Preparations of TiO2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde

Anatase TiO2 films were successfully prepared on foam nickel substrates by sol-gel technique using tetrabutyl titanate as precursor. The characteristics of the TiO2 films were investigated by XPS, XRD, FE-SEM, TEM and UV-Vis absorption spectra. The photocatalytic activities of TiO2 films were investigated by photocatalytic degradation reactions of gaseous acetaldehyde, an indoor pollutant, under ultraviolet light irradiation. It was found that Ni^2＋ doping into TiO2 films due to the foam nickel substrates resulted in the extension of absorption edges of TiO2 films from UV region to visible light region. The pre-heating for foam nickel substrates resulted in the formation of NiO layer, which prevented effectively the injection of photogenerated electrons from TiO2 films to metal nickel. The TiO2 films displayed high photocatalytic activity for the degradation of acetaldehyde, and were enhanced by calcining the substrates and coating TiO2 films repeatedly. The high activity was mainly attributed to the improvement of the characteristics of substrate surface and the increase of active sites on photocatalyst.     

空间粒子辐射环境下石墨膜力学性能的演变规律

目的将石墨膜置于9×10^5~9×10^7 rad(Si)总剂量下获得辐射改性石墨膜材料,探讨空间粒子辐射作用下石墨膜拉伸强度的演变规律。方法采用SEM、XRD、煅烧分析及XPS等手段分析石墨膜的结构及成分。结果石墨膜为有序堆积的层状结构,层间距为0.3355 nm,碳的质量分数高达99.75%,挥发分的质量分数为0.04%,灰分的质量分数为0.21%,XPS只检测到C1s及O1s峰。石墨膜的平均热膨胀系数为负值,且其峰值仅为-1.33×10^-6/℃,具备出色的结构稳定性。空间粒子辐射环境模拟试验表明,随着辐射剂量的升高,石墨膜的拉伸强度逐渐衰减,在更高剂量辐射下,石墨膜的拉伸强度趋向稳定。通过Raman光谱仪对辐射石墨膜结构的分析,揭示了力学性能的演变机理。结论辐射石墨膜的拉伸强度与其缺陷含量有很大的相关性,未经过辐射的原始石墨膜的缺陷含量最低,其拉伸强度最大,随着石墨膜的缺陷含量逐渐增多,其拉伸强度逐渐降低。     

Fabrication Mechanical Properties of Unidirectional Jute/PP Composites Using Jute Yarns by Film Stacking Method

This paper mainly focuses on the fabrication process of long fibre reinforced unidirectional thermoplastic composites made using both natural (untreated) treated jute yarns. Jute yarns were wound in layers onto a metallic frame. Polypropylene films were inserted between these layers and compression moulded to fabricate unidirectional jute/PP composite specimens. Static mechanical properties were evaluated from tensile three point bending tests. Pre- post-failure examination were carried out on the test specimens using optical scanning electron microscopy to analyse the test results and investigate the correlations between their impregnation state, processing conditions, mechanical performances and fracture morphologies. For the unidirectional jute/PP film-stacked composites, the results indicated that the processing condition at the moulding temperature of 160°C and moulding pressure of 2.0 MPa for 15 min was ideally suited to obtain optimized properties. Improved wettability of resin melts due to complete matrix fusion at this processing condition facilitated thorough impregnation with minimum microstructural imperfections (microvoids) being generated. Jute/PP composites that contained treated jute yarns have shown superiority in tensile bending properties. Jute yarns polished or coated with PVA/PP (polyvinyl alcohol/polypropylene) must have contributed positively to fibre/matrix interfacial interactions leading to matrix to fibre effective stress transfer, thereby improving their reinforcing effects. Tensile strength and modulus of PP resin increased by approximately 285% and 388%, respectively, due to 50 wt% reinforcement by natural jute yarns. Further improvements in strength and modulus were achieved by approximately 14% and 10%, respectively, when treated yarns were used . The maximum bending stress modulus of jute/PP composites containing untreated yarns were approximately 190% and 460% higher than those of the virgin PP materials, and bending properties were improved by further 11% and 23%, respectively, due to coating treatments on the yarn surface.     

光催化薄膜的亲水性及其应用

玻璃表面的雾化及建筑物表面的污染严重影响人们日常生活及工业。传统方法通常借助外力解决表面雾化及污染问题,如人工清洗,不仅维护成本高,而且施工难度大。光催化亲水薄膜作为一种具有特殊润湿性的表面,可高效持久地实现基底表面的防雾和自清洁功能。近年来,光催化薄膜防雾和自清洁性能的研究不断涌现,但相关的针对性综述却很少。本文详细阐述了光催化薄膜的亲水原理及亲水性评价方法,重点介绍了亲水性的改善方法,并对缺乏研究的亲水性与光催化分解有机污染物活性关系进行了简要概述,总结了国内外光催化薄膜亲水性的应用现状,分析了其存在问题及发展方向,旨在为光催化薄膜亲水性的研究及其应用起到一定的指导作用。     

UV/TiO2薄膜体系光降解酞酸酯研究

采用自制玻璃负载TiO2薄膜,研究了UV-V is/TiO2以及UV/TiO2/H2O2体系对2种酞酸酯DBP和DEHP的光催化降解情况。研究结果表明,TiO2在暗处对酞酸酯没有降解作用;UV/TiO2体系能有效光降解DBP和DEHP,TiO2具有明显的光催化作用,增强因子分别为fDBP=2.06,fDEHP=1.53;在一定浓度范围内DBP在UV/TiO2体系中的降解速率与其初始浓度成负一级动力学关系;UV/TiO2/H2O2体系对DBP的光降解能力远大于UV/TiO2和UV/H2O2体系,H2O2能显著提高TiO2的光催化活性。     

非晶态TiO2-W薄膜的光催化性能研究

采用磁控溅射技术在玻璃基片上制备了W掺杂的非晶态TiO2薄膜,用XRD、XPS和椭圆偏光测厚仪等对薄膜进行了微观分析.结果表明,TiO2-W薄膜为非晶态结构.Ti以 4价存在;W以0价和 6价形式存在,并且6价和0价W的原子浓度比为6.4:1;薄膜中Ti和W的原子浓度比为2.6:1.对5 mg·L-1的亚甲基蓝溶液光催化脱色试验表明,随着膜厚的增加,光催化降解率递增,当膜厚达到141 nm时,所制备的TiO2-W薄膜对亚甲基蓝的脱色率在2 h达到90%;当膜厚大于141 nm时,光催化降解率不再增加.     

CdS/TiO2复合半导体薄膜的制备及其光催化性能

以微弧氧化法制备出锐钛矿型TiO₂,进而以化学水浴法沉积CdS,通过调控时间,制备CdS/TiO₂复合半导体薄膜. X射线检测表明,微弧氧化所制备的TiO₂为锐钛矿结构, 化学水浴法制备的CdS主要以离子离子的方式沉积在TiO₂薄膜上. SEM及可见光催化降解亚甲基蓝的试验表明,沉积时间为15 min的复合半导体薄膜上的CdS粒子呈圆球形、单层孤立、均匀地分散在TiO₂表面,绝大多数粒子的粒径在nm级别,分布比较均匀,对亚甲基蓝有着较好的光催化性能,与TiO₂薄膜相比,复合半导体薄膜的光催化性能有很大的提高. 结合光催化评价结果,对复合半导体薄膜的光催化剂机制进行了讨论.      

不同光敏剂对LDPE薄膜光降解影响比较

合成硬脂酸铁（FeSt3）、硬脂酸铈（CeSt4）和硬脂酸锰（MnSt2）,用母粒法制备了可光降解LDPE薄膜。采用傅立叶红外变换光谱仪、万能材料试验机和乌氏粘度计测定羰基指数、断裂伸长率、拉伸强度和分子量,研究了这3种光敏剂及其用量对LDPE降解程度的影响。结果表明,3种光敏剂的光敏活性FeSt3〉CeSt4〉MnSt2;LDPE的光降解程度并非随着光敏剂含量的增加而增大,在控制用量的情况下。MnSt2更适合用作稳定剂;光降解使链结构发生了变化。分子量降低。     

新型光电催化反应器的设计及其反应动力学

研制了一种新型的光电催化反应器,并对PEG-2000模拟废水进行了降解动力学研究。结果表明,电解、光催化、光电催化去除0.5 g/L的PEG-2000模拟废水中COD为零级反应,从动力学角度来看,光电协同作用明显;在不同的外加偏压、初始pH值、曝气量和光强条件下,反应符合零级动力学规律;不同初始浓度PEG-2000模拟废水的光电催化反应具有不同的反应级数,高浓度时,此光电催化体系符合零级反应动力学规律,低浓度时,光电催化氧化符合一级反应动力学规律。     

In situ measurements of concentrations of Cd, Co, Fe and Mn in estuarine porewater using DGT

Vertical profiles of metals were measured by the in situ application of DGT (diffusive gradients in thin films). Well-defined laboratory systems ensured the good reproducibility and precision DGT accumulated metals on a chelex resin after diffusional transport through a layer of hydrogel. Three kinds of DGT probes (with three thicknesses of diffusive gel: 0.40 mm, 0.80 mm and 1.92 mm) measured interfacial concentration and induced flux from solid to solution phase which had intricate variations with depth. The DGT induced flux and interfacial concentration of four metals belonged to “partially sustained” state, indicating a labile equilibrium of metals between solid phase and porewater. The concentration profiles showed the good correlation between Mn and Co and peak concentrations of Mn and Fe between −2.00 cm and −5.25 cm with depth.