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近年来,随着激光、微弱信号测量以及瞬态测量技术等发展,对溶液中激发态离子的化学和物理行为的研究已日益受到人们的重视,激发态铀酰离子发光衰减的研究尤为活跃.Marcantonatos 等、Formosinho 等以及郑企克、王志麟等对高氯酸溶液中激发态铀酰离子的发光衰减过程进行了详细的研究.探讨了ClO_4~-溶液中pH 等对激发态铀酰离子的发光衰减的影响,观察到了一定的pH 条件下激发态铀(Ⅵ)的非单一指数衰减,并各自提出了不同的解释.值得提出的是,上述的一系列研究都是在高氯酸溶液中,其它体系中铀(Ⅵ)的发光哀减的研究进行得很少,报导则更少.1983年Joshi 等曾研究了80K 时SO_4~(2-) 相似文献
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采用煅烧的硫酸盐掺杂的含钛高炉渣(sulfate-modified titanium-bearing blast furnace slag, STBBFS)作为光催化剂, 研究了Cr(VI)-柠檬酸[Cr(VI)-CA]复合体系和Cr(VI)-柠檬酸-硝酸铁[Cr(VI)-CA-FN]复合体系对 STBBFS催化剂光催化活性的影响. 结果表明: 酸性条件下, 不同复合体系对STBBFS催化剂光催化活性的促进作用按Cr(VI)-CA-FN复合体系>Cr(VI)-CA复合体系>Cr(VI)单一体系增强. Cr(VI)-CA复合体系在pH=2.5, 反应50 min后STBBFS催化剂光催化活性为0.426 mg8226;min―18226;g―1时将溶液中的Cr(VI)全部还原; 而Cr(VI)-CA-FN复合体系在pH=2.5, 反应16 min后STBBFS催化剂光催化活性为1.2425 mg8226;min―18226;g―1时将溶液中的Cr(VI)全部还原. 两种复合体系中, Cr(VI)离子的光催化还原过程都遵循L-H动力学规律, 虽然加入CA和FN后, 降低了吸附对光催化还原Cr(VI)的影响, 但是Cr(VI)吸附至催化剂表面仍然是整个反应过程的关键. 相似文献
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0引言在绿色和蓝色长余辉发光材料达到应用程度之后,耐候性红色长余辉发光材料成为人们研究的重点。Eu3 、Sm3 激活的硫氧化物[1 ̄3]、Eu2 铝锶复合硫氧化物[4]和Y2O3∶Eu3 [5]等耐热耐水性红色长余辉材料被相继发现。Pr3 离子掺杂的碱土金属钛酸盐(M TiO3∶Pr,M=M g,Ca,Sr,Ba)是一种新型的红色长余辉发光材料。这种发光材料在615nm附近有很好的单色性红光发射。碱土金属钛酸盐基质化学性能稳定,已开始应用于场发射显示器(FE D)[6,7]。碱土金属钛酸盐是A BO3型化合物,具有钙钛矿结构。B all[8]曾通过在CaTiO3中掺入不同量的Sr2 … 相似文献
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报导在尿素存在下通过均相沉淀法由硝酸铜和重铬酸铵制备复合均匀胶体粒子的结果.研究了一些实验参数对其组成、形态和粒子大小的影响.确定了胶体粒子的制备条件.结果观测到,由硝酸铜和重铬酸铵溶液形成了球形的多刺的粒子,它的组成为水含铅酸铜. 相似文献
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4-(甲氧基取代苯甲酰基)-PMP的合成、表征及其对铀(Ⅵ)的萃取性能研究 总被引:1,自引:0,他引:1
合成了PMBP苯甲酰基苯环上不同位置取代的3个衍生物2_a、2_b、2_c,其中2_b、2_c为新化合物.制备了它们的酮体和烯醇体,并用元素分析和IR、UV、~1H NMR进行表征和研究.与PMBP相对照,分别测定了2_a、2_b、2_c的pK_a值、对水相铀酰离子萃取的K_(ex)、pH_(1/2)和萃合物组成.在萃取条件下,它们对铀(Ⅵ)的萃取能力顺序是:2_c>2_b>2_a>PMBP. 相似文献
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采用煅烧的硫酸盐掺杂的含钛高炉渣(sulfate-modified titanium-bearing blast furnace slag,STBBFS)作为光催化剂,研究了Cr(VI)-柠檬酸[Cr(VI)-CA]复合体系和Cr(VI)-柠檬酸-硝酸铁[Cr(VI)-CA-FN]复合体系对STBBFS催化剂光催化活性的影响.结果表明:酸性条件下,不同复合体系对STBBFS催化剂光催化活性的促进作用按Cr(VI)-CA-FN复合体系>Cr(VI)-CA复合体系>Cr(VI)单一体系增强.Cr(VI)-CA复合体系在pH=2.5,反应50 min后STBBFS催化剂光催化活性为0.426 mg·min-1·g-1时将溶液中的Cr(VI)全部还原;而Cr(VI)-CA-FN复合体系在pH=2.5,反应16 min后STBBFS催化剂光催化活性为1.2425 mg·min-1·g-1时将溶液中的Cr(VI)全部还原.两种复合体系中,Cr(VI)离子的光催化还原过程都遵循L-H动力学规律,虽然加入CA和FN后,降低了吸附对光催化还原Cr(VI)的影响,但是Cr(VI)吸附至催化剂表面仍然是整个反应过程的关键. 相似文献
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β-环糊精与对甲苯磺酰氯在低温碱性溶液中反应合成6-对甲苯磺酰酯-β-环糊精,并利用红外光谱和核磁共振氢谱对其进行表征;联苯甲酰与6-对甲苯磺酰酯-β-环糊精以摩尔比为1: 2反应合成一种新型的联苯甲酰桥联β-环糊精(BB β-CD)材料,并采用紫外可见分光光度法对其合成机理以及BB β-CD和联苯甲酰对U(VI)的吸附行为进行研究;同时采用扫描电镜对材料吸附U(VI)前后的外貌形态进行表征。通过间歇吸附法考察pH、反应时间、温度以及干扰离子等因素对吸附过程的影响。结果表明,相比联苯甲酰,BB β-CD能更有效地吸附U(VI),在pH=4.5,反应时间为60 min条件下,最大吸附量为12.16 mg·g-1,吸附率高达91.2%。动力学和热力学拟合结果表明,吸附过程更符合准二级动力学速率方程,Langmuir等温吸附模型比Freundlich等温吸附模型更适合模拟吸附过程,且吸附是自发吸热的过程。 相似文献
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The Photochemical Behavior of the Uranyl Ion (UO$\rm{{_{2}^{2+}}}$): a Dimer Perspective and Outlook
The complex formation of uranyl (UO ) with oxalic acid (HOOC? COOH) in acetone is studied by UV/VIS, absorption, luminescence, and excitation spectroscopy. Based on solid‐state crystallographic data, we propose a dimer structure with D2h symmetry for the complex in solution. This symmetry is vibrationally distorted to D2 by the out‐of‐plane equatorial‐ligand vibration. From the spectroscopic point of view, this vibration induces intensity in the transitions Πg←Σ and one component of Δg←Σ . From the photochemical point of view, this vibration induces a twisting mechanism that destroys the complex. From the theoretical point of view, it is worthwhile to notice that the symmetry of the odd out‐of‐plane vibration is the same as the symmetry of the odd LUMO (fxyz). By vibrating accordingly to the LUMO symmetry, the complex is self‐destroying by absorption of light, and the uranyl is regenerated. A small comment is devoted to a possible δ–δ interaction and the quintuple U2 bond distance proposed by Gagliardi and Ross [29]. 相似文献
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Two Uranyl Complexes with Pyromellitic Acid. A Heterometallic Complex with U=O–CuII Interaction 下载免费PDF全文
Lingling Liang Yige Cai Xiang Li Ronglan Zhang Jianshe Zhao Chiyang Liu Ng Seik Weng 《无机化学与普通化学杂志》2015,641(10):1744-1748
Two uranyl complexes based on pyromellitic acid were hydrothermally synthesized, and their X‐ray single‐crystal diffraction structures were determined. Complex [UO2(Hbtec)]–(Himd)+ · H2O ( 1 ) (H4btec = pyromellitic acid, imd = imidazole), is an ionic complex, which shows a typical (4, 4) topological structure in the space. A heterometallic complex, UO2Cu(btec)(phen) ( 2 ) (phen = 1,10‐phenanthroline) results from the reaction of uranyl nitrate and copper(II) bromide with pyromellitic acid. The structure of complex 2 revealed that the chains of UO7 and CuO3N2 units were connected to each other through the carboxyl groups and U=O–Cu interactions to create a two‐dimensional framework. 相似文献
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Selective and Sensitive Determination of Uranyl Ions in Complex Matrices by Ion Imprinted Polymers‐Based Electrochemical Sensor 下载免费PDF全文
Majid Kalate Bojdi Mohammad Behbahani Mostafa Najafi Akbar Bagheri Fariborz Omidi Sara Salimi 《Electroanalysis》2015,27(10):2458-2467
We report on the design of a UO22+‐selective electrode based on the use of UO22+ imprinted polymer nanoparticles (IP‐NPs), and its application for the differential pulse adsorptive cathodic stripping voltammetry determination of uranyl ions. A carbon paste electrode was modified with the IP‐NPs, and differential pulse adsorptive cathodic stripping voltammetry was applied as the detection technique after open‐circuit sorption of UO22+ ions. The modified electrode responses to UO22+ was linear in the 0.1 µg L?1 to 10 µg L?1 and in the 0.01 mg L?1 to 10 mg L?1. The method detection limit of the sensor was 0.03 µg L?1. 相似文献
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A new polymer containing double amidoxime groups per repeating unit was synthesized to enhance the metal ion uptake capacity. The adsorption properties of this new polymeric adsorbent, amidoximated poly(N,N-dipropionitrile acrylamide), for U(VI), V(V), Cu(II), Co(II) and Ni(II) ions were investigated by batch and flow-through processes at very low concentration levels (ppb). The chelating polymer showed high adsorption capacity for uranyl as well as vanadyl ions. In selectivity studies from a mixture of metal ions in aqueous solutions, the adsorbent showed high selectivity for uranyl and vanadyl ions in the following order: U(VI) > V(V) Co(II) = Cu(II) Ni(II) as determined by calculating the distribution coefficients D, of corresponding ions. The adsorption of uranyl and vanadyl ions from natural seawater by the new adsorbent was also examined in flow through mode. 相似文献
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FU Hua CHEN Xin LI Zhao-long ZHAO Yu-fen WANG Jingzun XIAO Hongzhan WUYi 《高等学校化学研究》1997,13(4):373-377
InfluenceofBasicityontheFormationofClusterIons/AdductIonsforOrganicAmmoniumHalidesbyPositiveSecondaryIonMasSpectrometryFUHua,... 相似文献
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Jonathan D. Woodward 《Journal of solid state chemistry》2004,177(11):3971-3976
The reactions of UO3 and TeO3 with KCl, RbCl, or CsCl at 800 °C for 5 d yield single crystals of A2[(UO2)3(TeO3)2O2] (A=K (1), Rb (2), and Cs (3)). These compounds are isostructural with one another, and their structures consist of two-dimensional sheets arranged in a stair-like topology separated by alkali metal cations. These sheets are comprised of zigzagging uranium(VI) oxide chains bridged by corner-sharing trigonal pyramidal TeO32− anions. The chains are composed of dimeric, edge-sharing, pentagonal bipyramidal UO7 moieties joined by edge-sharing tetragonal bipyramidal UO6 units. The lone-pair of electrons from the TeO3 groups are oriented in opposite directions with respect to one another on each side of the sheets rendering each individual sheet non-polar. The alkali metal cations form contacts with nearby tellurite oxygen atoms as well as with oxygen atoms from the uranyl moieties. Crystallographic data (193 K, MoKα, ): 1, triclinic, space group , , , , α=101.852(1)°, β=102.974(1)°, γ=100.081(1)°, , Z=2, R(F)=2.70% for 98 parameters and 1697 reflections with I>2σ(I); 2, triclinic, space group , , , , α=105.590(2)°, β=101.760(2)°, γ=99.456(2)°, , Z=2, R(F)=2.36% for 98 parameters and 1817 reflections with I>2σ(I); 3, triclinic, space group , , , , α=109.301(1)°, β=100.573(1)°, γ=99.504(1)°, , Z=2, R(F)=2.61% for 98 parameters and 1965 reflections with I>2σ(I). 相似文献
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High Energy Chemistry - The quenching of fluorescence (FL) of uranyl ion $${\text{UO}}_{2}^{{2 + }}$$ and tryptophan Trp during their selective intracomplex photoexcitation in aqueous and methanol... 相似文献
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树形聚酰胺胺与 Cu2+的络合作用 总被引:1,自引:0,他引:1
合成了4.0代聚酰胺胺 (PAMAM)树形分子 ,并合成出端基为羟基的PAMAM树形分子衍生物。用分光光度法研究了4.0代PAMAM树形分子及其衍生物与Cu2 的络合作用。结果表明当存在树形聚酰胺胺分子时 ,Cu2 水溶液的最大吸收波长显著紫移 ,随n(Cu2 )/n(PAMAM)增加 ,最大吸收波长红移 ;PAMAM树形分子与Cu2 的络合作用有多种形式 ,对端胺基树形分子主要存在Cu -N4 和Cu -N2 两种配位方式 ;对端羟基树形分子主要存在Cu -N2 的配位方式 ;随Cu2 的加入 ,络合形式和各种络合形式的相对比例发生变化 ;pH对络合形式有较大影响;随代数的增加 ,树形分子所能络合Cu2 的最大数目不断增加 ,但理论值与实验值有一定的误差 相似文献
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采用SAC/SAC-CI方法在CC-PV5Z基组下, 计算研究了He2+、He2++的基态及低激发态的分子特性, 给出了其基态和一些激发态的势能函数和光谱数据(Be、αe、ωe和ωeχe). 从群论出发推导了相应状态的离解极限;与已有实验结果的He2+(X2Σu+)相比, 计算结果令人满意. 还计算了激发态2Πu、4Σu+和4Πg的结构与光谱数据. 对于He2++, 计算的九个电子态中只有三个态(X1Σg+、1Σg+和1Σu+)属束缚态, 并得到了其光谱常数. 用价键理论模型的不相交规则对He2++基态的势能曲线极大点产生的原因做了较好的分析. 相似文献