Y/Eu co-doped TiO2:synthesis and photocatalytic activities under UV-light

Y and Eu co-doped nano-TiO2 photocatalysts were successfully prepared via a sol-gel method and characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), ultraviolet-visible spectrophotometry(UV-vis), photoluminescence(PL) and Fourier transform infrared(FT-IR) spectra. Experimental results indicated that Y and Eu doping inhibited the growth of crystalline size and the transformation from anatase to rutile phase and had the function of reducing particle reunion. At the same time, co-doping could also enhance the absorption in visible region and then narrowed the band gap. The photocatalytic activities of the samples were evaluated by the degradation of methylene blue(MB) under ultraviolet(UV) light irradiation, which showed much enhanced photocatalytic activities over un-doped TiO2. The degradation rate of 1.5% Y/Eu-TiO2 of methylene blue was 86%, which was about 5 times of that of un-doped TiO2, and the possible reasons for the improvement of photocatalytic activities were analyzed. In this experiment, the dopant amount of rare earth was 1.5% and the ratio of Y:Eu was 2:3 for the maximum photocatalytic degradation, and the sample calcined at 500 oC showed the best reactivity. For the best samples above, the removal rate of phenol under visble light was 53% whthin 2 h.     

Polymer-Immobilized Photosensitizers for Continuous Eradication of Bacteria

The photosensitizers Rose Bengal (RB) and methylene blue (MB), when immobilized in polystyrene, were found to exhibit high antibacterial activity in a continuous regime. The photosensitizers were immobilized by dissolution in chloroform, together with polystyrene, with further evaporation of the solvent, yielding thin polymeric films. Shallow reservoirs, bottom-covered with these films, were used for constructing continuous-flow photoreactors for the eradication of Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli and wastewater bacteria under illumination with visible white light using a luminescent lamp at a 1.8 mW·cm⁻² fluence rate. The bacterial concentration decreased by two to five orders of magnitude in separate reactors with either immobilized RB or MB, as well as in three reactors connected in series, which contained one of the photosensitizers. Bacterial eradication reached more than five orders of magnitude in two reactors connected in series, where the first reactor contained immobilized RB and the second contained immobilized MB.     

Interaction between gold (III) chloride and potassium hexacyanoferrate (II/III)—Does it lead to gold analogue of Prussian blue?

Prussian blue analogues are a class of compounds formed by the reaction between metal salt and potassium hexacyanoferrate (II/III). In our earlier report, the formation of Au@Prussian blue nano-composite was noticed on potential cycling the glassy carbon electrode in a medium containing gold (III) chloride and potassium hexacyanoferrate (III). Hence in this work, the formation of gold hexacyanoferrate was attempted by a simple chemical reaction. The reaction of gold (III) chloride with potassium hexacyanoferrate (II/III) was examined by UV–Vis spectroscopy and found that there is no redox reaction between gold (III) chloride and potassium hexacyanoferrate (III). However, the redox reaction occurs between gold (III) chloride and potassium hexacyanoferrate (II) leading to the formation of charge transfer band and the conversion of hexacyanoferrate (II) to hexacyanoferrate (III) was evidenced by the emergence of new absorption peaks in UV–Vis spectra. The oxidation state of gold in Au–Fe complex was found to be +1 from X-ray photoelectron spectroscopy. The stability of the Au–Fe complex was also studied by cyclic voltammetry. Cyclic voltammetric results indicated the presence of high spin iron in Au–Fe complex. Hence ‘as formed’ Au complex may be KFe_x[Au(CN)₂]_y. The results revealed that the formation of gold hexacyanoferrate was not feasible by simple chemical or electrochemical reaction in contrast to other Prussian blue analogues.     

纳米自洁涂料特性表征和评价方法研究进展

纳米自洁涂料的自清洁特性包括两方面：涂膜具有拒水、拒油和拒污染物特性，以及涂膜具有促进光降解污染物特性。前者特性的表征和评价方法，主要有涂膜化学成分分析、与水接触角和滚动角测定、对粉煤灰耐沽污性测定、对炭黑集灰效果测定、涂膜表面在纳米和微米水平上形貌观察等；后者特性的表征和评价方法，有涂膜对光降解亚甲基蓝和茜素红能力测定等。文章对纳米涂料自清洁特性的表征和评价方法进行综述。     

Photocatalytic oxidation of methylene blue dye under visible light by Ni doped Ag2S nanoparticles

Ag₂S nanoparticles were prepared using a hydrothermal method, and Ni was doped via a photo-assisted deposition method. The samples produced were characterized using different tools. Furthermore, the catalytic performance of the Ag₂S and Ni/Ag₂S samples was examined in the degradation of methylene blue dye under visible light. The UV–vis spectral analysis detected a red shift after loading of Ni. The maximum degradation efficiency achieved was 100% with 3 wt% Ni/Ag₂S as the photocatalyst after a 40-min reaction time. The catalyst could be reused without any loss in activity for the first five cycles.     

Synthesis of novel ZnO/carbon xerogel composites: Effect of carbon content and calcination temperature on their structural and photocatalytic properties

This paper reports the development of new ZnO/carbon xerogel composites (XZn w) for photocatalytic applications. The use of black wattle tannin as a precursor to the carbon xerogel aimed at reducing costs and environmental impacts. The composites were characterized by diffuse reflectance spectroscopy (DRS), BET surface area, scanning electron microscopy (FEG-SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), infrared spectroscopy (IR), and X-ray diffraction (XRD). The photocatalytic performance of the materials was evaluated in the decomposition process of methylene blue, a known toxic pollutant. The impacts of the catalyst dosage and calcination temperature on the photocatalytic process were also examined systematically. The X-ray profiles of the XZn w evidenced the existence of the hexagonal structure of the zinc oxide (wurtzite) in the composites. The XPS and XRD analyses confirmed the incorporation of carbon in the zinc oxide crystalline structure. The higher carbon content resulted in a larger surface area. All composites presented the ability to absorb radiation in less energetic wavelengths, contrary to pure zinc oxide that only absorbs radiation of wavelengths below 420?nm. The optimal dosage and calcination temperature were found to be 0.2?g?L^?1 and 300?°C. All the developed composites displayed significant photocatalytic activities in the decomposition of methylene blue under both visible and solar light. The composites had superior photocatalytic efficiency under visible light when compared to pure zinc oxide. The XZn 0.5 presented the best degradation efficiency under visible radiation. All materials presented similar photocatalytic responses under solar light, evidencing the synergy between the carbon xerogel and the zinc oxide. The photocatalytic mechanism was evaluated by trapping experiments to be mainly controlled by the electron vacancies that are generated during the photoexcitation of the composites.     

基于微旋流装置的大米淀粉吸附亚甲基蓝性能研究

以大米淀粉为吸附剂,在微旋流器中吸附亚甲基蓝水溶液模拟的印染废水。通过单因素试验分析淀粉浓度,分流比和进料流量对吸附效率和分离效率的影响规律。运用响应面分析法,对试验参数进行优化。结果表明:淀粉浓度、分流比和进料流量对吸附效率和分离效率均有影响,对吸附效率影响的大小顺序为淀粉浓度分流比进料流量,对分离效率影响的大小顺序为分流比进料流量淀粉浓度。综合考虑吸附效率和分离效率后得到最佳参数条件为:淀粉浓度1. 0%,分流比19%,进料流量1 080 kg/h,该条件下吸附效率为69. 2%,分离效率为74. 3%。     

Analysis of methylene chloride product labelling

From 1988, certain consumer products that contained the chemical methylene chloride (DCM) were required to display precautionary labelling, warning consumers of potential health hazards. To determine the effect of this labelling requirement, a survey of consumer use behaviour was conducted. Where possible, this survey paralleled an earlier 1986 study of DCM use practices. Results of the post-labelling study showed that while fewer customers reported reading the product labels, many precautionary behaviours increased. A small proportion of users reported altering their behaviour in response to reading on-product instructions. The relationship between the extent of label reading and precautionary behaviour was complex. After controlling for differences in product familiarity, significant linear relationships between the extent to which the label was read and the likelihood of utilizing certain ventilation techniques were observed for infrequent users of some products.     

Solution-processed cathode-interlayer-free deep blue organic light-emitting diodes

Efficient non-doped deep blue organic light-emitting diodes (OLEDs) were fabricated by solution-processing method by using a series of small molecules consisting of various contents of triphenylamine and phosphonate-featured fluorene units as the emitting layer. Without any electron-injection layer, one of the optimal devices with a simple double-layer device configuration exhibits a maximal current efficiency of 2.59 cd A⁻¹ at 6.8 V (1.72 mA cm⁻²) with a CIE coordinates of (0.163, 0.097). These double-layer devices are demonstrated with excellent color-stability under a wide range of operating current density. The current work indicates that electron-rich triphenylamine moiety incorporated with phosphonate-featured fluorene units could be utilized as building blocks to construct a multi-functional platform combining good electron-injection property, carrier-transport property, and efficient electroluminescence. It also provides an approach to achieve a structure-simplified color-stable efficient blue OLED.