Photocatalytic decoloration of water-soluble azo dyes by reduction based on bisulfite-mediated borohydride

Investigation of the photocatalytic decoloration of nine water-soluble anionic azo dyes widely used for the coloration of textiles was conducted in a photoreactor by a selected reduction based on bisulfite-mediated borohydride. The influence of the irradiation power on their decoloration was discussed in this work. The decoloration processes of two typical azo dyes, Reactive Red MS and C.I. Direct Blue 15 were examined with UV–vis measurement and their decoloration kinetics was also investigated. Moreover, identification of benzidine compounds released from the photoreduction of four direct dyestuffs was undertaken. The results indicated that the reduction of the dyes was significantly enhanced under the increasing irradiation. It was found that the overall degradation followed pseudo-first-order kinetics and two distinct stages were observed in the decoloration processes of Reactive Red MS and C.I. Direct Blue 15. The decay rates at first stage were slightly changed, but the decay rates at second stage were significantly affected by the light intensity. In addition, UV–vis spectra showed that the azo linkages in molecule structure of the dyes were destroyed during the decoloration. Finally, dimethoxyl benzidine or benzidine produced from the photoreduction of four direct dyes was identified as the decoloration products through a rapid spectrophotometric method.     

基于流动模拟的定位板浇注系统的优化

应用三维流动模拟软件HSCAE3D6 0对冰箱定位板注塑模的浇注系统进行优化。通过几种方案的比较,解决了流动不平衡的问题,获得了比较满意的成型效果。     

TiCl4水解法制备纳米TiO2粉体

以TiCl4为原料,采用低温液相水解法制备了纳米TiO2粉体,着重研究了Ti4 的浓度和添加聚乙烯吡咯烷酮(Polyvinylpyrrolidone,PVP)对产物的晶相、颗粒大小和表面形貌的影响.使用XRD,TEM,SEM,激光粒度测试仪对样品进行了表征.结果表明,Ti4 浓度影响TiO2粉体的相转变温度,随着Ti4 浓度的升高金红石相的含量逐渐升高,但粉体分散性变差;添加PVP提高了所得TiO2粉体的分散性,粒径降低为40～50 nm左右,并改善了粉体的形貌.     

Effect of structural and electrochemical properties of different Cr-doped contents of Li[Ni1/3Mn1/3Co1/3]O2

Layered Li[Ni_(1−x)/3Mn_(1−x)/3Co_(1−x)/3Cr_x]O₂ materials with x = 0, 0.01, 0.02, 0.03, 0.05 are prepared by a solid-state pyrolysis method. The oxide compounds were calcined with various Cr-doped contents, which result in greater difference in morphological (shape, particle size and specific surface area) and the electrochemical (first charge profile, reversible capacity and rate capability) differences. The Li[Ni_(1−x)/3Mn_(1−x)/3Co_(1−x)/3Cr_x]O₂ powders were characterized by means of X-ray diffraction (XRD), charge/discharge cycling, cyclic voltammetry, and SEM. XRD experiment revealed that the Li[Ni_(1−x)/3Mn_(1−x)/3Co_(1−x)/3Cr_x]O₂ (x = 0, 0.01, 0.02, 0.03, 0.05) were crystallized to well layered -NaFeO₂ structure. The first specific discharge capacity and coulombic efficiency of the electrode of Cr-doped materials were higher than that of pristine material. When x = 0.02, the sample showed the highest first discharge capacity of 241.9 mAh g⁻¹ at a current density of 30 mA g⁻¹ in the voltage range 2.3–4.6 V, and the Cr-doped samples exhibited higher discharge capacity and better cycleability under medium and high current densities at room temperature.     

内构件存在时提升管内流动及颗粒混合行为研究

he hydrodynamics and solids mixing behavior in a riser with blunt internals are studied. A uniform radial distribution for solids fraction and particle velocity achieves near the internals. The turbulent velocity of particles near the wall increases with the addition of the internals, with the lateral solids mixing enhanced significantly. Probability density distribution of particle velocity is bimodal in the riser with internals, which is similar to that in the conventional riser, indicating that no significant difference in the micro flow structure exists between the riser with internals and the conventional riser. At the same time, the axial solids mixing behavior changes insignificantly with the addition of internals. These results indicate that the micro flow structure in the riser is very stable, which changes insignificantly with the change of the bed structure.     

基于表面生物学改性的多孔状二氧化钛/磷灰石复合薄膜的制备

在钛合金表面采用微孤氧化得到一层多孔状的具有生物活性的二氧化钛，经随后水热处理可形成羟基磷灰石薄膜，提高钛合金表面的生物学性能，用SEM、XRD、EDX分析了薄膜的组织、结构和化学组成，同时考察了微弧氧化得到的二氧化钛膜的生物活性，结果表明，在室温条件下从含钙、磷离子的电解液中在钛合金基体上微弧氧化得到一层二氧化钛薄膜，蒸汽处理后得到具有生物活性的二氧化钛/羟基磷灰石复合薄膜，该膜多孔均匀，且生物活性高，有利于骨组织的吸附和生长。     

Synthesis and properties of poly(aryl ether sulfone ether ketone ketone) (PESEKK)

4,4′‐bis(Phenoxy)diphenyl sulfone (DPODPS) was synthesized by reaction of phenol with bis(4‐chlorophenyl) sulfone in tetramethylene sulfone in the presence of NaOH. Two poly(aryl ether sulfone ether ketone ketone)s (PESKKs) with high molecular weight were prepared by low temperature solution polycondensation of DPODPS and terephthaloyl chloride (TPC) or isophthaloyl chloride (IPC), respectively, in 1,2‐dichloroethane and in the presence of aluminum chloride (AlCl₃) and N‐methylpyrrolidone (NMP). The resulting polymers were characterized by various analytical techniques, such as FT‐IR, ¹H‐NMR, DSC, TG, and WAXD. The results show that the T_g and T_d of PESEKKs are much higher, but its T_m is lower than those of PEKK. The other results indicate that PESEKKs exhibit excellent thermostabilities at 300 ± 10°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 489–493, 2005     

Synthesis of polystyrene/poly(butyl acrylate) core–shell latex and its surface morphology

A polystyrene (PS)/poly(butyl acrylate) (PBA) composite emulsion was produced by seeded emulsion polymerization of butyl acrylate (BA) with PS seed particles which were prepared by emulsifier‐free polymerization of styrene with potassium persulfate (KPS) under a nitrogen atmosphere at 70°C for 24 h with stirring at 60 rpm and swelled with the BA monomer in an ethanol/water medium. The structure of the PS/PBA composite particles was confirmed by the presence of the characteristic absorption band attributed to PS and PBA from FTIR spectra. The particles for pure PS and PS/PBA with a low content of the BA monomer were almost spherical and regular. As the BA monomer content was increased, the particle size of the PS/PBA composite particles became larger, and more golf ball‐like particles were produced. The surface morphology of the PS/PBA composite particles was investigated by AFM and SEM. The T_g's attributed to PS and PBA in the PS/PBA composite particles were found at 110 and ?49°C, respectively. The thermal degradation of the pure PS and PS/PBA composite particles occurred in one and two steps, respectively. With an increasing amount of PBA, the initial thermal decomposition temperature increased. On the contrary the residual weight at 450°C decreased with an increasing amount of PBA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 595–601, 2003     

Shape‐memory polyurethane/multiwalled carbon nanotube fibers

Shape‐memory polyurethane/multiwalled carbon nanotube (SMP–MWNT) composites with various multiwalled carbon nanotube (MWNT) contents were synthesized, and the corresponding SMP–MWNT fibers were prepared by melt spinning. The influence of the MWNT content on the spinnability, fracture morphology, thermal and mechanical properties, and shape‐memory behavior of the shape‐memory polymer was studied. The spinning ability of SMP–MWNTs decreased significantly with increasing MWNT content. When the MWNT content reached 8.0 wt %, the fibers could not be produced because of the poor rheological properties of the composites. The melt‐blending, extrusion, and melt‐spinning processes for the shape‐memory fiber (SMF), particularly at low MWNT contents, caused the nanotubes to distribute homogeneously and preferentially align along the drawing direction of the SMF. The crystallization in the SMF was promoted at low MWNT contents because it acted as a nucleation agent. At high MWNT contents, however, the crystallization was hindered because the movement of the polyurethane chains was restricted. The homogeneously distributed and aligned MWNTs preserved the SMF with high tenacity and initial modulus. The recovery ratio and recovery force were also improved because the MWNTs helped to store the internal elastic energy during stretching and fixing. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Surface activity and solubilization of a novel series of functional polyurethane surfactants

Functional polyurethane surfactants (di‐block and tri‐block) were synthesized by addition polymerization of 2,4‐toluenediisocyanate with poly(propylene oxide) and monoallyl‐end‐capped poly(ethylene oxide). The chemical structure of the polyurethane surfactants was confirmed by Fourier transform infrared and ¹H NMR spectroscopy. These polymeric surfactants were found to have excellent surface activity. The lowest surface tension of polyurethane surfactant aqueous solutions could be reduced to 37.6 mN m^?1. All the polyurethane surfactants synthesized had low critical micelle concentrations and could reduce the surface tension even at very low concentration levels (10^?6–10^?5 mol L^?1). The solubilization of toluene in micelles of the synthesized polyurethane surfactants was studied using UV‐visible spectroscopy, and the results showed that they all exhibited good solubilization capacity. Possible solubilization positions of toluene in the micelles are conjectured. Copyright © 2006 Society of Chemical Industry