Catalytic Activity of Ba Doped Ta2O5 for Methylene Blue Degradation under Visible Light

2010 ◽  
Vol 156-157 ◽  
pp. 1440-1443
Author(s):  
Yan Hong Zhao ◽  
Min Sun ◽  
Shu Wei Wang ◽  
Wen Ming Tong ◽  
Xiao Jing Wang

The Ba doped tantalum oxide (Ba-Ta2O5) particles were synthesized using low temperature hydrothermal method. The phase structure of samples was characterized by X-ray diffraction (XRD). The result showed that Ba-Ta2O5 had still good crystallinity and belonged to rhombic crystal. The catalytic activity of samples was investigated with the degradation methylene blue (MB) under visible light. The degradation efficiency attained 82% when the reaction time was 12 h. The kinetics of MB degradation was respect to the first-order.

2011 ◽  
Vol 197-198 ◽  
pp. 281-284 ◽  
Author(s):  
Yan Hong Zhao ◽  
Li Chun Hou ◽  
Xiang Li ◽  
Xiaodong Yang ◽  
Xiao Jing Wang

Tungsten doped tantalum oxide (W-Ta2O5) particles were synthesized by a low temperature hydrothermal method. The phase structure of W-Ta2O5particles was characterized by X-ray diffraction (XRD). The XRD results indicated that the samples belonged to orthorhombic crystal. The photocatalytic activity of samples was investigated with degradation methylene blue (MB) under ultraviolet light. The degradation efficiency of MB under the catalysis of W-Ta2O5particles attained 91% when the reaction time was 7 h. The kinetics of MB degradation was respect to the first-order in the presence of the photocatalysts.


2016 ◽  
Vol 864 ◽  
pp. 117-122 ◽  
Author(s):  
Hesni Shabrany ◽  
Hendry Tju ◽  
Ardiansyah Taufik ◽  
Rosari Saleh

This paper discusses the catalytic activity of ZnO/CuO/nanographene platelets composites under visible light and ultrasound irradiation separately. The ZnO/CuO/nanographene platelets composites were synthesized using a sol-gel method. X-ray diffraction and nitrogen adsorption spectroscopy were employed to investigate the structural and surface area of the catalyst. The catalytic activity results showed that the presence of nanographene platelets in ZnO/CuO nanocomposites improved its efficiency in degrading methylene blue. A scavenger method was also used to understand the role of charged carriers and the active radical involved in the catalytic activity.


Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1453 ◽  
Author(s):  
Yun Liu ◽  
Yuanhong Xie ◽  
Mingjin Dai ◽  
Qingjiao Gong ◽  
Zhi Dang

A novel photo-Fenton catalyst named Ag/AgCl/MIL-101(Fe) was synthesized by the method of precipitation and photo reduction and characterized by X-ray diffraction patterns (XRD), Brunauer-Emmett-Teller (BET) measurements, Fourier transform infrared spectra (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectra. Moreover, the catalytic activity of the synthesized catalyst was tested using methylene blue (MB) as the target pollutant. The obtained results illustrated that the plasmonic material Ag/AgCl was successfully loaded on MIL-101(Fe) and the obtained catalyst exhibited an excellent catalytic activity under visible light at the neutral pH. According to the analyses of Plackett-Burman and Box-Behnken design, the optimum conditions for MB degradation were obtained. Under these conditions, the MB decolorization and mineralization efficiencies could reach to 99.75% and 65.43%, respectively. The recycling experiments also showed that the as-prepared catalyst displayed good reusability. In addition, the possible reaction mechanisms for the heterogeneous photo-Fenton system catalyzed by Ag/AgCl/MIL-101(Fe) were derived. The synthesized catalyst provides a promising approach to degrade organic pollutants in waste water.


2020 ◽  
Vol 9 (3) ◽  
pp. 21-26
Author(s):  
Hoa Dang Thi Ngoc ◽  
Tu Nguyen Thi Thanh

In this study, an efficient strategy for the synthesis of solvent titanium dioxide and titanium dioxide/graphitic carbon nitride (TiO2/g-C3N4) heterostructure photocatalyst was applied to fabricate a kind of visible-light-driven photocatalyst. The obtained samples were  characterised  by  means of  X-ray diffraction, infrared spectroscopy, ultraviolet–visible spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy and photoluminescence. The heterostructure shows higher absorption edge towards harvesting more solar energy compared with pure TiO2 and pure g-C3N4 respectively. The  photocatalytic  behaviour  under  visible light  and  kinetics of  the TiO2/g-C3N4 catalyst via methylene blue degradation were addressed. The results showed that the introduction of solvent titanium dioxide  into g-C3N4 enhanced  the  photocatalytic activity in  the  visible  light region.  TiO2/g-C3N4 is  potential  visible  light  driven photocatalyst  for  the  organic substances degradation in aqueous solutions.


2014 ◽  
Vol 70 (8) ◽  
pp. 1428-1433 ◽  
Author(s):  
C. Y. Kuo ◽  
C. H. Wu ◽  
J. T. Wu ◽  
Y. C. Chen

This study produced immobilized Cu2O via microwave irradiation. The surface properties of Cu2O were assessed by X-ray diffraction, scanning electron microscopy, and UV–vis spectroscopy. The catalytic activity of the generated Cu2O was examined for bisphenol (BPA) degradation in Cu2O/H2O2 and visible-light/Cu2O/H2O2 systems under various H2O2 concentrations. Cu2O can decompose H2O2 to generate radicals, similar to the Fenton-like process. The BPA degradation rate followed pseudo-first-order kinetics. The optimal H2O2 concentration was 30 mM and the BPA degradation rate under 30 mM H2O2 in the Cu2O/H2O2 and visible-light/Cu2O/H2O2 systems was 1.43 and 2.69 h−1, respectively. The original Cu2O partly oxidized into CuO in the visible-light/Cu2O/H2O2 system and the BPA degradation percentage declined to 51% from 100% after the fifth cycle.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed S. Yahia ◽  
Ahmed S. Elzaref ◽  
Magdy B. Awad ◽  
Ahmed M. Tony ◽  
Ahmed S. Elfeky

Abstract Commercial Granulated Active Carbon (GAC) has been modified using 10 Gy dose Gamma irradiation (GAC10 Gy) for increasing its ability of air purification. Both, the raw and treated samples were applied for removing Chlorpyrifos pesticide (CPF) from ambient midair. Physicochemical properties of the two materials were characterized by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. The phase formation and microstructure were monitored using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), supported with Energy-Dispersive X-ray (EDX). The Surface area measurement was detected using BET particle size prosometry. Obtained outcomes showed that, the maximum adsorption capacity, given by Langmuir equations, was greatly increased from 172.712 to 272.480 mg/g for GAC and GAC10 Gy, respectively, with high selectivity. The overall removal efficiency of GAC10 Gy was notably comparable to that of the original GAC-sorbent. The present study indicated that, gamma irradiation could be a promising technique for treating GAC and turned it more active in eliminating the pesticides pollutants from surrounding air. The data of equilibrium has been analyzed by Langmuir and Freundlich models, that were considerably better suited for the investigated materials than other models. The process kinetics of CPF adsorbed onto both tested carbon versions were found to obey the pseudo first order at all concentrations with an exception at 70 mg/l using GAC, where, the spontaneous exothermic adsorption of Chlorpyrifos is a strong function for the pseudo-first order (PFO) and pseudo second order (PSO) kinetics.


2014 ◽  
Vol 608 ◽  
pp. 224-229 ◽  
Author(s):  
Potjanaporn Chaengchawi ◽  
Karn Serivalsatit ◽  
Pornapa Sujaridworakun

A visible-light responsive CdS/ZnO nanocomposite photocatalyst was successfully synthesized by precipitation of CdS nanoparticles, using Cd (NO3)2 and Na2S as starting materials, on ZnO nanoparticles and then calcined at 400°C for 2 hours. The effects of the mole ratio of CdS and ZnO in the composites on their phase, morphology, and surface area were investigated by X-ray Diffraction (XRD), scanning electron microscope (SEM), Brunauer Emmett Teller method (BET), respectively. The photocatalytic degradation of methylene blue solution in the presence of composite products under visible-light irradiation was investigated. The results showed that the mole ratio of CdS and ZnO played a significant role on photocatalytic performance. The highest photocatalytic activity was obtained from the CdS/ZnO nanocomposite with mole ratio of 1:4, which is higher than that of pure CdS and pure ZnO.


1992 ◽  
Vol 45 (12) ◽  
pp. 1943 ◽  
Author(s):  
SJ Dunne ◽  
RC Burns ◽  
GA Lawrance

Oxidation of Ni2+,aq, by S2O82- to nickel(IV) in the presence of molybdate ion, as in the analogous manganese system, involves the formation of the soluble heteropolymolybdate anion [MMogO32]2- (M = Ni, Mn ). The nickel(IV) product crystallized as (NH4)6 [NiMogO32].6H2O from the reaction mixture in the rhombohedra1 space group R3, a 15.922(1), c 12.406(1) � ; the structure was determined by X-ray diffraction methods, and refined to a residual of 0.025 for 1741 independent 'observed' reflections. The kinetics of the oxidation were examined at 80 C over the pH range 3.0-5.2; a linear dependence on [S2O82-] and a non-linear dependence on l/[H+] were observed. The influence of variation of the Ni/Mo ratio between 1:10 and 1:25 on the observed rate constant was very small at pH 4.5, a result supporting the view that the precursor exists as the known [NiMo6O24H6]4- or a close analogue in solution. The pH dependence of the observed rate constant at a fixed oxidant concentration (0.025 mol dm-3) fits dequately to the expression kobs = kH [H+]/(Ka+[H+]) where kH = 0.0013 dm3 mol-1 s-1 and Ka = 4-0x10-5. The first-order dependence on peroxodisulfate subsequently yields a second-order rate constant of 0.042 dm3 mol-1 s-1. Under analogous conditions, oxidation of manganese(II) occurs eightfold more slowly than oxidation of nickel(II), whereas oxidation of manganese(II) by peroxomonosulfuric acid is 16-fold faster than oxidation by peroxodisulfate under similar conditions.


1984 ◽  
Vol 39 (8) ◽  
pp. 768-777 ◽  
Author(s):  
Ko Young Shin ◽  
Hanns-Peter Boehm

Graphite has been oxidized to graphite hydrogensulfate with (NH4)2S2Og in concentrated H2SO4. The stage 2 compound formed very rapidly, but further oxidation to stage 1 could be followed conveniently. X-ray diffraction of the intermediate phases showed nonintegral (00l)-reflections indicative of partial interstratification disorder. The interlayer spacing of the stage 1 compound increased with continued oxidation. The degree of oxidation as function of oxidation time has been determined from the position of the minima in the reflectance spectra. The density of the compounds and the ratio of acid molecules to anions in the intercalated layers has been estimated using these data and those of buoyancy measurements. There is a minimum in packing density early in the formation of the first stage. The kinetics of intercalation seems to be first order with respect to the free interlayer spaces.


2011 ◽  
Vol 301-303 ◽  
pp. 16-21 ◽  
Author(s):  
Yan Hong Zhao ◽  
Li Chun Hou ◽  
Wen Fei Liu ◽  
Sheng Liang ◽  
Xiao Jing Wang

Terbium doped tantalum oxide (Tb-Ta2O5) particles were synthesized with a low hydrothermal method. The phase structure of Tb-Ta2O5 obtained was performed by X-ray diffraction (XRD). The result revealed that the terbium doped Ta2O5 belongs to orthorhombic crystal. The electrochemical property of methylene blue (MB) at Tb-Ta2O5 film electrode in 0.5 mol dm-3 KCl aqueous solution was investigated with cyclic voltgrammetry (CV). The CV result indicated that the electrochemical kinetics of MB was diffusion controlling at Tb-Ta2O5 film electrode. Tb dopping imporved the electrochemical property of Ta2O5 film electrode. Tb-Ta2O5 is used as a kind of electrode material which has some new potential applications.


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