亚甲基蓝在云母表面吸附状态的研究

利用XPS测定吸附前后亚甲基蓝（MB）各原子的电子结合能的变化,以判断原子化学环境的改变,从而确定MB在云母表面的吸附位点是二甲胺基上的氮原子.通过AFM测量得到吸附于云母表面的MB分子的平均高度为0.820 nm,这证实了Hähner吸附模型的正确性,即MB分子的最大横截面以65～70°倾斜在云母的（001）表面上.     

Highly sensitive and selective measurements of cobalt by catalytic adsorptive cathodic stripping voltammetry

A very sensitive and selective catalytic adsorptive cathodic stripping procedure for trace measurements of cobalt is presented. The method is based on adsorptive accumulation of the cobalt-MTB (methyl thymol blue) complex onto a hanging mercury drop electrode, followed by reduction of the adsorbed species by voltammetric scan using differential pulse modulation. The reduction current is enhanced catalytically by nitrite. The optimum conditions for the analysis of cobalt include pH 9.0 (ammonia buffer), 2.0 μM methyl thymol blue, 0.8 M sodium nitrite and an accumulation potential of −0.5 V (versus Ag/AgCl). The peak current is proportional to the concentration of cobalt over the entire concentration range tested (0.02–500 ng ml⁻¹) with a detection limit of 0.005 ng ml⁻¹ for an accumulation time of 60 s. The method was applied to determination of cobalt in a mineral water sample and some analytical grade salts with satisfactory results.     

耐尔蓝-钍钼杂多酸光度法测定钍

本文研究超高灵敏光度法测定钍。在聚乙烯醇（PVA）存在下，耐尔蓝（NB）与钍钼杂多酸络阴离子形成离子缔合物。在1．2mol／L高氯酸介质中缔合物的最大吸收位于590nm，摩尔吸光系数ε值4．45×106L·mol－1·cm－1，钍量在0～28μg／L范围服从比耳定律；测定极限C（Th）3．4μg／L（n＝9）；对20μg／LTh分析9次的相对标准偏差1．5％；缔合物的摩尔组成Th：Mo：NB＝1：12：3。考察了50多种共存离子影响，允许100倍量Ce（Ⅲ）、50倍量U（Ⅵ）和等量Ti（Ⅳ）存在。本法用于地质样品中钍的测定，结果满意。     

The electrochemical behavior of hydrogen peroxide sensor based on new methylene blue as mediator

利用共价键合法,将新亚甲蓝(NMB)与辣根过氧化酶(HRP)修饰于玻碳电极表面,制成一种新型的电流型H2O2传感器。探讨了该传感器在0·1mol/L磷酸缓冲溶液(pH=7·0)中的电化学性质。结果表明,NMB作为介体能够有效地在辣根过氧化酶和电极之间传递电子。测得电子转移系数为0·861,表观反应速率常数为1·27s-1。研究了传感器对H2O2的响应及动力学性质,米氏常数为8·27μmol/L,线性响应范围为2·5~100μmol/L。同时研究了pH、缓冲容量及温度等因素对H2O2传感器的影响。     

菲并咪唑衍生物蓝光材料的合成、光物理性质及理论计算

合成了两个蓝光材料2-苯基-1H-[9,10-d]菲并咪唑(Phen-PI)和2-吡啶-1H-[9,10-d]菲并咪唑(PyriPI),光物理分析表明Phen-PI和Pyri-PI的最大发射峰分别位于371.5 nm,388.5 nm和403.5 nm,相对量子效率分别为0.383和0.528,激发态衰减寿命分别为3.87 ns和3.68 ns。通过密度泛函理论(DFT)对化合物的前线分子轨道成分和能级分布分析表明,当把Phen-PI中的苯基被吡啶环取代后,Pyri-PI的HOMO能级和LUMO能级分别下降0.09 e V和0.23 e V,同时Pyri-PI的HOMO轨道和LUMO轨道的能级差比Phen-PI减少0.14 e V,在理论层面上解释了Pyri-PI发射光谱的红移。     

Syntheses,X‐ray crystal structures,and emission properties of diprotonated tetrapyridylpyrazine and triprotonated terpyridine

A series of metal‐free compounds, that is, planar diprotonated tetraH₂(PF₆)₂ ( 1 ), planar monoprotonated bppzHPF₆ ( 2 ), nonplanar diprotonated bppzH₂(PF₆)₂ ( 3 ), and planar triprotonated terpyH₃Cl(PF₆)₂ ( 4 ), were prepared and characterized by electrospray ionization mass spectrometry, Ultraviolet–visible spectroscopy and cyclic voltammetry. Abbreviations used are tetra = tetra‐2‐pyridylpyrazine, bppz = 2,3‐bis(2‐pyridyl)pyrazine, and terpy = 2,2′:6′,2″‐terpyridine. The X‐ray crystal structures of the four compounds 1 , 2 , 3 , and 4 were determined. Both protonated pyridine rings are hydrogen bonded intramolecularly to the adjacent pyridine ring in compounds 1 and 3 . The π–π* absorption bands in the ultraviolet region for 1 , 2 , 3 , and 4 in acetonitrile were red‐shifted relative to those of the corresponding neutral unprotonated compounds. All the cyclic voltammetry for the protonated species, 1 , 2 , 3 , and 4 , showed the first reduction waves from ?0.37 to ?1.18 V, that were more positive than those of the neutral ones. Density functional theory was applied to interpret the planarity in 1 . The attachment of two protons to the two terminal tetra nitrogens in 1 leads to the remarkable emission (Φ = 0.031). The attachment of three protons to the three terpy nitrogens in 4 also gives the large quantum yield (Φ = 0.48). Copyright © 2015 John Wiley & Sons, Ltd.     

Photocatalytic degradation of acid blue 74 in water using Ag–Ag2O–Zno nanostuctures anchored on graphene oxide

Water pollution due to industrial effluents from industries which utilize dyes in the manufacturing of their products has serious implications on aquatic lives and the general environment. Thus, there is need for the removal of dyes from wastewater before being discharged into the environment. In this study, a nanocomposite consisting of silver, silver oxide (Ag₂O), zinc oxide (ZnO) and graphene oxide (GO) was synthesized, characterized and photocatalytically applied in the degradation (and possibly mineralization) of organic pollutants in water treatment process. The Ag–Ag₂O–ZnO nanostructure was synthesized by a co-precipitation method and calcined at 400 °C. It was functionalized using 3-aminopropyl triethoxysilane and further anchored on carboxylated graphene oxide via the formation of an amide bond to give the Ag–Ag₂O–ZnO/GO nanocomposite. The prepared nanocomposite was characterized by UV–Vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), energy dispersive X-ray spectrometry (EDX), Fourier transformed infrared spectroscopy (FTIR), and Raman spectroscopy. The applicability of Ag–Ag₂O–ZnO/GO nanocomposite as a photocatalyst was investigated in the photocatalytic degradation of acid blue 74 dye under visible light irradiation in synthetic wastewater containing the dye. The results indicated that Ag–Ag₂O–ZnO/GO nanocomposite has a higher photocatalytic activity (90% removal) compared to Ag–Ag₂O–ZnO (85% removal) and ZnO (75% removal) respectively and thus lends itself to application in water treatment, where the removal of organics is very important.     

Cu(II) catalyzed oxidation of mercaptoacetic acid by methylene blue in acidic medium: Influence of solvent and morphology

Kinetic studies on the Cu(II) catalyzed oxidation of mercaptoacetic acid (thioglycolic acid, TGA) by the model electron receptor methylene blue in acidic medium show that the reaction follows a second order kinetics in TGA. The order in methylene blue is unity but at higher [TGA], the order is 3/4. The rate shows an inverse relationship with [H⁺] and a second order dependence on [Cu(II)]. The reaction conforms to Arrhenius behavior in aqueous medium but resorts to anti-Arrhenius behavior in aqueous methanol and in aqueous acetone media. The reaction involves the in situ participation of nanoparticles which has been confirmed by SEM, XRD, and FTIR techniques. In aqueous medium, cauliflower shaped nanoparticles (44.21–74.33 nm) are obtained but in the presence of acetone and methanol, nanogranules (38.96–70.73 nm) and nanodisks (47.30–72.16 nm), respectively, are produced at 35°C as revealed by SEM images and XRD data. The reaction is characterized by the participation of two transition states in aqueous acetone medium and the kinetics of the reaction, especially the temperature dependence, is governed by the adsorption of methylene blue on copper nanoparticles as influenced by morphology inter alia dielectric constant of the reaction medium.     

Laser-Assisted Scalable Pore Fabrication in Graphene Membranes for Blue-Energy Generation

The osmotic energy from a salinity gradient (i. e. blue energy) is identified as a promising non-intermittent renewable energy source for a sustainable technology. However, this membrane-based technology is facing major limitations for large-scale viability, primarily due to the poor membrane performance. An atomically thin 2D nanoporous material with high surface charge density resolves the bottleneck and leads to a new class of membrane material the salinity gradient energy. Although 2D nanoporous membranes show extremely high performance in terms of energy generation through the single pore, the fabrication and technical challenges such as ion concentration polarization make the nanoporous membrane a non-viable solution. On the other hand, the mesoporous and micro porous structures in the 2D membrane result in improved energy generation with very low fabrication complexity. In the present work, we report femtosecond (fs) laser-assisted scalable fabrication of μm to mm size pores on Graphene membrane for blue energy generation for the first time. A remarkable osmotic power in the order of μW has been achieved using mm size pores, which is about six orders of magnitudes higher compared to nanoporous membranes, which is mainly due to the diffusion-osmosis driven large ionic flux. Our work paves the way towards fs laser-assisted scalable pore creation in the 2D membrane for large-scale osmotic power generation.