在Q235钢表面原位生长的氧化铁膜对其在含Cl-溶液中腐蚀行为的影响Ⅰ-原位生长的γ-FeOOH膜的防护性能

    利用动电位极化曲线和交流阻抗谱等电化学测量技术,研究了Q235钢表面原位生长的γ- FeOOH膜在0.25 mol/L Na₂SO₄+10^-4mol/L NaCl、0.25 mol/L Na₂SO₄+10-3mol/L NaCl、0.25 mol/L Na₂SO₄+10^-2 mol/L NaCl水溶液中的电化学行为及在不同浓度的Cl^-水溶液中γ-FeOOH膜对Q235钢的保护作用.结果表明,Cl^-含量较低时,γ-FeOOH膜的存在明显地促进了Q235钢的阴极反应,该膜对基材无保护作用;随Cl-浓度的增加,阴极电流密度大幅减小,当Cl^-浓度达到10^-2 mol/L时,γ-FeOOH 膜能在一定程度上抑制基材的腐蚀,此时γ-FeOOH膜表现出对基材有保护作用.     

磷-硫-钒-水体系酸性溶液中钒的提取热力学分析

针对含钒酸浸液中钒的有效提取问题，研究了298 K时磷-硫-钒-水溶液酸性体系中钒的提取热力学分析过程。结果表明，在 P(V)-V(V)-H₂O酸性溶液体系中，pH=1~4时VO₂⁺首先转变为磷钒杂多酸阴离子，pH=4~7时磷钒杂多酸阴离子转变为同多酸阴离子；在S(VI)-V(V)-H₂O酸性溶液体系中，pH=0~1时钒主要以VO₂⁺和 VO₂SO₄^-形式存在，pH=2~6时钒逐渐转变为同多酸阴离子；在P(V)-S(VI)-V(V)-H₂O酸性溶液体系中，pH=1~3 时VO₂⁺和 VO₂SO₄^-逐渐转变为磷钒杂多酸阴离子，当pΗ=2时ΣPV₁₄（所有磷钒杂多酸阴离子之和）的摩尔分数最大为88.55%；pH=4~6 时，磷钒杂多酸阴离子消失并逐渐转变为同多酸阴离子，当pΗ=5时ΣV₁₀（所有同多酸阴离子之和）的摩尔分数最大为100.00%。     

喷丸处理对45钢表面Al+注入层抗高温氧化性的影响

为改善45钢的抗高温氧化性能，在其表面制备单一Al⁺注入层和喷丸+Al⁺注入层。检测表征改性层的表面粗糙度、显微硬度、微观形貌、以及铝元素含量，并进行600℃、200 h下的抗高温氧化性能试验。研究结果表明：喷丸处理45钢表面呈现出凹坑、丘陵状、具有近似等轴状纳米晶结构，Al⁺注入使纳米晶进一步细化。喷丸处理使45钢的表面粗糙度Ra从0.42 μm增至1.15 μm，显微硬度、注入铝元素含量及氧化增重分别从单一Al⁺注入层的257 HV_0.05增至喷丸+Al⁺注入层的最高505 HV_0.05，从3.7%增至4.2%和从14.8 mg·cm^-2降至8.3 mg·cm^-2。即喷丸处理有效增强了45钢表面Al⁺注入层的抗高温氧化性能。     

油田采出水模拟溶液中咪唑啉类缓蚀剂残余浓度检测技术

目的 确立一种用于油田采出水中咪唑啉类缓蚀剂残余浓度检测的技术方法。方法 采用紫外–可见分光光度法测量了咪唑啉类缓蚀剂的紫外吸收光谱和吸光度,研究了油田采出水模拟溶液中矿化度、pH值及Fe³⁺等对缓蚀剂吸光度的影响,分析了不同因素影响下缓蚀剂浓度与吸光度之间的相关性。结果 采出水矿化度的变化及Na⁺、K⁺、Ca²⁺、Mg²⁺、Cl^?、SO4^2?、HCO3^?等离子的存在对缓蚀剂的吸光度值影响很小,对缓蚀剂浓度检测的影响轻微。然而,采出水中可能存在的悬浮物对缓蚀剂吸光度的测量具有显著影响,检测之前需要对采出水进行过滤处理。在碱性环境中pH值的变化(7~11)对缓蚀剂的吸光度基本无影响,而在酸性介质中pH值的变化(2.5~7)导致缓蚀剂的吸光度在–0.02~0.02范围内波动,引起的缓蚀剂浓度检测误差约为±5 mg/L。采出水中可能存在的Fe³⁺对缓蚀剂吸光度的测量影响很大,在缓蚀剂浓度检测过程中需要消除Fe³⁺对吸光度测量的干扰。结论 提出了油田采出水中咪唑啉类缓蚀剂残余浓度检测技术方案:取缓蚀剂样品配制至少2种浓度的缓蚀剂溶液,测定特征吸收峰波长λ和吸光度A,确定缓蚀剂浓度与吸光度的关系式A=kC;取未知浓度缓蚀剂采出水样;过滤处理;采用紫外–可见分光光度法在波长λ处测量水样吸光度A;Fe³⁺检测及浓度 测定;不含Fe³⁺时,依据CR=A/k计算缓蚀剂残余浓度CR,含有Fe³⁺时,依据 计算缓蚀剂残余浓度CR。     

纳米锑掺杂对回流焊Sn-3.0Ag-0.5Cu-xSb焊点界面IMC生长的影响机理

研究了纳米锑掺杂对回流焊过程中Sn-3.0Ag-0.5Cu-xSb(x=0,0.2%,1.0%和2.0%)焊点界面金属间化合物(IMC)生长动力学的影响.借助扫描电镜(SEM)观察了焊点的微观结构,利用X射线能谱分析(EDX)及X射线衍射谱仪(XRD)确定了IMC的相和成分.结果表明,部分纳米锑颗粒溶解在富锡相中形成SnSb二元相,部分纳米锑颗粒溶解在Ag₃Sn相中形成Ag₃Sb相,剩余部分沉降在界面Cu₆Sn₅金属间化合物层表面.随着纳米锑含量的增加,IMC厚度减小.当纳米锑的含量为1.0%时,IMC厚度最小.通过曲线拟合,确定出界面IMC层生长指数和扩散系数.结果表明,IMC层生长指数和扩散系数均随着纳米锑含量的增加而减小.当纳米锑的含量为1.0%,IMC层生长指数和扩散系数均有最小值,分别为0.326和10.31×10^-10 cm²/s.由热力学相图和吸附理论可知,Sn,Sb元素之间易形成SnSb化合物,引起Sn元素的活性、Cu-Sn金属间化合物形成的驱动力和界面自由能下降,从而导致Cu₆Sn₅金属间化合物生长速率下降,抑制IMC生长.     

用苦瓜提取液还原制备纳米银的研究

分别以中国种和印度种苦瓜的提取液为还原剂、硝酸银为前驱体制备纳米银颗粒，并采用紫外可见光谱(UV-Vis)、红外光谱(FTIR)、X射线衍射(XRD)、和透射电镜(TEM)进行表征。结果表明，当硝酸银浓度为10 mmol/L时，制备得到平均粒径最小为8.72和7.46 nm的球形纳米银颗粒。制备反应机理为类黄酮作为还原剂，通过失去H⁺由烯醇结构变为醌型结构来还原Ag⁺获得Ag⁰，蛋白质及其它三萜类化合物起保护剂作用。苦瓜提取液种类对纳米银的粒径、形貌、分散性及均匀性等总体影响不大。     

氨基功能化CoFe2O4-SiO2 磁性复合材料的制备及其在去除水中重金属离子的吸附性能

钴-铁氧体纳米粒子(CoFe₂O₄ NPs)通过改良的共沉淀法制备,CoFe₂O₄-SiO₂磁性复合材料通过st?ber法合成,为了吸附重金属离子CoFe₂O₄-SiO₂进行了氨基功能化。这种吸附剂的晶体结构、形貌、颗粒尺寸、化学组成和分子结构采用X射线衍射图谱(XRD)、扫描电子显微镜(SEM)以及傅里叶变换红外光谱(FTIR)进行表征。此复合材料具有优良的磁性能,由于其高的饱和磁化强度,磁铁可以将其在30秒内快速分离。同时,CoFe₂O₄ NPs的磁性能可以通过烧结温度进行调节,随烧结温度提高,磁性能增强。溶液的pH及反应时间对重金属离子吸附的影响进行了研究,此外此吸附剂对Cu (II)、Cd (II)、Mn (II) 和Zn (II)具有较高的吸附容量和去除率,这一结果使此复合材料可以潜在应用于废水中重金属离子的吸附上。     

自模板法合成银纳米碗

采用自模板法合成了碗状银纳米材料,研究了银纳米碗的结构和生长机理。结果表明：AgNO₃和NaOH反应生成Ag₂O纳米簇,然后加入还原剂甲醛,在Ag₂O模板表面形成Ag纳米壳,副产物CO₂则在Ag壳内聚集。随着反应的进行,不断增大的压力最终击穿Ag壳,形成了直径约为200 nm的Ag纳米碗。该方法为特殊结构贵金属纳米材料的研究提供了理论和实验基础。     

纳米Fe3O4负载啤酒酵母菌对铀的吸附性能与机理

以纳米Fe3O4磁性微粒负载啤酒酵母菌,制备一种新型铀吸附剂,考察其吸附铀的主要影响因素,即溶液pH值、铀初始浓度、吸附剂投加量及其粒度,分析吸附过程的反应动力学和等温吸附规律,并用扫描电镜和能谱仪分析吸附机理。结果表明:纳米Fe3O4负载啤酒酵母菌(NFSC)吸附铀的最佳条件是pH值为7.0,铀初始浓度为60 mg/L,NFSC加入量为50 mg,NFSC的最佳粒径为12 nm。NFSC对铀的吸附动力学较好地符合准二级动力学模型,相关系数为0.999 6;吸附等温线均能符合Langmuir和Freundlich等温线模型,说明该吸附体系是一个单层覆盖与多层吸附相结合的模式。扫描电镜和能谱图表明:NFSC吸附铀后表面形态发生变化,且吸附过程中共存物理吸附和化学吸附,属于混合吸附类型。     

Ti/Co3O4/RuO2-IrO2纳米结构阳极电催化析氧研究

目的 研发含纳米结构Co3O4中间层的Ti/Co3O4/RuO2-IrO2阳极,并对其电化学析氧性能进行研究,以提升Ti/RuO2-IrO2金属氧化物阳极的电化学析氧性能。方法 在Ti基底上电沉积制备Co(OH)2,烧结形成Co3O4纳米片结构,随后采用热分解工艺在Ti/Co3O4表面制备RuO2-IrO2电催化层,从而构建了Ti/Co3O4/ RuO2-IrO2复合阳极。使用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X-射线衍射仪(XRD)和电化学工作站对涂层的微观表面形貌、物相组成、电化学性能等进行观察与分析。结果 SEM显示出Ti/Co3O4纳米片上RuO2-IrO2的负载量随涂刷次数增加逐渐增多,最终完全遮盖Co3O4纳米片中间层。且随着RuO2- IrO2前驱体溶液涂覆次数的增加,XRD观察到RuO2-IrO2衍射峰强度在逐渐增大。TEM测试显示Co3O4中间层是由纳米颗粒堆叠组成且具有多孔结构。电化学极化曲线测试表明,涂覆三次RuO2-IrO2层的含Co3O4中间层阳极析氧电位最低,当电流密度达到10 mA/cm²时,析氧电位仅为1.326 V(vs. SCE),低于无中间层的Ti/RuO2-IrO2阳极(1.413 V)。循环伏安测试表明,Ti/Co3O4/RuO2-IrO2阳极的伏安电量达到62.83 mC/cm²,相较于Ti/RuO2-IrO2阳极的23.65 mC/cm²提高了166%。稳定性能试验表明,在经过1 000次循环稳定性试验后,加入Co3O4纳米片中间层的复合阳极的伏安电量降低了35.94%,低于无中间层阳极48.88%的伏安电量损耗率。循环极化试验后的Ti/Co3O4/RuO2-IrO2复合阳极的电化学活性仍明显优于循环极化试验前的Ti/RuO2-IrO2阳极。结论 Co3O4纳米片中间层的加入使得Ti/Co3O4/RuO2-IrO2阳极的电催化析氧性能和稳定性都得到了提升。     

Ida~（2-）-H_2O体系浸出低品位氧化锌矿

采用Ida2--H2O体系（亚氨二乙酸盐水溶液）处理高碱性脉石型低品位氧化锌矿,考察浸出时间、液固比、配体总浓度、温度及pH值对矿物中主金属Zn及杂质元素Ca、Mg、Cu、Ni、Fe、Pb、Cd的溶出影响。结果表明：在弱碱性Ida2--H2O体系中,Ca、Mg、Fe不会被大量溶出,有价金属Cu、Ni、Pb、Cd可部分随主金属Zn溶出而进入浸出液;在浸出时间4h、液固比5：1、配体总浓度0.9mol/L、温度70℃、pH8的优化条件下,锌浸出率为76.6%。     

Fabrication of Ag/polypyrrole coaxial nanocables through common ions adsorption effect

According to the common ions adsorption effect, Ag⁺ ions will be adsorbed onto the closest surface of silver nanowires after being immersed in AgNO₃ solution. This makes the surface of silver nanowires become the active sites to oxidize pyrrole monomer to form PPy sheath without adding other oxidizing agent. The results of FT-IR and UV–vis spectra show the formation of PPy chain when pyrrole monomer was added to the reaction mixture containing the disposed silver nanowires. TEM images further prove that the Ag/polypyrrole (PPy) coaxial nanocables have been fabricated. The thickness of PPy sheath can be controlled by adjusting the concentration of AgNO₃ aqueous solution, which used to dispose silver nanowires. To some extent, the thickness of PPy layer would increase with the increasing of the concentration of AgNO₃ solution. After the adsorbed Ag⁺ ions on the surface of silver nanowires reach to the saturation, the thickness of PPy layer would not change greatly with continuously increasing of AgNO₃ concentration.     

Synthesis of nanoscale zero-valent iron supported on exfoliated graphite for removal of nitrate

Nano ZVI particles supported on micro-scale exfoliated graphite were prepared by using KBH₄ as reducing agent in the H₂O/ethanol system. The supported ZVI materials generally have higher activity and greater flexibility for environmental remediation applications. The exfoliated graphite as the support was treated beforehand to hydrophilic material. Nano iron particles are deposited onto the rough graphite surface while those were formed by borohydride reduction. The possible nitrate reduction pathways were proposed. The TEM image shows that iron particles are highly dispersed on the surface of graphite and several of iron particles are imbedded in the pit of support surface. In this synthesis, iron particles have a nearly spherical shape with a grain size of 50–100 nm. The surface areas of materials with different iron loadings of 3.5%, 7.0%, 10.0%, 15.0% and 20.0%(mass fraction) are 2.89, 9.55, 8.45, 23.8 and 6.18 m²·g⁻¹ by BET surface analyzer. The chemical reduction of nitrate by supported nano ZVI in aqueous solution were tested in series batch experiments. Experiment results suggest that NO₃⁻ can be more rapidly reduced to NH₄⁺ at neutral pH and anaerobic conditions by supported nano ZVI than unsupported nano ZVI or ZVI scraps. The 15% nano Fe/graphite shows the best reduction efficiency contrasted with other Fe loading particles.     

A sorbent of expanded rice husk powder for removal of uranyl ion from aqueous solution

A novel sorbent for the removal of uranyl ion was prepared by expanded rice husk powder. Batch adsorption experiments were performed on factors of p H,temperature, initial uranyl ion concentration, adsorbent dosage and contact time to evaluate the adsorption capacity. The results show that the saturation adsorption capacity is 5.7 mgág~(-1) using expanded rice husk powder treating uranyl ion aqueous solution(80 mgáL~(-1)) for 24 h at 25 °C with initial pH3. Adsorption process could be well described by Langmuir isotherm model. The adsorption kinetic data are fitted well with pseudo-second-order model. The results obtained show that expanded rice husk adsorbent is a promising adsorbent for the removal of uranium from aqueous solutions.     

Preparation and characterization of visible light-driven AgCl/PPy photocatalyst

Visible light photoactive AgCl/polypyrrole (PPy) composites were prepared via the reaction between excessive Ag⁺ and Cl⁻ ions in the presence of PPy_. The AgCl/PPy composites were systematically characterized using Fourier transform infrared (FTIR) spectroscopy, Raman spectra, X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and Thermal gravity analysis (TGA). It was found that face-centered cubic AgCl nanocrystallite and 0.2 wt% PPy component existed in the composite and spherical AgCl/PPy nanoparticles were in the range of 200-600 nm. The AgCl/PPy composites showed higher visible light-driven photocatalytic activity and stability than that of AgCl. A photoreduction mechanism was postulated for AgCl/PPy photocatalyst on dye methyl orange (MO). The used AgCl/PPy photocatalyst was facilely regenerated by an oxidation process in aqueous FeCl₃ solution.     

Synthesis and photoactivity of the highly efficient Ag species/TiO2 nanoflakes photocatalysts

Ag species/TiO₂ nanoflakes photocatalysts with different relative contents (Ag⁺, Ag²⁺, Ag⁰) have been successfully synthesized by a simple template-free synthetic strategy. X-ray photoelectron spectroscopy, X-ray diffraction, and UV-vis diffuse reflectance spectra indicated that the dopant ions (Ag⁺ or Ag²⁺) were partly incorporated into the titanium dioxide nanoflakes. Meanwhile, part of the silver ions migrated to the surface after the subsequent calcination and aggregated into ultra-small metallic Ag nanoclusters (NCs) (1-2 nm), which are well dispersed on the surface of TiO₂ nanoflakes. The photocatalytic activities of the Ag species/TiO₂ materials obtained were evaluated by testing the photodegradation of the azo dye reactive brilliant X-3B (X-3B) under near UV irradiation. Interestingly, it was found that the maximum photocatalytic efficiency was observed when Ag species coexisted in three valence states (Ag⁺, Ag²⁺, Ag⁰ NCs), which was higher than that of Degussa P25. The high photocatalytic activity of the Ag species/TiO₂ can be attributed to the synergy effect of the three Ag species.     

Effect of solution temperature and ph on adsorption and density of surface charge at aluminum oxyhydroxide /NaF aqueous solution interface

The effect of temperature, pH, and adsorbed fluorine on the density of a surface charge at the aluminum oxyhydroxide /NaF aqueous solution interface is investigated using the method of potentiometric titration. The equilibrium of fluorine ion adsorption in analyzed. Products of electrochemical dimensional machining (ECDM) of an AMG-6 aluminum alloy thermally treated at 200°C are used as an adsorbent. The experiments on the adsorption have been carried out from an acetated buffer with the initial fluorine solution concentrations from 1.0 × 10⁻³ to 1.5 × 10⁻¹ M/l. The adsorption isotherms were plotted for solution temperatures of 20, 30, and 40°C. Adsorption is shown to obey the Langmuir adsorption model. It is demonstrated that, at all solution temperatures, the pH is 5 for the maximal fluorine adsorption on aluminum oxyhydroxide. It has been revealed that the surface charge at the aluminum oxyhydroxide /NaF aqueous solution interface depends on the solution temperature; i.e., the pH of a point of a zero charge point (pH_PZC) of the aluminum oxyhydroxide surface decreases with an increase in temperature. As is the case with temperature, adsorbed fluorine shifts pH_PZC toward smaller values, which is typical for specific adsorption. The temperature dependence of pH_PZC has made it possible to determine the standard mole enthalpy and entropy of surface-charge formation. The interaction of fluorine with aluminum oxyhydroxide is shown to be the result of the chemical affinity of F with surface centers of AlOH₂ ⁺ and AlOH and electrostatic attraction.     

Composition and morphology of complicated copper oxalate powder

In Cu(Ⅱ)-C2O42--NH3-NH4+-H2O system, complicated copper oxalate powders were synthesized by coordination-precipitation process with ammonium oxalate as precipitating agent. The composition and morphology of the powders were characterized by chemical analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR), and thermogravimetric and differential thermal analysis (TGA-DTA). The effects of temperature, copper ion concentration and pH value were investigated. The experimental results show that pure copper oxalate hydrate is prepared below a critical pH value of 6.0, whereas the powder turns to be a complicated copper salt combined with NH3 over the pH value. Probable chemical formula, CuC2O4·x(NH3) ·yH2O can be assumed, where x and y relate to experimental conditions. Technological parameters, such as temperature, initial copper concentration and solution pH value, have significant effects on particle size, morphology and dispersion of the powders. Powders with various morphologies, pie shape, spindle shape and rod shape, can be synthesized under certain technological conditions.     

Recovery of gold(III) ions by a chitosancoated magnetic nano-adsorbent

The monodisperse chitosan-coated Fe₃O₄ nanoparticles with a mean diameter of 13.5 nm and 4.92 wt% chitosan were used as an anionic magnetic nano-adsorbent for the recovery of Au(III) ions from aqueous solutions. It was found that Au(III) ions could be fast and efficiently adsorbed, and the adsorption capacity increased with the decrease in pH due to the protonation of the amino groups of chitosan. The adsorption data obeyed the Langmuir equation with a maximum adsorption capacity of 59.52 mg/g (1210 mg/g based on the weight of chitosan) and a Langmuir adsorption equilibrium constant of 0.066 l/mg. From the studies on the adsorption kinetics and thermodynamics of Au(III) ions, it was found that the adsorption process obeyed the pseudo-second-order kinetic model. Furthermore, the time required to reach the equilibrium was significantly shorter than those using the micro-sized adsorbents due to the large available surface area.     

通过水性还原法用NaBH4制备纳米铜颗粒过程中反应参数对制备过程的影响（英文）

通过水溶液还原法制备纳米铜颗粒,研究了不同反应条件对制备纳米铜的影响。制备纳米铜的最优条件是:当溶液 pH为12、温度为 313K、1%的明胶作为分散剂时,将0.4mol/L NaBH4加入含有 1.2mol/L 氨水的0.2mol/L CuSO4溶液中。此外,进行了一系列实验来模拟反应进程。结果表明,氨水能改变反应进程。当溶液 pH为10时,氨水将Cu2+转化为铜氨络合物,然后被 NaBH4还原为铜颗粒。当溶液pH为12时,氨水将Cu2+转化为氢氧化铜,然后被 NaBH4还原为铜颗粒。