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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Co-precipitation method,Nanoparticles,Zirconium Oxide
- چکیده:
- چکیده انگلیسی: In comparison to the previous researches, ZrO2 nanoparticles with higher surface area (85 m2/g) have been synthesized in this research. The as-prepared ZrO2 nanoparticles by co-precipitation method were characterized with X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The surface area of the sample was characterized by BET method. The effect of the growth parameters such as temperature, pH, Zr4+/template ratio and kind of template on the growth and morphology of ZrO2 nanoparticles have been investigated in detail. The results revealed that pH, temperature, Zr4+/template and kind of template have an important effect on the morphology and size of the ZrO2 nanoparticles. X Ray Diffraction (XRD) analysis of the superior nanoparticles that was prepared at pH=4, Temperature=70 oC, Zr4+/template ratio=2 and by sorbitol as template indicates the formation of nanocrystalline ZrO2tetragonal phase structure. The average particle size of the product is about 4.45 nm that was calculated from XRD pattern by the Debye-Scherrer formula.
- انتشار مقاله: 11-07-1390
- نویسندگان: Mahshad Alaei,Ali Morad Rashidi,Iida Bakhtiari
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Co-precipitation method,Nanoparticles,Nanorods,Magnesium oxide
- چکیده:
- چکیده انگلیسی: A facile and simple method was proposed to control the size and shape of the MgO nano structures with high surface area in the presence of efficient and cheap templates like PEG 200, PEG 600, PEG 4000 and sorbitol at low temperature within a little time. Nano rods and Nanoparticles have been achieved by applying these templates and altering other growth parameters. The products were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Thermo Gravimetric Analysis (TGA). The surface area of the samples was characterized by BET method. The effect of the growth parameters such as template, pH, Mg2+/template, molar ratio and temperature on the growth and morphology of MgO nano structures have been investigated in details. By tuning these parameters MgO nano rods and nano particles can be formed.
- انتشار مقاله: 11-07-1390
- نویسندگان: Mahshad Alaei,Mona Jalali,Alimorad Rashidi
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Congo red,WO3 nanoparticles,Photo degradation,Rhodamine B
- چکیده:
- چکیده انگلیسی: Tungsten trioxide nanoparticles with two different sizes (average particle sizes about 50 and 80 nm) were prepared by the spray pyrolysis method. Photo degradation of Congo Red (azo dye) showed that photo catalytic property of the as-prepared WO3 nanoparticles with average size about 80 nm is higher than the sample with average size about 50 nm. Photo degradation of Rhodamine B (cationic triarylmethane dye) showed that photo catalytic property of the as-prepared WO3 nanoparticles with average size about 50 nm is higher than the sample with average size about 80 nm. The samples were characterized with X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), EDX analysis and UV-visible spectrum. Different interactions between dyes and the photo catalyst surface, probably causes the inverse behavior of WO3 nanoparticles with two different sizes in Congo Red and Rhodamine B photo degradation reactions.
- انتشار مقاله: 18-06-1389
- نویسندگان: Mahshad Alaei,Ali Reza Mahjoub,Alimorad Rashidi
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: nanoparticle,Hydrothermal,Photo catalyst,WO3,nanorod
- چکیده:
- چکیده انگلیسی: Tungsten trioxide nanoparticles with monoclinic structure and average particle size about 80 nm were prepared by the spray pyrolysis method. WO3 nanorods with hexagonal structure and average dimension about 15 × 100 nm were synthesized in gram quantities by modified hydrothermal method at lower temperature and shorter reaction time in comparison to the previous research. Photo degradation of Congo Red showed that the as-prepared WO3 nanoparticles is more effective than nanorod structure. WO3 nanorods actually had no effect in Congo Red photo degradation. Therefore in this reaction, spherical morphology is superior to column morphology. The samples were characterized with X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), EDX analysis, UV-visible spectrum and Transmission Electron Microscopy (TEM).
- انتشار مقاله: 18-06-1389
- نویسندگان: Mahshad Alaei,Ali Reza Mahjoub,Alimorad Rashidi
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Nanoparticles,ZnO,Specific surface area,Spray pyrolysis
- چکیده:
- چکیده انگلیسی: Zinc oxide (ZnO) nanoparticles were synthesized by spray pyrolysis method using an aqueous solution of zinc acetate at various concentrations from 5 to 25 wt%. The decomposition of precursor solutions was carried out at 800, 1000 and 1200ºC under different atomizing pressures. The crystal structure and morphology of synthesized nanoparticles were characterized by X-Ray Diffraction (XRD) spectrometry and Transmission Electron Microscopy (TEM), which indicated that ZnO nanoparticles were of hexagonal wurtzite structure. The XRD, TEM and BET analyses of prepared ZnO powders with concentrations of 5-20 wt% showed that the crystallite size diameter and specific surface area of particles were in the range of 10-25 nm and 44-56 m2/g, respectively.It was found that impurity and unreacted zinc acetate appeared in the product with increase of precursor solution concentration beyond 20wt%.
- انتشار مقاله: 24-10-1387
- نویسندگان: Hamid Reza Ghaffarian,,Mahboobeh Saiedi,Mohammad Ali Sayyadnejad,Ali Morad Rashidi
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: kinetic,In situ combustion,Heavy oil,Auto-ignition
- چکیده:
- چکیده انگلیسی: Two facile and low cost routes were used for the synthesis of IF-WS2 nanoparticles. In this paper, preparation of IF-WS2 nanoparticles with two different methods was investigated. In the first method, WO3 nanoparticles were reacted with H2S gas in N2/H2 reducing atmosphere at 900 oC. The as-synthesized IF-WS2 nanoparticles are spherical shape with an average size of about 70 nm. In the second method, WO3 nanoparticles were reacted with Sulfur powder in H2 reducing atmosphere at 800 oC. All reaction conditions have been optimized. In this method, application of the harmful and poisonous H2S gas was eliminated. The as-prepared IF-WS2 nanoparticles are spherical shape with an average size of about 50 nm. In this research, it was revealed that in the first method, the reduction of WO3 nanoparticles before the reaction with H2S gas is very important in product quality and the output of the reaction will be increased. Also in contrast to that was proposed in the previous similar research, it was revealed that the preparation of IF-WS2 nanoparticles according to the second method can not be considered as large scale method because the product quality is directly dependent on the amount of WO3 nanoparticles that can not be considered exceeding 0.1 g. Besides, the preparation method of WO3 nanoparticles as precursor for the synthesis of IF-WS2 nanoparticles is different from previous similar researches. The solution of ammonium para tungstate (APT) and citric acid (as organic additive) was prepared and then the pH of solution was adjusted at 7 by using ammonium hydroxide. Firstly, the sample was heated to 250 oC for 1 h and secondly was calcined at 500 oC for 2 h to obtain yellow color powder of WO3 nanoparticles with an average size of about 50 nm. The samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
- انتشار مقاله: 29-11-1386
- نویسندگان: Mahshad Alaei,Alimorad Rashidi,Alireza Mahjoub
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: kinetic,In situ combustion,Heavy oil,Auto-ignition
- چکیده:
- چکیده انگلیسی: Two facile and low cost routes were used for the synthesis of IF-WS2 nanoparticles. In this paper, preparation of IF-WS2 nanoparticles with two different methods was investigated. In the first method, WO3 nanoparticles were reacted with H2S gas in N2/H2 reducing atmosphere at 900 oC. The as-synthesized IF-WS2 nanoparticles are spherical shape with an average size of about 70 nm. In the second method, WO3 nanoparticles were reacted with Sulfur powder in H2 reducing atmosphere at 800 oC. All reaction conditions have been optimized. In this method, application of the harmful and poisonous H2S gas was eliminated. The as-prepared IF-WS2 nanoparticles are spherical shape with an average size of about 50 nm. In this research, it was revealed that in the first method, the reduction of WO3 nanoparticles before the reaction with H2S gas is very important in product quality and the output of the reaction will be increased. Also in contrast to that was proposed in the previous similar research, it was revealed that the preparation of IF-WS2 nanoparticles according to the second method can not be considered as large scale method because the product quality is directly dependent on the amount of WO3 nanoparticles that can not be considered exceeding 0.1 g. Besides, the preparation method of WO3 nanoparticles as precursor for the synthesis of IF-WS2 nanoparticles is different from previous similar researches. The solution of ammonium para tungstate (APT) and citric acid (as organic additive) was prepared and then the pH of solution was adjusted at 7 by using ammonium hydroxide. Firstly, the sample was heated to 250 oC for 1 h and secondly was calcined at 500 oC for 2 h to obtain yellow color powder of WO3 nanoparticles with an average size of about 50 nm. The samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
- انتشار مقاله: 29-11-1386
- نویسندگان: Mahshad Alaei,Alimorad Rashidi,Alireza Mahjoub
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Carbon Nanotube,Porosity,MCM-41,Bamboo-structured,CVD
- چکیده:
- چکیده انگلیسی: Bamboo-structured carbon nanotubes are grown on Co-Mo/MCM-41 catalyst in the temperature range of 873-973 K by thermal chemical vapor deposition of acetylene. This study shows that the purified carbon nanotubes have open tips and the metals of the catalyst are not encapsulated. Thus, the bamboo-structure seems to grow from the base. Pore size distribution of the product is quite narrow and is in the range of 2- 5 nm similar to the catalyst pore size distribution. The results of this study demonstrate that by manipulating the template, the pore size distribution of the final product may be controlled. The so-prepared carbon nanotubes with controlled porosity are better suited for the application in gas adsorption and catalyst synthesis.
- انتشار مقاله: 11-02-1384
- نویسندگان: Alimorad Rashidi,Yadollah Mortazavi,Abbas Ali Khodadadi,Mohamma Mahdi Akbarnejad
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian (Iranica) Journal of Energy & Environment
- نوع مقاله: Journal Article
- کلمات کلیدی:
- چکیده:
- چکیده انگلیسی:
- انتشار مقاله: 11-10-1348
- نویسندگان: Razieh Jabari Seresht,Mohsen Jahanshahi,Ali Morad Rashidi,Ali Asghar Ghoreyshi
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Engineering, Transactions A: Basics
- نوع مقاله: Journal Article
- کلمات کلیدی: Nanofluid,Thermal conductivity,CNTs
- چکیده:
- چکیده انگلیسی: [if gte mso 9]> In the present work, the thermal conductivity coefficients of nanoparticle-oil suspensions for two types of carbon nanotubes, single-walled (SWNTs) and multi-walled (MWNTs) carbon nanotubes at 0.1, 0.2 and 0.3 wt.% were measured by a modified transient hot wire method (KD2-pro thermal property meter). Results showed that the thermal conductivity of suspension containing single-walled carbon nanotubes is higher than that of suspension containing multi-walled carbon nanotubes. It was also observed that the thermal conductivity coefficients of both nanofluids increase with increasing temperature.
- انتشار مقاله: 11-10-1348
- نویسندگان: Milad Tajik Jamal-Abad,Ali Morad Rashidi,Maryam Gohari
- مشاهده