Photocatalytic degradation of methylene blue on Fe3+-doped TiO2 nanoparticles under visible light irradiation

Fe³⁺-doped TiO₂ composite nanoparticles with different doping amounts were successfully synthesized using sol-gel method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultravioletvisible spectroscopy (UV-Vis) diffuse reflectance spectra (DRS). The photocatalytic degradation of methylene blue was used as a model reaction to evaluate the photocatalytic activity of Fe³⁺/TiO₂ nanoparticles under visible light irradiation. The influence of doping amount of Fe³⁺ (ω: 0.00%–3.00%) on photocatalytic activities of TiO₂ was investigated. Results show that the size of Fe³⁺/TiO₂ particles decreases with the increase of the amount of Fe³⁺ and their absorption spectra are broaden and absorption intensities are also increased. Doping Fe³⁺ can control the conversion of TiO₂ from anatase to rutile. The doping amount of Fe³⁺ remarkably affects the activity of the catalyst, and the optimum efficiency occurs at about the doping amount of 0.3%. The appropriate doping of Fe³⁺ can markedly increase the catalytic activity of TiO₂ under visible light irradiation. __________ Translated from Journal of Northwest Normal University (Natural Science), 2006, 42(6): 55–56 [译自: 西北师范大学学报(自然科学版)]     

真珠钙驱铅实验研究

研究了真珠钙驱铅效果，给亚急性中毒的大鼠服用后，可增加铅从尿中排量，降低骨中蓄积量，对防治铅中毒有一定作用。     

芥子气模拟剂2-氯乙基乙基硫醚的光催化降解

利用连续流动微反、原位红外和GC/MS等手段考察了芥子气模拟剂2-氯乙基乙基硫醚（2-CEES）在P25 TiO2上的光催化降解反应,证实CO2和H2O是这个反应的最终产物.详细的跟踪分析表明,除了CO2和H2O外,在反应的气相混合物中可检测到C2H4、CH3CHO、CH4、CO、HCl和H2S；少量小分子的羧酸、醚和砜；微量C2H5SC2H5、C2H5S2C2H5、C2H5SC2H4Cl和CH2ClCH2Cl等中间产物;在反应后的催化剂表面可检测到C2H5S2C2H5、C2H5SC2H4OH、C4H9S2C2H5和C2H5S2C2H4OH、等物.根据这些结果提出了2-CEES光催化降解的反应机理,推断2-CEES的光催化降解涉及脱氯、C－S键断裂、有机硫化物光聚合和裂解等复杂过程最终转化为CO2和H2O.认为各种硫物种在表面的积聚引起了催化剂的缓慢失活.     

12-钼磷酸—聚乙烯醇的光电子转移反应

12-钼磷酸—聚乙烯醇体系具有不可逆光致变色的特性。根据X射线光电子能谱、电子自旋共振谱、紫外及可见光谱的测试结果,笔者认为:在PMo_(12)-PVA的光电子转移反应中,PMo_(12)既是氧化剂也是光敏剂。PMo_(12)分子中氧可分成O_p、O_b和O_t三种情况.其中O_t可成为光化学的活性位置,它和PVA羟基上的氧均较易被紫外光激活。激活的0_t边使周围的一个电荷向金属原子(Mo~(Ⅵ))转移,边与PVA羟基上被激活的氧作用,电子就由此羟基上的氧向O_t转移,致使体系中部分PMo_(12)与PVA发生二电子或四电子氧化还原反应,形成Mo(Ⅵ、Ⅴ)配合物而变色,同时,PVA分子的部分羟基及该羟基位的碳上脱氢形成羰基而具有酮结构。此外,从Mo(V)的ESR特征信号随时间变化而减弱,但其吸收光谱的吸光度未变,于是推断该光化学反应过程中尚有Mo(Ⅳ)生成,已由XPS谱证实。     

Totally selective ring-opening of amino epoxides with ketones: a general entry to enantiopure (2R,3S)- and (2S,3S)-3-aminoalkano-1,2-diols

[Reaction: see text] Transformation of enantiopure diastereoisomers (2R,1'S)- and (2S,1'S)-2-(1-aminoalkyl)epoxides into the corresponding 4-(1-aminoalkyl)-1,3-dioxolanes is achieved by reaction with different ketones in the presence of BF3.Et2O. The conversion takes place in very high yields, total selectivity, and without epimerization. A mechanism to explain this transformation is proposed. The obtained 1,3-dioxolanes can be deprotected, and (2R,3S)- and (2S,3S)-3-aminoalkano-1,2-diols were isolated.     

YPxV1—xO4（0≤x≤1）：Dy^3＋的合成及其光谱性质的研究

本文报道了不同组成的ＹＰｘＶ１－ｘＯ４（０≤ｘ≤１）：Ｄｙ＾３＋的合成和结构。ＹＰｘＶ１－ｘＯ４（０≤ｘ≤１）为四方晶系，晶胞参数随ｘ的增大呈线性减小。基质的Ｓｔｏｋｅｓ位移随ｘ的增大逐渐变大，而激发光谱峰值则向短波方向移动。在ＹＰｘＶ１－ｘＯ４：０．００６Ｄｙ＾３＋体系中，ｘ＞０．４时出现的基质发射是由ＰＯ＾３－４引起的。基质及Ｄｙ＾３＋的发光效率和Ｄｙ＾３＋的发光强度的黄蓝比均与ｘ有关。同时探     

A novel route for waste water treatment: photo-assisted Fenton degradation of dye pollutants accumulated in natural polyelectrolyte microshells

The efficient accumulation of dyes in constructed natural polyelectrolyte microshells under moderate conditions, combined with the photo-assisted Fenton reagent, opens a new route for the effective elimination of dye pollutants from waste water.     

Phase separation behavior of epoxy resin modified with crosslinked rubber

Low molecular weight liquid rubber (ATBN = amine terminated butadiene acrylonitrile copolymer or CTBN = carboxyl terminated butadiene acrylonitrile copolymer)–DGEBA (diglycidyl ether of bisphenol A) blends indicated upper critical solution temperature (UCST) behavior. The phase separation behavior of the neat and crosslinked rubber (ATBN, CTBN)–epoxy blends was analyzed by a laser light scattering experiment. Lauryl peroxide (LPO) was employed to crosslink the rubber during the initial annealing stage. The onset point of the phase separation in the crosslinked ATBN–epoxy system occurred later than in the case of the neat ATBN–epoxy system. However, the onset point of the phase separation process started earlier in the case of the crosslinked CTBN–epoxy system. The domain correlation length of the crosslinked rubber-added system was smaller than that of the neat rubber-added system.     

α－Fe_2O_3微晶表面层厚度的Mossbauer谱表征

α－Ｆｅ＿２Ｏ＿３微晶表面层厚度的Ｍｏｓｓｂａｕｅｒ谱表征苏兴才，王寅生（中国科学技术大学近代化学系，合肥２３００２６）姜继森（华东师范大学化学系，上海２０００６２）关键词：表面层厚度，α－Ｆｅ＿２Ｏ＿３微晶，谱物质表面分子所处环境不同于内部分子，表...     

An electronic structure investigation of the BNO-BON-NBO system

The potential energy hypersurface of the ground triplet states of the BNO-BON-NBO system has been investigated using traditional ab initio electronic structure theory. The molecules studied have the molecular formula BON and include three linear and three angular species, and two transition states for the isomerization of an angular N-B-O to an angular B-O-N and a linear B-NO, respectively. All stationary points on the BNO-BON-NBO isomerization potential energy surface have been characterized employing UMP2, UMP4, and Gaussian-2 (G2) theory with the 6-311G(d), 6-311G(2d), and TZ2P basis sets. The isomerization for an angular N-BO to the linear B-NO has a lower energy barrier than that of the former to an angular B-ON. Energetics are presented with G2 energies. Two sets of resonance structures for both bent B-NO (boron nitrosyl) and B-ON (boron isonitrosyl) were proposed and the bonding in the two species was analyzed. For the purpose of comparison, the density functional theory based hybrid methods B3LYP/6-311G(d) and B3LYP/TZ2P have also been applied to both geometry optimization and single-point calculations. It is found that the B3LYP prediction of the nature of the linear B-O is contradictory to that made by all MPn(n = 2 and 4) calculations. The cause for this contradiction is discussed.