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Synthesis and highly visible-induced photocatalytic activity of CNT-CdSe composite for methylene blue solution  [cached]
Chen Ming-Liang,Oh Won-Chun
Nanoscale Research Letters , 2011,
Abstract: Carbon nanotube-cadmium selenide (CNT-CdSe) composite was synthesized by a facile hydrothermal method derived from multi-walled carbon nanotubes as a stating material. The as-prepared products were characterized by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectrophotometer. The as-synthesized CNT-CdSe composite efficiently catalyzed the photodegradation of methylene blue in aqueous solutions under visible-light irradiation, exhibiting higher photocatalytic activity.
α-Fe2O3纳米材料的固相合成及光催化降解亚甲基蓝性能
Solid-State Synthesis of α-Fe2O3 Nanomaterials and Photocatalytic Degradation Performance on Methylene Blue
 [PDF]

王碧军, 刘劲松, 李子全, 黄洁文, 李云朋, 丛孟启, 冯冰, 陈建康, 朱孔军, 裘进浩
Hans Journal of Nanotechnology (NAT) , 2016, DOI: 10.12677/NAT.2016.61003
Abstract:
采用固相法首先制备前驱体,然后不同温度热处理得到α-Fe2O3纳米材料,采用XRD、FTIR、FESEM、DRS等多种表征手段分析了材料的晶体结构、微观形貌与光学性能。结果表明,热处理温度升高,α-Fe2O3纳米材料粒径逐渐增大,其带隙宽度也逐渐升高,但均小于体相α-Fe2O3的带隙宽度(2.2 eV)。500℃热处理2 h所得α-Fe2O3纳米材料具有最高的可见光光催化效率和光降解速率常数,其分别为70.60%和6.78 × 10?3 min?1,太高或太低的热处理温度均会导致光催化效率降低,这主要受带隙大小和电子–空穴复合机率影响。
Precursors were synthesized by a solid-state synthesis method. And α-Fe2O3 nanomaterials were obtained by thermal decomposition of precursors at different calcination temperatures. The crystal structure, microstructure morphology and optical properties of the α-Fe2O3 nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Field scanning electron microscopy (FESEM), and UV-vis diffuse reflectance spectroscopy (DRS). The results show that the energy gap and particle size of the α-Fe2O3 nanomaterials increase with annealing temperature. But they are all less than bulk α-Fe2O3 (2.2 eV). The α-Fe2O3 nanoparticles prepared at 500?C for 2 h exhibit the highest visible-light photocatalytic efficiency of 70.60% and photodegradation rate constant, k, of 6.78 × 10?3 min?1, respectively. Too high or too low heat treatment temperature will result in the decrease of photocatalytic efficiency, which is mainly affected by band gap and electron-hole recombination probability.
Photocatalytic Degradation of Methylene Blue using ZnO Nano-Particles
H Masombaigi,A Rezaee,A Nasiri
Iranian Journal of Health and Environment , 2009,
Abstract: "nBackgrounds and Objectives: Textile industrial wastewaters are one of the important sources of environmental contaminants. In the recent years, use of advanced oxidation processes, by producing highly active and reactive components such as hydroxyl radicals has been proposed. The aim of this research is photocatalytic degradation of methylene blue dye using the ZnO-nanoparticle with UVA irradiation. "nMaterials and Methods: photocatalytic degradation of methylene blue color using the ZnO- nanoparticles excited with UVA irradiation. In this research, photocatalytic degradation of methylene blue dye was study using different concentration of ZnO-nanoparticles under UVA irradiation in a batch reactor. "nResults: The results of this research show that removal of methylene blue dye has direct correlation with UVA intensity. The best results of dye degradation were reported in concentration of 150 mg/L ZnO nano-particles and the radiation intensity of 240 μW/cm2. Rate of dye removal was decrease with increasing of color concentration. Subsequent of color degradation, the initial COD were decresed by %60. "nConclusion: The photocatalytic degradation process using ZnO nano-particles under UVA irradiation could be remove the methylene blue dye and 60% of COD.
Evaluation of Photocatalytic Active Coatings on Sintered Glass Tubes by Methylene Blue  [PDF]
Colin Awungacha Lekelefac,Peter Czermak,Michael Herrenbauer
International Journal of Photoenergy , 2013, DOI: 10.1155/2013/614567
Abstract: A comparative study between ten different photocatalytic active coatings was done. The effectiveness and photocatalytic activity of the coatings were studied by degradation experiments of methylene blue (MB) dye under UV light illumination. The reactor design consisting of sintered glass packed in a borosilicate tube placed between two planar dielectric barrier discharge lamps (Osram Planon) is reported for the first time. The coatings consisted of either titania, silica, or zinc on sintered borosilicate glass. The advantage of sol-gel in catalyst preparation was exploited to combine catalyst to act as cocatalyst. TiO2-P25 widely applied in suspension systems was effectively immobilized on sintered glass support with the aid of tetraethylorthosilicate (TEOS) solution which acted as support material. Results indicated that TiO2-P25+SiO2, TiO2-P25+SiO2+Pt, and TiOSO4_30,6wt% films showed highest degradation rates close to 100% after 90?min illumination with degradation rates exceeding 50% after 30?minutes. TTIP+Pt showed lowest degradation rate. 1. Introduction The textile and chemical industry face the challenge to adequately dispose their waste water. Releasing chemicals and colored waste water in the ecosystem is a source of pollution and damage to aquatic life. In order to treat waste water physicochemical methods such as adsorption [1], chemical methods such as chlorination and ozonation [2], and biological methods [3] are the most frequently used approaches. The catalytic system can either be homogeneous or heterogeneous. In a heterogeneous system, both adsorption and photocatalysis take place and have major advantages such as reuse of catalyst; minimization of catalyst leaching or resistance to extreme physical and chemical conditions. A heterogeneous system is tested in this study with use of coatings produced through sol-gel basis on sintered glass in a borosilicate glass tube. Currently most photocatalytic reactors used for water treatment are suspension reactors with the advantage of high catalytic efficiency [4]. However, the catalyst particles have to be recovered after reaction through means such as ultrafiltration which bring along an additional process step and higher cost. Also, particulate matter may accumulate in the reactor during the concentration of a process effluent. Due to these reasons, a photocatalytically active layer on a support material is of growing interest. The setbacks of immobilized system are the less photonic efficiency values attained compared to suspension reactors because of mass transfer limitation [5]. For a good
Decolorization of Methylene Blue with Sol via UV Irradiation Photocatalytic Degradation  [PDF]
Jun Yao,Chaoxia Wang
International Journal of Photoenergy , 2010, DOI: 10.1155/2010/643182
Abstract: sol was prepared for the degradation of methylene blue (MB) solution under ultraviolet (UV) irradiation. The absorption spectra of MB indicated that the maximum wavelength, 663?nm, almost kept the same. The performance of 92.3% for color removal was reached after 160?min. The particle size of sol was about 22.5?nm. X-ray diffraction showed that consisted of a single anatase phase. The small size and anatase phase probably resulted in high photocatalytic activity of sol. The degradation ratio decreased as the initial concentration of MB increased. The photodegradation efficiency decreased in the order of . Regarding catalyst load, the degradation increased with the mass of catalyst up to an amount of 1.5? then decreased as the mass continued to increase. The addition of to sol resulted in an increase on the degradation ratio. 1. Introduction The textile industry produced dye pollutants that were becoming a major source of environmental contamination. It was estimated that 10 to 15 percent of dyestuff without treatment was released in water during dyeing processes [1]. A variety of physical, chemical, and biological methods, such as adsorption, coagulation, membrane process, and oxidation-ozonation were presently available for treatment of dye wastewater [2–4]. The conventional processes were insufficient to purify the wastewaters. They just transferred the compounds from aqueous to another phase, thus causing secondary pollution problem [5, 6]. Semiconductor photocatalysts TiO2 was acting much interest for their potential applicability in degradation of dye pollutants [7–10]. The TiO2 catalyst could transform organic pollutants into biodegradable compounds of low molecular weight. Many papers [11–15] reported that TiO2 was prepared by the sol-gel progress for it was nonselective, room-temperature and inexpensive manufacturing cost. Huang et al. [16] prepared TiO2 sol by a sol-gel method. The microstructure and morphology of sol sample were characterized. Its performance for photodegradation of formaldehyde was investigated. However, the operational effects, such as catalyst concentration, initial formaldehyde concentration, and pH, in the degradation process were not considered. The TiO2 sol usually contained organic solvent as a major constituent [17–20]. Silva and Faria [21] first mixed tetrabutyl titanate, absolute alcohol, and polyethyleneglycol. Few quantity of deionized water was added and the volume fraction of organic solvent reached almost 98.2%. The degradation of TiO2 prepared using this method was only around 60%. The organic solvent slowed
Visible Light Photocatalytic Degradation of Methylene Blue and Malachite Green Dyes with CuWO4-GO Nano Composite  [PDF]
Sunitha Medidi, Sowmyasree Markapurapu, Mastan Rao Kotupalli, Rama Krishna Reddy Chinnam, Venkata Mahalakshmi Susarla, Hima Bindu Gandham, Paul Douglas Sanasi
Modern Research in Catalysis (MRC) , 2018, DOI: 10.4236/mrc.2018.72002
Abstract: Copper Tungstate-Graphene Oxide nano composites have been successfully applied as excellent catalysts for the photocatalytic degradation with Methylene blue and Malachite green dyes under visible light irradiation. A facile?solid state metathesis synthesis of copper tungstate (CuWO4) followed by ball milling and subsequent preparation of copper tungstate-graphene oxide?(CuWO4-GO) nano composite using a colloidal blending process and its application as a visible light photocatalyst for the degradation of Malachite green and Methylene blue dyes. The morphology and composition of copper tungstate (CuWO4) nano composite have been characterized using X-Ray Diffraction (XRD), UV-Visible Diffuse Reflectance Spectra (UV-DRS), Raman Spectra, Field Emission Scanning Electron Microscopy (FESEM)-EDS and UV Visible Spectroscopy. It shows a band gap value of 2.13 eV, an increase in range and intensity of light absorption and the reduction of electron-hole pair recombination in CuWO4 with the introducing of GO on to it.
Visible light photocatalytic decoloration of methylene blue on novel N-doped TiO2
Yan Wang,JiWei Zhang,ZhenSheng Jin,ZhiShen Wu,ShunLi Zhang
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0306-x
Abstract: Novel N-doped TiO2 (denoted as N-NTA600) was prepared by treating nanotube titanic acid (NTA) in NH3 flow. Its visible light photocatalytic activity, evaluated by decoloration reaction of methylene blue, is higher than that of N-P25(600) prepared by treatment of P25-TiO2 in the same condition. It is suggested that the origin of visible-light photocatalytic activity is single-electron-trapped oxygen vacancy (Vo ·) modified by chemisorbed NO.
Determination of the photocatalytic activity of TiO2 coatings on clay roofing tile substrates methylene blue as model pollutant
Lon?ar Eva S.,Radeka Miroslava M.,Petrovi? Sne?ana B.,Skapin Andrea S.
Acta Periodica Technologica , 2009, DOI: 10.2298/apt0940125l
Abstract: The photocatalytically active mesoporous coatings, based on titanium dioxide sols (Degussa), of the fired clay roofing tiles substrate were prepared by using poly(ethylene glycol) (PEG) M-600 and M-4000, as the structure directing agents. The coatings were deposited using spray technique followed by thermal treatment. Photocatalytic activity of the TiO2 coatings was evaluated by aqueous solution of methylene blue as model dye, deposited on the top of the coatings, after irradiation with UV light. The results were compared with the photocatalytic efficiency of some commercial self-cleaning products (clay roofing tiles, glass). The newly design coatings showed an interesting decolourisation performance (over 30 % after 24 h). It appeared that the procedure of photocatalytic activity determination, in the case of porous substrates, should be renewed by a preadsorption process.
Photocatalytic Degradation of Methylene Blue by Fe/ZnO/SiO2 Nanoparticles under Visiblelight  [PDF]
R. M. Mohamed,I. A. Mkhalid,E. S. Baeissa,M. A. Al-Rayyani
Journal of Nanotechnology , 2012, DOI: 10.1155/2012/329082
Abstract: The photocatalytic activity of Fe/ZnO/SiO2 catalysts under visible-light irradiation for the degradation of methylene blue was evaluated. The effect of pH, illumination time, amount of catalyst loaded, and initial dye concentration on the degradation efficiency of methylene blue was investigated. The results reveal that the optimum photocatalytic oxidation conditions of methylene blue are as follows: p H = 4 and illumination time is 30?min, the amount of catalyst loading is 0.075?g/L and 50?ppm methylene blue dye concentration. Under these conditions, the removal efficiency of methylene blue was 100%. 1. Introduction Water contamination becomes a serious issue due to the fact that 2% of dyes that are produced from different industries is discharged directly in aqueous effluent [1]. At the present time, the common industry processes are using dyes by textile industry to color their products. Since this industry also uses substantial amount of water in their processes to form highly colored effluent of this industry which generally has hazardous effect in our ecosystem due to the presence of these organic chemicals. So it was necessary to find a new way to remove colored dyes before discharging them into the environment [2, 3]. The various conventional technologies currently employed in the removal of colored effluents in industrial water are classical and do not lead to complete destruction of the dyes. These methods do not work efficiently due to high solubility of dyes as well as their resistance to chemical and biological degradation; also they just transfer the contaminants from one phase to another [4]. Therefore, there is a need to develop a novel treatment method that is more effective in eliminating dyes from the wastewater. Advanced oxidation processes (AOPs) are alternative techniques for destructing dyes in industrial water and these processes are relatively recent. They were developed to meet the increasing demand of an effective wastewater treatment. Semiconductor photocatalysts are newly developed AOPs and can be applied to degrade dyes conveniently [5]. ZnO is one of the most commonly used semiconductors in photocatalytic processes and SiO2 is characterized by its high surface area. In previous study, we prepared ZnO/SiO2 xerogel by conventional sol-gel method, in which tetraethyl orthosilicate (Si(OC2H5)4) was used as the precursor and zinc nitrate hexahydrated (Zn(NO3)2·6H2O) was the source of zinc. The prepared xerogel examined as photocatalyst for the degradation of methylene blue dye in aqueous solution under UV-light irradiation [6].
Photocatalytic degradation of methylene blue using a zinc oxide-cerium oxide catalyst  [cached]
Venkatesham Vuppala,Madhu Gattumane Motappa,Satyanarayana Suggala Venkata,Preetham Halugondanahalli Sadashivaiah
European Journal of Chemistry , 2012, DOI: 10.5155/eurjchem.3.2.191-195.564
Abstract: The photocatalytic degradation of methylene blue in aqueous solution was studied using a UV source in the presence of zinc oxide-cerium oxide (ZnO-Ce2O3) as photocatalyst, which was synthesized by a gel combustion technique and characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The particle size of the catalyst was found to be in between 45 to 60 nm. The effects of catalyst loading (1.0-8.0 g/L), pH (4.0-9.2) and dye concentration (5.0-20.0 mg/L) on the degradation were studied in a batch reactor. The degradation rate was found to be strongly dependent on these experimental parameters. Appreciable degradation of methylene blue was achieved when the catalyst was calcined before use. Best results were observed with a catalyst loading of 5 g/L at pH = 9.2.
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