LiLu(MoO_(4))_(2):Eu^(3+)的制备及其对Fe^(3+)离子的荧光检测研究

Fe^(3+)在生命过程中扮演着重要的角色,开发一种能够快速定量检测Fe^(3+)离子的荧光探针有着重要意义。采用溶胶-凝胶法成功制备了四方相白钨矿结构的LiLu(MoO_(4))_(2):Eu^(3+)荧光粉,粒径为1~2μm;通过荧光光谱研究了所得荧光粉的光学性质,确定了Eu^(3+)的最佳发光掺杂摩尔浓度为15%。所得LiLu(MoO_(4))_(2):15%Eu^(3+)对Fe^(3+)离子的检测下限为14.4μmol/L,并且具有高选择性和抗干扰性。

B位Fe^(3+)掺杂Na_(0.5)Bi_(0.49)TiO_(3)陶瓷的电导性能

采用固相合成法制备了x=0,0.02,0.04和0.06的Na_(0.5)Bi_(0.49)Ti_(1-x)Fe_(x)O_(3-δ)(NBT)粉末材料,经压制成型并在1000~1150℃烧结制备了片状陶瓷样品。通过XRD,SEM和EIS测试研究了Fe^(3+)掺杂量x对NBT陶瓷性能的影响。结果表明,NBT材料在掺杂Fe^(3+)后出现了新相NaBiTi_(6)O_(14),且含量随x的增加而变多。材料在掺杂后的烧结温度降低了100~150℃,同时材料的晶粒变得细小。在300~700℃测试温度范围内,x=0.02,0.04和0.06的样品的电导率在相同温度下都处于同一数量级,相对于x=0的样品的电导率提升了约1000倍。x=0.04的样品具有最高的电导率,在600℃和700℃的测试温度下,电导率分别达到9.8 mS/cm和17.0 mS/cm。

多晶材料NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)的合成与性能

在未来储能市场和低速车领域,钠离子电池前景广泛,正极材料的选择很关键。采用共沉淀法并结合高温烧结制备层状氧化物NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM333),借助XRD、SEM和恒流充放电等方法,分析NFM333材料的结构、形貌和电化学性能。NFM333材料为典型的O3结构,呈现多晶特征,作为钠离子电池正极具有较高的比容量、良好的倍率性能和稳定的循环性能。材料以0.3C在2.0~4.0 V充放电,-20℃、-30℃和-40℃下的放电比容量分别为20℃下的85.55%、72.88%和45.19%。循环伏安(CV)测试发现,较好的电化学性能归因于较高的离子扩散速率和良好的离子迁移动力学。

水溶性煤基发光碳点的室温快速合成及其在Fe^(3+)离子检测中的应用

碳量子点具有优异的光学性质,良好的水溶性、低毒性、原料来源广、成本低、生物相容性好等诸多优点,广泛应用于发光器件、生物检测、能源存储与转换领域,但在实际应用中还存在合成过程复杂、产率低等挑战。本文以煤为原料,以甲酸和双氧水为氧化剂,在室温下可大量合成煤基发光碳点,考查了氧化剂的添加量、反应时间对煤基发光碳点的产率及反光性质的影响,结果表明煤基发光碳点产率高达54%,且具有良好的水溶性、光稳定性、耐盐性和较高的发光量子效率。制备的煤基发光碳点可用于Fe^(3+)离子的特异性检测,检测限低于600 nmol L^(-1)。该合成方法为煤的高附加值利用和设计开发煤基新材料提供了新途径。

A ternary phased SnO_2-Fe_2O_3/SWCNTs nanocomposite as a high performance anode material for lithium ion batteries

A new SnO2-Fe2O3/SWCNTs（single-walled carbon nanotubes） ternary nanocomposite was first synthesized by a facile hydrothermal approach.SnO2 and Fe2O3 nanoparticles（NPs） were homogeneously located on the surface of SWCNTs,as confirmed by X-ray diffraction（XRD）,transmission electron microscope（TEM） and energy dispersive X-ray spectroscopy（EDX）.Due to the synergistic effect of different components,the as synthesized SnO2-Fe2O3/SWCNTs composite as an anode material for lithium-ion batteries exhibited excellent electrochemical performance with a high capacity of 692 mAh·g-1 which could be maintained after 50 cycles at 200 mA·g-1.Even at a high rate of2000 mA·g-1,the capacity was still remained at 656 mAh·g-1.

REDUCTION OF FERRIC IRON IN THE TITANIUM SULFATE SOLUTION BY THE ION EXCHANGE MEMBRANE PRIMARY CELL METHOD

In the production process of titanium dioxide with sulfuric acid, the contamination of the titanium sulfate solution (the ilmenite leaching solution) in the Fe 3+ reduction stage by iron scraps is a practical problem because it is difficult to guarantee the quality of the iron scraps. In this research, a new method, called the ion exchange membrane primary cell method, for reduction of Fe 3+ in the titanium sulfate solution has been advanced. The positive compartment of the primary cell consists of lead (copper) electrode and the titanium sulfate solution, and the negative compartment consists of iron electrode and acidic FeSO 4 solution. The anion ion exchange membrane is used as the diaphragm between two compartments. Fe 3+ in the titanium sulfate solution is reduced by the electric discharge of the primary cell. The effects of temperature, stirring strength of the solution and membrane area on the reduction rate have been investigated. The experimental result shows that the optimum current density can be higher than 100 A/m 2.

Facile Fabrication of Fe3O4@TiO2@C Yolk–Shell Spheres as Anode Material for Lithium Ion Batteries

Transition metal oxides have been actively exploited for application in lithium ion batteries due to their facile synthesis,high specific capacity,and environmental-friendly.In this paper,Fe3O4@TiO2@C yolk-shell(Y-S)spheres,used as anode material for lithium ion batteries,were successfully fabricated by Stober method.XRD patterns reveal that Fe3O4@TiO2@C Y-S spheres possess a good crystallinity.But the diffraction peaks’intensity of Fe3O4 crystals in the composites is much weaker than that of bare Fe3O4 spheres,indicating that the outer anatase TiO2@C layer can cover up the diffraction peaks of inner Fe3O4 spheres.The yolk-shell structure of Fe3O4@TiO2@C spheres is further characterized by TEM,HAADFSTEM,and EDS mapping.The yolk-shell structure is good for improving the cycling stability of the inner Fe3O4 spheres during lithium ions insertion-extraction processes.When tested at 200 mA/g,the Fe3O4@TiO2@C Y-S spheres can provide a stable discharge capacity of 450 mAh/g over 100 cycles,which is much better than that of bare Fe3O4 spheres and TiO2@C spheres.Furthermore,cyclic voltammetry curves show that the composites have a good cycling stability compared to bare Fe3O4 spheres.

Electrochemical Sensing of Heavy Metal Ions based on Monodisperse Single-crystal Fe_3O_4 Microspheres

Single-crystal Fe_3 O_4 with monodisperse microspheres structure has been used for individual electrochemical detection of heavy metal ions. Morphology and structure of the as-prepared Fe_3 O_4 microspheres were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM) and X-ray diffraction(XRD). Meanwhile the electrochemical properties of the Fe_3 O_4 microspheres modified glass carbon electrodes(GCE) were characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS), and the enhanced electrochemical response in stripping voltammetry for individual detection of Pb(Ⅱ), Hg(Ⅱ), Cu(Ⅱ), and Cd(Ⅱ) was evaluated using square wave anodic stripping voltammetry(SWASV). With high specific surface area and excellent catalytic activity toward heavy metal ions, the as-prepared monodisperse and single-crystal Fe_3 O_4 microspheres show a preferable sensing sensitivity(22.2 μA/μM) and limit of detection(0.0699 μM) toward Pb(Ⅱ). Furthermore, the electrochemical sensor of Fe_3 O_4 microspheres exhibits excellent stability and it also offers potential practical applicability for the determination of heavy metal ions in real water samples. This study provides a potential simple and low cost iron oxide for the construction of sensitive electrochemical sensors applied to monitor and control the pollution of toxic metal ions.

Researches on the Growth Habit and Optical Properties of Fe^(3+) Ion Doped KDP Crystal

During the process of KDP crystal growth, metal ions strongly affect the growth habit and optical properties of KDP single crystal. In this paper, KDP crystals were grown from an aqueous solution doped with different concentration of Fe^3＋ dopant by traditional temperaturereduction method and ＂point-seed＂ rapid growth method. Furthermore, we examined the light scatter and measured the transmission of these KDP crystals. It is found that the dopant of Fe^3＋ ion can improve the stability of the KDP growth solution when its concentration is less than 30 ppm. The effects of Fe^3＋ ion on the growth habit and optical properties of KDP crystal are also obvious.

Photocatalytic Activity of Nanosized TiO_2 Enhanced by co-doping with Fe^(3+) and Nd^(3+) Ions

In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was evaluated by degrading methylene blue (MB) solution. The results indicated that TiO2 crystalline size was reduced and phase transformation of anatase to rutile was suppressed as the content of doped Nd3+ ion increased in the co-doped TiO2. The UV-vis spectra of co-doped TiO2 seemed to simply overlay two spectra of single metal doped TiO2, and had significantly increased absorbance in the ranges of 400～500 nm, 565～600 nm and 730～765 nm as compared to pure TiO2. The photocatalytic activity of co-doped TiO2 was obviously enhanced, and raised about 30% compared to that of pure TiO2 as doped Nd3+ content was 0.15% and Fe3+ content was 0.05%, respectively. The enhanced catalytic activity was attributed to a synergistic effect of two doped ions, where doped Fe3+ ion inhibited the recombination of photogenerated electron and hole, and Nd3+ ion brought more surface carboxyl to promote the degradation reaction.

Adsorption of Fe^(3+) Ions from Aqueous Solution by Natural and Synthetic Apatites: Kinetic, Equilibrium and Thermodynamic Study

In this study, the adsorption kinetics, equilibrium and thermodynamics of Fe3+ ions on natural (NAP) and synthetic (HAP) apaties were examined. The adsorption efficiency of Fe3+ onto the NAP and HAP was increased with increasing temperature. The kinetics of adsorption of Fe3+ ions was discussed using three kinetic models, the pseudo-first-order, the pseudo-second-order and the intra-particle diffusion model. The experimental data fitted very well the pseudo-second-order kinetic model. The initial sorption rate and the activation energy were also calculated. The activation energy of the sorption was calculated as 37.15 and 49.84 kJ·mol 1 for NAP and HAP, respectively. Experimental results were also analysed by the Langmuir, Freundlich and Dubinin–Redushkevich (D–R) isotherm equations at different temperatures. RL separation factor for Langmuir and the n value for Freundlich isotherm show that Fe3+ ions are favorably adsorbed by NAP and HAP. Various thermodynamic parameters such as enthalpy (ΔH), Gibbs free energy (ΔG) and entropy (ΔS) changes were computed and the results showed that the adsorption of Fe3+ ions onto NAP and HAP were spontaneous and endothermic in nature.

Synthesis and Characterization of a New Fe_2O_3 Pillared Triple-layered Perovskite KSr_2Nb_3O_(10)

A n-Hexyl NH 3Sr 2Nb 3O 10 is obtained by the stepwise ion-exchange reaction,then is dispersed in aqueous solution of trinuclear acetato-hydroxo iron(III) nitrate,[Fe 3(OCOCH 3) 7OH·2H 2O]NO 3,and the interlayer potassium cations of the perovskite niobate are exchanged with the partially hydrolyzed trinuclear acetato complex ions.On heating,the exchanged complex ions are converted into iron oxide pillars which keep the perovskite sheets apart.The product is characterized by XRD,SEM,EDAX and surface area measurement respectively.

过渡金属Fe^(3+)离子掺杂改性TiO_2的光催化性能研究进展

对近年来利用过渡金属Fe3+离子掺杂改性TiO2的光催化性能研究进行了综述.分析了掺杂金属Fe3+离子的电位、电子轨道构型、化合价、离子半径、浓度和掺杂制备方式对TiO2光催化性能的影响,并提出应用前景、存在问题和发展方向.通过掺杂过渡金属Fe3+离子改进TiO2光催化剂的禁带宽度,使反应的响应光谱向可见光扩展,并且有效地抑制电子-空穴的复合,提高半导体的光催化效率,通过改性可以直接利用太阳能.另外,针对掺杂机理尚不清楚、光量子效率仍然不高和回收困难的缺点.采用溶胶-凝胶法制备负载型掺杂改性纳米TiO2成为研究的热点,其中利用非耐热材料可以制成上浮型负载体,更利于回收,成为研究的新方向.

胡敏酸吸附解吸Fe^(3+)反应特征研究

采用C-25葡聚糖凝胶层析方法研究了在不同酸度、离子强度、温度条件下胡敏酸(HA)吸附解吸Fe3+特征。结果表明,在相同离子强度、反应温度条件下,随着pH的升高,HA对Fe(Ⅲ)最大吸附量Smax和吸附平衡常数k增加,标准摩尔自由能变ΔGom绝对值减小。相同pH和温度下,离子强度从0.00到0.10mol L-1,HA对Fe(Ⅲ)最大吸附量Smax和吸附亲和力常数k增加,自由能变ΔGom绝对值减小,但离子强度从0.10 mol L-1继续上升到0.15 mol L-1,则上述特征常数变化刚好相反。温度升高,胡敏酸吸附Fe3+的最大吸附量、吸附平衡常数k、自由能变ΔGom绝对值均较大幅度降低,表明升高温度对吸附反应不利。吸附反应的焓变ΔHom和熵变ΔSom均小于零,为放热反应,反应向更有序状态进行;在相同条件下,pH越大,焓变ΔHom和熵变ΔrSθm绝对值越大,表明pH越大,越有利于吸附反应的进行。随着pH的升高,Fe3+被还原的百分率η减小,用幂函数方程拟合,相关系数达到显著水平。随着pH的降低,胡敏酸铁Fe3+解吸率增大;对解吸率曲线进行拟合,线形方程具有显著的相关系数。胡敏酸吸附Fe3+的反应为包括胡敏酸内部和外部结合的“两相”反应。

Fe^(3+)掺杂Li_4Ti_5O_(12)的结构及电化学性能

采用高温固相法合成Li4FexTi5-xO12(x=0.025,0.1,0.2)负极材料。通过X射线衍射、扫描电镜、充放电性能测试等对掺杂Fe3+的Li4Ti5O12材料的组成、结构、形貌进行表征,并对其电化学性能进行研究。结果表明,所合成的材料具有良好的尖晶石结构,无杂相。适当Fe3+掺杂能细化材料,提高材料的电子导电性,使材料的循环性能得到改善。Li4Fe0.025Ti4.975O12的充电容量最佳,0.1C倍率下首次充电比容量达到162.5 mA.h/g,循环性能较好。

反相离子对高效液相色谱法分离金属配合物{Fe[3-(2-吡啶基)-5,6-二苯基-1,2,4-三嗪]_(3)}^(2+)几何异构体

采用反相离子对高效液相色谱法分离测定了金属配合物{Fe[3-(2-吡啶基)-5,6-二苯基-1,2,4-三嗪]_(3)}^(2+)([Fe(PDT)_(3)]^(2+))的两种几何异构体,研究了流动相中有机改性剂(乙腈、甲醇)的含量、不同种类和浓度的离子对试剂(高氯酸钠和十二烷基硫酸钠(SDS))对色谱分离的影响。并在不同的试验条件下,对所获得的色谱参数(保留因子(k)、分离度、选择性因子等)进行了探讨。在不同种类及浓度的离子对试剂条件下,二元流动相中乙腈的含量与两种几何异构体的lnk之间均呈显著的线性关系。研究进一步发现SDS的浓度变化对异构体的保留因子影响程度更为显著。在上述实验的基础上,引入更能灵活调节洗脱强度和分离度的三元流动相(乙腈/甲醇/水),优化选择了三元流动相中有机改性剂的比例以及离子对试剂的种类和浓度,使得异构体的色谱分离得到了满意的结果。实验结果表明,异构体的峰面积(A)和浓度(C)之间的线性关系良好,面式和经式异构体的检测限分别为4.28和3.44ng/mL(S/N=3)。

LiNbO_3：Fe^（3＋1）晶体中Fe^（3＋）离子的发射光谱研究

在１００００～４００００ｃｍ－１范围内，观测得ＬｉＮｂＯ３晶体掺Ｆｅ３＋离子的发射光谱与赵等的理论预言基本一致，从而证明了Ｆｅ３＋离子杂质在ＬｉＮｂＯ３中取代Ｎｂ５＋离子。

Fe^(3+)掺杂TiO_2玻璃薄膜太阳光催化降解H酸的研究

采用溶胶-凝胶法在玻璃表面上制备了掺杂Fe3+的TiO2薄膜,用XRD、IR对其进行表征.在太阳光的照射下,以H酸为目标物,用自制敞开连续流平板式光催化反应器,进行了光催化法降解试验.结果表明:适量Fe3+的掺杂可明显提高TiO2玻璃薄膜在太阳光下的催化性能,掺Fe3+的摩尔质量百分数为(Fe3+/TiO2)0.06%时的光催化活性最高.太阳光照射3 h,H酸脱色率达到72.5%,反应速率遵从Langmuir-Hinshelwood方程,表观速率常数K′=0.007 4 min-1.

石墨烯碳点的制备及在Fe^(3+)检测中的应用

运用水热合成方法制备出氧化石墨烯,以水和肼做还原剂,制备出石墨烯碳点,分析了时间、pH、温度、盐离子浓度对碳点的稳定性影响,探索了碳点在检测Fe^(3+)中的应用,结果表明:1.0g石墨烯,180℃、8h条件下,制得的石墨烯碳点分散性好、均匀性强,盐溶液浓度在0~2.4M、pH值3~9、温度20~80℃下,碳点的荧光强度相对比较稳定,12h内减弱率仅为14.28%;在其它金属离子存在下,制备出的碳点能够选择性地发生荧光猝灭,是一种极为有效的Fe^(3+)荧光检测剂。

基于对羟基苯甲醛的水溶性Fe^(3+)离子探针的研究

设计合成了两个具有水溶性的对羟基苯甲醛Schiff碱,其中之一含有D-氨基葡萄糖单元。化合物用元素分析和1HNMR进行了表征,并将它们作为受体应用于金属阳离子的识别。该类化合物与Fe3+离子作用,紫外光谱发生明显变化,并形成1:1的复合物,而在受体溶液中即使加入10倍量的Na+、K+、Ba2+、Ca2+、Cu2+、Zn2+、Ni2+、Cd2+、Pb2+等金属离子,也不会使光谱有明显的变化,因此能作为水溶液中Fe3+离子探针。