Preparation of Bi2WO6 Powders with Micro-Carbon Spheres Acting as a Template by Refluxing Method

2017 ◽  
Vol 748 ◽  
pp. 22-26 ◽  
Author(s):  
Yue Lin ◽  
Hai Feng Chen

Firstly, we made the glucose as raw material to prepare carbon microspheres hydrothermal method. Then carbon microspheres use as a template, and Bi (NO3)3.5H2O and Na2WO4.2H2O as raw material to synthesize the Bi2WO6/carbon composite by refluxing method. Finally, Bi2WO6 samples were obtained by calcination so as to remove the template. And samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflection absorption spectroscopy (DRS). The Rhodamine B (RhB) was simulated as the sewage under the visible light to study the impact of the illumination time, calcination temperature and the amount of catalyst. The results show that Bi2WO6 synthesized by calcination at 500 °C had the best photocatalytic performance, and when samples (30 mg) was put into RhB solution (10 mg/L) and illumination for 180 min, the degradation rate could reach 92%, which demonstrated that the samples exhibit excellent visible photocatalytic performance.

2005 ◽  
Vol 498-499 ◽  
pp. 420-424
Author(s):  
M.A.F. Ramalho ◽  
Lisiane Navarro de Lima Santana ◽  
Gelmires Araújo Neves ◽  
Hélio Lucena Lira

The recycling of industrial residues has being intensified all over the world, mainly due to the increase of the impact to the environment, and the growing volume of solid residues that put in risk the public health and degrade the natural resources. So, the aim of this work is to study the potentiality of the residue from kaolin industry, as ceramic raw material to produce porcelanate gres. A composition was formulated, mixed and forming by pressing (from 30 MPa to 50 MPa). After, it was sinterized at temperatures of 1180°C, 1200°C, 1220°C and 1240°C. The samples were submitted to physical and mechanical tests and characterized by X-ray diffraction and scanning electron microscopy. The preliminary results from physical and mechanical properties showed that the residue can be used to produce porcelanate gres according to Brasilian Norms (NBR 13818), at temperatures of 1220°C and 1240°C.


2012 ◽  
Vol 580 ◽  
pp. 535-538 ◽  
Author(s):  
Bin Yu ◽  
Hai Feng Chen ◽  
Ting Yan

WO3 nanocrystals have been successfully synthesized via an ion induced auxiliary hydrothermal method. The experiment products were characterized by powder X-ray diffraction (XRD) and the Photocatalytic oxidation performance of products were characterized by using the photocatalytic oxidation of methyl orange under the condition of hydrogen peroxide. The optimal amount of catalyst required for catalytic oxidation experiments and the concentration of methyl orange (MO) were determined. The experimental results indicated that with he enhancement of metallicity in alkali main group, the photocatalytic activity of the WO3 induced by alkali metal cation increased; The SO42- has higher induce catalytic activity than Cl- when the type and quantity of cation are the same; however, the ion induction on the impact of surface area is quite different, and it founded that they comply with this regular pattern, that is Na+> K+> Li+ and SO42-> Cl-.


2012 ◽  
Vol 550-553 ◽  
pp. 192-195
Author(s):  
Dao Xin Wu ◽  
Hai Xia Tong ◽  
Chang Bin Xia

Vanadium doped rutile titania was prepared by low temperature hydrolysis using Tetrabutyl titanate as raw material. Powers were characterized by X-ray diffraction spectrum (XRD)、diffuse reflection spectra(DRS)、fluorescence spectra (FS). At 1073K, Doped concentration have been in a certain range, Vanadiumcould be doped into the lattice of rutile TiO2in the way of replacement, which would cause no change in rutile TiO2crystalline state with sunlight as the light source, pH=6.0, catalyst concentration was 1.0g.L-1, concentration of methyl orange was 5.0mg.L-1. It has been shown that Vanadium doped TiO2powders(1.0%,1073K) has been the most photodegradation efficiency, and the degradation efficiency was 97.2% after 6h.


2008 ◽  
Vol 368-372 ◽  
pp. 1503-1506 ◽  
Author(s):  
Xin Ping Lin ◽  
Fu Qiang Huang ◽  
Wen Deng Wang ◽  
Zhi Chao Shan ◽  
Jian Lin Shi

A series of layered-structure Bi-based oxychlorides such as BiOCl, Bi3O4Cl, Na0.5Bi1.5O2Cl, Bi4NbO8Cl and MBiO2Cl (M = Ca, Sr, Ba, Cd, Pb) used as efficient photocatalysts. Among them, Bi3O4Cl (Eg = 2.79 eV), Na0.5Bi1.5O2Cl (Eg = 3.03 eV), Bi4NbO8Cl (Eg = 2.38 eV) and PbBiO2Cl (Eg = 2.45 eV) are visible-light-responsive. The powders synthesized by solid state reactions were characterized by X-ray diffraction (XRD) and UV-Vis diffuse reflection spectrum. Their photocatalytic activities were evaluated by the degradation of methyl orange. The results generally show that the UV-induced photocatalytic performances of the novel oxychloride catalysts are better than or comparable to that of anatase TiO2. The high photocatalytic performance of Bi-based oxychlorides is mainly ascribed to the presence of strong internal static electric fields between layers.


2019 ◽  
Vol 74 (10) ◽  
pp. 937-944 ◽  
Author(s):  
Babiker Y. Abdulkhair ◽  
Mutaz E. Salih ◽  
Nuha Y. Elamin ◽  
A. MA. Fatima ◽  
A. Modwi

AbstractStrenuous efforts have been employed to prepare zinc oxide (ZnO) with eco-friendly methods; however, few studies have reported the fabrication of ZnO using a sustainable procedure. In this study, spherical ZnO nanoparticles were successfully fabricated for photocatalysis applications using a simple and eco-friendly method using an arabinose sugar solution. The ZnO nanoparticles with a wurtzite structure were obtained by combining zinc nitrate and arabinose in water, followed by heating, evaporation, and calcinations at different annealing temperatures. The annealed ZnO photocatalysts were characterised via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The findings revealed a hexagonal wurtzite structure and good crystallinity with crystallite size increasing from 18 to 31 nm by means of an increase in the annealing temperature. The photocatalytic performance was examined to determine the degradation of mix dye waste. The spherical ZnO nanoparticles showed mix pollutant degradation of 84 % in 25 min at 400 °C.


2020 ◽  
Vol 9 (1) ◽  
pp. 359-365
Author(s):  
Hui Shu ◽  
Yujian Song ◽  
Qiang Liu ◽  
Maobin Luo

AbstractTiO2 has many advantages, such as UV resistance, thermal stability, and antibacterial; the attention toward TiO2 composite materials (TCMs) is rapidly increasing in the protection of stone culture relics. An innovative rod-shaped TCM was synthesized in this study. The structure and morphology of TCM were studied by X-ray diffraction and scanning electron microscopy. The acid resistance, weather resistance, hydrophilicity, and photocatalytic performance of TCM had been investigated. The experimental results indicated that TCM has good protection effects. The stone sample treated with TCM has stronger acid resistance and weather resistance, better hydrophilicity, and more excellent photocatalytic activity compared with the untreated stone. More importantly, the stone treated with TCM has better acid resistance and weather resistance than that treated with normal shaped TiO2 materials of the previous study. This work describes an effective way to protect stone cultural relics.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mikolaj Grabowski ◽  
Ewa Grzanka ◽  
Szymon Grzanka ◽  
Artur Lachowski ◽  
Julita Smalc-Koziorowska ◽  
...  

AbstractThe aim of this paper is to give an experimental evidence that point defects (most probably gallium vacancies) induce decomposition of InGaN quantum wells (QWs) at high temperatures. In the experiment performed, we implanted GaN:Si/sapphire substrates with helium ions in order to introduce a high density of point defects. Then, we grew InGaN QWs on such substrates at temperature of 730 °C, what caused elimination of most (but not all) of the implantation-induced point defects expanding the crystal lattice. The InGaN QWs were almost identical to those grown on unimplanted GaN substrates. In the next step of the experiment, we annealed samples grown on unimplanted and implanted GaN at temperatures of 900 °C, 920 °C and 940 °C for half an hour. The samples were examined using Photoluminescence, X-ray Diffraction and Transmission Electron Microscopy. We found out that the decomposition of InGaN QWs started at lower temperatures for the samples grown on the implanted GaN substrates what provides a strong experimental support that point defects play important role in InGaN decomposition at high temperatures.


2020 ◽  
Vol 849 ◽  
pp. 113-118
Author(s):  
Yayat Iman Supriyatna ◽  
Slamet Sumardi ◽  
Widi Astuti ◽  
Athessia N. Nainggolan ◽  
Ajeng W. Ismail ◽  
...  

The purpose of this study is to characterize Lampung iron sand and to conduct preliminary experiments on the TiO2 synthesis which can be used for the manufacturing of functional food packaging. The iron sand from South Lampung Regency, Lampung Province that will be utilized as raw material. The experiment was initiated by sieving the iron sand on 80, 100, 150, 200 and 325 mesh sieves. Analysis using X-Ray Fluorescence (XRF) to determine the element content and X-Ray Diffraction (XRD) to observe the mineralization of the iron sand was conducted. The experiment was carried out through the stages of leaching, precipitation, and calcination. Roasting was applied firstly by putting the iron sand into the muffle furnace for 5 hours at a temperature of 700°C. Followed by leaching using HCl for 48 hours and heated at 105°C with a stirring speed of 300 rpm. The leaching solution was filtered with filtrate and solid residue as products. The solid residue was then leached using 10% H2O2 solution. The leached filtrate was heated at 105°C for 40 minutes resulting TiO2 precipitates (powder). Further, the powder was calcined and characterized. Characterization of raw material using XRF shows the major elements of Fe, Ti, Mg, Si, Al and Ca. The highest Ti content is found in mesh 200 with 9.6%, while iron content is about 80.7%. While from the XRD analysis, it shows five mineral types namely magnetite (Fe3O4), Rhodonite (Mn, Fe, Mg, Ca) SiO3, Quart (SiO2), Ilmenite (FeOTiO2) and Rutile (TiO2). The preliminary experiment showed that the Ti content in the synthesized TiO2 powder is 21.2%. The purity of TiO2 is low due to the presence of Fe metal which is dissolved during leaching, so that prior to precipitation purification is needed to remove impurities such as iron and other metals.


Author(s):  
F. Mostefa ◽  
Nasr Eddine Bouhamou ◽  
H.A. Mesbah ◽  
Salima Aggoun ◽  
D. Mekhatria

This work aims to study the feasibility of making a geopolymer cement based on dredged sediments, from the Fergoug dam (Algeria) and to evaluate their construction potential particularly interesting in the field of special cementitious materials. These sediments due to their mineralogical composition as aluminosilicates; are materials that can be used after heat treatment. Sedimentary clays were characterized before and after calcination by X-ray diffraction, ATG / ATD, spectroscopy (FTIR) and XRF analysis. The calcination was carried out on the raw material sieved at 80 μm for a temperature of 750 ° C, for 3.4 and 5 hours. The reactivity of the calcined products was measured using isothermal calorimetric analysis (DSC) on pastes prepared by mixing an alkaline solution of sodium hydroxide (NaOH) 8 M in an amount allowing to have a Na / Al ratio close to 1 (1: 1). Also, cubic mortar samples were prepared with a ratio L / S: 0.8, sealed and cured for 24 hours at 60 ° C and then at room temperature until the day they were submited to mechanical testing. to check the extent of geopolymerization. The results obtained allowed to optimize the calcination time of 5 hours for a better reactivity of these sediments, and a concentration of 8M of sodium hydroxide and more suitable to have the best mechanical performances.


2012 ◽  
Vol 620 ◽  
pp. 314-319
Author(s):  
Nur Amira Mamat Razali ◽  
Fauziah Abdul Aziz ◽  
Saadah Abdul Rahman

Hardwood is wood from angiosperm trees. The characteristic of hardwood include flowers, endosperm within seeds and the production of fruits that contain the seeds. This paper aims to discuss the preparation and characterization of cellulose obtained from hardwood. The hardwood Merbau (Intsia bijuga) was chosen as raw material in this study. Alkaline treatment and delignification methods were used for the preparation of cellulose. Acid hydrolysis was employed to produce cellulose nanocrystal (CNC). The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The final product, from both trated and untreated samples were then compared.


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