²⁺ efficient energy transfer. The Mn²⁺ emission shifted red along with the replacement of barium by strontium, which was due to the change of crystal field. A composition-optimized phosphor, BSLS:0.10Ce³⁺, 0.05Mn²⁺ (Ba = 65), exhibited strong and broad red-emitting and supreme thermal stability. The results suggest that this phosphor is suitable as a red component for NUV LED or high pressure Hg vapor (HPMV) lamp.     

Nanocrystallization and photoluminescence of Ce/Dy/Eu-doped fluorosilicate glass ceramics

Ce³⁺-Eu²⁺-Dy³⁺-Eu³⁺-doped fluorosilicate glass ceramics containing orthorhombic CaCeOF₃ nanocrystals were prepared by annealing the precursor glass above 640 °C, along with the reduction of Eu³⁺ → Eu²⁺. Under near ultraviolet excitation, the emission bands of Eu²⁺ or Dy³⁺ were enhanced by several ten or hundred times, owing to energy transfers from Ce³⁺ to Eu²⁺ or Dy³⁺. The glass and glass ceramics emitted warm white light deriving from the blue, yellow and red emission from Eu²⁺, Dy³⁺ and Eu³⁺. Tuning the annealing temperature, the Eu²⁺/Eu³⁺ ratio and the warm white Commission Internationale de I’Eclairage (CIE) coordinates can be adjusted. Thus, the present materials can be applied on warm white high power light-emitting-diodes for indoor illumination application.