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31.
《Arabian Journal of Chemistry》2020,13(1):431-443
Crystalline orthorhombic Bi2WO6 powders were synthesized by a hydrothermal method from aqueous solutions of Bi(NO3)3·5H2O and Na2WO4·2H2O over a range of three selected pH values (2.0, 5.0 and 7.0), using NaOH as precipitating agent. The as-prepared catalysts were characterized by XRD, BET, FE-SEM, TEM, XPS and UV-vis spectroscopy. The effect of pH-synthesis on crystallinity, morphologies, surface area and optical absorption properties, were investigated. Although the pH has a marked influence on morphology, the nature of the precipitating agent (NaOH or TEA) also influences the morphology and surface structure composition, as it is observed in the present work. Three different probe molecules were used to evaluate the photo-catalytic properties under two illumination conditions (UV and Visible): Methyl Orange and Rhodamine B were chosen as dye substrates and Phenol as a transparent substrate. The photo-catalytic activities are strongly dependent not only on the pH used in the synthesis but also on the nature of the chosen substrate in assessing the photo-catalytic activities. Results were compared with those obtained when using TiO2(P25, Evonik) in the same experimental conditions. The photo-catalytic activity of one of the synthesised samples has been evaluated by exposing a mixture of Rhodamine B and Phenol in water, to different illumination conditions. Our results provide new evidences about the issue of whether dyes are suitable substrates to assess the activity of a photo-catalyst. 相似文献
32.
《Arabian Journal of Chemistry》2020,13(11):8338-8346
The photodegradation of an industrial azo dye C.I Basic Red 46 was examined in a fixed-bed photoreactor using UV-lamps simulated to the solar irradiation. In our photodecolorization study, the UV/TiO2 process was optimized using the Box-Behnken approach to evaluate the synergistic effects of three independent parameters (initial concentration of the dye, flow rate, and UV intensity) on mineralization effectiveness. The response surface methodology was in good promise with the prediction model (coefficients of determination of decolorization and mineralization were R2Dec = 0.997 and R2TOC = 0.994, respectively). The effects of the factors could be estimated from a second–order polynomial equation and student’s t-test. The optimal parameters of decolorization and mineralization were as follows: initial concentration of colorant 25 mg L−1, rate of fluid flow 0.3 L min−1, and ultraviolet light intensity 38.1 W m−2. The decolorization and mineralization removal efficiency under these optimal conditions were 100% and 57.63% respectively. These results indicate that optimization using response surface methodology, based on the Box-Behnken approach, is an excellent tool for determining the optimal conditions, and the process can be easily extrapolated for a specific treatment of real waste water containing the azo dye C.I Basic Red 46. Also, the intermediates that were produced during photodegradation process of Basic Red 46 were determined by GC/MS. 相似文献
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34.
《印度化学会志》2023,100(3):100928
A new azo β-diketone (NA1) compound is synthesized by coupling reaction of 4-aminoantipyrine with acetylacetone. The NA1 compound is characterized via FTIR, Mass, 1H NMR and 13C NMR spectroscopies. The keto-enol tautomers of the compound electronic structures and energies are investigated using density functional theory (DFT) via B3LYP method/6-311G (d,p) level. The NA1 compound nonlinear optical (NLO) properties are studied via the diffraction patterns (DPs) and the Z-scan where the compound nonlinear index of refraction (NIR), the optical limiting (OLg) property using 473 nm visible, low power, continuous (cw) laser beam are used while the all-optical switching (AOS) property is studied using two laser beams of wavelengths 473 nm and 532 nm. 相似文献
35.
Shengchang Guo 《Journal of solid state chemistry》2004,177(12):4597-4604
A large anionic pigment has been intercalated into a layered double hydroxide (LDH) host by ion-exchange of an Mg/Al LDH-nitrate precursor with a solution of C.I. Pigment Red 48:2 (the calcium salt of 4-((5-chloro-4-methyl-2-sulfophenyl)azo)-3-hydroxy-2-naphthalene-carboxylic acid), in ethane-1,2-diol. After intercalation of the pigment, the interlayer distance in the LDH increases from 0.86 to 1.72 nm. Infrared spectra and TG-DTA curves reveal the presence of a complex system of supramolecular host-guest interactions. The UV-visible diffuse reflectance spectra of C.I. Pigment Red 48:2 show marked changes after heating at 200 °C and above, whereas there are no significant changes in the spectra of the intercalated pigment after heating at temperatures up to 300 °C, showing that the thermostability is markedly enhanced by intercalation in the LDH host. The pigment-intercalated LDHs exhibits much higher photostability to UV light than the pristine pigment, in the case of both the pure solids and their composites with polypropylene, as shown by measurement of CIE 1976 L*a*b* color difference (ΔE) values. 相似文献
36.
改性PAN纤维与铁离子的配位结构及其对染料降解的催化作用 总被引:8,自引:0,他引:8
在室温条件下应用偕胺肟改性聚丙烯腈纤维(AO-PAN)与FeCl3反应制备了聚丙烯腈纤维铁配合物(Fe-AO-PAN), 并分别使用X射线光电子能谱(XPS)、傅立叶红外光谱(FTIR)、动态热机械分析(DTMA)和电导法对Fe-AO-PAN进行了表征以确定其组成结构. 然后将Fe-AO-PAN作为非均相Fenton 催化剂应用于两种常用偶氮染料C.I.活性红195(RR 195)和C.I.酸性黑234(AB 234)的光催化氧化降解反应中, 考察了其对降解反应的催化作用. 结果表明, Fe-AO-PAN中的Fe3+能够与AO-PAN表面三个偕胺肟(AO)链节单元的三个氨基氮原子和三个羟基氧原子进行配位反应, 配位数为6. 在Fe-AO-PAN和辐射光存在下, 两种染料的氧化降解反应速度显著加快, 染料结构中的偶氮键和芳香环结构都遭到破坏. PAN纤维腈基转化率的提高不仅能够明显增加Fe-AOPAN表面结构中Fe3+含量, 而且可显著促进其对染料氧化降解反应的催化作用. 相似文献
37.
Excessive consumption of substances such as food colorants, exposure to doses of metal ions, antibiotic residues and pesticides residues above maximum tolerance limit have a detrimental effect on human health. Hence in detecting these harmful substances, the development of sensitive, selective and convenient analytical tools is an essential step. Graphene and graphene like 2D graphitic carbon nitride have shown great promise in the development of electrochemical sensors for determining the levels of these substances in different samples. In this paper, graphene and graphene like 2D graphitic carbon nitride applications on the determination of various food colorants in foods and drinks such as azo dyes (tartrazine, allura red, amaranth, carmine and sunset yellow); metal ions contaminants, antibiotic and pesticide residues in the environment are reviewed. 相似文献
38.
39.
Jan Muzikar Gerard Rozing Tom van de Goor Christine Eberwein Ernst Kenndler 《Journal of chromatography. A》2002,950(1-2)
A method based on capillary zone electrophoresis is presented for the determination of the purity of commercial dimeric cyanine dyes (TOTO, YOYO, BOBO, all -1 and -3 species, LOLO-1, POPO-1) that are common as fluorescent probes for nucleic acid staining. These dyes are tetracharged cations, and have a strong tendency to interact with negatively charged centres, where they are rapidly adsorbed, especially from aqueous solutions. Thus anionic sites at the capillary wall must be avoided, and aqueous buffers are not suitable. The method introduced here avoids both complications, using non-aqueous N,N-dimethylacetamide as solvent, and suppressing the dissociation of silanol groups at the capillary surface due to selection of acidic separation conditions (20 mmol/l perchloric acid as background electrolyte). The present method enables the determination of the purity of all 10 dyes in less than 15 min. The selectivity of the method allows separation of at least five main and differentiating a number of unresolved minor contaminants as demonstrated in detail for TOTO-3 as an example. Quantitation (with 100% normalisation of the peak areas) of nine lots of this dye results in a purity between 33 and 87%. 相似文献
40.