Papers by Keyword: Methyl Orange (MO)

Abstract: In the present study, three kinds of zeolite (NaP1, NaA, and NaX) were synthesized by a hydrothermal method. These zeolites were modified by cetyl trimethyl-ammonium bromide (CTAB), and used to adsorb methyl orange (MO). NaP1 had the highest adsorption capacity, with a 99.7% MO removal percentage. An orthogonal experiment was conducted to determine the influence of adsorbent dosage, solution pH, initial MO concentration, contact time, and solution temperature on NaP1. The results showed that the initial MO concentration had the most significant effect. The adsorption isotherms of the zeolites are in a good agreement with the Langmuir formula, and the adsorption mechanism is also discussed.

Abstract: In order to study the ion effect on titania phase structure, crystallite size, and photocatalytic activity, Rb+-doped TiO2 nanoparticles were prepared via a modified sol-gel method and characterized by means of X-ray diffraction, Energy Dispersive X-rays spectroscopy and transmission electron microscopy. The photocatalytic activity of the elaborated powders was studied following the degradation of methyl orange. The results indicate that doping Rb+ increases the BET surface area of TiO2 crystals, decreases the crystal size, reduces the diminishing rates of surface area with increasing calcinations temperature, raises the temperature at which anatase changes into rutile phase, and so significantly increases the photocatalytic activity of TiO2. The kinetics of the methyl orange degradation fits Langmuir-Hinshelwood kinetics model well.

Abstract: Ag doped TiO2 was formed on the surface of carbon nanotube(CNT) by the sol-gel method, and characterized by TEM, XRD. The photocatalytic activity of the Ag-TiO2 /CNT was evaluated in degradation of methyl orange with a 300 W high pressure mercury lamp. Effect of Ag doping quantity on the photocatalytic activity of the photocatalys was investigated.The photocatalytic experiment indicated that the photocatalytic activity was firstly improved and then decreased with an increase of amount of Ag doped in TiO2 nanoparticles,the optimal doping quantity was 0.8% silver （ mass fraction of TiO2）, methyl orange could be degraded 99.3 % by Ag-TiO2/CNT under the optimal conditions after 120min.

Abstract: BaV2O6 photocatalyst was prepared by liquid-phase deposition method in paper and different calcination temperature effecting photocatalytic activity were investigated. X-ray diffraction (XRD) has been employed to characterize the as-synthesized materials. The photocatalytic activity was evaluated by degradation of Methy lorange(MO) under the UV-light.It was found that as-prepared BaV2O6 with molar ratio of V5+ to Ba3+ be 2:1, pH=7 and calcinated under 500°C for 4h exhibits higher activity than any other calcination temperature. The highest degragation rate was about 65% or so in 100min.

Abstract: BiVO4 hollow nano-fiber photocatalytic material was prepared via two steps method of soaking and thermal transition using the cotton fiber as the template. The as-prepared samples were characterized by XRD, SEM and BET. The photocatalytic activity under visible light was evaluated by photocatalytic degradation of methyl orange(MO) in the solution. It was found that the samples calcinated at 400°C for 3.5 h had the hollow tube structure which is the copy of the cotton fibre structure and had the best photocatalytic activity. The decolorization rate of methyl orange can reach to be 97 % or so, increased 16 % than that of sample that prepared with no cotton fiber template. It indicated that the sample’s morphology and the specific surface area was the main reason of higher photocatalytic activity.

Abstract: The functions of applied potential to the photoelectrocatalytic degradation process of methyl orange were investigated. When using 0.05 M NaCl and under different applied potentials, the degradation rate increased obviously with increasing applied potential. When the applied potential was between 0.6 V-1.0 V, the degradation rate was enhanced drastically. The detected current values got larger as the applied potential increased from 0 up to 1.2 V. There was no direct electro-degradation to the dye in the solution. The applied potential and the irradiated light had synergetic effect when they were applied to the solution at the same time. While after irradiation for 0 to 60 min, with the increasing reaction time, methyl orange absorption peak intensity shrank obviously. The azo and benzene groups in methyl orange degraded totally under photocatalytic process.

Abstract: The compound photocatalytic materials of TiO2/SnO2 films with bilayer structure supported on polyacrylonitrile based carbon fiber (PAN-CF) substrates were prepared via the dip-coating technology, and Titanium dioxide (TiO2) and tin dioxide (SnO2) precursory sol were prepared by sol-gel method. Field emission scanning electron microscopy (FE-SEM), X-ray energy spectrum (EDS) and X-ray diffraction (XRD) were used to characterize the structure of materials, and methyl orange (MO) with concentration of 80mg/L as the target degradants was used to investigate the photocatalytic property of the composites under UV irradiation. The results revealed that the photocatalytic activity of composite is effectively enhanced result from the application of TiO2/SnO2 bilayer structure films, which can be considered as that the recombination of photo-induced electrons is restrained by SnO2 film effectively, and the 3#-TiO2/SnO2/CF exhibited optimum catalytic performance. In addition, the superiority of carbon fiber as carrier was played fully due to the generation of porous films, which is favorable to capture the intermediate products.

Abstract: Photoelectrocatalytic oxidation of methyl orange on TiO₂ films were investigated in KNO₃ solution. In the potential range up to 1.2 V, electro-degradation rates were fairly low that was less than 1%. Degradation rates on the two films were larger at higher potentials. The film prepared without PEG showed better activities than the film prepared with PEG during the whole range of potential. Methyl orange degradation rate increased with increasing KNO₃ concentration from 0 to 0.010 mol/l. After 120 min of irradiation, methyl orange degradation rate on the film with PEG was 89.5%, while degradation rate on the film without PEG was 92.0% after the same period.

Abstract: When potential was less than 1.2 V, electro-degradation rate was not more than 1.2% on both the films prepared using PEG or not. The film prepared with addition of PEG showed better degradation rates in the whole potential range than the film prepared without using of PEG. The highest degradation rates existed at 1.1 V of applied potential for both of the film electrodes, where degradation rate on film with PEG was 93.6% and the rate was 92.2% on the film without PEG. Methyl orange degradation rates increased with increasing KCl concentration from 0 to 0.7 mol/l, while degradation rates dropped down at even higher potential. Degradation rates increased with prolonged irradiation time for both of the two film electrodes.

Abstract: Porous TiO₂ film was prepared by a sol-gel method using PEG1000 as pore forming template. The porous film and normal film were used as electrodes in a photoelectrocatalytic reactor. The functions of applied potential and concentration of NaH₂PO₄ to the photoelectrocatalytic degradation process of methyl orange were investigated. The results show that methyl orange cannot be degraded solely by the applied potential. Under the applied potential of 2 V, 49.9% of the initial dye can be removed on the normal TiO₂ film electrode, which is much better than the 31.1% removal rate on the porous TiO₂ film electrode. The normal TiO₂ film electrode has better performance than the porous TiO₂ film in the whole NaH₂PO₄ concentration range. After 80 min of reaction, degradation rate is 93.7% on the normal TiO₂ film electrode. After 100 min of reaction, degradation rate is 89.7% on the porous TiO₂ film electrode.