热辅助紫外光催化氧化方法用于总磷检测的实验研究和动力学分析(英文)

A novel thermal-assisted ultra-violet (UV) photocatalysis digestion method for the determination of total phos-phorus (TP) in water samples was introduced in this work. The photocatalytic experiments for TP digestion were conducted using a 365 nm wavelength UV light and TiO2 particles as the photocatalyst. Sodium tripolyphosphate and sodium glycerophosphate were used as the typical components of TP and the digested samples were then determined by spectrophotometry after phosphomolybdenum blue reaction. The effects of operational parameters such as reaction time and temperature were studied for the digestion of TP and the kinetic analysis of two typical components was performed in this paper. The pseudo-first-order rate constants k of two phosphorus compounds at different temperatures were obtained and the Arrhenius equation was employed to explain the effect of temperature on rate constant k. Compared with the conventional thermal digestion method for TP detection, it was found that the temperature was decreased from 120 °C to 60 °C with same conversion rate and time in this thermal-assisted UV digestion method, which enabled the digestion process work at normal pressure. Compared with the individual ultra-violet (UV) photocatalysis process, the digestion time was also decreased from several hours to half an hour using the thermal-assisted UV digestion method. This method wil not lead to secondary pol ution since no oxidant was needed in the thermal-assisted UV photocatalysis digestion process, which made it more compatible with electrochemical detection of TP.     

Photorheologically reversible micelle composed of polymerizable cationic surfactant and 4-phenylazo benzoic acid☆

A photorheologically reversible micelle composed of polymerizable cationic surfactant n-cetyl dimethylallyl ammonium chloride(CDAAC) and trans-4-phenylazo benzoic acid(trans-ACA) was prepared.The effects of molar ratio of CDAAC/trans-ACA,time of UV and visible light irradiation and temperature on the rheological properties of micellar system were investigated.The results show that before UV irradiation the system with an optimum CDAAC/trans-ACA molar ratio of 1.4 forms viscoelastic micelles at 45 °C.After 365 nm UV irradiation,the viscosities of micelle systems with different concentrations at fixed molar ratio of 1.4 are decreased by 85%–95%.The CDAAC/trans-ACA(14 mmol·L-1/10 mmol·L-1) micelle system exhibits shear thinning property and its viscosity is decreased obviously with the increases of UV irradiation time less than 1 h.The rheological process during UV irradiation for CDAAC/trans-ACA(14 mmol·L-1/10 mmol·L-1) micelle proves that viscosity,elastic modulus G′ and viscous modulus G″ will reduce quickly with the UV light.Furthermore,the micelle system after 1 h UVirradiation is able to revert to its initial high viscosity with 460 nm visible light irradiation for 4 h,and the micelle can be cycled between low and high viscosity states by repetitive UV and visible light irradiations.The UV–Vis spectra of CDAAC/trans-ACA micelle indicate that its photosensitive rheological properties are related closely to photoisomerization of trans-ACA to cis-ACA.     

侧光光纤引导的内源可见光催化降解亚甲基蓝(英文)

The side-glowing optical fibers (SOFs) were chosen as the conducting medium of endogenous light; and 20 mg·L-1 methylene blue was chosen as the target to be degraded. The SOF is made up of quartz core with a silicon cladding, which can emit light through side surface more uniformly and transmit light for longer distance to avoid attenuation of light by liquid medium. The filament lamp was chosen as visible light source. Different reaction conditions, such as the presence of optical fiber or not, the quantity of SOF, light irradiation intensity were tested by measuring the methylene blue degradation of methylene blue. The results show that suitable reaction conditions were 1.167 g·L-1 Ag + /TiO 2 with 7% (by mass) of Ag + doped in TiO 2 , and 500 roots of SOF (30 cm length in solution). The photocatalytic degradation efficiency under 300W lamp irradiation for 8h was about 97%. And the photocatalytic degradation efficiency of methylene blue degradation was proportional to SOF quantity, light irradiation intensity and catalytic dosage within a certain range. Compared with general UV and visible light SOFs could save a huge amount of energy and cost, in the potential applications in dealing with organic pollutants on a large scale.     

Mechanochemical Synthesis of Visible-light Induced Photocatalyst with Nitrogen and Carbon Doping

Nitrogen and/or carbon doped titania photocatalysts were prepared by a novel mechanochemical method. The prepared powders possessed two absorption edges around 400 and 540 nm wavelengths and showed excellent photocatalytic ability for nitrogen monoxide oxidation under visible light irradiation. Under the irradiation of visible light of wavelength >510 nm, 37% of nitrogen monoxide could be continuously removed by the carbon and nitrogen co-doped titania prepared by planetary ball milling of P-25 titania-10% hexamethylenetetramine mixture followed by calcination in air at 400?C.     

Light olefin production by catalytic co-cracking of Fischer–Tropsch distillate with methanol and the reaction kinetics investigation

Catalytic co-cracking of Fischer–Tropsch(FT) light distillate and methanol combines highly endothermic olefin cracking reaction with exothermic methanol conversion over ZSM-5 catalyst to produce light olefins through a nearly thermoneutral process. The kinetic behavior of co-cracking reactions was investigated by different feed conditions: methanol feed only, olefin feed only and co-feed of methanol with olefins or F–T distillate. The results showed that methanol converted to C_2–C_6 olefins in first-order parallel reaction at low space time, methylation and oligomerization–cracking prevailed for the co-feed of methanol and C_2–C_5 olefins, while for C_6–C_8 olefins,monomolecular cracking was the dominant reaction whether fed alone or co-fed with methanol. For FT distillate and methanol co-feed, alkanes were almost un-reactive, C_3–C_5 olefins were obtained as main products, accounting for 71 wt% for all products. A comprehensive co-cracking reaction scheme was proposed and the model parameters were estimated by the nonlinear least square method. It was verified by experimental data that the kinetic model was reliable to predict major product distribution for co-cracking of FT distillate with methanol and could be used for further reactor development and process design.     

燃烧法制备二氧化钛催化剂的条件对其可见光催化性能的影响

Titania catalysts were synthesized by a solution combustion method （SCM）. Photodegradation of 4-chlorophenol （4-CP） using the synthesized catalysts was studied under both visible light （λ≥420nm） and sunlight irradiation. The effect of preparation conditions on photocatalytic activities of the synthesized catalysts was investigated. The optimal photocatalytic activity of the catalyst （denoted as A1 ） was obtained under the following synthesis conditions： ignition temperature of 350~C, fuel ratio （ φ） of 1 and calcination time of lh. The degradation and mineralization ratio of 4-CP were 78.2% and 53.7% respectively under visible light irradiation for 3h using catalyst A1. And the catalyst A1 also showed high photocatalytic activity under sunlight irradiation.     

One step synthesis and characterization of copper doped sulfated titania and its enhanced photocatalytic activity in visible light by degradation of methyl orange

This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying(2.0%–10.0%, by mass) by single step sol gel method. The synthesized photo catalyst has been characterized by employing various techniques like X-ray Diffraction(XRD), Ultraviolet–Visible Diffuse Reflection Spectroscopy(UV–Vis DRS), X-ray Photoelectron Spectroscopy(XPS), Scanning Electron Microscopy(SEM), Energy Dispersive Spectrometry(EDS), Fourier Transform Infrared Spectroscopic Studies(FT-IR), and Transmission Electron Microscopy(TEM). From the XRD and TEM results, all the samples were reported in anatase phase with reduction in particle size in the range of 7 to 12 nm. SEM indicated the change in morphology of the particles. The presence of copper in titania lattice was evidenced by XPS. From UV–Vis DRS and FT-IR studies indicated that prominent absorption shift is observed towards visible region(red shift), the entry of Cu2+into Ti O2 lattice as a substitutional dopant and SO42-ions were covalently bonded with Ti4 +on the surface of the copper doped titania respectively.The photocatalytic activity studies were investigated by considering methyl orange(MO) as dye pollutant in the presence of the visible light. The effect of various parameters like effect of dosage of the catalyst, dopant concentration, p H of the solution, and concentration of the dye was studied in detail.     

纳米N掺杂TiO2的制备及可见光催化活性研究

N-doped TiO2 nanoparticle photocatalysts were prepared through a sol-gel procedure using NH4C1 as the nitrogen source and followed by calcination at certain temperature. Systematic studies for the preparation parameters and their impact on the structure and photocatalytic activity under ultraviolet （UV） and visible light irra-diation were carried out. Multiple techniques （XRD, TEM, DRIF, DSC, and XPS） were commanded to characterize the crystal structures and chemical binding of N-doped TiO2. Its photocatalytic activity was examined by the deg- radation of organic compounds. The catalytic activity of the prepared N-doped TiO2 nanoparticles under visible light （λ〉400nm） irradiation is evidenced by the decomposition of 4-chlorophenol, showing that nitrogen atoms in the N-doped TiO2 nanoparticle catalyst are responsible for the visible light catalytic activity. The N-doped TiO2 nanoparticle catalyst prepared with this modified route exhibits higher catalytic activity under UV irradiation in contrast to TiO2 without N-doping. It is suggested that the doped nitrogen here is located at the interstitial site of TiO2 lattice.     

Experimental research on breakup of 2D power law liquid film☆

On account of limited knowledge of the breakup of power law liquid film, the process of its disintegration and atomization was studied by using a planar liquid film. A linear stability analysis was adopted to predict the breakup characteristics of the power law film. The predicting formulas of stripping breakup length and diameter of ligament were put forward presently. Through high-speed photography and laser light sheet illumination, different breakup characteristics of flat power law film under different conditions were derived. The characteristic dimension of breakup regimes were defined and extracted. The effects of several parameters (injection pressure, ambient pressure, nozzle structure and fluid property) on the stripping breakup length and spray angle were investigated. The results revealed that increasing both the velocity of liquid film and the ambient pressure facilitated the breakup of film, reduced the stripping breakup length and enlarged the spray angle in different extents. The comparison between theoretical and experimental results was conducted to validate the feasibility of the linear stability theory.     

金属卟啉催化的甲苯氧化及工艺优化

Catalytic activities of a series of metalloporphyrin complexes in selective aerobic oxidation of toluene were investigated.The effects of different central metal ions in metalloporphyrins[T（p-Cl）PPMCl（M=Fe,Co,Mn,Cu）] on the reaction course had been examined and it was found that T（p-Cl）PPCu presented the highest catalytic activity in the reaction.The reaction conditions of toluene oxidation were optimized by using orthogonal experiment design.Five relevant factors were investigated：temperature,air pressure,catalyst loading,air flow rate and reaction time.The effects of the five factors on both toluene conversion and total yield of benzaldehyde and benzyl alcohol were discussed.The research results showed that the reaction temperature was the most significant factor influencing toluene oxidation.On the basis of the margin analysis,the optimum conditions for the toluene conversion and the total yield of benzaldehyde and benzyl alcohol respectively were achieved,under which the toluene conversion was up to 14.67%and the total yield of benzaldehyde and benzyl alcohol reached 5.89%.     

二芳基乙烯类光致变色化合物的合成及其光电性质研究

在氮气及-78℃条件下,合成了两种二芳基乙烯类光致变色化合物1,2-双(2-甲基-5-(4-N,N-二甲氨基苯基)噻吩-3-基)全氟环戊烯(Ⅰa)和1,2-双(2-甲基-5-萘基噻吩-3-基)全氟环戊烯(Ⅱa),通过紫外-可见吸收光谱、荧光光谱、循环伏安法对其光谱特性和电化学性质进行了初步研究。在254nm紫外光照射下,Ⅰa和Ⅱa的氯仿溶液均由无色变为蓝色,最大吸收峰分别为620和570nm,在适当波长可见光照射下,均从有色态返回到无色态。通过UV-Vis光谱考察了这两种二芳基乙烯类化合物在溶液中的光致变色反应的动力学特征,实验结果表明,二芳基乙烯类光致变色化合物的闭环反应属于零级反应,开环反应为一级。电化学研究表明,在溶液中,Ⅰa和Ⅱa可发生不可逆的阳极氧化反应。     

光致变色化合物螺萘并吡喃的合成及光谱性能

以2-萘酚、苯肼和3-甲基-2-丁酮为原料,设计并合成了一种含萘环螺吡喃类光致变色化合物:1,3,3-三甲基吲哚啉螺萘并吡喃,通过1HNMR、IR和元素分析表征了它的分子结构,利用紫外光谱和荧光光谱对目标化合物的吸收光谱和光致发光光谱进行了研究,初步探索了目标产物的光致变色性能。吸收光谱结果表明,目标分子(闭环体)的二氯甲烷溶液(1×10-4mol/L)在可见光区基本无吸收而呈现无色,但经254 nm的紫外光照射后其开环体在480 nm处有较强的吸收而呈现红色(A=1.1),停止紫外光照射溶液恢复为无色,显示了良好的光致变色性能;发光光谱结果显示,目标分子经紫外光激发后其开环体在433 nm处有较强的蓝光发射。     

Photoswitching electrospun nanofiber based on a spironaphthoxazine-isophorone-based fluorescent dye system

A bistable photoswitching photochromic spironaphthoxazine/isophorone-based fluorescent dye system was investigated. The photoregulated fluorescence switching behavior of a spironaphthoxazine/isophorone dye loaded poly(methyl methacrylate) nanofiber was also studied. Reversible modulation of fluorescence intensity was achieved using alternating irradiation with UV and visible light. The erasable and rewritable optical storage based on spironaphthoxazine/isophorone dye loaded poly(methyl methacrylate) nanofiber has been developed.     

Oberflächenstrukturierung polymerer Fasern durch UV-Laserbestrahlung, 15. Beschreibung des Temperaturfeldes in PETP-Polymeren während und nach der Laserbestrahlung mit einem gepulsten UV-Laser

For understanding the generation of UV laser induced surface structures of PETP polymers the temperature field within the irradiated surface is calculated in dependence on the laser irradiation wavelength (193 nm, 248 nm, 308 nm), pulse time, pulse form, the irradiation intensity and depth, using temperature-independent material data of PETP polymers known from literature. For this purpose the solution function of the one-dimensional heat differential equation is used. Depending on the order of magnitude of the absorption coefficient of the polymer for UV light of different wavelengths, surface temperatures of approx. 16 000°C (193 nm), 11 000°C (248 nm) and 500°C (308 nm) are calculated at the end of the laser pulse. The temperature input within the polymer layer is limited to only a very small penetration depth. For the irradiation with the two laser wavelengths of 193 nm and 248 nm this is less then 0.4 μm. The cooling process is considerably slower, reaching the initial temperature after approx. 4 μs.     

Direct coloration of textiles with photochromic dyes. Part 3: dyeing of wool with photochromic acid dyes

Wool dyed with two isomeric water‐soluble spirooxazine‐based photochromic acid dyes, which were specifically designed and synthesised for direct application to protein and polyamide substrates, showed reversible change from a pale yellowish colour to blue when exposed to sunlight or UV light. With the first dye, significantly higher photochromic colour change was obtained when the wool was bleached, a feature attributed to a more open fibre structure which may facilitate penetration of the non‐planar dye anion and also the photocoloration reaction which requires a change in molecular geometry. Experimentation demonstrated that the optimum conditions for application of this dye to wool was from an aqueous dyebath at neutral pH and a temperature of 60 °C. An investigation using HPLC demonstrated that the dye was susceptible to decomposition in aqueous solution at higher temperatures and at lower pH values. The second dye was also applied to wool fabric to give a fabric with similar photochromic properties. The technical performance of the dyed fabrics, in terms of washfastness and photostability, was assessed.     

Optimisation of organic solvent–pH buffer solutions to improve the photochromic performance of plant‐derived 3‐deoxyanthocyanidin dye

Plant‐derived 3‐deoxyanthocyanidins are photochromic materials that are coloured under ultraviolet (UV) irradiation and decoloured under light‐shielded storage. In this study, the optimised solvent composition is investigated to enhance the photochromic performance of luteolinidin, a 3‐deoxyanthocyanidin derivative. The visible absorbance ratio between the solution after UV irradiation and after storage in the dark, an index of photochromic performance, was found to be affected by the pH of the solution, and the value reached a maximum when the pH of the solution was 5.7. The type of organic solvent, which is necessary to dissolve luteolinidin, also affected the photochromic performance. When diethylene glycol or dipropylene glycol was used, the value of the absorbance ratio was especially large. Furthermore, this optimised solvent composition displayed excellent photochromic properties with an extract from the sorghum grain shell containing a large amount of 3‐deoxyanthocyanins.     

Synthesis of novel photochromic spiropyran dyes containing quaternary ammonium salt or cinnamoyl moiety and their properties as photoinitiators

Three novel spiropyran (SP) dyes containing quaternary ammonium salt or cinnamoyl moiety were synthesized and their photosensitive properties as photoinitiator were characterized by UV–vis spectroscopy. The intramolecular electron transfer of SP dyes containing quaternary ammonium salt was much faster and can initiate the photopolymerization under UV irradiation though the photochromic properties than those of SPs containing cinnamoyl group. A photoinitiation system containing SPs and the hexaarylbisimidazoles was studies, and the initiation properties were tested by monitoring the conversion rate of double‐bond at 810 and 1640 cm^?1 with ‐time infrared spectroscopy. It was found that the system containing our SP derivatives exhibited much higher initiating efficiency than ever reported SP dyes in the photopolymerization of 2‐phenoxyethylacrylate/N‐vinylcarbazole. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Improved photochromic and fatigue performance of (E)‐dicyclopropylmethylene‐(2,5‐dimethyl‐3‐furylethylidene)‐succinicanhydride doped in polyurethane thin film

Improved photochromic properties and fatigue performance of (E)‐dicyclopropylmethylene‐(2,5‐dimethyl‐3‐furylethylidene)‐succinicanhydride doped in polyurethane thin film were discussed in this study. Fulgide 1‐E doped in polyurethane polymer films was heated at various annealing temperatures. Upon irradiation with UV light (366 nm), fulgide 1‐E undergoes a conrotatory ring closure to the pink‐colored closed form 1‐C . The latter color was switched back to the original color when the films were irradiated with white light. The kinetics of photocoloration and photobleaching processes was followed spectrophotometrically by monitoring the absorbance of the ring‐closed product 1‐C at its λ_max of 525 nm. The first‐order plots of photocoloration reaction show distinct linear line and the slope of which corresponding to the first‐order rate constants k. It was found that for photocoloration reaction, the rate constant of the photocoloration reaction is slower than the photobleaching reaction, and both reactions decrease with increasing the annealing temperatures. It was found that there was almost complete loss of photochemical fatigue resistance of fulgide 1 doped in polyurethane polymer film irrespective of the annealing temperature. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Photo and thermal properties of cinnamoyl Pluronic F‐127

Cinnamoyl chloride was covalently attached to the ends of Pluronic F‐127 chains. The molar ratio of cinnamoyl groups to Pluronic F‐127 of the cinnamoyl Pluronic F‐127 (Cin‐Plu) was calculated to be about 1:1 on a ¹H NMR spectrum. The melting point (around 52 °C) of Cin‐Plu was somewhat less than that (around 55 °C) of Pluronic F‐127. Furthermore, the melting point of Cin‐Plu decreased to around 50 °C on UV irradiation. The micellization temperature of Pluronic F‐127 was around 15 °C and it was affected neither by the covalent attachment of cinnamoyl chloride nor the UV irradiation. On the other hand, Pluronic F‐127 solution (22% w/v) in distilled water became a gel at around 28 °C and Cin‐Plu solution (22% w/v) at around 39 °C. The elevation in the gelation temperature is possibly because the cinnamoyl group interferes with the intermolecular hydrophobic interaction of propylene oxide blocks, a main cause for the gelation. Cin‐Plu solution (22% w/v) which had been subjected to UV irradiation (365 nm, 400 W) for 3 h exhibited no gelation temperature but a gradual increase in viscosity when the solution temperature increased from 17 °C to 37 °C, possibly due to the coexistence of dimeric Cin‐Plu and monomeric Cin‐Plu. © 2013 Society of Chemical Industry     

Wavelength sensitivity of the photodegradation of poly(methyl methacrylate)

Poly(methyl methacrylate) (PMMA) was photolyzed with monochromatic light of wavelengths 260, 280, 300, 320, 400, and 500 nm in vacuo by the use of the Okazaki Large Spectrograph. UV spectral changes, the quantum yields of main-chain scission (?cs), and effects of wavelength were investigated. UV spectral changes around 280 nm were observed with irradiation at 260 nm. The ?cs has a maximum value in case of irradiation with 300 nm light. It turned out that photodegradation of PMMA took place by irradiation of 260–320 nm light but did not by irradiation with the light longer wavelength than 340 nm. The average values of ?cs obtained in this work were 0.84 × 10^?4, 1.06 × 10^?4, 4.21 × 10^?4, 1.23 × 10^?4, 0, and 0 for irradiations at 260, 280, 300, 320, 400, and 500 nm, respectively. It was found that the photo-induced side-chain scission initiates the main-chain scission of PMMA by irradiation of 260 and 280 nm light. © 1993 John Wiley & Sons, Inc.