Papers by Keyword: AZO Dye

Abstract: This study explored the decolorization kinetics of azo dye (methyl orange) with the presence of high entropy alloys (HEAs) as a catalyst in the Fenton process. The kinetic reaction of the azo dye was determined using the first and second-order kinetics model. The slope from the first pseudo kinetics model was determined to compute the decolorization rate constant (K) This present work showed that the model was significantly well fitted with the experimental data. The highest K value of HEA catalyst was occurred at 30 minutes within 60 minutes of the Fenton reaction. The obtained result also showed the efficiency of the high entropy alloys (HEAs) rapidly degraded the azo dyes.

Abstract: FeCoNiAlSi and FeCoNiAlBSi high entropy alloys (HEAs) were synthesized by mechanical alloying. Phase evolution, crystallite size, lattice strain, microstructure and morphology for the two alloys were investigated. It was found that two simple structures which are face-centred cubic (FCC) and body-centered cubic (BCC/B2) solid solution appear in FeCoNiAlSi HEA after 50 h of milling. Formation of Fe₂B peak was observed in the XRD pattern when a small amount of boron was added to the base alloys. The particle size of the alloy was increased after 20 h of milling time. The structural analysis shows that the average crystallite size decreases while lattice grain size increases with the increasing milling time. The morphology structure of the milled powders shows the particles size becomes rounded, flat and rough as the milling time prolongs. The newly developed HEA synthesized by mechanical alloying is expected to provide prominent efficiency in degradation of azo dyes (Methyl Orange). Although the HEAs have been reported to provide larger surface area and excellent capacity, only a few studies have been reported on degradation of azo dye by using HEAs as catalyst. Therefore, the method derived from the results of this study will contribute in treating azo dyes for wastewater treatment. Keywords: azo dye; high entropy alloys; mechanical alloying; crystal structure; morphology

Abstract: Simple, sensitive and accurate spectrophotometric methods have been developed for the determination of Sulphamethoxazole (SMZ) drug . This method based on the reaction of Sulphamethoxazole (SMZ) with new organic reagent (BYN) it was prepare by reaction between ethyl acetoacetate with 2,4-Dinitrophenylhydrazine. The azo dye product shows absorption maximum at 435 nm. The linearity ranges of Sulphamethoxazole are (2-14 μg.mL^-1) with molar absorptivity (14412.77 L.mol^-1.cm^-1), Sandell's sensitivity index (0.0175 μg.cm-²) , detection limit and Quantification limit ( 0.057, 0.175 μg / ml) respectively. The results showed there are no interferences of excipients on the determination of the drug. The proposed method has been successfully applied for the determination of sulfanilamide in pure and pharmaceutical formulations.

Abstract: Oxidative decolorization of azo dyes with a heterogeneous catalyst copper phthalocyanine supported Mg-Al hydrotalcites was studied and the influence factors such as initial pH value, temperature, H₂O₂ and CuPc-LDHs/H₂O₂ system were discussed. The results indicated that acidic solution and high temperature were conducive to oxidative decoloration of methyl orange. CuPc-LDHs/H₂O₂ system showed excellent oxidative decoloration capacity to remove azo dyes. The effects of oxidative decolorization of azo dyes were related to the molecular structure and weight of azo dyes. Oxidative decoloration effects followed the order as congo red > amido black > methyl blue> methyl orange> methylene blue.

Abstract: The study combines the UV/TiO₂ and an ultrasonic procedure to degrade the azo dye wastewater of Acid Yellow 17 and investigates the effects of various factors including the quantities of TiO₂ and iron ions added on the efficiency of the removal of the azo dye wastewater of Acid Yellow 17. The experimental results reveal the a significant additive effects occurs through the combination of the two procedures under the 13 watts UV irradiations and 10 watts ultrasound. The analysis of the catalyst properties indicates that there are no evident changes of the appearance of the crystal and TiO₂ catalyst when UV/TiO₂ is combined with ultrasonic procedures. Since the formation of hydrogen peroxide (ND≦1 mg L^-1) was not detected during the reactions, the additions of Fe (II) and Fe (III) are unable to induce the Fenton-like reaction effectively. Nevertheless, the additions of Fe ions significantly affect the degradation rate of the dye. Moreover, the effect of Fe (III) was found to be superior to that of Fe (II) under the same concentration.

Abstract: Cu/TiO₂ photocatalysts with different metal loading were prepared via modified depositionprecipitation method with the intention to reduce the band gap for Orange II degradation and mineralization under visible light radiation. The photocatalysts were characterized using thermal gravimetric analysis, powder X-ray diffraction, diffuse reflectance UV-Visible spectroscopy and field-emission scanning electron microscopy. 10 wt% photocatalysts showed the best performance compared to the bare TiO₂.

Abstract: The photoalignment properties of thin films made from several azo-containing thiophene-based acrylate with respect to the commercially available nematic liquid crystal (MLC 6873-100; ε>o) is reported. As observed, the photoalignment ability of these films is influenced by the number and disposition of fluoro-substituents and the position of attachment of the terminal thiophene moiety. Inclusion of a lateral fluoro-substituent (s) provides excellent photo alignment ability whereas the non-fluorinated counterpart tends to give unsatisfactory alignment quality. The performed study showed also that 2-substituted thiophenes give better photoalignment quality.

Abstract: Bioelectrochemical systems or electrochemical reduction reactors have great potential for treating wastewater that contains dyes for decolorization. They are reported to enhance decolorization rate and degree with external energy supply and to help microorganisms or noble metal as catalysts. Till now literatures regarding dye decolorization with electron reduction using BESs or electrochemical reactors is deficient. This paper reviews the performance limitations, future prospects, and improvements of the common used dyes decolorization and decolorization with external voltage or current supply in Bioelectrochemical systems.

Abstract: In the previous study, the decolorization of azo dye was significantly enhanced by the light irradiation. The aim of this study is to investigate the effect of methyl orange decolorization under light-emitting diode (LED). The effect of media, pHs, and nitrogens on methyl orange decolorization by freely suspended cells are examined. The results showed that the optimal conditions for the methyl orange decolorization by the Tsukamurella sp. J8025 are incubation at 30 °C and pH 8.0 in YEME medium under white-light LED.

Abstract: In this study we investigated the use of a microbial fuel cell (MFC) to abioticlly cathodic decolorization of a model azo dye, Methyl Orange (MO). Experimental results showed that electricity could be continuously generated the MO-fed MFC and MO was successfully decolorized in the cathode. The decolorization rate was highly dependent on the catholyte pH. When pH was varied from 3.0 to 9.0, the k value in relation to MO degradation decreased from 0.298 to 0.016 μmol min^-1, and the maximum power density decreased from 34.77 to 1.51 mW m^-2. Sulfanilic acid and N,N-dimethyl-p-phenylenediamine were identified as the decolorization products of MO by HPLC-MS.